[PATCH 0/2] LoongArch: Add Loongson-3 CPUFreq driver support

[PATCH 0/2] LoongArch: Add Loongson-3 CPUFreq driver support

[Huacai Chen]

This series add architectural preparation and CPUFreq driver for
Loongson-3 (based on LoongArch).

Some of LoongArch processors support DVFS, their IOCSR.FEATURES has
IOCSRF_FREQSCALE set. And they has a micro-core in the package called
SMC (System Management Controller) to scale frequency, voltage, etc.

Huacai Chen(2):
 LoongArch: Add architectural preparation for CPUFreq.
 cpufreq: Add Loongson-3 CPUFreq driver support.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
2.27.0

[PATCH 1/2] LoongArch: Add architectural preparation for CPUFreq

[Huacai Chen]

Add architectural preparation for CPUFreq driver, including: Kconfig,
register definition and platform device registration.

Some of LoongArch processors support DVFS, their IOCSR.FEATURES has
IOCSRF_FREQSCALE set. And they has a micro-core in the package called
SMC (System Management Controller) to scale frequency, voltage, etc.

Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 arch/loongarch/Kconfig                 |  1 +
 arch/loongarch/include/asm/loongarch.h |  3 +++
 arch/loongarch/power/platform.c        | 15 +++++++++++++++
 3 files changed, 19 insertions(+)

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index e38139c576ee..dffa9c454123 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -696,6 +696,7 @@ config ARCH_HIBERNATION_POSSIBLE
 
 source "kernel/power/Kconfig"
 source "drivers/acpi/Kconfig"
+source "drivers/cpufreq/Kconfig"
 
 endmenu
 
diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index eb09adda54b7..7d89b2ecf2c2 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -1053,11 +1053,14 @@
 #define LOONGARCH_IOCSR_NODECNT		0x408
 
 #define LOONGARCH_IOCSR_MISC_FUNC	0x420
+#define  IOCSR_MISC_FUNC_SOFT_INT	BIT_ULL(10)
 #define  IOCSR_MISC_FUNC_TIMER_RESET	BIT_ULL(21)
 #define  IOCSR_MISC_FUNC_EXT_IOI_EN	BIT_ULL(48)
 
 #define LOONGARCH_IOCSR_CPUTEMP		0x428
 
+#define LOONGARCH_IOCSR_SMCMBX		0x51c
+
 /* PerCore CSR, only accessible by local cores */
 #define LOONGARCH_IOCSR_IPI_STATUS	0x1000
 #define LOONGARCH_IOCSR_IPI_EN		0x1004
diff --git a/arch/loongarch/power/platform.c b/arch/loongarch/power/platform.c
index 3ea8e07aa225..a19353f7d1b0 100644
--- a/arch/loongarch/power/platform.c
+++ b/arch/loongarch/power/platform.c
@@ -34,6 +34,21 @@ void enable_pci_wakeup(void)
 		acpi_write_bit_register(ACPI_BITREG_PCIEXP_WAKE_DISABLE, 0);
 }
 
+static struct platform_device loongson3_cpufreq_device = {
+	.name = "loongson3_cpufreq",
+	.id = -1,
+};
+
+static int __init loongson_cpufreq_init(void)
+{
+	if (!cpu_has_scalefreq)
+		return -ENODEV;
+
+	return platform_device_register(&loongson3_cpufreq_device);
+}
+
+arch_initcall(loongson_cpufreq_init);
+
 static int __init loongson3_acpi_suspend_init(void)
 {
 #ifdef CONFIG_ACPI
-- 
2.43.0

[PATCH 2/2] cpufreq: Add Loongson-3 CPUFreq driver support

[Huacai Chen]

Some of LoongArch processors (Loongson-3 series) support DVFS, their
IOCSR.FEATURES has IOCSRF_FREQSCALE set. And they has a micro-core in
the package called SMC (System Management Controller), which can be
used to detect temperature, control fans, scale frequency and voltage,
etc.

The Loongson-3 CPUFreq driver is very simple now, it communicate with
SMC, get DVFS info, set target frequency from CPUFreq core, and so on.

There is a command list to interact with SMC, widely-used commands in
the CPUFreq driver include:

CMD_GET_VERSION: Get SMC firmware version.

CMD_GET_FEATURE: Get enabled SMC features.

CMD_SET_FEATURE: Enable SMC features, such as basic DVFS, BOOST.

CMD_GET_FREQ_LEVEL_NUM: Get the number of normal frequency levels.

CMD_GET_FREQ_BOOST_NUM: Get the number of boost frequency levels.

CMD_GET_FREQ_LEVEL_INFO: Get the detail info of a frequency level.

CMD_GET_FREQ_INFO: Get the current frequency.

CMD_SET_FREQ_INFO: Set the target frequency.

In future we will add automatic frequency scaling, which is similar to
Intel's HWP (HardWare P-State).

Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/cpufreq/Kconfig             |  12 +
 drivers/cpufreq/Makefile            |   1 +
 drivers/cpufreq/loongson3_cpufreq.c | 442 ++++++++++++++++++++++++++++
 3 files changed, 455 insertions(+)
 create mode 100644 drivers/cpufreq/loongson3_cpufreq.c

diff --git a/MAINTAINERS b/MAINTAINERS
index aacccb376c28..f2e47ec28d77 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12968,6 +12968,7 @@ F:	Documentation/arch/loongarch/
 F:	Documentation/translations/zh_CN/arch/loongarch/
 F:	arch/loongarch/
 F:	drivers/*/*loongarch*
+F:	drivers/cpufreq/loongson3_cpufreq.c
 
 LOONGSON GPIO DRIVER
 M:	Yinbo Zhu <zhuyinbo@loongson.cn>
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 94e55c40970a..10cda6f2fe1d 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -262,6 +262,18 @@ config LOONGSON2_CPUFREQ
 	  If in doubt, say N.
 endif
 
+if LOONGARCH
+config LOONGSON3_CPUFREQ
+	tristate "Loongson3 CPUFreq Driver"
+	help
+	  This option adds a CPUFreq driver for Loongson processors which
+	  support software configurable cpu frequency.
+
+	  Loongson-3 family processors support this feature.
+
+	  If in doubt, say N.
+endif
+
 if SPARC64
 config SPARC_US3_CPUFREQ
 	tristate "UltraSPARC-III CPU Frequency driver"
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 8d141c71b016..0f184031dd12 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_POWERNV_CPUFREQ)		+= powernv-cpufreq.o
 # Other platform drivers
 obj-$(CONFIG_BMIPS_CPUFREQ)		+= bmips-cpufreq.o
 obj-$(CONFIG_LOONGSON2_CPUFREQ)		+= loongson2_cpufreq.o
+obj-$(CONFIG_LOONGSON3_CPUFREQ)		+= loongson3_cpufreq.o
 obj-$(CONFIG_SH_CPU_FREQ)		+= sh-cpufreq.o
 obj-$(CONFIG_SPARC_US2E_CPUFREQ)	+= sparc-us2e-cpufreq.o
 obj-$(CONFIG_SPARC_US3_CPUFREQ)		+= sparc-us3-cpufreq.o
diff --git a/drivers/cpufreq/loongson3_cpufreq.c b/drivers/cpufreq/loongson3_cpufreq.c
new file mode 100644
index 000000000000..5dbac0d55a32
--- /dev/null
+++ b/drivers/cpufreq/loongson3_cpufreq.c
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CPUFreq driver for the loongson-3 processors
+ *
+ * All revisions of Loongson-3 processor support this feature.
+ *
+ * Author: Huacai Chen <chenhuacai@loongson.cn>
+ * Copyright (C) 2020-2024 Loongson Technology Corporation Limited
+ */
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/cpufreq.h>
+#include <linux/platform_device.h>
+#include <linux/units.h>
+
+#include <asm/idle.h>
+#include <asm/loongarch.h>
+#include <asm/loongson.h>
+
+/* Message */
+union smc_message {
+	u32 value;
+	struct {
+		u32 id		: 4;
+		u32 info	: 4;
+		u32 val		: 16;
+		u32 cmd		: 6;
+		u32 extra	: 1;
+		u32 complete	: 1;
+	};
+};
+
+/* Command return values */
+#define CMD_OK				0  /* No error */
+#define CMD_ERROR			1  /* Regular error */
+#define CMD_NOCMD			2  /* Command does not support */
+#define CMD_INVAL			3  /* Invalid Parameter */
+
+/* Version commands */
+/*
+ * CMD_GET_VERSION - Get interface version
+ * Input: none
+ * Output: version
+ */
+#define CMD_GET_VERSION			0x1
+
+/* Feature commands */
+/*
+ * CMD_GET_FEATURE - Get feature state
+ * Input: feature ID
+ * Output: feature flag
+ */
+#define CMD_GET_FEATURE			0x2
+
+/*
+ * CMD_SET_FEATURE - Set feature state
+ * Input: feature ID, feature flag
+ * output: none
+ */
+#define CMD_SET_FEATURE			0x3
+
+/* Feature IDs */
+#define FEATURE_SENSOR			0
+#define FEATURE_FAN			1
+#define FEATURE_DVFS			2
+
+/* Sensor feature flags */
+#define FEATURE_SENSOR_ENABLE		BIT(0)
+#define FEATURE_SENSOR_SAMPLE		BIT(1)
+
+/* Fan feature flags */
+#define FEATURE_FAN_ENABLE		BIT(0)
+#define FEATURE_FAN_AUTO		BIT(1)
+
+/* DVFS feature flags */
+#define FEATURE_DVFS_ENABLE		BIT(0)
+#define FEATURE_DVFS_BOOST		BIT(1)
+#define FEATURE_DVFS_AUTO		BIT(2)
+#define FEATURE_DVFS_SINGLE_BOOST	BIT(3)
+
+/* Sensor commands */
+/*
+ * CMD_GET_SENSOR_NUM - Get number of sensors
+ * Input: none
+ * Output: number
+ */
+#define CMD_GET_SENSOR_NUM		0x4
+
+/*
+ * CMD_GET_SENSOR_STATUS - Get sensor status
+ * Input: sensor ID, type
+ * Output: sensor status
+ */
+#define CMD_GET_SENSOR_STATUS		0x5
+
+/* Sensor types */
+#define SENSOR_INFO_TYPE		0
+#define SENSOR_INFO_TYPE_TEMP		1
+
+/* Fan commands */
+/*
+ * CMD_GET_FAN_NUM - Get number of fans
+ * Input: none
+ * Output: number
+ */
+#define CMD_GET_FAN_NUM			0x6
+
+/*
+ * CMD_GET_FAN_INFO - Get fan status
+ * Input: fan ID, type
+ * Output: fan info
+ */
+#define CMD_GET_FAN_INFO		0x7
+
+/*
+ * CMD_SET_FAN_INFO - Set fan status
+ * Input: fan ID, type, value
+ * Output: none
+ */
+#define CMD_SET_FAN_INFO		0x8
+
+/* Fan types */
+#define FAN_INFO_TYPE_LEVEL		0
+
+/* DVFS commands */
+/*
+ * CMD_GET_FREQ_LEVEL_NUM - Get number of freq levels
+ * Input: CPU ID
+ * Output: number
+ */
+#define CMD_GET_FREQ_LEVEL_NUM		0x9
+
+/*
+ * CMD_GET_FREQ_BOOST_LEVEL - Get number of boost levels
+ * Input: CPU ID
+ * Output: number
+ */
+#define CMD_GET_FREQ_BOOST_LEVEL	0x10
+
+/*
+ * CMD_GET_FREQ_LEVEL_INFO - Get freq level info
+ * Input: CPU ID, level ID
+ * Output: level info
+ */
+#define CMD_GET_FREQ_LEVEL_INFO		0x11
+
+/*
+ * CMD_GET_FREQ_INFO - Get freq info
+ * Input: CPU ID, type
+ * Output: freq info
+ */
+#define CMD_GET_FREQ_INFO		0x12
+
+/*
+ * CMD_SET_FREQ_INFO - Set freq info
+ * Input: CPU ID, type, value
+ * Output: none
+ */
+#define CMD_SET_FREQ_INFO		0x13
+
+/* Freq types */
+#define FREQ_INFO_TYPE_FREQ		0
+#define FREQ_INFO_TYPE_LEVEL		1
+
+#define FREQ_MAX_LEVEL			(16 + 1)
+
+enum freq {
+	FREQ_LEV0, /* Reserved */
+	FREQ_LEV1, FREQ_LEV2, FREQ_LEV3, FREQ_LEV4,
+	FREQ_LEV5, FREQ_LEV6, FREQ_LEV7, FREQ_LEV8,
+	FREQ_LEV9, FREQ_LEV10, FREQ_LEV11, FREQ_LEV12,
+	FREQ_LEV13, FREQ_LEV14, FREQ_LEV15, FREQ_LEV16,
+	FREQ_RESV
+};
+
+struct loongson3_freq_data {
+	unsigned int cur_cpu_freq;
+	struct cpufreq_frequency_table table[];
+};
+
+static struct mutex cpufreq_mutex[MAX_PACKAGES];
+static struct cpufreq_driver loongson3_cpufreq_driver;
+static DEFINE_PER_CPU(struct loongson3_freq_data *, freq_data);
+
+static inline int do_service_request(union smc_message *msg)
+{
+	int retries;
+	union smc_message last;
+
+	last.value = iocsr_read32(LOONGARCH_IOCSR_SMCMBX);
+	if (!last.complete)
+		return -EPERM;
+
+	iocsr_write32(msg->value, LOONGARCH_IOCSR_SMCMBX);
+	iocsr_write32(iocsr_read32(LOONGARCH_IOCSR_MISC_FUNC) | IOCSR_MISC_FUNC_SOFT_INT,
+		      LOONGARCH_IOCSR_MISC_FUNC);
+
+	for (retries = 0; retries < 10000; retries++) {
+		msg->value = iocsr_read32(LOONGARCH_IOCSR_SMCMBX);
+		if (msg->complete)
+			break;
+
+		usleep_range(8, 12);
+	}
+
+	if (!msg->complete || msg->cmd != CMD_OK)
+		return -EPERM;
+
+	return 0;
+}
+
+static unsigned int loongson3_cpufreq_get(unsigned int cpu)
+{
+	union smc_message msg;
+
+	msg.id		= cpu;
+	msg.info	= FREQ_INFO_TYPE_FREQ;
+	msg.cmd		= CMD_GET_FREQ_INFO;
+	msg.extra	= 0;
+	msg.complete	= 0;
+	do_service_request(&msg);
+
+	per_cpu(freq_data, cpu)->cur_cpu_freq = msg.val * KILO;
+
+	return per_cpu(freq_data, cpu)->cur_cpu_freq;
+}
+
+static int loongson3_cpufreq_set(struct cpufreq_policy *policy, int freq_level)
+{
+	union smc_message msg;
+
+	msg.id		= cpu_data[policy->cpu].core;
+	msg.info	= FREQ_INFO_TYPE_LEVEL;
+	msg.val		= freq_level;
+	msg.cmd		= CMD_SET_FREQ_INFO;
+	msg.extra	= 0;
+	msg.complete	= 0;
+	do_service_request(&msg);
+
+	return 0;
+}
+
+/*
+ * Here we notify other drivers of the proposed change and the final change.
+ */
+static int loongson3_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	unsigned int cpu = policy->cpu;
+	unsigned int package = cpu_data[cpu].package;
+
+	if (!cpu_online(cpu))
+		return -ENODEV;
+
+	/* setting the cpu frequency */
+	mutex_lock(&cpufreq_mutex[package]);
+	loongson3_cpufreq_set(policy, index);
+	mutex_unlock(&cpufreq_mutex[package]);
+
+	return 0;
+}
+
+static int loongson3_cpufreq_get_freq_table(int cpu)
+{
+	union smc_message msg;
+	int i, ret, boost_level, max_level, freq_level;
+	struct loongson3_freq_data *data;
+
+	if (per_cpu(freq_data, cpu))
+		return 0;
+
+	msg.id		= cpu;
+	msg.cmd		= CMD_GET_FREQ_LEVEL_NUM;
+	msg.extra	= 0;
+	msg.complete	= 0;
+	ret = do_service_request(&msg);
+	if (ret < 0)
+		return ret;
+	max_level = msg.val;
+
+	msg.id		= cpu;
+	msg.cmd		= CMD_GET_FREQ_BOOST_LEVEL;
+	msg.extra	= 0;
+	msg.complete	= 0;
+	ret = do_service_request(&msg);
+	if (ret < 0)
+		return ret;
+	boost_level = msg.val;
+
+	freq_level = min(max_level, FREQ_MAX_LEVEL);
+	data = kzalloc(struct_size(data, table, freq_level + 1), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	for (i = 0; i < freq_level; i++) {
+		msg.id		= cpu;
+		msg.info	= FREQ_INFO_TYPE_FREQ;
+		msg.cmd		= CMD_GET_FREQ_LEVEL_INFO;
+		msg.val		= i;
+		msg.complete	= 0;
+
+		ret = do_service_request(&msg);
+		if (ret < 0) {
+			kfree(data);
+			return ret;
+		}
+
+		data->table[i].frequency = msg.val * KILO;
+		data->table[i].driver_data = FREQ_LEV0 + i;
+		data->table[i].flags = (i >= boost_level) ? CPUFREQ_BOOST_FREQ : 0;
+	}
+
+	data->table[freq_level].frequency = CPUFREQ_TABLE_END;
+	data->table[freq_level].driver_data = FREQ_RESV;
+	data->table[freq_level].flags = 0;
+
+	per_cpu(freq_data, cpu) = data;
+
+	return 0;
+}
+
+static int loongson3_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+	int ret;
+
+	if (!cpu_online(policy->cpu))
+		return -ENODEV;
+
+	ret = loongson3_cpufreq_get_freq_table(policy->cpu);
+	if (ret < 0)
+		return ret;
+
+	policy->cur = loongson3_cpufreq_get(policy->cpu);
+	policy->cpuinfo.transition_latency = 10000;
+	policy->freq_table = per_cpu(freq_data, policy->cpu)->table;
+	cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));
+
+	if (policy_has_boost_freq(policy)) {
+		ret = cpufreq_enable_boost_support();
+		if (ret < 0) {
+			pr_warn("cpufreq: Failed to enable boost: %d\n", ret);
+			return ret;
+		}
+		loongson3_cpufreq_driver.boost_enabled = true;
+	}
+
+	return 0;
+}
+
+static int loongson3_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+	return 0;
+}
+
+static struct cpufreq_driver loongson3_cpufreq_driver = {
+	.name = "loongson3",
+	.flags = CPUFREQ_CONST_LOOPS,
+	.init = loongson3_cpufreq_cpu_init,
+	.exit = loongson3_cpufreq_cpu_exit,
+	.verify = cpufreq_generic_frequency_table_verify,
+	.target_index = loongson3_cpufreq_target,
+	.get = loongson3_cpufreq_get,
+	.attr = cpufreq_generic_attr,
+};
+
+static struct platform_device_id cpufreq_id_table[] = {
+	{ "loongson3_cpufreq", },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(platform, cpufreq_id_table);
+
+static struct platform_driver loongson3_platform_driver = {
+	.driver = {
+		.name = "loongson3_cpufreq",
+	},
+	.id_table = cpufreq_id_table,
+};
+
+static int configure_cpufreq_info(void)
+{
+	int ret;
+	union smc_message msg;
+
+	msg.cmd		= CMD_GET_VERSION;
+	msg.extra	= 0;
+	msg.complete	= 0;
+	ret = do_service_request(&msg);
+	if (ret < 0 || msg.val < 0x1)
+		return -EPERM;
+
+	msg.id		= FEATURE_DVFS;
+	msg.cmd		= CMD_SET_FEATURE;
+	msg.val		= FEATURE_DVFS_ENABLE | FEATURE_DVFS_BOOST;
+	msg.extra	= 0;
+	msg.complete	= 0;
+	ret = do_service_request(&msg);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int __init cpufreq_init(void)
+{
+	int i, ret;
+
+	ret = platform_driver_register(&loongson3_platform_driver);
+	if (ret)
+		return ret;
+
+	ret = configure_cpufreq_info();
+	if (ret)
+		goto err;
+
+	for (i = 0; i < MAX_PACKAGES; i++)
+		mutex_init(&cpufreq_mutex[i]);
+
+	ret = cpufreq_register_driver(&loongson3_cpufreq_driver);
+	if (ret)
+		goto err;
+
+	pr_info("cpufreq: Loongson-3 CPU frequency driver.\n");
+
+	return 0;
+
+err:
+	platform_driver_unregister(&loongson3_platform_driver);
+	return ret;
+}
+
+static void __exit cpufreq_exit(void)
+{
+	cpufreq_unregister_driver(&loongson3_cpufreq_driver);
+	platform_driver_unregister(&loongson3_platform_driver);
+}
+
+module_init(cpufreq_init);
+module_exit(cpufreq_exit);
+
+MODULE_AUTHOR("Huacai Chen <chenhuacai@loongson.cn>");
+MODULE_DESCRIPTION("CPUFreq driver for Loongson-3 processors");
+MODULE_LICENSE("GPL");
-- 
2.43.0

Re: [PATCH 2/2] cpufreq: Add Loongson-3 CPUFreq driver support

[Huacai Chen]

Hi, Rafael and Viresh,

Could you please take some time to review this patch? Thank you.

Huacai

On Wed, Jun 12, 2024 at 2:42 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
>
> Some of LoongArch processors (Loongson-3 series) support DVFS, their
> IOCSR.FEATURES has IOCSRF_FREQSCALE set. And they has a micro-core in
> the package called SMC (System Management Controller), which can be
> used to detect temperature, control fans, scale frequency and voltage,
> etc.
>
> The Loongson-3 CPUFreq driver is very simple now, it communicate with
> SMC, get DVFS info, set target frequency from CPUFreq core, and so on.
>
> There is a command list to interact with SMC, widely-used commands in
> the CPUFreq driver include:
>
> CMD_GET_VERSION: Get SMC firmware version.
>
> CMD_GET_FEATURE: Get enabled SMC features.
>
> CMD_SET_FEATURE: Enable SMC features, such as basic DVFS, BOOST.
>
> CMD_GET_FREQ_LEVEL_NUM: Get the number of normal frequency levels.
>
> CMD_GET_FREQ_BOOST_NUM: Get the number of boost frequency levels.
>
> CMD_GET_FREQ_LEVEL_INFO: Get the detail info of a frequency level.
>
> CMD_GET_FREQ_INFO: Get the current frequency.
>
> CMD_SET_FREQ_INFO: Set the target frequency.
>
> In future we will add automatic frequency scaling, which is similar to
> Intel's HWP (HardWare P-State).
>
> Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  drivers/cpufreq/Kconfig             |  12 +
>  drivers/cpufreq/Makefile            |   1 +
>  drivers/cpufreq/loongson3_cpufreq.c | 442 ++++++++++++++++++++++++++++
>  3 files changed, 455 insertions(+)
>  create mode 100644 drivers/cpufreq/loongson3_cpufreq.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index aacccb376c28..f2e47ec28d77 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12968,6 +12968,7 @@ F:      Documentation/arch/loongarch/
>  F:     Documentation/translations/zh_CN/arch/loongarch/
>  F:     arch/loongarch/
>  F:     drivers/*/*loongarch*
> +F:     drivers/cpufreq/loongson3_cpufreq.c
>
>  LOONGSON GPIO DRIVER
>  M:     Yinbo Zhu <zhuyinbo@loongson.cn>
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index 94e55c40970a..10cda6f2fe1d 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -262,6 +262,18 @@ config LOONGSON2_CPUFREQ
>           If in doubt, say N.
>  endif
>
> +if LOONGARCH
> +config LOONGSON3_CPUFREQ
> +       tristate "Loongson3 CPUFreq Driver"
> +       help
> +         This option adds a CPUFreq driver for Loongson processors which
> +         support software configurable cpu frequency.
> +
> +         Loongson-3 family processors support this feature.
> +
> +         If in doubt, say N.
> +endif
> +
>  if SPARC64
>  config SPARC_US3_CPUFREQ
>         tristate "UltraSPARC-III CPU Frequency driver"
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index 8d141c71b016..0f184031dd12 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -103,6 +103,7 @@ obj-$(CONFIG_POWERNV_CPUFREQ)               += powernv-cpufreq.o
>  # Other platform drivers
>  obj-$(CONFIG_BMIPS_CPUFREQ)            += bmips-cpufreq.o
>  obj-$(CONFIG_LOONGSON2_CPUFREQ)                += loongson2_cpufreq.o
> +obj-$(CONFIG_LOONGSON3_CPUFREQ)                += loongson3_cpufreq.o
>  obj-$(CONFIG_SH_CPU_FREQ)              += sh-cpufreq.o
>  obj-$(CONFIG_SPARC_US2E_CPUFREQ)       += sparc-us2e-cpufreq.o
>  obj-$(CONFIG_SPARC_US3_CPUFREQ)                += sparc-us3-cpufreq.o
> diff --git a/drivers/cpufreq/loongson3_cpufreq.c b/drivers/cpufreq/loongson3_cpufreq.c
> new file mode 100644
> index 000000000000..5dbac0d55a32
> --- /dev/null
> +++ b/drivers/cpufreq/loongson3_cpufreq.c
> @@ -0,0 +1,442 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * CPUFreq driver for the loongson-3 processors
> + *
> + * All revisions of Loongson-3 processor support this feature.
> + *
> + * Author: Huacai Chen <chenhuacai@loongson.cn>
> + * Copyright (C) 2020-2024 Loongson Technology Corporation Limited
> + */
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/cpufreq.h>
> +#include <linux/platform_device.h>
> +#include <linux/units.h>
> +
> +#include <asm/idle.h>
> +#include <asm/loongarch.h>
> +#include <asm/loongson.h>
> +
> +/* Message */
> +union smc_message {
> +       u32 value;
> +       struct {
> +               u32 id          : 4;
> +               u32 info        : 4;
> +               u32 val         : 16;
> +               u32 cmd         : 6;
> +               u32 extra       : 1;
> +               u32 complete    : 1;
> +       };
> +};
> +
> +/* Command return values */
> +#define CMD_OK                         0  /* No error */
> +#define CMD_ERROR                      1  /* Regular error */
> +#define CMD_NOCMD                      2  /* Command does not support */
> +#define CMD_INVAL                      3  /* Invalid Parameter */
> +
> +/* Version commands */
> +/*
> + * CMD_GET_VERSION - Get interface version
> + * Input: none
> + * Output: version
> + */
> +#define CMD_GET_VERSION                        0x1
> +
> +/* Feature commands */
> +/*
> + * CMD_GET_FEATURE - Get feature state
> + * Input: feature ID
> + * Output: feature flag
> + */
> +#define CMD_GET_FEATURE                        0x2
> +
> +/*
> + * CMD_SET_FEATURE - Set feature state
> + * Input: feature ID, feature flag
> + * output: none
> + */
> +#define CMD_SET_FEATURE                        0x3
> +
> +/* Feature IDs */
> +#define FEATURE_SENSOR                 0
> +#define FEATURE_FAN                    1
> +#define FEATURE_DVFS                   2
> +
> +/* Sensor feature flags */
> +#define FEATURE_SENSOR_ENABLE          BIT(0)
> +#define FEATURE_SENSOR_SAMPLE          BIT(1)
> +
> +/* Fan feature flags */
> +#define FEATURE_FAN_ENABLE             BIT(0)
> +#define FEATURE_FAN_AUTO               BIT(1)
> +
> +/* DVFS feature flags */
> +#define FEATURE_DVFS_ENABLE            BIT(0)
> +#define FEATURE_DVFS_BOOST             BIT(1)
> +#define FEATURE_DVFS_AUTO              BIT(2)
> +#define FEATURE_DVFS_SINGLE_BOOST      BIT(3)
> +
> +/* Sensor commands */
> +/*
> + * CMD_GET_SENSOR_NUM - Get number of sensors
> + * Input: none
> + * Output: number
> + */
> +#define CMD_GET_SENSOR_NUM             0x4
> +
> +/*
> + * CMD_GET_SENSOR_STATUS - Get sensor status
> + * Input: sensor ID, type
> + * Output: sensor status
> + */
> +#define CMD_GET_SENSOR_STATUS          0x5
> +
> +/* Sensor types */
> +#define SENSOR_INFO_TYPE               0
> +#define SENSOR_INFO_TYPE_TEMP          1
> +
> +/* Fan commands */
> +/*
> + * CMD_GET_FAN_NUM - Get number of fans
> + * Input: none
> + * Output: number
> + */
> +#define CMD_GET_FAN_NUM                        0x6
> +
> +/*
> + * CMD_GET_FAN_INFO - Get fan status
> + * Input: fan ID, type
> + * Output: fan info
> + */
> +#define CMD_GET_FAN_INFO               0x7
> +
> +/*
> + * CMD_SET_FAN_INFO - Set fan status
> + * Input: fan ID, type, value
> + * Output: none
> + */
> +#define CMD_SET_FAN_INFO               0x8
> +
> +/* Fan types */
> +#define FAN_INFO_TYPE_LEVEL            0
> +
> +/* DVFS commands */
> +/*
> + * CMD_GET_FREQ_LEVEL_NUM - Get number of freq levels
> + * Input: CPU ID
> + * Output: number
> + */
> +#define CMD_GET_FREQ_LEVEL_NUM         0x9
> +
> +/*
> + * CMD_GET_FREQ_BOOST_LEVEL - Get number of boost levels
> + * Input: CPU ID
> + * Output: number
> + */
> +#define CMD_GET_FREQ_BOOST_LEVEL       0x10
> +
> +/*
> + * CMD_GET_FREQ_LEVEL_INFO - Get freq level info
> + * Input: CPU ID, level ID
> + * Output: level info
> + */
> +#define CMD_GET_FREQ_LEVEL_INFO                0x11
> +
> +/*
> + * CMD_GET_FREQ_INFO - Get freq info
> + * Input: CPU ID, type
> + * Output: freq info
> + */
> +#define CMD_GET_FREQ_INFO              0x12
> +
> +/*
> + * CMD_SET_FREQ_INFO - Set freq info
> + * Input: CPU ID, type, value
> + * Output: none
> + */
> +#define CMD_SET_FREQ_INFO              0x13
> +
> +/* Freq types */
> +#define FREQ_INFO_TYPE_FREQ            0
> +#define FREQ_INFO_TYPE_LEVEL           1
> +
> +#define FREQ_MAX_LEVEL                 (16 + 1)
> +
> +enum freq {
> +       FREQ_LEV0, /* Reserved */
> +       FREQ_LEV1, FREQ_LEV2, FREQ_LEV3, FREQ_LEV4,
> +       FREQ_LEV5, FREQ_LEV6, FREQ_LEV7, FREQ_LEV8,
> +       FREQ_LEV9, FREQ_LEV10, FREQ_LEV11, FREQ_LEV12,
> +       FREQ_LEV13, FREQ_LEV14, FREQ_LEV15, FREQ_LEV16,
> +       FREQ_RESV
> +};
> +
> +struct loongson3_freq_data {
> +       unsigned int cur_cpu_freq;
> +       struct cpufreq_frequency_table table[];
> +};
> +
> +static struct mutex cpufreq_mutex[MAX_PACKAGES];
> +static struct cpufreq_driver loongson3_cpufreq_driver;
> +static DEFINE_PER_CPU(struct loongson3_freq_data *, freq_data);
> +
> +static inline int do_service_request(union smc_message *msg)
> +{
> +       int retries;
> +       union smc_message last;
> +
> +       last.value = iocsr_read32(LOONGARCH_IOCSR_SMCMBX);
> +       if (!last.complete)
> +               return -EPERM;
> +
> +       iocsr_write32(msg->value, LOONGARCH_IOCSR_SMCMBX);
> +       iocsr_write32(iocsr_read32(LOONGARCH_IOCSR_MISC_FUNC) | IOCSR_MISC_FUNC_SOFT_INT,
> +                     LOONGARCH_IOCSR_MISC_FUNC);
> +
> +       for (retries = 0; retries < 10000; retries++) {
> +               msg->value = iocsr_read32(LOONGARCH_IOCSR_SMCMBX);
> +               if (msg->complete)
> +                       break;
> +
> +               usleep_range(8, 12);
> +       }
> +
> +       if (!msg->complete || msg->cmd != CMD_OK)
> +               return -EPERM;
> +
> +       return 0;
> +}
> +
> +static unsigned int loongson3_cpufreq_get(unsigned int cpu)
> +{
> +       union smc_message msg;
> +
> +       msg.id          = cpu;
> +       msg.info        = FREQ_INFO_TYPE_FREQ;
> +       msg.cmd         = CMD_GET_FREQ_INFO;
> +       msg.extra       = 0;
> +       msg.complete    = 0;
> +       do_service_request(&msg);
> +
> +       per_cpu(freq_data, cpu)->cur_cpu_freq = msg.val * KILO;
> +
> +       return per_cpu(freq_data, cpu)->cur_cpu_freq;
> +}
> +
> +static int loongson3_cpufreq_set(struct cpufreq_policy *policy, int freq_level)
> +{
> +       union smc_message msg;
> +
> +       msg.id          = cpu_data[policy->cpu].core;
> +       msg.info        = FREQ_INFO_TYPE_LEVEL;
> +       msg.val         = freq_level;
> +       msg.cmd         = CMD_SET_FREQ_INFO;
> +       msg.extra       = 0;
> +       msg.complete    = 0;
> +       do_service_request(&msg);
> +
> +       return 0;
> +}
> +
> +/*
> + * Here we notify other drivers of the proposed change and the final change.
> + */
> +static int loongson3_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
> +{
> +       unsigned int cpu = policy->cpu;
> +       unsigned int package = cpu_data[cpu].package;
> +
> +       if (!cpu_online(cpu))
> +               return -ENODEV;
> +
> +       /* setting the cpu frequency */
> +       mutex_lock(&cpufreq_mutex[package]);
> +       loongson3_cpufreq_set(policy, index);
> +       mutex_unlock(&cpufreq_mutex[package]);
> +
> +       return 0;
> +}
> +
> +static int loongson3_cpufreq_get_freq_table(int cpu)
> +{
> +       union smc_message msg;
> +       int i, ret, boost_level, max_level, freq_level;
> +       struct loongson3_freq_data *data;
> +
> +       if (per_cpu(freq_data, cpu))
> +               return 0;
> +
> +       msg.id          = cpu;
> +       msg.cmd         = CMD_GET_FREQ_LEVEL_NUM;
> +       msg.extra       = 0;
> +       msg.complete    = 0;
> +       ret = do_service_request(&msg);
> +       if (ret < 0)
> +               return ret;
> +       max_level = msg.val;
> +
> +       msg.id          = cpu;
> +       msg.cmd         = CMD_GET_FREQ_BOOST_LEVEL;
> +       msg.extra       = 0;
> +       msg.complete    = 0;
> +       ret = do_service_request(&msg);
> +       if (ret < 0)
> +               return ret;
> +       boost_level = msg.val;
> +
> +       freq_level = min(max_level, FREQ_MAX_LEVEL);
> +       data = kzalloc(struct_size(data, table, freq_level + 1), GFP_KERNEL);
> +       if (!data)
> +               return -ENOMEM;
> +
> +       for (i = 0; i < freq_level; i++) {
> +               msg.id          = cpu;
> +               msg.info        = FREQ_INFO_TYPE_FREQ;
> +               msg.cmd         = CMD_GET_FREQ_LEVEL_INFO;
> +               msg.val         = i;
> +               msg.complete    = 0;
> +
> +               ret = do_service_request(&msg);
> +               if (ret < 0) {
> +                       kfree(data);
> +                       return ret;
> +               }
> +
> +               data->table[i].frequency = msg.val * KILO;
> +               data->table[i].driver_data = FREQ_LEV0 + i;
> +               data->table[i].flags = (i >= boost_level) ? CPUFREQ_BOOST_FREQ : 0;
> +       }
> +
> +       data->table[freq_level].frequency = CPUFREQ_TABLE_END;
> +       data->table[freq_level].driver_data = FREQ_RESV;
> +       data->table[freq_level].flags = 0;
> +
> +       per_cpu(freq_data, cpu) = data;
> +
> +       return 0;
> +}
> +
> +static int loongson3_cpufreq_cpu_init(struct cpufreq_policy *policy)
> +{
> +       int ret;
> +
> +       if (!cpu_online(policy->cpu))
> +               return -ENODEV;
> +
> +       ret = loongson3_cpufreq_get_freq_table(policy->cpu);
> +       if (ret < 0)
> +               return ret;
> +
> +       policy->cur = loongson3_cpufreq_get(policy->cpu);
> +       policy->cpuinfo.transition_latency = 10000;
> +       policy->freq_table = per_cpu(freq_data, policy->cpu)->table;
> +       cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));
> +
> +       if (policy_has_boost_freq(policy)) {
> +               ret = cpufreq_enable_boost_support();
> +               if (ret < 0) {
> +                       pr_warn("cpufreq: Failed to enable boost: %d\n", ret);
> +                       return ret;
> +               }
> +               loongson3_cpufreq_driver.boost_enabled = true;
> +       }
> +
> +       return 0;
> +}
> +
> +static int loongson3_cpufreq_cpu_exit(struct cpufreq_policy *policy)
> +{
> +       return 0;
> +}
> +
> +static struct cpufreq_driver loongson3_cpufreq_driver = {
> +       .name = "loongson3",
> +       .flags = CPUFREQ_CONST_LOOPS,
> +       .init = loongson3_cpufreq_cpu_init,
> +       .exit = loongson3_cpufreq_cpu_exit,
> +       .verify = cpufreq_generic_frequency_table_verify,
> +       .target_index = loongson3_cpufreq_target,
> +       .get = loongson3_cpufreq_get,
> +       .attr = cpufreq_generic_attr,
> +};
> +
> +static struct platform_device_id cpufreq_id_table[] = {
> +       { "loongson3_cpufreq", },
> +       { /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(platform, cpufreq_id_table);
> +
> +static struct platform_driver loongson3_platform_driver = {
> +       .driver = {
> +               .name = "loongson3_cpufreq",
> +       },
> +       .id_table = cpufreq_id_table,
> +};
> +
> +static int configure_cpufreq_info(void)
> +{
> +       int ret;
> +       union smc_message msg;
> +
> +       msg.cmd         = CMD_GET_VERSION;
> +       msg.extra       = 0;
> +       msg.complete    = 0;
> +       ret = do_service_request(&msg);
> +       if (ret < 0 || msg.val < 0x1)
> +               return -EPERM;
> +
> +       msg.id          = FEATURE_DVFS;
> +       msg.cmd         = CMD_SET_FEATURE;
> +       msg.val         = FEATURE_DVFS_ENABLE | FEATURE_DVFS_BOOST;
> +       msg.extra       = 0;
> +       msg.complete    = 0;
> +       ret = do_service_request(&msg);
> +       if (ret < 0)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +static int __init cpufreq_init(void)
> +{
> +       int i, ret;
> +
> +       ret = platform_driver_register(&loongson3_platform_driver);
> +       if (ret)
> +               return ret;
> +
> +       ret = configure_cpufreq_info();
> +       if (ret)
> +               goto err;
> +
> +       for (i = 0; i < MAX_PACKAGES; i++)
> +               mutex_init(&cpufreq_mutex[i]);
> +
> +       ret = cpufreq_register_driver(&loongson3_cpufreq_driver);
> +       if (ret)
> +               goto err;
> +
> +       pr_info("cpufreq: Loongson-3 CPU frequency driver.\n");
> +
> +       return 0;
> +
> +err:
> +       platform_driver_unregister(&loongson3_platform_driver);
> +       return ret;
> +}
> +
> +static void __exit cpufreq_exit(void)
> +{
> +       cpufreq_unregister_driver(&loongson3_cpufreq_driver);
> +       platform_driver_unregister(&loongson3_platform_driver);
> +}
> +
> +module_init(cpufreq_init);
> +module_exit(cpufreq_exit);
> +
> +MODULE_AUTHOR("Huacai Chen <chenhuacai@loongson.cn>");
> +MODULE_DESCRIPTION("CPUFreq driver for Loongson-3 processors");
> +MODULE_LICENSE("GPL");
> --
> 2.43.0
>

Re: [PATCH 2/2] cpufreq: Add Loongson-3 CPUFreq driver support

[Viresh Kumar]

On 12-06-24, 14:42, Huacai Chen wrote:
> Some of LoongArch processors (Loongson-3 series) support DVFS, their
> IOCSR.FEATURES has IOCSRF_FREQSCALE set. And they has a micro-core in
> the package called SMC (System Management Controller), which can be
> used to detect temperature, control fans, scale frequency and voltage,
> etc.
> 
> The Loongson-3 CPUFreq driver is very simple now, it communicate with
> SMC, get DVFS info, set target frequency from CPUFreq core, and so on.
> 
> There is a command list to interact with SMC, widely-used commands in
> the CPUFreq driver include:
> 
> CMD_GET_VERSION: Get SMC firmware version.
> 
> CMD_GET_FEATURE: Get enabled SMC features.
> 
> CMD_SET_FEATURE: Enable SMC features, such as basic DVFS, BOOST.
> 
> CMD_GET_FREQ_LEVEL_NUM: Get the number of normal frequency levels.
> 
> CMD_GET_FREQ_BOOST_NUM: Get the number of boost frequency levels.
> 
> CMD_GET_FREQ_LEVEL_INFO: Get the detail info of a frequency level.
> 
> CMD_GET_FREQ_INFO: Get the current frequency.
> 
> CMD_SET_FREQ_INFO: Set the target frequency.
> 
> In future we will add automatic frequency scaling, which is similar to
> Intel's HWP (HardWare P-State).
> 
> Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  drivers/cpufreq/Kconfig             |  12 +
>  drivers/cpufreq/Makefile            |   1 +
>  drivers/cpufreq/loongson3_cpufreq.c | 442 ++++++++++++++++++++++++++++
>  3 files changed, 455 insertions(+)
>  create mode 100644 drivers/cpufreq/loongson3_cpufreq.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index aacccb376c28..f2e47ec28d77 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12968,6 +12968,7 @@ F:	Documentation/arch/loongarch/
>  F:	Documentation/translations/zh_CN/arch/loongarch/
>  F:	arch/loongarch/
>  F:	drivers/*/*loongarch*
> +F:	drivers/cpufreq/loongson3_cpufreq.c
>  
>  LOONGSON GPIO DRIVER
>  M:	Yinbo Zhu <zhuyinbo@loongson.cn>
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index 94e55c40970a..10cda6f2fe1d 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -262,6 +262,18 @@ config LOONGSON2_CPUFREQ
>  	  If in doubt, say N.
>  endif
>  
> +if LOONGARCH
> +config LOONGSON3_CPUFREQ
> +	tristate "Loongson3 CPUFreq Driver"
> +	help
> +	  This option adds a CPUFreq driver for Loongson processors which
> +	  support software configurable cpu frequency.
> +
> +	  Loongson-3 family processors support this feature.
> +
> +	  If in doubt, say N.
> +endif
> +
>  if SPARC64
>  config SPARC_US3_CPUFREQ
>  	tristate "UltraSPARC-III CPU Frequency driver"
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index 8d141c71b016..0f184031dd12 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -103,6 +103,7 @@ obj-$(CONFIG_POWERNV_CPUFREQ)		+= powernv-cpufreq.o
>  # Other platform drivers
>  obj-$(CONFIG_BMIPS_CPUFREQ)		+= bmips-cpufreq.o
>  obj-$(CONFIG_LOONGSON2_CPUFREQ)		+= loongson2_cpufreq.o
> +obj-$(CONFIG_LOONGSON3_CPUFREQ)		+= loongson3_cpufreq.o
>  obj-$(CONFIG_SH_CPU_FREQ)		+= sh-cpufreq.o
>  obj-$(CONFIG_SPARC_US2E_CPUFREQ)	+= sparc-us2e-cpufreq.o
>  obj-$(CONFIG_SPARC_US3_CPUFREQ)		+= sparc-us3-cpufreq.o
> diff --git a/drivers/cpufreq/loongson3_cpufreq.c b/drivers/cpufreq/loongson3_cpufreq.c
> new file mode 100644
> index 000000000000..5dbac0d55a32
> --- /dev/null
> +++ b/drivers/cpufreq/loongson3_cpufreq.c
> @@ -0,0 +1,442 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * CPUFreq driver for the loongson-3 processors
> + *
> + * All revisions of Loongson-3 processor support this feature.
> + *
> + * Author: Huacai Chen <chenhuacai@loongson.cn>
> + * Copyright (C) 2020-2024 Loongson Technology Corporation Limited
> + */
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/cpufreq.h>
> +#include <linux/platform_device.h>
> +#include <linux/units.h>
> +
> +#include <asm/idle.h>
> +#include <asm/loongarch.h>
> +#include <asm/loongson.h>
> +
> +/* Message */
> +union smc_message {
> +	u32 value;
> +	struct {
> +		u32 id		: 4;
> +		u32 info	: 4;
> +		u32 val		: 16;
> +		u32 cmd		: 6;
> +		u32 extra	: 1;
> +		u32 complete	: 1;
> +	};
> +};
> +
> +/* Command return values */
> +#define CMD_OK				0  /* No error */
> +#define CMD_ERROR			1  /* Regular error */
> +#define CMD_NOCMD			2  /* Command does not support */
> +#define CMD_INVAL			3  /* Invalid Parameter */
> +
> +/* Version commands */
> +/*
> + * CMD_GET_VERSION - Get interface version
> + * Input: none
> + * Output: version
> + */
> +#define CMD_GET_VERSION			0x1
> +
> +/* Feature commands */
> +/*
> + * CMD_GET_FEATURE - Get feature state
> + * Input: feature ID
> + * Output: feature flag
> + */
> +#define CMD_GET_FEATURE			0x2
> +
> +/*
> + * CMD_SET_FEATURE - Set feature state
> + * Input: feature ID, feature flag
> + * output: none
> + */
> +#define CMD_SET_FEATURE			0x3
> +
> +/* Feature IDs */
> +#define FEATURE_SENSOR			0
> +#define FEATURE_FAN			1
> +#define FEATURE_DVFS			2
> +
> +/* Sensor feature flags */
> +#define FEATURE_SENSOR_ENABLE		BIT(0)
> +#define FEATURE_SENSOR_SAMPLE		BIT(1)
> +
> +/* Fan feature flags */
> +#define FEATURE_FAN_ENABLE		BIT(0)
> +#define FEATURE_FAN_AUTO		BIT(1)
> +
> +/* DVFS feature flags */
> +#define FEATURE_DVFS_ENABLE		BIT(0)
> +#define FEATURE_DVFS_BOOST		BIT(1)
> +#define FEATURE_DVFS_AUTO		BIT(2)
> +#define FEATURE_DVFS_SINGLE_BOOST	BIT(3)
> +
> +/* Sensor commands */
> +/*
> + * CMD_GET_SENSOR_NUM - Get number of sensors
> + * Input: none
> + * Output: number
> + */
> +#define CMD_GET_SENSOR_NUM		0x4
> +
> +/*
> + * CMD_GET_SENSOR_STATUS - Get sensor status
> + * Input: sensor ID, type
> + * Output: sensor status
> + */
> +#define CMD_GET_SENSOR_STATUS		0x5
> +
> +/* Sensor types */
> +#define SENSOR_INFO_TYPE		0
> +#define SENSOR_INFO_TYPE_TEMP		1
> +
> +/* Fan commands */
> +/*
> + * CMD_GET_FAN_NUM - Get number of fans
> + * Input: none
> + * Output: number
> + */
> +#define CMD_GET_FAN_NUM			0x6
> +
> +/*
> + * CMD_GET_FAN_INFO - Get fan status
> + * Input: fan ID, type
> + * Output: fan info
> + */
> +#define CMD_GET_FAN_INFO		0x7
> +
> +/*
> + * CMD_SET_FAN_INFO - Set fan status
> + * Input: fan ID, type, value
> + * Output: none
> + */
> +#define CMD_SET_FAN_INFO		0x8
> +
> +/* Fan types */
> +#define FAN_INFO_TYPE_LEVEL		0
> +
> +/* DVFS commands */
> +/*
> + * CMD_GET_FREQ_LEVEL_NUM - Get number of freq levels
> + * Input: CPU ID
> + * Output: number
> + */
> +#define CMD_GET_FREQ_LEVEL_NUM		0x9
> +
> +/*
> + * CMD_GET_FREQ_BOOST_LEVEL - Get number of boost levels
> + * Input: CPU ID
> + * Output: number
> + */
> +#define CMD_GET_FREQ_BOOST_LEVEL	0x10
> +
> +/*
> + * CMD_GET_FREQ_LEVEL_INFO - Get freq level info
> + * Input: CPU ID, level ID
> + * Output: level info
> + */
> +#define CMD_GET_FREQ_LEVEL_INFO		0x11
> +
> +/*
> + * CMD_GET_FREQ_INFO - Get freq info
> + * Input: CPU ID, type
> + * Output: freq info
> + */
> +#define CMD_GET_FREQ_INFO		0x12
> +
> +/*
> + * CMD_SET_FREQ_INFO - Set freq info
> + * Input: CPU ID, type, value
> + * Output: none
> + */
> +#define CMD_SET_FREQ_INFO		0x13
> +
> +/* Freq types */
> +#define FREQ_INFO_TYPE_FREQ		0
> +#define FREQ_INFO_TYPE_LEVEL		1
> +
> +#define FREQ_MAX_LEVEL			(16 + 1)
> +
> +enum freq {
> +	FREQ_LEV0, /* Reserved */
> +	FREQ_LEV1, FREQ_LEV2, FREQ_LEV3, FREQ_LEV4,
> +	FREQ_LEV5, FREQ_LEV6, FREQ_LEV7, FREQ_LEV8,
> +	FREQ_LEV9, FREQ_LEV10, FREQ_LEV11, FREQ_LEV12,
> +	FREQ_LEV13, FREQ_LEV14, FREQ_LEV15, FREQ_LEV16,
> +	FREQ_RESV
> +};
> +
> +struct loongson3_freq_data {
> +	unsigned int cur_cpu_freq;

You never use it. Remove it.

> +	struct cpufreq_frequency_table table[];
> +};
> +
> +static struct mutex cpufreq_mutex[MAX_PACKAGES];
> +static struct cpufreq_driver loongson3_cpufreq_driver;
> +static DEFINE_PER_CPU(struct loongson3_freq_data *, freq_data);
> +
> +static inline int do_service_request(union smc_message *msg)
> +{
> +	int retries;
> +	union smc_message last;
> +
> +	last.value = iocsr_read32(LOONGARCH_IOCSR_SMCMBX);
> +	if (!last.complete)
> +		return -EPERM;
> +
> +	iocsr_write32(msg->value, LOONGARCH_IOCSR_SMCMBX);
> +	iocsr_write32(iocsr_read32(LOONGARCH_IOCSR_MISC_FUNC) | IOCSR_MISC_FUNC_SOFT_INT,
> +		      LOONGARCH_IOCSR_MISC_FUNC);
> +
> +	for (retries = 0; retries < 10000; retries++) {
> +		msg->value = iocsr_read32(LOONGARCH_IOCSR_SMCMBX);
> +		if (msg->complete)
> +			break;
> +
> +		usleep_range(8, 12);
> +	}
> +
> +	if (!msg->complete || msg->cmd != CMD_OK)
> +		return -EPERM;
> +
> +	return 0;
> +}
> +
> +static unsigned int loongson3_cpufreq_get(unsigned int cpu)
> +{
> +	union smc_message msg;
> +
> +	msg.id		= cpu;
> +	msg.info	= FREQ_INFO_TYPE_FREQ;
> +	msg.cmd		= CMD_GET_FREQ_INFO;
> +	msg.extra	= 0;
> +	msg.complete	= 0;
> +	do_service_request(&msg);
> +
> +	per_cpu(freq_data, cpu)->cur_cpu_freq = msg.val * KILO;
> +
> +	return per_cpu(freq_data, cpu)->cur_cpu_freq;
> +}
> +
> +static int loongson3_cpufreq_set(struct cpufreq_policy *policy, int freq_level)
> +{
> +	union smc_message msg;
> +
> +	msg.id		= cpu_data[policy->cpu].core;
> +	msg.info	= FREQ_INFO_TYPE_LEVEL;
> +	msg.val		= freq_level;
> +	msg.cmd		= CMD_SET_FREQ_INFO;
> +	msg.extra	= 0;
> +	msg.complete	= 0;
> +	do_service_request(&msg);
> +
> +	return 0;
> +}
> +
> +/*
> + * Here we notify other drivers of the proposed change and the final change.
> + */
> +static int loongson3_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
> +{
> +	unsigned int cpu = policy->cpu;
> +	unsigned int package = cpu_data[cpu].package;
> +
> +	if (!cpu_online(cpu))

No need to check this.

> +		return -ENODEV;
> +
> +	/* setting the cpu frequency */
> +	mutex_lock(&cpufreq_mutex[package]);

No locking required here. Core doesn't call them in parallel.

> +	loongson3_cpufreq_set(policy, index);
> +	mutex_unlock(&cpufreq_mutex[package]);
> +
> +	return 0;
> +}
> +
> +static int loongson3_cpufreq_get_freq_table(int cpu)
> +{
> +	union smc_message msg;
> +	int i, ret, boost_level, max_level, freq_level;
> +	struct loongson3_freq_data *data;
> +
> +	if (per_cpu(freq_data, cpu))
> +		return 0;

Will this ever be true ?

> +
> +	msg.id		= cpu;
> +	msg.cmd		= CMD_GET_FREQ_LEVEL_NUM;
> +	msg.extra	= 0;
> +	msg.complete	= 0;
> +	ret = do_service_request(&msg);
> +	if (ret < 0)
> +		return ret;
> +	max_level = msg.val;
> +


> +	msg.id		= cpu;
> +	msg.cmd		= CMD_GET_FREQ_BOOST_LEVEL;
> +	msg.extra	= 0;
> +	msg.complete	= 0;
> +	ret = do_service_request(&msg);
> +	if (ret < 0)
> +		return ret;
> +	boost_level = msg.val;

This stuff is repeated a lot, maybe create a generic function for this
?

> +
> +	freq_level = min(max_level, FREQ_MAX_LEVEL);
> +	data = kzalloc(struct_size(data, table, freq_level + 1), GFP_KERNEL);

devm_kzalloc(pdev, ...) ?

> +	if (!data)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < freq_level; i++) {
> +		msg.id		= cpu;
> +		msg.info	= FREQ_INFO_TYPE_FREQ;
> +		msg.cmd		= CMD_GET_FREQ_LEVEL_INFO;
> +		msg.val		= i;
> +		msg.complete	= 0;
> +
> +		ret = do_service_request(&msg);
> +		if (ret < 0) {
> +			kfree(data);
> +			return ret;
> +		}
> +
> +		data->table[i].frequency = msg.val * KILO;
> +		data->table[i].driver_data = FREQ_LEV0 + i;
> +		data->table[i].flags = (i >= boost_level) ? CPUFREQ_BOOST_FREQ : 0;
> +	}
> +
> +	data->table[freq_level].frequency = CPUFREQ_TABLE_END;
> +	data->table[freq_level].driver_data = FREQ_RESV;
> +	data->table[freq_level].flags = 0;
> +
> +	per_cpu(freq_data, cpu) = data;
> +
> +	return 0;
> +}
> +
> +static int loongson3_cpufreq_cpu_init(struct cpufreq_policy *policy)
> +{
> +	int ret;
> +
> +	if (!cpu_online(policy->cpu))

No need to check this. Core takes care of this already.

> +		return -ENODEV;
> +
> +	ret = loongson3_cpufreq_get_freq_table(policy->cpu);
> +	if (ret < 0)
> +		return ret;
> +
> +	policy->cur = loongson3_cpufreq_get(policy->cpu);
> +	policy->cpuinfo.transition_latency = 10000;
> +	policy->freq_table = per_cpu(freq_data, policy->cpu)->table;
> +	cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));
> +
> +	if (policy_has_boost_freq(policy)) {
> +		ret = cpufreq_enable_boost_support();
> +		if (ret < 0) {
> +			pr_warn("cpufreq: Failed to enable boost: %d\n", ret);
> +			return ret;
> +		}
> +		loongson3_cpufreq_driver.boost_enabled = true;
> +	}
> +
> +	return 0;
> +}
> +
> +static int loongson3_cpufreq_cpu_exit(struct cpufreq_policy *policy)
> +{
> +	return 0;
> +}

Just drop the routine, it is optional.

> +
> +static struct cpufreq_driver loongson3_cpufreq_driver = {
> +	.name = "loongson3",
> +	.flags = CPUFREQ_CONST_LOOPS,
> +	.init = loongson3_cpufreq_cpu_init,
> +	.exit = loongson3_cpufreq_cpu_exit,
> +	.verify = cpufreq_generic_frequency_table_verify,
> +	.target_index = loongson3_cpufreq_target,
> +	.get = loongson3_cpufreq_get,
> +	.attr = cpufreq_generic_attr,
> +};
> +
> +static struct platform_device_id cpufreq_id_table[] = {
> +	{ "loongson3_cpufreq", },
> +	{ /* sentinel */ }
> +};
> +

Remove this blank line please.

> +MODULE_DEVICE_TABLE(platform, cpufreq_id_table);
> +
> +static struct platform_driver loongson3_platform_driver = {
> +	.driver = {
> +		.name = "loongson3_cpufreq",
> +	},
> +	.id_table = cpufreq_id_table,
> +};
> +
> +static int configure_cpufreq_info(void)
> +{
> +	int ret;
> +	union smc_message msg;
> +
> +	msg.cmd		= CMD_GET_VERSION;
> +	msg.extra	= 0;
> +	msg.complete	= 0;
> +	ret = do_service_request(&msg);
> +	if (ret < 0 || msg.val < 0x1)
> +		return -EPERM;
> +
> +	msg.id		= FEATURE_DVFS;
> +	msg.cmd		= CMD_SET_FEATURE;
> +	msg.val		= FEATURE_DVFS_ENABLE | FEATURE_DVFS_BOOST;
> +	msg.extra	= 0;
> +	msg.complete	= 0;
> +	ret = do_service_request(&msg);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int __init cpufreq_init(void)
> +{
> +	int i, ret;
> +
> +	ret = platform_driver_register(&loongson3_platform_driver);
> +	if (ret)
> +		return ret;

What is the use of this platform driver ? I thought the whole purpose
of the platform device/driver in your case was to probe this driver.
In that case cpufreq_init() should only be doing above and not the
below part. The rest should be handled in the probe() function of the
driver.

> +
> +	ret = configure_cpufreq_info();
> +	if (ret)
> +		goto err;
> +
> +	for (i = 0; i < MAX_PACKAGES; i++)
> +		mutex_init(&cpufreq_mutex[i]);

You don't need this at all.

> +
> +	ret = cpufreq_register_driver(&loongson3_cpufreq_driver);
> +	if (ret)
> +		goto err;
> +
> +	pr_info("cpufreq: Loongson-3 CPU frequency driver.\n");

Make this pr_debug if you want.. There is not much use of this for the
user.

> +
> +	return 0;
> +
> +err:
> +	platform_driver_unregister(&loongson3_platform_driver);
> +	return ret;
> +}
> +
> +static void __exit cpufreq_exit(void)
> +{
> +	cpufreq_unregister_driver(&loongson3_cpufreq_driver);
> +	platform_driver_unregister(&loongson3_platform_driver);
> +}
> +
> +module_init(cpufreq_init);
> +module_exit(cpufreq_exit);

You can just use: module_platform_driver() instead of above functions
and declarations.

> +
> +MODULE_AUTHOR("Huacai Chen <chenhuacai@loongson.cn>");
> +MODULE_DESCRIPTION("CPUFreq driver for Loongson-3 processors");
> +MODULE_LICENSE("GPL");

-- 
viresh

Re: [PATCH 2/2] cpufreq: Add Loongson-3 CPUFreq driver support

[Huacai Chen]

Hi, Viresh,

Thank you for your review.

On Tue, Jun 25, 2024 at 3:56 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 12-06-24, 14:42, Huacai Chen wrote:
> > Some of LoongArch processors (Loongson-3 series) support DVFS, their
> > IOCSR.FEATURES has IOCSRF_FREQSCALE set. And they has a micro-core in
> > the package called SMC (System Management Controller), which can be
> > used to detect temperature, control fans, scale frequency and voltage,
> > etc.
> >
> > The Loongson-3 CPUFreq driver is very simple now, it communicate with
> > SMC, get DVFS info, set target frequency from CPUFreq core, and so on.
> >
> > There is a command list to interact with SMC, widely-used commands in
> > the CPUFreq driver include:
> >
> > CMD_GET_VERSION: Get SMC firmware version.
> >
> > CMD_GET_FEATURE: Get enabled SMC features.
> >
> > CMD_SET_FEATURE: Enable SMC features, such as basic DVFS, BOOST.
> >
> > CMD_GET_FREQ_LEVEL_NUM: Get the number of normal frequency levels.
> >
> > CMD_GET_FREQ_BOOST_NUM: Get the number of boost frequency levels.
> >
> > CMD_GET_FREQ_LEVEL_INFO: Get the detail info of a frequency level.
> >
> > CMD_GET_FREQ_INFO: Get the current frequency.
> >
> > CMD_SET_FREQ_INFO: Set the target frequency.
> >
> > In future we will add automatic frequency scaling, which is similar to
> > Intel's HWP (HardWare P-State).
> >
> > Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> > ---
> >  drivers/cpufreq/Kconfig             |  12 +
> >  drivers/cpufreq/Makefile            |   1 +
> >  drivers/cpufreq/loongson3_cpufreq.c | 442 ++++++++++++++++++++++++++++
> >  3 files changed, 455 insertions(+)
> >  create mode 100644 drivers/cpufreq/loongson3_cpufreq.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index aacccb376c28..f2e47ec28d77 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -12968,6 +12968,7 @@ F:    Documentation/arch/loongarch/
> >  F:   Documentation/translations/zh_CN/arch/loongarch/
> >  F:   arch/loongarch/
> >  F:   drivers/*/*loongarch*
> > +F:   drivers/cpufreq/loongson3_cpufreq.c
> >
> >  LOONGSON GPIO DRIVER
> >  M:   Yinbo Zhu <zhuyinbo@loongson.cn>
> > diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> > index 94e55c40970a..10cda6f2fe1d 100644
> > --- a/drivers/cpufreq/Kconfig
> > +++ b/drivers/cpufreq/Kconfig
> > @@ -262,6 +262,18 @@ config LOONGSON2_CPUFREQ
> >         If in doubt, say N.
> >  endif
> >
> > +if LOONGARCH
> > +config LOONGSON3_CPUFREQ
> > +     tristate "Loongson3 CPUFreq Driver"
> > +     help
> > +       This option adds a CPUFreq driver for Loongson processors which
> > +       support software configurable cpu frequency.
> > +
> > +       Loongson-3 family processors support this feature.
> > +
> > +       If in doubt, say N.
> > +endif
> > +
> >  if SPARC64
> >  config SPARC_US3_CPUFREQ
> >       tristate "UltraSPARC-III CPU Frequency driver"
> > diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> > index 8d141c71b016..0f184031dd12 100644
> > --- a/drivers/cpufreq/Makefile
> > +++ b/drivers/cpufreq/Makefile
> > @@ -103,6 +103,7 @@ obj-$(CONFIG_POWERNV_CPUFREQ)             += powernv-cpufreq.o
> >  # Other platform drivers
> >  obj-$(CONFIG_BMIPS_CPUFREQ)          += bmips-cpufreq.o
> >  obj-$(CONFIG_LOONGSON2_CPUFREQ)              += loongson2_cpufreq.o
> > +obj-$(CONFIG_LOONGSON3_CPUFREQ)              += loongson3_cpufreq.o
> >  obj-$(CONFIG_SH_CPU_FREQ)            += sh-cpufreq.o
> >  obj-$(CONFIG_SPARC_US2E_CPUFREQ)     += sparc-us2e-cpufreq.o
> >  obj-$(CONFIG_SPARC_US3_CPUFREQ)              += sparc-us3-cpufreq.o
> > diff --git a/drivers/cpufreq/loongson3_cpufreq.c b/drivers/cpufreq/loongson3_cpufreq.c
> > new file mode 100644
> > index 000000000000..5dbac0d55a32
> > --- /dev/null
> > +++ b/drivers/cpufreq/loongson3_cpufreq.c
> > @@ -0,0 +1,442 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * CPUFreq driver for the loongson-3 processors
> > + *
> > + * All revisions of Loongson-3 processor support this feature.
> > + *
> > + * Author: Huacai Chen <chenhuacai@loongson.cn>
> > + * Copyright (C) 2020-2024 Loongson Technology Corporation Limited
> > + */
> > +#include <linux/delay.h>
> > +#include <linux/module.h>
> > +#include <linux/cpufreq.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/units.h>
> > +
> > +#include <asm/idle.h>
> > +#include <asm/loongarch.h>
> > +#include <asm/loongson.h>
> > +
> > +/* Message */
> > +union smc_message {
> > +     u32 value;
> > +     struct {
> > +             u32 id          : 4;
> > +             u32 info        : 4;
> > +             u32 val         : 16;
> > +             u32 cmd         : 6;
> > +             u32 extra       : 1;
> > +             u32 complete    : 1;
> > +     };
> > +};
> > +
> > +/* Command return values */
> > +#define CMD_OK                               0  /* No error */
> > +#define CMD_ERROR                    1  /* Regular error */
> > +#define CMD_NOCMD                    2  /* Command does not support */
> > +#define CMD_INVAL                    3  /* Invalid Parameter */
> > +
> > +/* Version commands */
> > +/*
> > + * CMD_GET_VERSION - Get interface version
> > + * Input: none
> > + * Output: version
> > + */
> > +#define CMD_GET_VERSION                      0x1
> > +
> > +/* Feature commands */
> > +/*
> > + * CMD_GET_FEATURE - Get feature state
> > + * Input: feature ID
> > + * Output: feature flag
> > + */
> > +#define CMD_GET_FEATURE                      0x2
> > +
> > +/*
> > + * CMD_SET_FEATURE - Set feature state
> > + * Input: feature ID, feature flag
> > + * output: none
> > + */
> > +#define CMD_SET_FEATURE                      0x3
> > +
> > +/* Feature IDs */
> > +#define FEATURE_SENSOR                       0
> > +#define FEATURE_FAN                  1
> > +#define FEATURE_DVFS                 2
> > +
> > +/* Sensor feature flags */
> > +#define FEATURE_SENSOR_ENABLE                BIT(0)
> > +#define FEATURE_SENSOR_SAMPLE                BIT(1)
> > +
> > +/* Fan feature flags */
> > +#define FEATURE_FAN_ENABLE           BIT(0)
> > +#define FEATURE_FAN_AUTO             BIT(1)
> > +
> > +/* DVFS feature flags */
> > +#define FEATURE_DVFS_ENABLE          BIT(0)
> > +#define FEATURE_DVFS_BOOST           BIT(1)
> > +#define FEATURE_DVFS_AUTO            BIT(2)
> > +#define FEATURE_DVFS_SINGLE_BOOST    BIT(3)
> > +
> > +/* Sensor commands */
> > +/*
> > + * CMD_GET_SENSOR_NUM - Get number of sensors
> > + * Input: none
> > + * Output: number
> > + */
> > +#define CMD_GET_SENSOR_NUM           0x4
> > +
> > +/*
> > + * CMD_GET_SENSOR_STATUS - Get sensor status
> > + * Input: sensor ID, type
> > + * Output: sensor status
> > + */
> > +#define CMD_GET_SENSOR_STATUS                0x5
> > +
> > +/* Sensor types */
> > +#define SENSOR_INFO_TYPE             0
> > +#define SENSOR_INFO_TYPE_TEMP                1
> > +
> > +/* Fan commands */
> > +/*
> > + * CMD_GET_FAN_NUM - Get number of fans
> > + * Input: none
> > + * Output: number
> > + */
> > +#define CMD_GET_FAN_NUM                      0x6
> > +
> > +/*
> > + * CMD_GET_FAN_INFO - Get fan status
> > + * Input: fan ID, type
> > + * Output: fan info
> > + */
> > +#define CMD_GET_FAN_INFO             0x7
> > +
> > +/*
> > + * CMD_SET_FAN_INFO - Set fan status
> > + * Input: fan ID, type, value
> > + * Output: none
> > + */
> > +#define CMD_SET_FAN_INFO             0x8
> > +
> > +/* Fan types */
> > +#define FAN_INFO_TYPE_LEVEL          0
> > +
> > +/* DVFS commands */
> > +/*
> > + * CMD_GET_FREQ_LEVEL_NUM - Get number of freq levels
> > + * Input: CPU ID
> > + * Output: number
> > + */
> > +#define CMD_GET_FREQ_LEVEL_NUM               0x9
> > +
> > +/*
> > + * CMD_GET_FREQ_BOOST_LEVEL - Get number of boost levels
> > + * Input: CPU ID
> > + * Output: number
> > + */
> > +#define CMD_GET_FREQ_BOOST_LEVEL     0x10
> > +
> > +/*
> > + * CMD_GET_FREQ_LEVEL_INFO - Get freq level info
> > + * Input: CPU ID, level ID
> > + * Output: level info
> > + */
> > +#define CMD_GET_FREQ_LEVEL_INFO              0x11
> > +
> > +/*
> > + * CMD_GET_FREQ_INFO - Get freq info
> > + * Input: CPU ID, type
> > + * Output: freq info
> > + */
> > +#define CMD_GET_FREQ_INFO            0x12
> > +
> > +/*
> > + * CMD_SET_FREQ_INFO - Set freq info
> > + * Input: CPU ID, type, value
> > + * Output: none
> > + */
> > +#define CMD_SET_FREQ_INFO            0x13
> > +
> > +/* Freq types */
> > +#define FREQ_INFO_TYPE_FREQ          0
> > +#define FREQ_INFO_TYPE_LEVEL         1
> > +
> > +#define FREQ_MAX_LEVEL                       (16 + 1)
> > +
> > +enum freq {
> > +     FREQ_LEV0, /* Reserved */
> > +     FREQ_LEV1, FREQ_LEV2, FREQ_LEV3, FREQ_LEV4,
> > +     FREQ_LEV5, FREQ_LEV6, FREQ_LEV7, FREQ_LEV8,
> > +     FREQ_LEV9, FREQ_LEV10, FREQ_LEV11, FREQ_LEV12,
> > +     FREQ_LEV13, FREQ_LEV14, FREQ_LEV15, FREQ_LEV16,
> > +     FREQ_RESV
> > +};
> > +
> > +struct loongson3_freq_data {
> > +     unsigned int cur_cpu_freq;
>
> You never use it. Remove it.
Emm, it is used in loongson3_cpufreq_get().

>
> > +     struct cpufreq_frequency_table table[];
> > +};
> > +
> > +static struct mutex cpufreq_mutex[MAX_PACKAGES];
> > +static struct cpufreq_driver loongson3_cpufreq_driver;
> > +static DEFINE_PER_CPU(struct loongson3_freq_data *, freq_data);
> > +
> > +static inline int do_service_request(union smc_message *msg)
> > +{
> > +     int retries;
> > +     union smc_message last;
> > +
> > +     last.value = iocsr_read32(LOONGARCH_IOCSR_SMCMBX);
> > +     if (!last.complete)
> > +             return -EPERM;
> > +
> > +     iocsr_write32(msg->value, LOONGARCH_IOCSR_SMCMBX);
> > +     iocsr_write32(iocsr_read32(LOONGARCH_IOCSR_MISC_FUNC) | IOCSR_MISC_FUNC_SOFT_INT,
> > +                   LOONGARCH_IOCSR_MISC_FUNC);
> > +
> > +     for (retries = 0; retries < 10000; retries++) {
> > +             msg->value = iocsr_read32(LOONGARCH_IOCSR_SMCMBX);
> > +             if (msg->complete)
> > +                     break;
> > +
> > +             usleep_range(8, 12);
> > +     }
> > +
> > +     if (!msg->complete || msg->cmd != CMD_OK)
> > +             return -EPERM;
> > +
> > +     return 0;
> > +}
> > +
> > +static unsigned int loongson3_cpufreq_get(unsigned int cpu)
> > +{
> > +     union smc_message msg;
> > +
> > +     msg.id          = cpu;
> > +     msg.info        = FREQ_INFO_TYPE_FREQ;
> > +     msg.cmd         = CMD_GET_FREQ_INFO;
> > +     msg.extra       = 0;
> > +     msg.complete    = 0;
> > +     do_service_request(&msg);
> > +
> > +     per_cpu(freq_data, cpu)->cur_cpu_freq = msg.val * KILO;
> > +
> > +     return per_cpu(freq_data, cpu)->cur_cpu_freq;
> > +}
> > +
> > +static int loongson3_cpufreq_set(struct cpufreq_policy *policy, int freq_level)
> > +{
> > +     union smc_message msg;
> > +
> > +     msg.id          = cpu_data[policy->cpu].core;
> > +     msg.info        = FREQ_INFO_TYPE_LEVEL;
> > +     msg.val         = freq_level;
> > +     msg.cmd         = CMD_SET_FREQ_INFO;
> > +     msg.extra       = 0;
> > +     msg.complete    = 0;
> > +     do_service_request(&msg);
> > +
> > +     return 0;
> > +}
> > +
> > +/*
> > + * Here we notify other drivers of the proposed change and the final change.
> > + */
> > +static int loongson3_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
> > +{
> > +     unsigned int cpu = policy->cpu;
> > +     unsigned int package = cpu_data[cpu].package;
> > +
> > +     if (!cpu_online(cpu))
>
> No need to check this.
OK, thanks.

>
> > +             return -ENODEV;
> > +
> > +     /* setting the cpu frequency */
> > +     mutex_lock(&cpufreq_mutex[package]);
>
> No locking required here. Core doesn't call them in parallel.
I'm a bit confused, I think different cores may call .target() in
parallel. Cores in the same package share the same
LOONGARCH_IOCSR_SMCMBX register, so I think the lock is required.

>
> > +     loongson3_cpufreq_set(policy, index);
> > +     mutex_unlock(&cpufreq_mutex[package]);
> > +
> > +     return 0;
> > +}
> > +
> > +static int loongson3_cpufreq_get_freq_table(int cpu)
> > +{
> > +     union smc_message msg;
> > +     int i, ret, boost_level, max_level, freq_level;
> > +     struct loongson3_freq_data *data;
> > +
> > +     if (per_cpu(freq_data, cpu))
> > +             return 0;
>
> Will this ever be true ?
Yes, loongson3_cpufreq_get_freq_table() is called multiple times while
CPU hotplug.

>
> > +
> > +     msg.id          = cpu;
> > +     msg.cmd         = CMD_GET_FREQ_LEVEL_NUM;
> > +     msg.extra       = 0;
> > +     msg.complete    = 0;
> > +     ret = do_service_request(&msg);
> > +     if (ret < 0)
> > +             return ret;
> > +     max_level = msg.val;
> > +
>
>
> > +     msg.id          = cpu;
> > +     msg.cmd         = CMD_GET_FREQ_BOOST_LEVEL;
> > +     msg.extra       = 0;
> > +     msg.complete    = 0;
> > +     ret = do_service_request(&msg);
> > +     if (ret < 0)
> > +             return ret;
> > +     boost_level = msg.val;
>
> This stuff is repeated a lot, maybe create a generic function for this
> ?
Do you means move the msg filling into do_service_request()?

>
> > +
> > +     freq_level = min(max_level, FREQ_MAX_LEVEL);
> > +     data = kzalloc(struct_size(data, table, freq_level + 1), GFP_KERNEL);
>
> devm_kzalloc(pdev, ...) ?
OK, that seems better.

>
> > +     if (!data)
> > +             return -ENOMEM;
> > +
> > +     for (i = 0; i < freq_level; i++) {
> > +             msg.id          = cpu;
> > +             msg.info        = FREQ_INFO_TYPE_FREQ;
> > +             msg.cmd         = CMD_GET_FREQ_LEVEL_INFO;
> > +             msg.val         = i;
> > +             msg.complete    = 0;
> > +
> > +             ret = do_service_request(&msg);
> > +             if (ret < 0) {
> > +                     kfree(data);
> > +                     return ret;
> > +             }
> > +
> > +             data->table[i].frequency = msg.val * KILO;
> > +             data->table[i].driver_data = FREQ_LEV0 + i;
> > +             data->table[i].flags = (i >= boost_level) ? CPUFREQ_BOOST_FREQ : 0;
> > +     }
> > +
> > +     data->table[freq_level].frequency = CPUFREQ_TABLE_END;
> > +     data->table[freq_level].driver_data = FREQ_RESV;
> > +     data->table[freq_level].flags = 0;
> > +
> > +     per_cpu(freq_data, cpu) = data;
> > +
> > +     return 0;
> > +}
> > +
> > +static int loongson3_cpufreq_cpu_init(struct cpufreq_policy *policy)
> > +{
> > +     int ret;
> > +
> > +     if (!cpu_online(policy->cpu))
>
> No need to check this. Core takes care of this already.
OK, thanks.

>
> > +             return -ENODEV;
> > +
> > +     ret = loongson3_cpufreq_get_freq_table(policy->cpu);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     policy->cur = loongson3_cpufreq_get(policy->cpu);
> > +     policy->cpuinfo.transition_latency = 10000;
> > +     policy->freq_table = per_cpu(freq_data, policy->cpu)->table;
> > +     cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));
> > +
> > +     if (policy_has_boost_freq(policy)) {
> > +             ret = cpufreq_enable_boost_support();
> > +             if (ret < 0) {
> > +                     pr_warn("cpufreq: Failed to enable boost: %d\n", ret);
> > +                     return ret;
> > +             }
> > +             loongson3_cpufreq_driver.boost_enabled = true;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int loongson3_cpufreq_cpu_exit(struct cpufreq_policy *policy)
> > +{
> > +     return 0;
> > +}
>
> Just drop the routine, it is optional.
OK, thanks.

>
> > +
> > +static struct cpufreq_driver loongson3_cpufreq_driver = {
> > +     .name = "loongson3",
> > +     .flags = CPUFREQ_CONST_LOOPS,
> > +     .init = loongson3_cpufreq_cpu_init,
> > +     .exit = loongson3_cpufreq_cpu_exit,
> > +     .verify = cpufreq_generic_frequency_table_verify,
> > +     .target_index = loongson3_cpufreq_target,
> > +     .get = loongson3_cpufreq_get,
> > +     .attr = cpufreq_generic_attr,
> > +};
> > +
> > +static struct platform_device_id cpufreq_id_table[] = {
> > +     { "loongson3_cpufreq", },
> > +     { /* sentinel */ }
> > +};
> > +
>
> Remove this blank line please.
OK, thanks.

>
> > +MODULE_DEVICE_TABLE(platform, cpufreq_id_table);
> > +
> > +static struct platform_driver loongson3_platform_driver = {
> > +     .driver = {
> > +             .name = "loongson3_cpufreq",
> > +     },
> > +     .id_table = cpufreq_id_table,
> > +};
> > +
> > +static int configure_cpufreq_info(void)
> > +{
> > +     int ret;
> > +     union smc_message msg;
> > +
> > +     msg.cmd         = CMD_GET_VERSION;
> > +     msg.extra       = 0;
> > +     msg.complete    = 0;
> > +     ret = do_service_request(&msg);
> > +     if (ret < 0 || msg.val < 0x1)
> > +             return -EPERM;
> > +
> > +     msg.id          = FEATURE_DVFS;
> > +     msg.cmd         = CMD_SET_FEATURE;
> > +     msg.val         = FEATURE_DVFS_ENABLE | FEATURE_DVFS_BOOST;
> > +     msg.extra       = 0;
> > +     msg.complete    = 0;
> > +     ret = do_service_request(&msg);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     return 0;
> > +}
> > +
> > +static int __init cpufreq_init(void)
> > +{
> > +     int i, ret;
> > +
> > +     ret = platform_driver_register(&loongson3_platform_driver);
> > +     if (ret)
> > +             return ret;
>
> What is the use of this platform driver ? I thought the whole purpose
> of the platform device/driver in your case was to probe this driver.
> In that case cpufreq_init() should only be doing above and not the
> below part. The rest should be handled in the probe() function of the
> driver.
This driver file is now a very basic version, in future it will be a
little like intel_pstate that has more than one cpufreq_drivers
(active/passive, hwp/nohwp, etc.), so it will register different
cpufreq_drivers depends on the result of configure_cpufreq_info().

>
> > +
> > +     ret = configure_cpufreq_info();
> > +     if (ret)
> > +             goto err;
> > +
> > +     for (i = 0; i < MAX_PACKAGES; i++)
> > +             mutex_init(&cpufreq_mutex[i]);
>
> You don't need this at all.
See above.

>
> > +
> > +     ret = cpufreq_register_driver(&loongson3_cpufreq_driver);
> > +     if (ret)
> > +             goto err;
> > +
> > +     pr_info("cpufreq: Loongson-3 CPU frequency driver.\n");
>
> Make this pr_debug if you want.. There is not much use of this for the
> user.
Emm, I just want to see a line in dmesg.


>
> > +
> > +     return 0;
> > +
> > +err:
> > +     platform_driver_unregister(&loongson3_platform_driver);
> > +     return ret;
> > +}
> > +
> > +static void __exit cpufreq_exit(void)
> > +{
> > +     cpufreq_unregister_driver(&loongson3_cpufreq_driver);
> > +     platform_driver_unregister(&loongson3_platform_driver);
> > +}
> > +
> > +module_init(cpufreq_init);
> > +module_exit(cpufreq_exit);
>
> You can just use: module_platform_driver() instead of above functions
> and declarations.
>
> > +
> > +MODULE_AUTHOR("Huacai Chen <chenhuacai@loongson.cn>");
> > +MODULE_DESCRIPTION("CPUFreq driver for Loongson-3 processors");
> > +MODULE_LICENSE("GPL");
>
> --
> viresh
>

Re: [PATCH 2/2] cpufreq: Add Loongson-3 CPUFreq driver support

[Viresh Kumar]

On 26-06-24, 11:51, Huacai Chen wrote:
> On Tue, Jun 25, 2024 at 3:56 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > On 12-06-24, 14:42, Huacai Chen wrote:
> > > +struct loongson3_freq_data {
> > > +     unsigned int cur_cpu_freq;
> >
> > You never use it. Remove it.
> Emm, it is used in loongson3_cpufreq_get().

Yeah, you are just filling it there and reading immediately after
that, which can be done directly too. But you don't use it anywhere
else.

> > > +static int loongson3_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
> > > +{
> > > +     unsigned int cpu = policy->cpu;
> > > +     unsigned int package = cpu_data[cpu].package;
> > > +
> > > +     if (!cpu_online(cpu))
> > > +             return -ENODEV;
> > > +
> > > +     /* setting the cpu frequency */
> > > +     mutex_lock(&cpufreq_mutex[package]);
> >
> > No locking required here. Core doesn't call them in parallel.

s/Core/CPUFreq core/

> I'm a bit confused, I think different cores may call .target() in
> parallel.

Not for same policy, but for different yes.

> Cores in the same package share the same
> LOONGARCH_IOCSR_SMCMBX register, so I think the lock is required.

If that is the access you are protecting, then you better move the
lock to do_service_request() instead, which gets called from other
places too.

What exactly is a package here though ? A group of CPUs doing DVFS
together ? Governed by the same policy structure ? In that case, you
don't need a lock as the cpufreq core guarantees to not call multiple
target_index() routines in parallel for the same policy.

> > > +     msg.id          = cpu;
> > > +     msg.cmd         = CMD_GET_FREQ_LEVEL_NUM;
> > > +     msg.extra       = 0;
> > > +     msg.complete    = 0;
> > > +     ret = do_service_request(&msg);
> > > +     if (ret < 0)
> > > +             return ret;
> > > +     max_level = msg.val;
> > > +
> >
> >
> > > +     msg.id          = cpu;
> > > +     msg.cmd         = CMD_GET_FREQ_BOOST_LEVEL;
> > > +     msg.extra       = 0;
> > > +     msg.complete    = 0;
> > > +     ret = do_service_request(&msg);
> > > +     if (ret < 0)
> > > +             return ret;
> > > +     boost_level = msg.val;
> >
> > This stuff is repeated a lot, maybe create a generic function for this
> > ?
> Do you means move the msg filling into do_service_request()?

Yeah, the filling of the msg structure, the call to
do_service_request() and returning msg.val.

> > > +static int __init cpufreq_init(void)
> > > +{
> > > +     int i, ret;
> > > +
> > > +     ret = platform_driver_register(&loongson3_platform_driver);
> > > +     if (ret)
> > > +             return ret;
> >
> > What is the use of this platform driver ? I thought the whole purpose
> > of the platform device/driver in your case was to probe this driver.
> > In that case cpufreq_init() should only be doing above and not the
> > below part. The rest should be handled in the probe() function of the
> > driver.
> This driver file is now a very basic version, in future it will be a
> little like intel_pstate that has more than one cpufreq_drivers
> (active/passive, hwp/nohwp, etc.), so it will register different
> cpufreq_drivers depends on the result of configure_cpufreq_info().

At this moment we can only review the current version on its merit.
For the current version, the way things are done is simply wrong. We
can review later once you have more things to add to this. So simplify
it to the best of our understanding for now and make as many changes
later as you need.

> > > +     ret = cpufreq_register_driver(&loongson3_cpufreq_driver);
> > > +     if (ret)
> > > +             goto err;
> > > +
> > > +     pr_info("cpufreq: Loongson-3 CPU frequency driver.\n");
> >
> > Make this pr_debug if you want.. There is not much use of this for the
> > user.
> Emm, I just want to see a line in dmesg.

Yeah, a debug message is what you need then. We don't want to print
too much unnecessarily on the console, unless there is an error.

-- 
viresh

Re: [PATCH 2/2] cpufreq: Add Loongson-3 CPUFreq driver support

[Huacai Chen]

On Wed, Jun 26, 2024 at 12:34 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 26-06-24, 11:51, Huacai Chen wrote:
> > On Tue, Jun 25, 2024 at 3:56 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > > On 12-06-24, 14:42, Huacai Chen wrote:
> > > > +struct loongson3_freq_data {
> > > > +     unsigned int cur_cpu_freq;
> > >
> > > You never use it. Remove it.
> > Emm, it is used in loongson3_cpufreq_get().
>
> Yeah, you are just filling it there and reading immediately after
> that, which can be done directly too. But you don't use it anywhere
> else.
OK, I will remove this field.

>
> > > > +static int loongson3_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
> > > > +{
> > > > +     unsigned int cpu = policy->cpu;
> > > > +     unsigned int package = cpu_data[cpu].package;
> > > > +
> > > > +     if (!cpu_online(cpu))
> > > > +             return -ENODEV;
> > > > +
> > > > +     /* setting the cpu frequency */
> > > > +     mutex_lock(&cpufreq_mutex[package]);
> > >
> > > No locking required here. Core doesn't call them in parallel.
>
> s/Core/CPUFreq core/
>
> > I'm a bit confused, I think different cores may call .target() in
> > parallel.
>
> Not for same policy, but for different yes.
>
> > Cores in the same package share the same
> > LOONGARCH_IOCSR_SMCMBX register, so I think the lock is required.
>
> If that is the access you are protecting, then you better move the
> lock to do_service_request() instead, which gets called from other
> places too.
>
> What exactly is a package here though ? A group of CPUs doing DVFS
> together ? Governed by the same policy structure ? In that case, you
> don't need a lock as the cpufreq core guarantees to not call multiple
> target_index() routines in parallel for the same policy.
A package here is a group of CPUs sharing the same control register,
not a group sharing the same policy. And yes, it is better to move the
lock to do_service_request().


>
> > > > +     msg.id          = cpu;
> > > > +     msg.cmd         = CMD_GET_FREQ_LEVEL_NUM;
> > > > +     msg.extra       = 0;
> > > > +     msg.complete    = 0;
> > > > +     ret = do_service_request(&msg);
> > > > +     if (ret < 0)
> > > > +             return ret;
> > > > +     max_level = msg.val;
> > > > +
> > >
> > >
> > > > +     msg.id          = cpu;
> > > > +     msg.cmd         = CMD_GET_FREQ_BOOST_LEVEL;
> > > > +     msg.extra       = 0;
> > > > +     msg.complete    = 0;
> > > > +     ret = do_service_request(&msg);
> > > > +     if (ret < 0)
> > > > +             return ret;
> > > > +     boost_level = msg.val;
> > >
> > > This stuff is repeated a lot, maybe create a generic function for this
> > > ?
> > Do you means move the msg filling into do_service_request()?
>
> Yeah, the filling of the msg structure, the call to
> do_service_request() and returning msg.val.
OK, I will do in the next version.

>
> > > > +static int __init cpufreq_init(void)
> > > > +{
> > > > +     int i, ret;
> > > > +
> > > > +     ret = platform_driver_register(&loongson3_platform_driver);
> > > > +     if (ret)
> > > > +             return ret;
> > >
> > > What is the use of this platform driver ? I thought the whole purpose
> > > of the platform device/driver in your case was to probe this driver.
> > > In that case cpufreq_init() should only be doing above and not the
> > > below part. The rest should be handled in the probe() function of the
> > > driver.
> > This driver file is now a very basic version, in future it will be a
> > little like intel_pstate that has more than one cpufreq_drivers
> > (active/passive, hwp/nohwp, etc.), so it will register different
> > cpufreq_drivers depends on the result of configure_cpufreq_info().
>
> At this moment we can only review the current version on its merit.
> For the current version, the way things are done is simply wrong. We
> can review later once you have more things to add to this. So simplify
> it to the best of our understanding for now and make as many changes
> later as you need.
OK, I will accept your suggestion.

>
> > > > +     ret = cpufreq_register_driver(&loongson3_cpufreq_driver);
> > > > +     if (ret)
> > > > +             goto err;
> > > > +
> > > > +     pr_info("cpufreq: Loongson-3 CPU frequency driver.\n");
> > >
> > > Make this pr_debug if you want.. There is not much use of this for the
> > > user.
> > Emm, I just want to see a line in dmesg.
>
> Yeah, a debug message is what you need then. We don't want to print
> too much unnecessarily on the console, unless there is an error.
Emm, the initialization print isn't very noisy, I will keep this line.
But all other issues will be addressed.

Huacai
>
> --
> viresh
>

Re: [PATCH 0/2] LoongArch: Add Loongson-3 CPUFreq driver support

[Xi Ruoyao]

On Wed, 2024-06-12 at 14:42 +0800, Huacai Chen wrote:
> This series add architectural preparation and CPUFreq driver for
> Loongson-3 (based on LoongArch).
> 
> Some of LoongArch processors support DVFS, their IOCSR.FEATURES has
> IOCSRF_FREQSCALE set. And they has a micro-core in the package called
> SMC (System Management Controller) to scale frequency, voltage, etc.
> 
> Huacai Chen(2):
>  LoongArch: Add architectural preparation for CPUFreq.
>  cpufreq: Add Loongson-3 CPUFreq driver support.
> 
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

A question: is it OK to enable cpufreq when overclocking is set via the
firmware?

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University

Re: [PATCH 0/2] LoongArch: Add Loongson-3 CPUFreq driver support

[Huacai Chen]

On Mon, Jun 24, 2024 at 9:30 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> On Wed, 2024-06-12 at 14:42 +0800, Huacai Chen wrote:
> > This series add architectural preparation and CPUFreq driver for
> > Loongson-3 (based on LoongArch).
> >
> > Some of LoongArch processors support DVFS, their IOCSR.FEATURES has
> > IOCSRF_FREQSCALE set. And they has a micro-core in the package called
> > SMC (System Management Controller) to scale frequency, voltage, etc.
> >
> > Huacai Chen(2):
> >  LoongArch: Add architectural preparation for CPUFreq.
> >  cpufreq: Add Loongson-3 CPUFreq driver support.
> >
> > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
>
> A question: is it OK to enable cpufreq when overclocking is set via the
> firmware?
Yes, it's OK.

>
> --
> Xi Ruoyao <xry111@xry111.site>
> School of Aerospace Science and Technology, Xidian University
>