* [PATCH 6/6] cpufreq: Loongson1: Add cpufreq driver for Loongson1B
@ 2014-10-10 3:43 Kelvin Cheung
2014-10-10 4:40 ` Viresh Kumar
0 siblings, 1 reply; 3+ messages in thread
From: Kelvin Cheung @ 2014-10-10 3:43 UTC (permalink / raw)
To: linux-pm, linux-kernel; +Cc: rjw, viresh.kumar, linux-mips, ralf, Kelvin Cheung
Signed-off-by: Kelvin Cheung <keguang.zhang@gmail.com>
---
drivers/cpufreq/Kconfig | 10 ++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/ls1x-cpufreq.c | 217 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 228 insertions(+)
create mode 100644 drivers/cpufreq/ls1x-cpufreq.c
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index ffe350f..99464d7 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -250,6 +250,16 @@ config LOONGSON2_CPUFREQ
If in doubt, say N.
+config LOONGSON1_CPUFREQ
+ tristate "Loongson1 CPUFreq Driver"
+ help
+ This option adds a CPUFreq driver for loongson1 processors which
+ support software configurable cpu frequency.
+
+ For details, take a look at <file:Documentation/cpu-freq/>.
+
+ If in doubt, say N.
+
endmenu
menu "PowerPC CPU frequency scaling drivers"
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index db6d9a2..aca7bd3 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -98,6 +98,7 @@ obj-$(CONFIG_CRIS_MACH_ARTPEC3) += cris-artpec3-cpufreq.o
obj-$(CONFIG_ETRAXFS) += cris-etraxfs-cpufreq.o
obj-$(CONFIG_IA64_ACPI_CPUFREQ) += ia64-acpi-cpufreq.o
obj-$(CONFIG_LOONGSON2_CPUFREQ) += loongson2_cpufreq.o
+obj-$(CONFIG_LOONGSON1_CPUFREQ) += ls1x-cpufreq.o
obj-$(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/ls1x-cpufreq.c b/drivers/cpufreq/ls1x-cpufreq.c
new file mode 100644
index 0000000..3d9a410
--- /dev/null
+++ b/drivers/cpufreq/ls1x-cpufreq.c
@@ -0,0 +1,217 @@
+/*
+ * CPU Frequency Scaling for Loongson 1 SoC
+ *
+ * Copyright (C) 2014 Zhang, Keguang <keguang.zhang@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <cpufreq.h>
+#include <loongson1.h>
+
+static struct {
+ struct clk *clk; /* CPU clk */
+ struct clk *mux_clk; /* MUX of CPU clk */
+ struct clk *pll_clk; /* PLL clk */
+ struct clk *osc_clk; /* OSC clk */
+ unsigned int max_freq;
+ unsigned int min_freq;
+ struct cpufreq_frequency_table *freq_tbl;
+} ls1x_cpufreq;
+
+static int ls1x_cpufreq_notifier(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ if (val == CPUFREQ_POSTCHANGE)
+ current_cpu_data.udelay_val = loops_per_jiffy;
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block ls1x_cpufreq_notifier_block = {
+ .notifier_call = ls1x_cpufreq_notifier
+};
+
+static int ls1x_cpufreq_target(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ struct device *dev = get_cpu_device(policy->cpu);
+ unsigned int old_freq, new_freq;
+
+ old_freq = policy->cur;
+ new_freq = ls1x_cpufreq.freq_tbl[index].frequency;
+
+ /*
+ * The procedure of reconfiguring CPU clk is as below.
+ *
+ * - Reparent CPU clk to OSC clk
+ * - Reset CPU clock (very important)
+ * - Reconfigure CPU DIV
+ * - Reparent CPU clk back to CPU DIV clk
+ */
+
+ dev_dbg(dev, "%u KHz --> %u KHz\n", old_freq, new_freq);
+ clk_set_parent(policy->clk, ls1x_cpufreq.osc_clk);
+ __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) | RST_CPU_EN | RST_CPU,
+ LS1X_CLK_PLL_DIV);
+ __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN | RST_CPU),
+ LS1X_CLK_PLL_DIV);
+ clk_set_rate(ls1x_cpufreq.mux_clk, new_freq * 1000);
+ clk_set_parent(policy->clk, ls1x_cpufreq.mux_clk);
+
+ return 0;
+}
+
+static int ls1x_cpufreq_init(struct cpufreq_policy *policy)
+{
+ struct device *dev = get_cpu_device(policy->cpu);
+ struct cpufreq_frequency_table *freq_tbl;
+ unsigned int pll_freq, freq;
+ int steps, i;
+
+ pll_freq = clk_get_rate(ls1x_cpufreq.pll_clk) / 1000;
+
+ steps = 1 << DIV_CPU_WIDTH;
+ freq_tbl = kzalloc(sizeof(*freq_tbl) * steps, GFP_KERNEL);
+ if (!freq_tbl) {
+ dev_err(dev, "failed to alloc cpufreq_frequency_table\n");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < (steps - 1); i++) {
+ freq = pll_freq / (i + 1);
+ if ((freq < ls1x_cpufreq.min_freq) ||
+ (freq > ls1x_cpufreq.max_freq))
+ freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID;
+ else
+ freq_tbl[i].frequency = freq;
+ dev_dbg(dev, "cpufreq table: index %d: frequency %d\n", i,
+ freq_tbl[i].frequency);
+ }
+ freq_tbl[i].frequency = CPUFREQ_TABLE_END;
+ ls1x_cpufreq.freq_tbl = freq_tbl;
+
+ policy->clk = ls1x_cpufreq.clk;
+ return cpufreq_generic_init(policy, ls1x_cpufreq.freq_tbl, 0);
+}
+
+static struct cpufreq_driver ls1x_cpufreq_driver = {
+ .name = "cpufreq-ls1x",
+ .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = ls1x_cpufreq_target,
+ .get = cpufreq_generic_get,
+ .init = ls1x_cpufreq_init,
+ .attr = cpufreq_generic_attr,
+};
+
+static int ls1x_cpufreq_remove(struct platform_device *pdev)
+{
+ cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ cpufreq_unregister_driver(&ls1x_cpufreq_driver);
+ clk_put(ls1x_cpufreq.osc_clk);
+ clk_put(ls1x_cpufreq.clk);
+
+ return 0;
+}
+
+static int ls1x_cpufreq_probe(struct platform_device *pdev)
+{
+ struct plat_ls1x_cpufreq *pdata = pdev->dev.platform_data;
+ struct clk *clk;
+ int ret;
+
+ if (!pdata && !pdata->clk_name && !pdata->osc_clk_name) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ clk = clk_get(NULL, pdata->clk_name);
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "unable to get %s clock\n",
+ pdata->clk_name);
+ ret = PTR_ERR(clk);
+ goto out;
+ }
+ ls1x_cpufreq.clk = clk;
+
+ clk = clk_get_parent(clk);
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "unable to get parent of %s clock\n",
+ __clk_get_name(ls1x_cpufreq.clk));
+ ret = PTR_ERR(clk);
+ goto err_mux;
+ }
+ ls1x_cpufreq.mux_clk = clk;
+
+ clk = clk_get_parent(clk);
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "unable to get parent of %s clock\n",
+ __clk_get_name(ls1x_cpufreq.mux_clk));
+ ret = PTR_ERR(clk);
+ goto err_mux;
+ }
+ ls1x_cpufreq.pll_clk = clk;
+
+ clk = clk_get(NULL, pdata->osc_clk_name);
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "unable to get %s clock\n",
+ pdata->osc_clk_name);
+ ret = PTR_ERR(clk);
+ goto err_mux;
+ }
+ ls1x_cpufreq.osc_clk = clk;
+
+ ls1x_cpufreq.max_freq = pdata->max_freq;
+ ls1x_cpufreq.min_freq = pdata->min_freq;
+
+ ret = cpufreq_register_driver(&ls1x_cpufreq_driver);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register cpufreq driver: %d\n",
+ ret);
+ goto err_driver;
+ }
+
+ ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+
+ if (!ret)
+ goto out;
+
+ dev_err(&pdev->dev, "failed to register cpufreq notifier: %d\n", ret);
+
+ cpufreq_unregister_driver(&ls1x_cpufreq_driver);
+err_driver:
+ clk_put(ls1x_cpufreq.osc_clk);
+err_mux:
+ clk_put(ls1x_cpufreq.clk);
+out:
+ return ret;
+}
+
+static struct platform_driver ls1x_cpufreq_platdrv = {
+ .driver = {
+ .name = "ls1x-cpufreq",
+ .owner = THIS_MODULE,
+ },
+ .probe = ls1x_cpufreq_probe,
+ .remove = ls1x_cpufreq_remove,
+};
+
+module_platform_driver(ls1x_cpufreq_platdrv);
+
+MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
+MODULE_DESCRIPTION("Loongson 1 CPUFreq driver");
+MODULE_LICENSE("GPL");
--
1.9.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 6/6] cpufreq: Loongson1: Add cpufreq driver for Loongson1B
2014-10-10 3:43 [PATCH 6/6] cpufreq: Loongson1: Add cpufreq driver for Loongson1B Kelvin Cheung
@ 2014-10-10 4:40 ` Viresh Kumar
0 siblings, 0 replies; 3+ messages in thread
From: Viresh Kumar @ 2014-10-10 4:40 UTC (permalink / raw)
To: Kelvin Cheung, Mike Turquette
Cc: linux-pm, Linux Kernel Mailing List, Rafael J. Wysocki,
linux-mips, Ralf Baechle
On 10 October 2014 09:13, Kelvin Cheung <keguang.zhang@gmail.com> wrote:
Why should we apply this patch and what is it all about ?
That's what this field is used for, please don't leave it empty.
> Signed-off-by: Kelvin Cheung <keguang.zhang@gmail.com>
> ---
> drivers/cpufreq/Kconfig | 10 ++
> drivers/cpufreq/Makefile | 1 +
> drivers/cpufreq/ls1x-cpufreq.c | 217 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 228 insertions(+)
> create mode 100644 drivers/cpufreq/ls1x-cpufreq.c
>
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index ffe350f..99464d7 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -250,6 +250,16 @@ config LOONGSON2_CPUFREQ
>
> If in doubt, say N.
>
> +config LOONGSON1_CPUFREQ
> + tristate "Loongson1 CPUFreq Driver"
> + help
> + This option adds a CPUFreq driver for loongson1 processors which
> + support software configurable cpu frequency.
> +
> + For details, take a look at <file:Documentation/cpu-freq/>.
> +
> + If in doubt, say N.
> +
> endmenu
>
> menu "PowerPC CPU frequency scaling drivers"
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index db6d9a2..aca7bd3 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -98,6 +98,7 @@ obj-$(CONFIG_CRIS_MACH_ARTPEC3) += cris-artpec3-cpufreq.o
> obj-$(CONFIG_ETRAXFS) += cris-etraxfs-cpufreq.o
> obj-$(CONFIG_IA64_ACPI_CPUFREQ) += ia64-acpi-cpufreq.o
> obj-$(CONFIG_LOONGSON2_CPUFREQ) += loongson2_cpufreq.o
> +obj-$(CONFIG_LOONGSON1_CPUFREQ) += ls1x-cpufreq.o
Why don't name it like loongson1 to maintain consistency ?
> obj-$(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/ls1x-cpufreq.c b/drivers/cpufreq/ls1x-cpufreq.c
> new file mode 100644
> index 0000000..3d9a410
> --- /dev/null
> +++ b/drivers/cpufreq/ls1x-cpufreq.c
> @@ -0,0 +1,217 @@
> +/*
> + * CPU Frequency Scaling for Loongson 1 SoC
> + *
> + * Copyright (C) 2014 Zhang, Keguang <keguang.zhang@gmail.com>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/cpu.h>
> +#include <linux/cpufreq.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include <cpufreq.h>
> +#include <loongson1.h>
Okay, it looks like I have forgotten some of the C basics :)
But wouldn't the above two lines search for this file in <include/*>, unless
you have compiled it with something like -I include/linux ??
And even then I don't think loongson1.h is present there ..
What am I missing ?
> +
> +static struct {
> + struct clk *clk; /* CPU clk */
> + struct clk *mux_clk; /* MUX of CPU clk */
> + struct clk *pll_clk; /* PLL clk */
> + struct clk *osc_clk; /* OSC clk */
> + unsigned int max_freq;
> + unsigned int min_freq;
> + struct cpufreq_frequency_table *freq_tbl;
> +} ls1x_cpufreq;
> +
> +static int ls1x_cpufreq_notifier(struct notifier_block *nb,
> + unsigned long val, void *data)
> +{
> + if (val == CPUFREQ_POSTCHANGE)
> + current_cpu_data.udelay_val = loops_per_jiffy;
> +
> + return NOTIFY_OK;
> +}
Why don't you do this at a single place in mips core instead of every
mips cpufreq driver ?
> +static struct notifier_block ls1x_cpufreq_notifier_block = {
> + .notifier_call = ls1x_cpufreq_notifier
> +};
> +
> +static int ls1x_cpufreq_target(struct cpufreq_policy *policy,
> + unsigned int index)
> +{
> + struct device *dev = get_cpu_device(policy->cpu);
Why don't you just save this pointer initially ? And actually
instead of this you should use pdev->dev for all this prints.
This 'dev' is for CPU0 not for driver.
> + unsigned int old_freq, new_freq;
> +
> + old_freq = policy->cur;
> + new_freq = ls1x_cpufreq.freq_tbl[index].frequency;
> +
> + /*
> + * The procedure of reconfiguring CPU clk is as below.
> + *
> + * - Reparent CPU clk to OSC clk
> + * - Reset CPU clock (very important)
> + * - Reconfigure CPU DIV
> + * - Reparent CPU clk back to CPU DIV clk
> + */
> +
> + dev_dbg(dev, "%u KHz --> %u KHz\n", old_freq, new_freq);
> + clk_set_parent(policy->clk, ls1x_cpufreq.osc_clk);
> + __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) | RST_CPU_EN | RST_CPU,
> + LS1X_CLK_PLL_DIV);
> + __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN | RST_CPU),
> + LS1X_CLK_PLL_DIV);
> + clk_set_rate(ls1x_cpufreq.mux_clk, new_freq * 1000);
> + clk_set_parent(policy->clk, ls1x_cpufreq.mux_clk);
> +
> + return 0;
> +}
> +
> +static int ls1x_cpufreq_init(struct cpufreq_policy *policy)
> +{
> + struct device *dev = get_cpu_device(policy->cpu);
> + struct cpufreq_frequency_table *freq_tbl;
> + unsigned int pll_freq, freq;
> + int steps, i;
> +
> + pll_freq = clk_get_rate(ls1x_cpufreq.pll_clk) / 1000;
> +
> + steps = 1 << DIV_CPU_WIDTH;
> + freq_tbl = kzalloc(sizeof(*freq_tbl) * steps, GFP_KERNEL);
You never free it, right ? Even on module-removal. Also, why don't allocate
it once at probe time only ?
> + if (!freq_tbl) {
> + dev_err(dev, "failed to alloc cpufreq_frequency_table\n");
> + return -ENOMEM;
> + }
> +
> + for (i = 0; i < (steps - 1); i++) {
> + freq = pll_freq / (i + 1);
> + if ((freq < ls1x_cpufreq.min_freq) ||
> + (freq > ls1x_cpufreq.max_freq))
> + freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID;
> + else
> + freq_tbl[i].frequency = freq;
> + dev_dbg(dev, "cpufreq table: index %d: frequency %d\n", i,
> + freq_tbl[i].frequency);
> + }
> + freq_tbl[i].frequency = CPUFREQ_TABLE_END;
> + ls1x_cpufreq.freq_tbl = freq_tbl;
> +
> + policy->clk = ls1x_cpufreq.clk;
> + return cpufreq_generic_init(policy, ls1x_cpufreq.freq_tbl, 0);
> +}
> +
> +static struct cpufreq_driver ls1x_cpufreq_driver = {
> + .name = "cpufreq-ls1x",
> + .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
> + .verify = cpufreq_generic_frequency_table_verify,
> + .target_index = ls1x_cpufreq_target,
> + .get = cpufreq_generic_get,
> + .init = ls1x_cpufreq_init,
> + .attr = cpufreq_generic_attr,
> +};
> +
> +static int ls1x_cpufreq_remove(struct platform_device *pdev)
> +{
> + cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block,
> + CPUFREQ_TRANSITION_NOTIFIER);
> + cpufreq_unregister_driver(&ls1x_cpufreq_driver);
> + clk_put(ls1x_cpufreq.osc_clk);
> + clk_put(ls1x_cpufreq.clk);
> +
> + return 0;
> +}
> +
> +static int ls1x_cpufreq_probe(struct platform_device *pdev)
> +{
> + struct plat_ls1x_cpufreq *pdata = pdev->dev.platform_data;
> + struct clk *clk;
> + int ret;
> +
Try this code here:
pdata = NULL;
> + if (!pdata && !pdata->clk_name && !pdata->osc_clk_name) {
And tell me what happens here then. :)
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + clk = clk_get(NULL, pdata->clk_name);
To make life simple, why not use devm_clk_get() here and at other places ?
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "unable to get %s clock\n",
> + pdata->clk_name);
> + ret = PTR_ERR(clk);
> + goto out;
> + }
> + ls1x_cpufreq.clk = clk;
> +
> + clk = clk_get_parent(clk);
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "unable to get parent of %s clock\n",
> + __clk_get_name(ls1x_cpufreq.clk));
@Mike: Is it fine to include clk-provider for this?
> + ret = PTR_ERR(clk);
> + goto err_mux;
> + }
> + ls1x_cpufreq.mux_clk = clk;
> +
> + clk = clk_get_parent(clk);
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "unable to get parent of %s clock\n",
> + __clk_get_name(ls1x_cpufreq.mux_clk));
> + ret = PTR_ERR(clk);
> + goto err_mux;
> + }
> + ls1x_cpufreq.pll_clk = clk;
> +
> + clk = clk_get(NULL, pdata->osc_clk_name);
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "unable to get %s clock\n",
> + pdata->osc_clk_name);
> + ret = PTR_ERR(clk);
> + goto err_mux;
> + }
> + ls1x_cpufreq.osc_clk = clk;
> +
> + ls1x_cpufreq.max_freq = pdata->max_freq;
> + ls1x_cpufreq.min_freq = pdata->min_freq;
> +
> + ret = cpufreq_register_driver(&ls1x_cpufreq_driver);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to register cpufreq driver: %d\n",
> + ret);
> + goto err_driver;
> + }
> +
> + ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block,
> + CPUFREQ_TRANSITION_NOTIFIER);
> +
> + if (!ret)
> + goto out;
> +
> + dev_err(&pdev->dev, "failed to register cpufreq notifier: %d\n", ret);
> +
> + cpufreq_unregister_driver(&ls1x_cpufreq_driver);
> +err_driver:
> + clk_put(ls1x_cpufreq.osc_clk);
> +err_mux:
> + clk_put(ls1x_cpufreq.clk);
> +out:
> + return ret;
> +}
> +
> +static struct platform_driver ls1x_cpufreq_platdrv = {
> + .driver = {
> + .name = "ls1x-cpufreq",
> + .owner = THIS_MODULE,
> + },
> + .probe = ls1x_cpufreq_probe,
> + .remove = ls1x_cpufreq_remove,
> +};
> +
> +module_platform_driver(ls1x_cpufreq_platdrv);
> +
> +MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
> +MODULE_DESCRIPTION("Loongson 1 CPUFreq driver");
> +MODULE_LICENSE("GPL");
> --
> 1.9.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 6/6] cpufreq: Loongson1: Add cpufreq driver for Loongson1B
[not found] <CAJhJPsW+h9DEEEKfhBdz3e4tTxmA_ZBR6SbLr2jY6XJY7pMHhA@mail.gmail.com>
@ 2014-10-14 7:22 ` Viresh Kumar
0 siblings, 0 replies; 3+ messages in thread
From: Viresh Kumar @ 2014-10-14 7:22 UTC (permalink / raw)
To: Kelvin Cheung
Cc: Mike Turquette, linux-pm, Linux Kernel Mailing List,
Rafael J. Wysocki, linux-mips, Ralf Baechle
On 14 October 2014 12:29, Kelvin Cheung <keguang.zhang@gmail.com> wrote:
>
> 2014-10-10 12:40 GMT+08:00 Viresh Kumar <viresh.kumar@linaro.org>:
>> > +#include <cpufreq.h>
>> > +#include <loongson1.h>
>>
>> Okay, it looks like I have forgotten some of the C basics :)
>> But wouldn't the above two lines search for this file in <include/*>, unless
>> you have compiled it with something like -I include/linux ??
>> And even then I don't think loongson1.h is present there ..
>>
>> What am I missing ?
>
>
> The two header files are located in arch/mips/include/asm/mach-loongson1
Okay, but I didn't knew it works this way as well. I thought preprocessor will
search in include/ and arch/mips/include/ directories only and so you need to
do this:
#include <asm/mach-loongson1/cpufreq.h>
Do you know why it works directly in your case? Probably for readability above
might be better ?
>> > +static int ls1x_cpufreq_notifier(struct notifier_block *nb,
>> > + unsigned long val, void *data)
>> > +{
>> > + if (val == CPUFREQ_POSTCHANGE)
>> > + current_cpu_data.udelay_val = loops_per_jiffy;
>> > +
>> > + return NOTIFY_OK;
>> > +}
>>
>> Why don't you do this at a single place in mips core instead of every
>> mips cpufreq driver ?
>
>
> Most of MIPS CPUs use performance counter as the system timer, which is built-in to the CPU core. They can't do cpufreq due to lack of external timer. Therefore, the above section is not a common code.
Not sure if I understood your reply Or you understood mine :)
Let me try again to clarify the question. On freq change you need
to update 'current_cpu_data.udelay_val', this is done in both
loongson drivers.
What I was asking you is to register the notifier in some core code,
so that this isn't required to be done in all cpufreq drivers.
NOTE: The notifier routine will only be called if cpufreq is enabled
for the platform..
>> > +static int ls1x_cpufreq_probe(struct platform_device *pdev)
>> > +{
>> > + struct plat_ls1x_cpufreq *pdata = pdev->dev.platform_data;
>> > + struct clk *clk;
>> > + int ret;
>> > +
>>
>> Try this code here:
>>
>> pdata = NULL;
>>
>> > + if (!pdata && !pdata->clk_name && !pdata->osc_clk_name) {
>>
>> And tell me what happens here then. :)
>
>
> I will add an error message here.
Did you try what I asked you to? I wasn't talking about the message..
Though you better add it as well..
What I have asked you will result in kernel crash ..
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-10-14 7:22 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-10-10 3:43 [PATCH 6/6] cpufreq: Loongson1: Add cpufreq driver for Loongson1B Kelvin Cheung
2014-10-10 4:40 ` Viresh Kumar
[not found] <CAJhJPsW+h9DEEEKfhBdz3e4tTxmA_ZBR6SbLr2jY6XJY7pMHhA@mail.gmail.com>
2014-10-14 7:22 ` Viresh Kumar
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