[PATCH 8/9] platform/x86: asus-wmi: add apu_mem setting

["Luke D. Jones" <luke@ljones.dev>]

Exposes the APU memory setting available on a few ASUS models such as
the ROG Ally.

Signed-off-by: Luke D. Jones <luke@ljones.dev>
---
 .../ABI/testing/sysfs-platform-asus-wmi       |   8 ++
 drivers/platform/x86/asus-wmi.c               | 109 ++++++++++++++++++
 include/linux/platform_data/x86/asus-wmi.h    |   3 +
 3 files changed, 120 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-platform-asus-wmi b/Documentation/ABI/testing/sysfs-platform-asus-wmi
index ac881e72e374..d221a3bc1a81 100644
--- a/Documentation/ABI/testing/sysfs-platform-asus-wmi
+++ b/Documentation/ABI/testing/sysfs-platform-asus-wmi
@@ -245,3 +245,11 @@ Description:
 		Show the maximum performance and efficiency core countin format
 		0x[E][P] where [E] is the efficiency core count, and [P] is
 		the perfromance core count.
+
+What:		/sys/devices/platform/<platform>/apu_mem
+Date:		Jun 2024
+KernelVersion:	6.11
+Contact:	"Luke Jones" <luke@ljones.dev>
+Description:
+		Set the maximum available system memory for the APU.
+		  * Min=0, Max=8
diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index f62a36dfcd4b..4b5fbae8c563 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -855,6 +855,112 @@ static DEVICE_ATTR_RW(cores_enabled);
 WMI_SIMPLE_SHOW(cores_max, "0x%x\n", ASUS_WMI_DEVID_CORES_MAX);
 static DEVICE_ATTR_RO(cores_max);
 
+/* Device memory available to APU */
+
+static ssize_t apu_mem_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct asus_wmi *asus = dev_get_drvdata(dev);
+	int err;
+	u32 mem;
+
+	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_APU_MEM, &mem);
+	if (err < 0)
+		return err;
+
+	switch (mem) {
+	case 256:
+		mem = 0;
+		break;
+	case 258:
+		mem = 1;
+		break;
+	case 259:
+		mem = 2;
+		break;
+	case 260:
+		mem = 3;
+		break;
+	case 261:
+		mem = 4;
+		break;
+	case 262:
+		mem = 8;
+		break;
+	case 263:
+		mem = 5;
+		break;
+	case 264:
+		mem = 6;
+		break;
+	case 265:
+		mem = 7;
+		break;
+	default:
+		mem = 4;
+		break;
+	}
+
+	return sysfs_emit(buf, "%d\n", mem);
+}
+
+static ssize_t apu_mem_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	struct asus_wmi *asus = dev_get_drvdata(dev);
+	int result, err;
+	u32 mem;
+
+	result = kstrtou32(buf, 10, &mem);
+	if (result)
+		return result;
+
+	switch (mem) {
+	case 0:
+		mem = 0;
+		break;
+	case 1:
+		mem = 258;
+		break;
+	case 2:
+		mem = 259;
+		break;
+	case 3:
+		mem = 260;
+		break;
+	case 4:
+		mem = 261;
+		break;
+	case 5:
+		mem = 263;
+		break;
+	case 6:
+		mem = 264;
+		break;
+	case 7:
+		mem = 265;
+		break;
+	case 8:
+		mem = 262;
+		break;
+	default:
+		return -EIO;
+	}
+
+	err = asus_wmi_set_devstate(ASUS_WMI_DEVID_APU_MEM, mem, &result);
+	if (err) {
+		pr_warn("Failed to set apu_mem: %d\n", err);
+		return err;
+	}
+
+	pr_info("APU memory changed, reboot required\n");
+	sysfs_notify(&asus->platform_device->dev.kobj, NULL, "apu_mem");
+
+	return count;
+}
+static DEVICE_ATTR_RW(apu_mem);
+
 /* Tablet mode ****************************************************************/
 
 static void asus_wmi_tablet_mode_get_state(struct asus_wmi *asus)
@@ -4100,6 +4206,7 @@ static struct attribute *platform_attributes[] = {
 	&dev_attr_panel_fhd.attr,
 	&dev_attr_cores_enabled.attr,
 	&dev_attr_cores_max.attr,
+	&dev_attr_apu_mem.attr,
 	&dev_attr_mini_led_mode.attr,
 	&dev_attr_available_mini_led_mode.attr,
 	NULL
@@ -4176,6 +4283,8 @@ static umode_t asus_sysfs_is_visible(struct kobject *kobj,
 	else if (attr == &dev_attr_cores_enabled.attr
 		|| attr == &dev_attr_cores_max.attr)
 		ok = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CORES_SET);
+	else if (attr == &dev_attr_apu_mem.attr)
+		ok = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_APU_MEM);
 	else if (attr == &dev_attr_mini_led_mode.attr)
 		ok = asus->mini_led_dev_id != 0;
 	else if (attr == &dev_attr_available_mini_led_mode.attr)
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 5a56e7e97785..efe608861e55 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -121,6 +121,9 @@
  /* Maximum Intel E-core and P-core availability */
 #define ASUS_WMI_DEVID_CORES_MAX	0x001200D3
 
+/* Set the memory available to the APU */
+#define ASUS_WMI_DEVID_APU_MEM		0x000600C1
+
 /* MCU powersave mode */
 #define ASUS_WMI_DEVID_MCU_POWERSAVE   0x001200E2
 
-- 
2.45.1