[PATCH v16 4/9] platform/x86: asus-armoury: add apu-mem control support

Denis Benato
2025-10-30T13:03:36Z

Implement the APU memory size control under the asus-armoury module using
the fw_attributes class.

This allows the APU allocated memory size to be adjusted depending on
the users priority. A reboot is required after change.

Co-developed-by: Denis Benato <denis.benato@linux.dev>
Signed-off-by: Denis Benato <denis.benato@linux.dev>
Signed-off-by: Luke D. Jones <luke@ljones.dev>
---
drivers/platform/x86/asus-armoury.c | 105 ++++++++++++++++++++-
include/linux/platform_data/x86/asus-wmi.h | 2 +
2 files changed, 104 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/asus-armoury.c b/drivers/platform/x86/asus-armoury.c
index 20edf4f5370a..fe80d5d04300 100644
--- a/drivers/platform/x86/asus-armoury.c
+++ b/drivers/platform/x86/asus-armoury.c
@@ -160,11 +160,12 @@ static int armoury_get_devstate(struct kobj_attribute *attr, u32 *retval, u32 de
* armoury_set_devstate() - Set the WMI function state.
* @attr: The kobj_attribute associated to called WMI function.
* @dev_id: The WMI method ID to call.
- * @retval:
- * * Pointer to where to store the value returned from WMI or NULL.
+ * @retval: Where to store the value returned from WMI or NULL.
*
* Intended usage is from sysfs attribute setting associated WMI function.
- * Before calling set the presence of the function should be checked.
+ * Before calling the presence of the function should be checked.
+ *
+ * Every WMI write MUST go through this function to enforce safety checks.
*
* Results !1 is usually considered a fail by ASUS, but some WMI methods
* (like eGPU or CPU cores) do use > 1 to return a status code or similar:
@@ -172,6 +173,7 @@ static int armoury_get_devstate(struct kobj_attribute *attr, u32 *retval, u32 de
* and should perform relevant checks.
*
* Returns:
+ * * %-EINVAL - attempt to set a dangerous or unsupported value.
* * %-EIO - WMI function returned an error.
* * %0 - successful and retval is filled.
* * %other - error from WMI call.
@@ -182,6 +184,26 @@ static int armoury_set_devstate(struct kobj_attribute *attr,
u32 result;
int err;

+ /*
+ * Prevent developers from bricking devices or issuing dangerous
+ * commands that can be difficult or impossible to recover from.
+ */
+ switch (dev_id) {
+ case ASUS_WMI_DEVID_APU_MEM:
+ /*
+ * A hard reset might suffice to save the device,
+ * but there is no value in sending these commands.
+ */
+ if (value == 0x100 || value == 0x101) {
+ pr_err("Refusing to set APU memory to unsafe value: 0x%x\n", value);
+ return -EINVAL;
+ }
+ break;
+ default:
+ /* No known problems are known for this dev_id */
+ break;
+ }
+
err = asus_wmi_set_devstate(dev_id, value, retval ? retval : &result);
if (err) {
if (attr)
@@ -592,6 +614,82 @@ static ssize_t egpu_enable_possible_values_show(struct kobject *kobj, struct kob
}
ASUS_ATTR_GROUP_ENUM(egpu_enable, "egpu_enable", "Enable the eGPU (also disables dGPU)");

+/* Device memory available to APU */
+
+/*
+ * Values map for APU reserved memory (index + 1 number of GB).
+ * Some looks out of order, but are actually correct.
+ */
+static u32 apu_mem_map[] = {
+ [0] = 0x000, /* called "AUTO" on the BIOS, is the minimum available */
+ [1] = 0x102,
+ [2] = 0x103,
+ [3] = 0x104,
+ [4] = 0x105,
+ [5] = 0x107,
+ [6] = 0x108,
+ [7] = 0x109,
+ [8] = 0x106,
+};
+
+static ssize_t apu_mem_current_value_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ int err;
+ u32 mem;
+
+ err = armoury_get_devstate(attr, &mem, ASUS_WMI_DEVID_APU_MEM);
+ if (err)
+ return err;
+
+ /* After 0x000 is set, a read will return 0x100 */
+ if (mem == 0x100)
+ return sysfs_emit(buf, "0\n");
+
+ for (unsigned int i = 0; i < ARRAY_SIZE(apu_mem_map); i++) {
+ if (apu_mem_map[i] == mem)
+ return sysfs_emit(buf, "%u\n", i);
+ }
+
+ pr_warn("Unrecognised value for APU mem 0x%08x\n", mem);
+ return -EIO;
+}
+
+static ssize_t apu_mem_current_value_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ int result, err;
+ u32 requested, mem;
+
+ result = kstrtou32(buf, 10, &requested);
+ if (result)
+ return result;
+
+ if (requested >= ARRAY_SIZE(apu_mem_map))
+ return -EINVAL;
+ mem = apu_mem_map[requested];
+
+ err = armoury_set_devstate(attr, mem, NULL, ASUS_WMI_DEVID_APU_MEM);
+ if (err) {
+ pr_warn("Failed to set apu_mem 0x%x: %d\n", mem, err);
+ return err;
+ }
+
+ pr_info("APU memory changed to %uGB, reboot required\n", requested + 1);
+ sysfs_notify(kobj, NULL, attr->attr.name);
+
+ asus_set_reboot_and_signal_event();
+
+ return count;
+}
+
+static ssize_t apu_mem_possible_values_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ return attr_enum_list(buf, ARRAY_SIZE(apu_mem_map));
+}
+ASUS_ATTR_GROUP_ENUM(apu_mem, "apu_mem", "Set available system RAM (in GB) for the APU to use");
+
/* Simple attribute creation */
ASUS_ATTR_GROUP_ENUM_INT_RO(charge_mode, "charge_mode", ASUS_WMI_DEVID_CHARGE_MODE, "0;1;2",
"Show the current mode of charging");
@@ -611,6 +709,7 @@ static const struct asus_attr_group armoury_attr_groups[] = {
{ &egpu_connected_attr_group, ASUS_WMI_DEVID_EGPU_CONNECTED },
{ &egpu_enable_attr_group, ASUS_WMI_DEVID_EGPU },
{ &dgpu_disable_attr_group, ASUS_WMI_DEVID_DGPU },
+ { &apu_mem_attr_group, ASUS_WMI_DEVID_APU_MEM },

{ &charge_mode_attr_group, ASUS_WMI_DEVID_CHARGE_MODE },
{ &boot_sound_attr_group, ASUS_WMI_DEVID_BOOT_SOUND },
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 10acd5d52e38..a4f6bab93a6f 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -137,6 +137,8 @@
/* dgpu on/off */
#define ASUS_WMI_DEVID_DGPU 0x00090020

+#define ASUS_WMI_DEVID_APU_MEM 0x000600C1
+
/* gpu mux switch, 0 = dGPU, 1 = Optimus */
#define ASUS_WMI_DEVID_GPU_MUX 0x00090016
#define ASUS_WMI_DEVID_GPU_MUX_VIVO 0x00090026
--
2.51.2