Add a uma/ directory containing two sysfs files as interfaces to
inspect or change UMA carveout size. These files are:

- uma/carveout_options: a read-only file listing all the available
  UMA allocation options and their index.

- uma/carveout: a file that is both readable and writable. On read,
  it shows the index of the current setting. Writing a valid index
  into this file allows users to change the UMA carveout size to that
  option on the next boot.

Co-developed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Yo-Jung Leo Lin (AMD) <Leo.Lin@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h        |   4 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c   |   7 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 138 +++++++++++++++++++++++++++++
 3 files changed, 149 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 6bf626a51dfc..177376ff5811 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1846,4 +1846,8 @@ void amdgpu_device_set_uid(struct amdgpu_uid *uid_info,
 			   uint64_t uid);
 uint64_t amdgpu_device_get_uid(struct amdgpu_uid *uid_info,
 			       enum amdgpu_uid_type type, uint8_t inst);
+
+int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev);
+void amdgpu_acpi_uma_option_fini(struct amdgpu_device *adev);
+
 #endif
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
index bdafcde51107..b2779fc2f712 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
@@ -1288,6 +1288,12 @@ static int amdgpu_acpi_event(struct notifier_block *nb,
 int amdgpu_acpi_init(struct amdgpu_device *adev)
 {
 	struct amdgpu_atif *atif = &amdgpu_acpi_priv.atif;
+	int rc;
+
+	rc = amdgpu_acpi_uma_option_init(adev);
+
+	if (rc)
+		drm_dbg(adev_to_drm(adev), "Not creating uma carveout interfaces: %d", rc);
 
 	if (atif->notifications.brightness_change) {
 		if (adev->dc_enabled) {
@@ -1340,6 +1346,7 @@ void amdgpu_acpi_get_backlight_caps(struct amdgpu_dm_backlight_caps *caps)
 void amdgpu_acpi_fini(struct amdgpu_device *adev)
 {
 	unregister_acpi_notifier(&adev->acpi_nb);
+	amdgpu_acpi_uma_option_fini(adev);
 }
 
 /**
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index a7594ae44b20..979298d9c213 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -36,6 +36,7 @@
 #include <linux/pci.h>
 #include <linux/pci-p2pdma.h>
 #include <linux/apple-gmux.h>
+#include <linux/nospec.h>
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_client_event.h>
@@ -7835,3 +7836,140 @@ u64 amdgpu_device_get_uid(struct amdgpu_uid *uid_info,
 
 	return uid_info->uid[type][inst];
 }
+
+static ssize_t carveout_options_show(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(ddev);
+	struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
+	uint32_t memory_carved;
+	ssize_t size = 0;
+
+	if (!uma_info || !uma_info->num_entries)
+		return -ENODEV;
+
+	for (int i = 0; i < uma_info->num_entries; i++) {
+		memory_carved = uma_info->entries[i].memory_carved_mb;
+		if (memory_carved >= SZ_1G/SZ_1M) {
+			size += sysfs_emit_at(buf, size, "%d: %s (%u GB)\n",
+					      i,
+					      uma_info->entries[i].name,
+					      memory_carved >> 10);
+		} else {
+			size += sysfs_emit_at(buf, size, "%d: %s (%u MB)\n",
+					      i,
+					      uma_info->entries[i].name,
+					      memory_carved);
+		}
+	}
+
+	return size;
+}
+static DEVICE_ATTR_RO(carveout_options);
+
+static ssize_t carveout_show(struct device *dev,
+			     struct device_attribute *attr,
+			     char *buf)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(ddev);
+
+	return sysfs_emit(buf, "%u\n", adev->uma_info.uma_option_index);
+}
+
+static ssize_t carveout_store(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(ddev);
+	struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
+	struct amdgpu_uma_carveout_option *opt;
+	unsigned long val;
+	uint8_t flags;
+	int r;
+
+	r = kstrtoul(buf, 10, &val);
+	if (r)
+		return r;
+
+	if (val >= uma_info->num_entries)
+		return -EINVAL;
+
+	val = array_index_nospec(val, uma_info->num_entries);
+	opt = &uma_info->entries[val];
+
+	if (!(opt->flags & AMDGPU_UMA_FLAG_AUTO) &&
+	    !(opt->flags & AMDGPU_UMA_FLAG_CUSTOM)) {
+		drm_err_once(ddev, "Option %lu not supported due to lack of Custom/Auto flag", val);
+		return -EINVAL;
+	}
+
+	flags = opt->flags;
+	flags &= ~((flags & AMDGPU_UMA_FLAG_AUTO) >> 1);
+
+	guard(mutex)(&uma_info->update_lock);
+
+	r = amdgpu_acpi_set_uma_allocation_size(adev, val, flags);
+	if (r)
+		return r;
+
+	uma_info->uma_option_index = val;
+
+	return count;
+}
+static DEVICE_ATTR_RW(carveout);
+
+static struct attribute *amdgpu_uma_attrs[] = {
+	&dev_attr_carveout.attr,
+	&dev_attr_carveout_options.attr,
+	NULL
+};
+
+const struct attribute_group amdgpu_uma_attr_group = {
+	.name = "uma",
+	.attrs = amdgpu_uma_attrs
+};
+
+int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev)
+{
+	int rc;
+
+	if (!amdgpu_acpi_is_set_uma_allocation_size_supported())
+		return -ENODEV;
+
+	rc = amdgpu_atomfirmware_get_uma_carveout_info(adev, &adev->uma_info);
+	if (rc) {
+		drm_dbg(adev_to_drm(adev),
+			"Failed to parse UMA carveout info from VBIOS: %d\n", rc);
+		goto out_info;
+	}
+
+	mutex_init(&adev->uma_info.update_lock);
+
+	rc = devm_device_add_group(adev->dev, &amdgpu_uma_attr_group);
+	if (rc) {
+		drm_dbg(adev_to_drm(adev), "Failed to add UMA carveout sysfs interfaces %d\n", rc);
+		goto out_attr;
+	}
+
+	return 0;
+
+out_attr:
+	mutex_destroy(&adev->uma_info.update_lock);
+out_info:
+	return rc;
+}
+
+void amdgpu_acpi_uma_option_fini(struct amdgpu_device *adev)
+{
+	struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
+
+	if (!amdgpu_acpi_is_set_uma_allocation_size_supported())
+		return;
+
+	mutex_destroy(&uma_info->update_lock);
+	uma_info->num_entries = 0;
+}

-- 
2.43.0

On 12/5/2025 12:20 PM, Yo-Jung Leo Lin (AMD) wrote:
> Add a uma/ directory containing two sysfs files as interfaces to
> inspect or change UMA carveout size. These files are:
> 
> - uma/carveout_options: a read-only file listing all the available
>    UMA allocation options and their index.
> 
> - uma/carveout: a file that is both readable and writable. On read,
>    it shows the index of the current setting. Writing a valid index
>    into this file allows users to change the UMA carveout size to that
>    option on the next boot.
> 
> Co-developed-by: Mario Limonciello (AMD) <superm1@kernel.org>
> Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
> Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
> Signed-off-by: Yo-Jung Leo Lin (AMD) <Leo.Lin@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu.h        |   4 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c   |   7 ++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 138 +++++++++++++++++++++++++++++
>   3 files changed, 149 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 6bf626a51dfc..177376ff5811 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1846,4 +1846,8 @@ void amdgpu_device_set_uid(struct amdgpu_uid *uid_info,
>   			   uint64_t uid);
>   uint64_t amdgpu_device_get_uid(struct amdgpu_uid *uid_info,
>   			       enum amdgpu_uid_type type, uint8_t inst);
> +
> +int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev);
> +void amdgpu_acpi_uma_option_fini(struct amdgpu_device *adev);
> +
>   #endif
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> index bdafcde51107..b2779fc2f712 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> @@ -1288,6 +1288,12 @@ static int amdgpu_acpi_event(struct notifier_block *nb,
>   int amdgpu_acpi_init(struct amdgpu_device *adev)
>   {
>   	struct amdgpu_atif *atif = &amdgpu_acpi_priv.atif;
> +	int rc;
> +
> +	rc = amdgpu_acpi_uma_option_init(adev);
> +
> +	if (rc)
> +		drm_dbg(adev_to_drm(adev), "Not creating uma carveout interfaces: %d", rc);
>   
>   	if (atif->notifications.brightness_change) {
>   		if (adev->dc_enabled) {
> @@ -1340,6 +1346,7 @@ void amdgpu_acpi_get_backlight_caps(struct amdgpu_dm_backlight_caps *caps)
>   void amdgpu_acpi_fini(struct amdgpu_device *adev)
>   {
>   	unregister_acpi_notifier(&adev->acpi_nb);
> +	amdgpu_acpi_uma_option_fini(adev);
>   }
>   
>   /**
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index a7594ae44b20..979298d9c213 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -36,6 +36,7 @@
>   #include <linux/pci.h>
>   #include <linux/pci-p2pdma.h>
>   #include <linux/apple-gmux.h>
> +#include <linux/nospec.h>
>   
>   #include <drm/drm_atomic_helper.h>
>   #include <drm/drm_client_event.h>
> @@ -7835,3 +7836,140 @@ u64 amdgpu_device_get_uid(struct amdgpu_uid *uid_info,
>   
>   	return uid_info->uid[type][inst];
>   }
> +
> +static ssize_t carveout_options_show(struct device *dev,
> +				     struct device_attribute *attr,
> +				     char *buf)
> +{
> +	struct drm_device *ddev = dev_get_drvdata(dev);
> +	struct amdgpu_device *adev = drm_to_adev(ddev);
> +	struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
> +	uint32_t memory_carved;
> +	ssize_t size = 0;
> +
> +	if (!uma_info || !uma_info->num_entries)
> +		return -ENODEV;
> +
> +	for (int i = 0; i < uma_info->num_entries; i++) {
> +		memory_carved = uma_info->entries[i].memory_carved_mb;
> +		if (memory_carved >= SZ_1G/SZ_1M) {
> +			size += sysfs_emit_at(buf, size, "%d: %s (%u GB)\n",
> +					      i,
> +					      uma_info->entries[i].name,
> +					      memory_carved >> 10);
> +		} else {
> +			size += sysfs_emit_at(buf, size, "%d: %s (%u MB)\n",
> +					      i,
> +					      uma_info->entries[i].name,
> +					      memory_carved);
> +		}
> +	}
> +
> +	return size;
> +}
> +static DEVICE_ATTR_RO(carveout_options);
> +
> +static ssize_t carveout_show(struct device *dev,
> +			     struct device_attribute *attr,
> +			     char *buf)
> +{
> +	struct drm_device *ddev = dev_get_drvdata(dev);
> +	struct amdgpu_device *adev = drm_to_adev(ddev);
> +
> +	return sysfs_emit(buf, "%u\n", adev->uma_info.uma_option_index);
> +}
> +
> +static ssize_t carveout_store(struct device *dev,
> +			      struct device_attribute *attr,
> +			      const char *buf, size_t count)
> +{
> +	struct drm_device *ddev = dev_get_drvdata(dev);
> +	struct amdgpu_device *adev = drm_to_adev(ddev);
> +	struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
> +	struct amdgpu_uma_carveout_option *opt;
> +	unsigned long val;
> +	uint8_t flags;
> +	int r;
> +
> +	r = kstrtoul(buf, 10, &val);
> +	if (r)
> +		return r;
> +
> +	if (val >= uma_info->num_entries)
> +		return -EINVAL;
> +
> +	val = array_index_nospec(val, uma_info->num_entries);
> +	opt = &uma_info->entries[val];
> +
> +	if (!(opt->flags & AMDGPU_UMA_FLAG_AUTO) &&
> +	    !(opt->flags & AMDGPU_UMA_FLAG_CUSTOM)) {
> +		drm_err_once(ddev, "Option %lu not supported due to lack of Custom/Auto flag", val);
> +		return -EINVAL;
> +	}
> +
> +	flags = opt->flags;
> +	flags &= ~((flags & AMDGPU_UMA_FLAG_AUTO) >> 1);
> +
> +	guard(mutex)(&uma_info->update_lock);
> +
> +	r = amdgpu_acpi_set_uma_allocation_size(adev, val, flags);
> +	if (r)
> +		return r;
> +
> +	uma_info->uma_option_index = val;
> +
> +	return count;
> +}
> +static DEVICE_ATTR_RW(carveout);
> +
> +static struct attribute *amdgpu_uma_attrs[] = {
> +	&dev_attr_carveout.attr,
> +	&dev_attr_carveout_options.attr,
> +	NULL
> +};
> +
> +const struct attribute_group amdgpu_uma_attr_group = {
> +	.name = "uma",
> +	.attrs = amdgpu_uma_attrs
> +};
> +
> +int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev)
> +{

To clarify on the comment about moving this to amdgpu_device -

UMA option is a device specific option which could be set through acpi. 
Options are retrieved through atom tables.

So the function names remain amdgpu_device_uma_option_init/fini() and 
init/fini are called within amdgpu_device.c

Thanks,
Lijo

> +	int rc;
> +
> +	if (!amdgpu_acpi_is_set_uma_allocation_size_supported())
> +		return -ENODEV;
> +
> +	rc = amdgpu_atomfirmware_get_uma_carveout_info(adev, &adev->uma_info);
> +	if (rc) {
> +		drm_dbg(adev_to_drm(adev),
> +			"Failed to parse UMA carveout info from VBIOS: %d\n", rc);
> +		goto out_info;
> +	}
> +
> +	mutex_init(&adev->uma_info.update_lock);
> +
> +	rc = devm_device_add_group(adev->dev, &amdgpu_uma_attr_group);
> +	if (rc) {
> +		drm_dbg(adev_to_drm(adev), "Failed to add UMA carveout sysfs interfaces %d\n", rc);
> +		goto out_attr;
> +	}
> +
> +	return 0;
> +
> +out_attr:
> +	mutex_destroy(&adev->uma_info.update_lock);
> +out_info:
> +	return rc;
> +}
> +
> +void amdgpu_acpi_uma_option_fini(struct amdgpu_device *adev)
> +{
> +	struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
> +
> +	if (!amdgpu_acpi_is_set_uma_allocation_size_supported())
> +		return;
> +
> +	mutex_destroy(&uma_info->update_lock);
> +	uma_info->num_entries = 0;
> +}
>

On 12/5/2025 4:04 PM, Lazar, Lijo wrote:
> 
> 
> On 12/5/2025 12:20 PM, Yo-Jung Leo Lin (AMD) wrote:
>> Add a uma/ directory containing two sysfs files as interfaces to
>> inspect or change UMA carveout size. These files are:
>>
>> - uma/carveout_options: a read-only file listing all the available
>>    UMA allocation options and their index.
>>
>> - uma/carveout: a file that is both readable and writable. On read,
>>    it shows the index of the current setting. Writing a valid index
>>    into this file allows users to change the UMA carveout size to that
>>    option on the next boot.
>>
>> Co-developed-by: Mario Limonciello (AMD) <superm1@kernel.org>
>> Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
>> Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
>> Signed-off-by: Yo-Jung Leo Lin (AMD) <Leo.Lin@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h        |   4 +
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c   |   7 ++
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 138 +++++++++++++++++++ 
>> ++++++++++
>>   3 files changed, 149 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/ 
>> amd/amdgpu/amdgpu.h
>> index 6bf626a51dfc..177376ff5811 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> @@ -1846,4 +1846,8 @@ void amdgpu_device_set_uid(struct amdgpu_uid 
>> *uid_info,
>>                  uint64_t uid);
>>   uint64_t amdgpu_device_get_uid(struct amdgpu_uid *uid_info,
>>                      enum amdgpu_uid_type type, uint8_t inst);
>> +
>> +int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev);
>> +void amdgpu_acpi_uma_option_fini(struct amdgpu_device *adev);
>> +
>>   #endif
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/ 
>> drm/amd/amdgpu/amdgpu_acpi.c
>> index bdafcde51107..b2779fc2f712 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
>> @@ -1288,6 +1288,12 @@ static int amdgpu_acpi_event(struct 
>> notifier_block *nb,
>>   int amdgpu_acpi_init(struct amdgpu_device *adev)
>>   {
>>       struct amdgpu_atif *atif = &amdgpu_acpi_priv.atif;
>> +    int rc;
>> +
>> +    rc = amdgpu_acpi_uma_option_init(adev);
>> +
>> +    if (rc)
>> +        drm_dbg(adev_to_drm(adev), "Not creating uma carveout 
>> interfaces: %d", rc);
>>       if (atif->notifications.brightness_change) {
>>           if (adev->dc_enabled) {
>> @@ -1340,6 +1346,7 @@ void amdgpu_acpi_get_backlight_caps(struct 
>> amdgpu_dm_backlight_caps *caps)
>>   void amdgpu_acpi_fini(struct amdgpu_device *adev)
>>   {
>>       unregister_acpi_notifier(&adev->acpi_nb);
>> +    amdgpu_acpi_uma_option_fini(adev);
>>   }
>>   /**
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/ 
>> drm/amd/amdgpu/amdgpu_device.c
>> index a7594ae44b20..979298d9c213 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -36,6 +36,7 @@
>>   #include <linux/pci.h>
>>   #include <linux/pci-p2pdma.h>
>>   #include <linux/apple-gmux.h>
>> +#include <linux/nospec.h>
>>   #include <drm/drm_atomic_helper.h>
>>   #include <drm/drm_client_event.h>
>> @@ -7835,3 +7836,140 @@ u64 amdgpu_device_get_uid(struct amdgpu_uid 
>> *uid_info,
>>       return uid_info->uid[type][inst];
>>   }
>> +
>> +static ssize_t carveout_options_show(struct device *dev,
>> +                     struct device_attribute *attr,
>> +                     char *buf)
>> +{
>> +    struct drm_device *ddev = dev_get_drvdata(dev);
>> +    struct amdgpu_device *adev = drm_to_adev(ddev);
>> +    struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
>> +    uint32_t memory_carved;
>> +    ssize_t size = 0;
>> +
>> +    if (!uma_info || !uma_info->num_entries)
>> +        return -ENODEV;
>> +
>> +    for (int i = 0; i < uma_info->num_entries; i++) {
>> +        memory_carved = uma_info->entries[i].memory_carved_mb;
>> +        if (memory_carved >= SZ_1G/SZ_1M) {
>> +            size += sysfs_emit_at(buf, size, "%d: %s (%u GB)\n",
>> +                          i,
>> +                          uma_info->entries[i].name,
>> +                          memory_carved >> 10);
>> +        } else {
>> +            size += sysfs_emit_at(buf, size, "%d: %s (%u MB)\n",
>> +                          i,
>> +                          uma_info->entries[i].name,
>> +                          memory_carved);
>> +        }
>> +    }
>> +
>> +    return size;
>> +}
>> +static DEVICE_ATTR_RO(carveout_options);
>> +
>> +static ssize_t carveout_show(struct device *dev,
>> +                 struct device_attribute *attr,
>> +                 char *buf)
>> +{
>> +    struct drm_device *ddev = dev_get_drvdata(dev);
>> +    struct amdgpu_device *adev = drm_to_adev(ddev);
>> +
>> +    return sysfs_emit(buf, "%u\n", adev->uma_info.uma_option_index);
>> +}
>> +
>> +static ssize_t carveout_store(struct device *dev,
>> +                  struct device_attribute *attr,
>> +                  const char *buf, size_t count)
>> +{
>> +    struct drm_device *ddev = dev_get_drvdata(dev);
>> +    struct amdgpu_device *adev = drm_to_adev(ddev);
>> +    struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
>> +    struct amdgpu_uma_carveout_option *opt;
>> +    unsigned long val;
>> +    uint8_t flags;
>> +    int r;
>> +
>> +    r = kstrtoul(buf, 10, &val);
>> +    if (r)
>> +        return r;
>> +
>> +    if (val >= uma_info->num_entries)
>> +        return -EINVAL;
>> +
>> +    val = array_index_nospec(val, uma_info->num_entries);
>> +    opt = &uma_info->entries[val];
>> +
>> +    if (!(opt->flags & AMDGPU_UMA_FLAG_AUTO) &&
>> +        !(opt->flags & AMDGPU_UMA_FLAG_CUSTOM)) {
>> +        drm_err_once(ddev, "Option %lu not supported due to lack of 
>> Custom/Auto flag", val);
>> +        return -EINVAL;
>> +    }
>> +
>> +    flags = opt->flags;
>> +    flags &= ~((flags & AMDGPU_UMA_FLAG_AUTO) >> 1);
>> +
>> +    guard(mutex)(&uma_info->update_lock);
>> +
>> +    r = amdgpu_acpi_set_uma_allocation_size(adev, val, flags);
>> +    if (r)
>> +        return r;
>> +
>> +    uma_info->uma_option_index = val;
>> +
>> +    return count;
>> +}
>> +static DEVICE_ATTR_RW(carveout);
>> +
>> +static struct attribute *amdgpu_uma_attrs[] = {
>> +    &dev_attr_carveout.attr,
>> +    &dev_attr_carveout_options.attr,
>> +    NULL
>> +};
>> +
>> +const struct attribute_group amdgpu_uma_attr_group = {
>> +    .name = "uma",
>> +    .attrs = amdgpu_uma_attrs
>> +};
>> +
>> +int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev)
>> +{
> 
> To clarify on the comment about moving this to amdgpu_device -
> 
> UMA option is a device specific option which could be set through acpi. 
> Options are retrieved through atom tables.
> 
> So the function names remain amdgpu_device_uma_option_init/fini() and 
> init/fini are called within amdgpu_device.c
> 

Couple of additional comments below -

> Thanks,
> Lijo
> 
>> +    int rc;
>> +

It's better to have an early exit from here itself if it's not APU. 
Otherwise, the dbg prints will show up even on dGPUs.

There also needs to be a check for availability of BIOS (adev->bios) and 
(adev->is_atom_fw). For example in Instinct APUs, driver doesn't read 
bios image (adev->bios is NULL).

Thanks,
Lijo

>> +    if (!amdgpu_acpi_is_set_uma_allocation_size_supported())
>> +        return -ENODEV;
>> +
>> +    rc = amdgpu_atomfirmware_get_uma_carveout_info(adev, &adev- 
>> >uma_info);
>> +    if (rc) {
>> +        drm_dbg(adev_to_drm(adev),
>> +            "Failed to parse UMA carveout info from VBIOS: %d\n", rc);
>> +        goto out_info;
>> +    }
>> +
>> +    mutex_init(&adev->uma_info.update_lock);
>> +
>> +    rc = devm_device_add_group(adev->dev, &amdgpu_uma_attr_group);
>> +    if (rc) {
>> +        drm_dbg(adev_to_drm(adev), "Failed to add UMA carveout sysfs 
>> interfaces %d\n", rc);
>> +        goto out_attr;
>> +    }
>> +
>> +    return 0;
>> +
>> +out_attr:
>> +    mutex_destroy(&adev->uma_info.update_lock);
>> +out_info:
>> +    return rc;
>> +}
>> +
>> +void amdgpu_acpi_uma_option_fini(struct amdgpu_device *adev)
>> +{
>> +    struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
>> +
>> +    if (!amdgpu_acpi_is_set_uma_allocation_size_supported())
>> +        return;
>> +
>> +    mutex_destroy(&uma_info->update_lock);
>> +    uma_info->num_entries = 0;
>> +}
>>
>