drm/amdgpu: Add sysfs interfaces for NPS mode

Add a sysfs interface to see available NPS modes to switch to -

	cat /sys/bus/pci/devices/../available_memory_paritition

Make the current_memory_partition sysfs node read/write for requesting a
new NPS mode. The request is only cached and at a later point a driver
unload/reload is required to switch to the new NPS mode.

Ex:
	echo NPS1 > /sys/bus/pci/devices/../current_memory_paritition
	echo NPS4 > /sys/bus/pci/devices/../current_memory_paritition

The above interfaces will be available only if the SOC supports more than
one NPS mode.

Also modify the current memory partition sysfs logic to be more
generic.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c

@@ -1118,6 +1118,79 @@ release_buffer:
 	return ret;
 }
 
+static const char *nps_desc[] = {
+	[AMDGPU_NPS1_PARTITION_MODE] = "NPS1",
+	[AMDGPU_NPS2_PARTITION_MODE] = "NPS2",
+	[AMDGPU_NPS3_PARTITION_MODE] = "NPS3",
+	[AMDGPU_NPS4_PARTITION_MODE] = "NPS4",
+	[AMDGPU_NPS6_PARTITION_MODE] = "NPS6",
+	[AMDGPU_NPS8_PARTITION_MODE] = "NPS8",
+};
+
+static ssize_t available_memory_partition_show(struct device *dev,
+					       struct device_attribute *addr,
+					       char *buf)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(ddev);
+	int size = 0, mode;
+	char *sep = "";
+
+	for_each_inst(mode, adev->gmc.supported_nps_modes) {
+		size += sysfs_emit_at(buf, size, "%s%s", sep, nps_desc[mode]);
+		sep = ", ";
+	}
+	size += sysfs_emit_at(buf, size, "\n");
+
+	return size;
+}
+
+static ssize_t current_memory_partition_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);
+	enum amdgpu_memory_partition mode;
+	struct amdgpu_hive_info *hive;
+	int i;
+
+	mode = UNKNOWN_MEMORY_PARTITION_MODE;
+	for_each_inst(i, adev->gmc.supported_nps_modes) {
+		if (!strncasecmp(nps_desc[i], buf, strlen(nps_desc[i]))) {
+			mode = i;
+			break;
+		}
+	}
+
+	if (mode == UNKNOWN_MEMORY_PARTITION_MODE)
+		return -EINVAL;
+
+	if (mode == adev->gmc.gmc_funcs->query_mem_partition_mode(adev)) {
+		dev_info(
+			adev->dev,
+			"requested NPS mode is same as current NPS mode, skipping\n");
+		return count;
+	}
+
+	/* If device is part of hive, all devices in the hive should request the
+	 * same mode. Hence store the requested mode in hive.
+	 */
+	hive = amdgpu_get_xgmi_hive(adev);
+	if (hive) {
+		atomic_set(&hive->requested_nps_mode, mode);
+		amdgpu_put_xgmi_hive(hive);
+	} else {
+		adev->gmc.requested_nps_mode = mode;
+	}
+
+	dev_info(
+		adev->dev,
+		"NPS mode change requested, please remove and reload the driver\n");
+
+	return count;
+}
+
 static ssize_t current_memory_partition_show(
 	struct device *dev, struct device_attribute *addr, char *buf)
 {
@@ -1126,38 +1199,47 @@ static ssize_t current_memory_partition_show(
 	enum amdgpu_memory_partition mode;
 
 	mode = adev->gmc.gmc_funcs->query_mem_partition_mode(adev);
-	switch (mode) {
+	if ((mode > ARRAY_SIZE(nps_desc)) ||
-	case AMDGPU_NPS1_PARTITION_MODE:
+	    (BIT(mode) & AMDGPU_ALL_NPS_MASK) != BIT(mode))
-		return sysfs_emit(buf, "NPS1\n");
-	case AMDGPU_NPS2_PARTITION_MODE:
-		return sysfs_emit(buf, "NPS2\n");
-	case AMDGPU_NPS3_PARTITION_MODE:
-		return sysfs_emit(buf, "NPS3\n");
-	case AMDGPU_NPS4_PARTITION_MODE:
-		return sysfs_emit(buf, "NPS4\n");
-	case AMDGPU_NPS6_PARTITION_MODE:
-		return sysfs_emit(buf, "NPS6\n");
-	case AMDGPU_NPS8_PARTITION_MODE:
-		return sysfs_emit(buf, "NPS8\n");
-	default:
 		return sysfs_emit(buf, "UNKNOWN\n");
-	}
+
+	return sysfs_emit(buf, "%s\n", nps_desc[mode]);
 }
 
-static DEVICE_ATTR_RO(current_memory_partition);
+static DEVICE_ATTR_RW(current_memory_partition);
+static DEVICE_ATTR_RO(available_memory_partition);
 
 int amdgpu_gmc_sysfs_init(struct amdgpu_device *adev)
 {
+	bool nps_switch_support;
+	int r = 0;
+
 	if (!adev->gmc.gmc_funcs->query_mem_partition_mode)
 		return 0;
 
+	nps_switch_support = (hweight32(adev->gmc.supported_nps_modes &
+					AMDGPU_ALL_NPS_MASK) > 1);
+	if (!nps_switch_support)
+		dev_attr_current_memory_partition.attr.mode &=
+			~(S_IWUSR | S_IWGRP | S_IWOTH);
+	else
+		r = device_create_file(adev->dev,
+				       &dev_attr_available_memory_partition);
+
+	if (r)
+		return r;
+
 	return device_create_file(adev->dev,
 				  &dev_attr_current_memory_partition);
 }
 
 void amdgpu_gmc_sysfs_fini(struct amdgpu_device *adev)
 {
+	if (!adev->gmc.gmc_funcs->query_mem_partition_mode)
+		return;
+
 	device_remove_file(adev->dev, &dev_attr_current_memory_partition);
+	device_remove_file(adev->dev, &dev_attr_available_memory_partition);
 }
 
 int amdgpu_gmc_get_nps_memranges(struct amdgpu_device *adev,

drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h

@@ -73,6 +73,11 @@ enum amdgpu_memory_partition {
 	AMDGPU_NPS8_PARTITION_MODE = 8,
 };
 
+#define AMDGPU_ALL_NPS_MASK                                                  \
+	(BIT(AMDGPU_NPS1_PARTITION_MODE) | BIT(AMDGPU_NPS2_PARTITION_MODE) | \
+	 BIT(AMDGPU_NPS3_PARTITION_MODE) | BIT(AMDGPU_NPS4_PARTITION_MODE) | \
+	 BIT(AMDGPU_NPS6_PARTITION_MODE) | BIT(AMDGPU_NPS8_PARTITION_MODE))
+
 /*
  * GMC page fault information
  */
@@ -308,6 +313,7 @@ struct amdgpu_gmc {
 	uint8_t num_mem_partitions;
 	const struct amdgpu_gmc_funcs	*gmc_funcs;
 	enum amdgpu_memory_partition	requested_nps_mode;
+	uint32_t supported_nps_modes;
 
 	struct amdgpu_xgmi xgmi;
 	struct amdgpu_irq_src	ecc_irq;