drm/amdgpu: add debugfs for reset registers list

List of register populated for dump collection during the GPU reset.
Signed-off-by: Somalapuram Amaranath <Amaranath.Somalapuram@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1094,6 +1094,10 @@ struct amdgpu_device {
 	struct ip_discovery_top         *ip_top;
 
 	struct mutex			benchmark_mutex;
+
+	/* reset dump register */
+	uint32_t                        *reset_dump_reg_list;
+	int                             num_regs;
 };
 
 static inline struct amdgpu_device *drm_to_adev(struct drm_device *ddev)

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

@@ -1638,6 +1638,86 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_ib_preempt, NULL,
 DEFINE_DEBUGFS_ATTRIBUTE(fops_sclk_set, NULL,
 			amdgpu_debugfs_sclk_set, "%llu\n");
 
+static ssize_t amdgpu_reset_dump_register_list_read(struct file *f,
+				char __user *buf, size_t size, loff_t *pos)
+{
+	struct amdgpu_device *adev = (struct amdgpu_device *)file_inode(f)->i_private;
+	char reg_offset[12];
+	int i, ret, len = 0;
+
+	if (*pos)
+		return 0;
+
+	memset(reg_offset, 0, 12);
+	ret = down_read_killable(&adev->reset_sem);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < adev->num_regs; i++) {
+		sprintf(reg_offset, "0x%x\n", adev->reset_dump_reg_list[i]);
+		up_read(&adev->reset_sem);
+		if (copy_to_user(buf + len, reg_offset, strlen(reg_offset)))
+			return -EFAULT;
+
+		len += strlen(reg_offset);
+		ret = down_read_killable(&adev->reset_sem);
+		if (ret)
+			return ret;
+	}
+
+	up_read(&adev->reset_sem);
+	*pos += len;
+
+	return len;
+}
+
+static ssize_t amdgpu_reset_dump_register_list_write(struct file *f,
+			const char __user *buf, size_t size, loff_t *pos)
+{
+	struct amdgpu_device *adev = (struct amdgpu_device *)file_inode(f)->i_private;
+	char reg_offset[11];
+	uint32_t *tmp;
+	int ret, i = 0, len = 0;
+
+	do {
+		memset(reg_offset, 0, 11);
+		if (copy_from_user(reg_offset, buf + len,
+					min(10, ((int)size-len)))) {
+			ret = -EFAULT;
+			goto error_free;
+		}
+
+		tmp = krealloc_array(tmp, i + 1, sizeof(uint32_t), GFP_KERNEL);
+		if (sscanf(reg_offset, "%X %n", &tmp[i], &ret) != 1) {
+			ret = -EINVAL;
+			goto error_free;
+		}
+
+		len += ret;
+		i++;
+	} while (len < size);
+
+	ret = down_write_killable(&adev->reset_sem);
+	if (ret)
+		goto error_free;
+
+	swap(adev->reset_dump_reg_list, tmp);
+	adev->num_regs = i;
+	up_write(&adev->reset_sem);
+	ret = size;
+
+error_free:
+	kfree(tmp);
+	return ret;
+}
+
+static const struct file_operations amdgpu_reset_dump_register_list = {
+	.owner = THIS_MODULE,
+	.read = amdgpu_reset_dump_register_list_read,
+	.write = amdgpu_reset_dump_register_list_write,
+	.llseek = default_llseek
+};
+
 int amdgpu_debugfs_init(struct amdgpu_device *adev)
 {
 	struct dentry *root = adev_to_drm(adev)->primary->debugfs_root;
@@ -1706,6 +1786,8 @@ int amdgpu_debugfs_init(struct amdgpu_device *adev)
 			    &amdgpu_debugfs_vm_info_fops);
 	debugfs_create_file("amdgpu_benchmark", 0200, root, adev,
 			    &amdgpu_benchmark_fops);
+	debugfs_create_file("amdgpu_reset_dump_register_list", 0644, root, adev,
+			    &amdgpu_reset_dump_register_list);
 
 	adev->debugfs_vbios_blob.data = adev->bios;
 	adev->debugfs_vbios_blob.size = adev->bios_size;