drm/amd/pm: Add debugfs info for STB

Add debugfs hook.
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/amdgpu_pm.c

@@ -3759,5 +3759,7 @@ void amdgpu_debugfs_pm_init(struct amdgpu_device *adev)
 					 adev,
 					 &amdgpu_debugfs_pm_prv_buffer_fops,
 					 adev->pm.smu_prv_buffer_size);
+
+	amdgpu_smu_stb_debug_fs_init(adev);
 #endif
 }

drivers/gpu/drm/amd/pm/inc/amdgpu_smu.h

@@ -1420,6 +1420,7 @@ int smu_wait_for_event(struct amdgpu_device *adev, enum smu_event_type event,
 		       uint64_t event_arg);
 int smu_get_ecc_info(struct smu_context *smu, void *umc_ecc);
 int smu_stb_collect_info(struct smu_context *smu, void *buff, uint32_t size);
+void amdgpu_smu_stb_debug_fs_init(struct amdgpu_device *adev);
 
 #endif
 #endif

drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c

@@ -3193,3 +3193,89 @@ int smu_stb_collect_info(struct smu_context *smu, void *buf, uint32_t size)
 	 */
 	return smu->ppt_funcs->stb_collect_info(smu, buf, size);
 }
+
+#if defined(CONFIG_DEBUG_FS)
+
+static int smu_stb_debugfs_open(struct inode *inode, struct file *filp)
+{
+	struct amdgpu_device *adev = filp->f_inode->i_private;
+	struct smu_context *smu = &adev->smu;
+	unsigned char *buf;
+	int r;
+
+	buf = kvmalloc_array(smu->stb_context.stb_buf_size, sizeof(*buf), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	r = smu_stb_collect_info(smu, buf, smu->stb_context.stb_buf_size);
+	if (r)
+		goto out;
+
+	filp->private_data = buf;
+
+	return 0;
+
+out:
+	kvfree(buf);
+	return r;
+}
+
+static ssize_t smu_stb_debugfs_read(struct file *filp, char __user *buf, size_t size,
+				loff_t *pos)
+{
+	struct amdgpu_device *adev = filp->f_inode->i_private;
+	struct smu_context *smu = &adev->smu;
+
+
+	if (!filp->private_data)
+		return -EINVAL;
+
+	return simple_read_from_buffer(buf,
+				       size,
+				       pos, filp->private_data,
+				       smu->stb_context.stb_buf_size);
+}
+
+static int smu_stb_debugfs_release(struct inode *inode, struct file *filp)
+{
+	kvfree(filp->private_data);
+	filp->private_data = NULL;
+
+	return 0;
+}
+
+/*
+ * We have to define not only read method but also
+ * open and release because .read takes up to PAGE_SIZE
+ * data each time so and so is invoked multiple times.
+ *  We allocate the STB buffer in .open and release it
+ *  in .release
+ */
+static const struct file_operations smu_stb_debugfs_fops = {
+	.owner = THIS_MODULE,
+	.open = smu_stb_debugfs_open,
+	.read = smu_stb_debugfs_read,
+	.release = smu_stb_debugfs_release,
+	.llseek = default_llseek,
+};
+
+#endif
+
+void amdgpu_smu_stb_debug_fs_init(struct amdgpu_device *adev)
+{
+#if defined(CONFIG_DEBUG_FS)
+
+	struct smu_context *smu = &adev->smu;
+
+	if (!smu->stb_context.stb_buf_size)
+		return;
+
+	debugfs_create_file_size("amdgpu_smu_stb_dump",
+			    S_IRUSR,
+			    adev_to_drm(adev)->primary->debugfs_root,
+			    adev,
+			    &smu_stb_debugfs_fops,
+			    smu->stb_context.stb_buf_size);
+#endif
+
+}