[PATCHv1 1/2] firmware: Add streaming support

[yi1 . li]

From: Yi Li <yi1.li@xxxxxxxxxxxxxxx>

Load firmware in multiple chucks(4KB) instead of the whole big firmware file
at once. The streaming support is added in the driver_data_request_sync API
based on Luis R. Rodriguez's 20170329-driver-data-v2-try3 branch.

Signed-off-by: Yi Li <yi1.li@xxxxxxxxxxxxxxx>
---
 drivers/base/firmware_class.c | 119 +++++++++++++++++++++++++++++++++++++++++-
 include/linux/driver_data.h   |  13 +++++
 2 files changed, 131 insertions(+), 1 deletion(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index cc3c224..beecbf5 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -569,6 +569,73 @@ fw_get_filesystem_firmware(struct device *device, struct firmware_buf *buf)
 	return rc;
 }
 
+static int
+fw_stream_filesystem_firmware(struct device *device, struct firmware_buf *buf,
+			      size_t offset, size_t length, char **path)
+{
+	int i, len;
+	int rc = 0;
+	struct file *file;
+
+	buf->size = 0;
+	if (!buf->data) {
+		buf->data = vmalloc(length);
+		if (!buf->data) {
+			rc = -ENOMEM;
+			return rc;
+		}
+	}
+
+	/* skip the repeating folder searching */
+	if (*path) {
+		file = filp_open(*path, O_RDONLY, 0);
+		if (IS_ERR(file)) {
+			rc = -ENOENT;
+			return rc;
+		}
+
+		buf->size = kernel_read(file, offset, (char *)buf->data,
+					length);
+		fput(file);
+		return rc;
+	}
+
+	dev_info(device, "search %s in the folder\n", buf->fw_id);
+	*path = __getname();
+	if (!*path)
+		return -ENOMEM;
+
+	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
+		/* skip the unset customized path */
+		if (!fw_path[i][0])
+			continue;
+
+		len = snprintf(*path, PATH_MAX, "%s/%s",
+			       fw_path[i], buf->fw_id);
+		if (len >= PATH_MAX) {
+			rc = -ENAMETOOLONG;
+			break;
+		}
+
+		file = filp_open(*path, O_RDONLY, 0);
+		if (IS_ERR(file)) {
+			rc = -ENOENT;
+			continue;
+		}
+
+		buf->size = kernel_read(file, offset, (char *)buf->data,
+					length);
+		rc = 0;
+		fput(file);
+		break;
+	}
+
+	if (rc)
+		dev_err(device, "loading %s failed with error %d\n",
+			*path, rc);
+	return rc;
+}
+
 /* firmware holds the ownership of pages */
 static void firmware_free_data(const struct firmware *fw)
 {
@@ -1310,6 +1377,46 @@ _request_firmware_prepare(struct firmware **firmware_p, const char *name,
 	return 1; /* need to load */
 }
 
+static int
+_stream_firmware(const struct firmware **firmware_p, const char *name,
+		 struct driver_data_params *data_params,
+		 struct device *device)
+{
+	int ret;
+	struct firmware *fw = NULL;
+	size_t offset = data_params->req_params.streaming_reqs.offset;
+	size_t buf_size = data_params->req_params.streaming_reqs.buf_size;
+
+	if ((!firmware_p) || (!name || name[0] == '\0')) {
+		dev_err(device, "invalid firmware pointer or file name\n");
+		return -EINVAL;
+	}
+
+	if (!*firmware_p) {
+		ret = _request_firmware_prepare(&fw, name, device, data_params);
+		if (ret <= 0) {
+			dev_err(device, "%s: failed %d\n",
+				__func__, ret);
+		}
+	} else {
+		fw = (struct firmware *)*firmware_p;
+	}
+
+	ret = fw_stream_filesystem_firmware(device, fw->priv, offset, buf_size,
+				data_params->req_params.streaming_reqs.path);
+	if (ret) {
+		if (!driver_data_param_optional(&data_params->req_params))
+			dev_warn(device,
+				 "streaming %s failed with error %d\n",
+				 name, ret);
+	} else {
+		ret = assign_firmware_buf(fw, device, data_params);
+	}
+	*firmware_p = fw;
+
+	return ret;
+}
+
 /* called from request_firmware() and request_firmware_work_func() */
 static int
 _request_firmware(const struct firmware **firmware_p, const char *name,
@@ -1577,7 +1684,17 @@ int driver_data_request_sync(const char *name,
 	__module_get(sync_reqs->module);
 	get_device(device);
 
-	ret = _request_firmware(&driver_data, name, &params, device);
+	if (req_params->streaming_reqs.streaming) {
+		/* For streaming, driver_data is recycled and kept */
+		if (!req_params->keep)
+			return -EINVAL;
+
+		ret = _stream_firmware(req_params->streaming_reqs.driver_data,
+				       name, &params, device);
+		driver_data = *req_params->streaming_reqs.driver_data;
+	} else {
+		ret = _request_firmware(&driver_data, name, &params, device);
+	}
 	if (ret && driver_data_param_optional(req_params))
 		ret = driver_data_sync_opt_call_cb(req_params);
 	else
diff --git a/include/linux/driver_data.h b/include/linux/driver_data.h
index fda1e71..ee485a5 100644
--- a/include/linux/driver_data.h
+++ b/include/linux/driver_data.h
@@ -62,6 +62,16 @@ struct driver_data_reqs {
 	gfp_t gfp;
 };
 
+struct driver_data_streaming_reqs {
+	bool streaming;
+	char **path;
+	size_t offset;
+	size_t buf_size;
+	const struct firmware **driver_data;
+	void *opt_ctx1;
+	void *opt_ctx2;
+};
+
 /**
  * struct driver_data_req_params - driver data request parameters
  * @optional: if true it is not a hard requirement by the caller that this
@@ -93,6 +103,8 @@ struct driver_data_reqs {
  *	digit will be placed in the middle, followed by the @api_name_postfix.
  * @sync_reqs: synchronization requirements
  *
+ * @streaming_reqs: streaming requirements
+ *
  * This data structure is intended to carry all requirements and specifications
  * required to complete the task to get the requested driver date file to the
  * caller.
@@ -107,6 +119,7 @@ struct driver_data_req_params {
 	const char *api_name_postfix;
 	struct driver_data_reqs sync_reqs;
 	const union driver_data_cbs cbs;
+	struct driver_data_streaming_reqs streaming_reqs;
 };
 
 /*
-- 
2.7.4