[alsa-devel] [PATCH v2 01/17] platform/chrome: Add EC command msg wrapper

[Prashant Malani]

Many callers of cros_ec_cmd_xfer_status() use a similar set up of
allocating and filling a message buffer and then copying any received
data to a target buffer.

Create a utility function cros_ec_cmd() that performs this setup so that
callers can use this function instead. Subsequent patches will convert
callers of cros_ec_cmd_xfer_status() to the new function instead.

Signed-off-by: Prashant Malani <pmalani at chromium.org>
---

Changes in v2:
- Renamed function to cros_ec_cmd()
- Added result pointer parameter.
- Removed references to cros_ec_cmd_xfer() or cros_ec_cmd_xfer_status()
  from documentation.

 drivers/platform/chrome/cros_ec_proto.c     | 58 +++++++++++++++++++++
 include/linux/platform_data/cros_ec_proto.h |  4 ++
 2 files changed, 62 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 3cfa643f1d073d..b3d5368f596813 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -572,6 +572,64 @@ int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 }
 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
 
+/**
+ * cros_ec_cmd() - Utility function to send commands to ChromeOS EC.
+ * @ec: EC device struct.
+ * @version: Command version number (often 0).
+ * @command: Command ID including offset.
+ * @outdata: Data to be sent to the EC.
+ * @outsize: Size of the &outdata buffer.
+ * @indata: Data to be received from the EC.
+ * @insize: Size of the &indata buffer.
+ * @result: Result of the transfer command.
+ *
+ * This function sends a command to the EC and also performs some of the common
+ * setup involved in doing so. This includes allocating and filling up a
+ * &struct cros_ec_command message buffer, and copying the received data to
+ * another buffer.
+ *
+ * Return: The number of bytes transferred on success or negative error code.
+ */
+int cros_ec_cmd(struct cros_ec_device *ec, u32 version, u32 command,
+		void *outdata, u32 outsize, void *indata,
+		u32 insize, u32 *result)
+{
+	struct cros_ec_command *msg;
+	int ret;
+
+	msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->version = version;
+	msg->command = command;
+	msg->outsize = outsize;
+	msg->insize = insize;
+
+	if (outdata && outsize > 0)
+		memcpy(msg->data, outdata, outsize);
+
+	ret = cros_ec_cmd_xfer(ec, msg);
+	if (result)
+		*result = msg->result;
+	if (ret < 0) {
+		dev_err(ec->dev, "Command xfer error (err:%d)\n", ret);
+		goto cleanup;
+	} else if (msg->result != EC_RES_SUCCESS) {
+		dev_dbg(ec->dev, "Command result (err: %d)\n", msg->result);
+		ret = -EPROTO;
+		goto cleanup;
+	}
+
+	if (insize)
+		memcpy(indata, msg->data, insize);
+
+cleanup:
+	kfree(msg);
+	return ret;
+}
+EXPORT_SYMBOL(cros_ec_cmd);
+
 static int get_next_event_xfer(struct cros_ec_device *ec_dev,
 			       struct cros_ec_command *msg,
 			       struct ec_response_get_next_event_v1 *event,
diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
index ba591477019180..54b9bbf9a07c0c 100644
--- a/include/linux/platform_data/cros_ec_proto.h
+++ b/include/linux/platform_data/cros_ec_proto.h
@@ -218,6 +218,10 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 			    struct cros_ec_command *msg);
 
+int cros_ec_cmd(struct cros_ec_device *ec_dev, u32 version, u32 command,
+		void *outdata, u32 outsize, void *indata, u32 insize,
+		u32 *result);
+
 int cros_ec_query_all(struct cros_ec_device *ec_dev);
 
 int cros_ec_get_next_event(struct cros_ec_device *ec_dev,
-- 
2.25.0.341.g760bfbb309-goog