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From:   Guenter Roeck <linux@roeck-us.net>
To:     Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc:     Benson Leung <bleung@chromium.org>, linux-kernel@vger.kernel.org,
        Guenter Roeck <linux@roeck-us.net>,
        Yu-Hsuan Hsu <yuhsuan@chromium.org>,
        Prashant Malani <pmalani@chromium.org>
Subject: [PATCH] platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
Date:   Sat,  4 Jul 2020 07:26:07 -0700
Message-Id: <20200704142607.171400-1-linux@roeck-us.net>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The EC reports a variety of error codes. Most of those, with the exception
of EC_RES_INVALID_VERSION, are converted to -EPROTO. As result, the actual
error code gets lost. Convert all EC errors to Linux error codes to report
a more meaningful error to the caller to aid debugging.

Cc: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Cc: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/platform/chrome/cros_ec_proto.c | 37 +++++++++++++++++++------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 3e745e0fe092..10aa9e483d35 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -543,6 +543,29 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
 }
 EXPORT_SYMBOL(cros_ec_cmd_xfer);
 
+static const int cros_ec_error_map[] = {
+	[EC_RES_INVALID_COMMAND] = -EOPNOTSUPP,
+	[EC_RES_ERROR] = -EIO,
+	[EC_RES_INVALID_PARAM] = -EINVAL,
+	[EC_RES_ACCESS_DENIED] = -EACCES,
+	[EC_RES_INVALID_RESPONSE] = -EPROTO,
+	[EC_RES_INVALID_VERSION] = -ENOTSUPP,
+	[EC_RES_INVALID_CHECKSUM] = -EBADMSG,
+	[EC_RES_IN_PROGRESS] = -EINPROGRESS,
+	[EC_RES_UNAVAILABLE] = -ENODATA,
+	[EC_RES_TIMEOUT] = -ETIMEDOUT,
+	[EC_RES_OVERFLOW] = -EOVERFLOW,
+	[EC_RES_INVALID_HEADER] = -EBADR,
+	[EC_RES_REQUEST_TRUNCATED] = -EBADR,
+	[EC_RES_RESPONSE_TOO_BIG] = -EFBIG,
+	[EC_RES_BUS_ERROR] = -EFAULT,
+	[EC_RES_BUSY] = -EBUSY,
+	[EC_RES_INVALID_HEADER_VERSION] = -EBADMSG,
+	[EC_RES_INVALID_HEADER_CRC] = -EBADMSG,
+	[EC_RES_INVALID_DATA_CRC] = -EBADMSG,
+	[EC_RES_DUP_UNAVAILABLE] = -ENODATA,
+};
+
 /**
  * cros_ec_cmd_xfer_status() - Send a command to the ChromeOS EC.
  * @ec_dev: EC device.
@@ -555,8 +578,7 @@ EXPORT_SYMBOL(cros_ec_cmd_xfer);
  *
  * Return:
  * >=0 - The number of bytes transferred
- * -ENOTSUPP - Operation not supported
- * -EPROTO - Protocol error
+ * <0 - Linux error code
  */
 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 			    struct cros_ec_command *msg)
@@ -566,13 +588,12 @@ int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 	ret = cros_ec_cmd_xfer(ec_dev, msg);
 	if (ret < 0) {
 		dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
-	} else if (msg->result == EC_RES_INVALID_VERSION) {
-		dev_dbg(ec_dev->dev, "Command invalid version (err:%d)\n",
-			msg->result);
-		return -ENOTSUPP;
 	} else if (msg->result != EC_RES_SUCCESS) {
-		dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
-		return -EPROTO;
+		if (msg->result < ARRAY_SIZE(cros_ec_error_map) && cros_ec_error_map[msg->result])
+			ret = cros_ec_error_map[msg->result];
+		else
+			ret = -EPROTO;
+		dev_dbg(ec_dev->dev, "Command result (err: %d [%d])\n", msg->result, ret);
 	}
 
 	return ret;
-- 
2.17.1