serdev_device_write_buf() returns negative numbers on errors. When
the return value compares to unsigned integer `len`, it promotes to
quite large positive number.
Fix it.
Fixes: 04a8bdd135 ("platform/chrome: cros_ec_uart: Add transport layer")
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20230109081554.3792547-1-tzungbi@kernel.org
serdev_device_set_client_ops() is called before `ec_dev` is fully
initialized. This can result in cros_ec_uart_rx_bytes() being called
while `ec_dev` is still not initialized, resulting in a kernel panic.
Call serdev_device_set_client_ops() after `ec_dev` is initialized.
Fixes: 04a8bdd135 ("platform/chrome: cros_ec_uart: Add transport layer")
Signed-off-by: Robert Zieba <robertzieba@google.com>
[tzungbi: modified commit message and fixed context conflict.]
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20221229094738.2304044-1-tzungbi@kernel.org
This patch does following:
1. Adds a new cros-ec-uart driver. This driver can send EC requests on
UART and process response packets received on UART transport.
2. Once probed, this driver will initialize the serdev device based on
the underlying information in the ACPI resource. After serdev device
properties are set, this driver will register itself cros-ec.
3. High level driver can use this implementation to talk to ChromeOS
Embedded Controller device in case it supports UART as transport.
4. When cros-ec driver initiates a request packet, outgoing message is
processed in buffer and sent via serdev. Once bytes are sent, driver
enables a wait_queue.
5. Since ChromeOS EC device sends response asynchronously, AP's TTY
driver accumulates response bytes and calls the registered callback.
TTY driver can send multiple callback for bytes ranging from 1 to MAX
bytes supported by EC device.
6. Driver waits for EC_MSG_DEADLINE_MS to collect and process received
bytes. It wakes wait_queue if expected bytes are received or else
wait_queue timeout. Based on the error condition, driver returns
data_len or error to cros_ec.
Signed-off-by: Bhanu Prakash Maiya <bhanumaiya@chromium.org>
Co-developed-by: Mark Hasemeyer <markhas@chromium.org>
Signed-off-by: Mark Hasemeyer <markhas@chromium.org>
Reviewed-by: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20221227123212.v13.1.If7926fcbad397bc6990dd725690229bed403948c@changeid
