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path: root/drivers/platform/chrome/cros_ec_uart.c
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2023-01-18platform/chrome: cros_ec_uart: fix negative type promoted to highTzung-Bi Shih
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: 04a8bdd135cc ("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
2023-01-05platform/chrome: cros_ec_uart: fix race conditionRobert Zieba
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: 04a8bdd135cc ("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
2023-01-05platform/chrome: cros_ec_uart: Add DT enumeration supportBhanu Prakash Maiya
Existing firmware uses the "PRP0001" _HID and an associated compatible string to enumerate the cros_ec_uart. Add DT enumeration support for already shipped firmware. 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.v13.3.Ie23c217d69ff25d7354db942613f143bbc8ef891@changeid
2022-12-28platform/chrome: cros_ec_uart: Add transport layerBhanu Prakash Maiya
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