From: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
In a suspend-resume edge case, the OPM is timing out in ucsi_resume and
the PPM is getting stuck waiting for a command complete ack. Add a write
timeout recovery task that will get us out of this state.
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
Signed-off-by: Łukasz Bartosik <ukaszb@xxxxxxxxxxxx>
---
drivers/usb/typec/ucsi/cros_ec_ucsi.c | 83 ++++++++++++++++++++++++++-
1 file changed, 82 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/typec/ucsi/cros_ec_ucsi.c b/drivers/usb/typec/ucsi/cros_ec_ucsi.c
index aae0bf106494..3e6b59aba275 100644
--- a/drivers/usb/typec/ucsi/cros_ec_ucsi.c
+++ b/drivers/usb/typec/ucsi/cros_ec_ucsi.c
@@ -7,6 +7,7 @@
#include <linux/container_of.h>
#include <linux/dev_printk.h>
+#include <linux/jiffies.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
@@ -29,6 +30,9 @@
*/
#define WRITE_TMO_MS 5000
+/* Number of times to attempt recovery from a write timeout before giving up. */
+#define WRITE_TMO_CTR_MAX 5
+
struct cros_ucsi_data {
struct device *dev;
struct ucsi *ucsi;
@@ -36,6 +40,8 @@ struct cros_ucsi_data {
struct cros_ec_device *ec;
struct notifier_block nb;
struct work_struct work;
+ struct delayed_work write_tmo;
+ int tmo_counter;
struct completion complete;
unsigned long flags;
@@ -101,7 +107,33 @@ static int cros_ucsi_async_control(struct ucsi *ucsi, u64 cmd)
static int cros_ucsi_sync_control(struct ucsi *ucsi, u64 cmd)
{
- return ucsi_sync_control_common(ucsi, cmd);
+ struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
+ int ret;
+
+ ret = ucsi_sync_control_common(ucsi, cmd);
+ if (ret)
+ goto out;
+
+ /* Successful write. Cancel any pending recovery work. */
+ cancel_delayed_work_sync(&udata->write_tmo);
+
+ return 0;
+out:
+ /* EC may return -EBUSY if CCI.busy is set. Convert this to a timeout.
+ */
+ if (ret == -EBUSY)
+ ret = -ETIMEDOUT;
+
+ /* Schedule recovery attempt when we timeout or tried to send a command
+ * while still busy.
+ */
+ if (ret == -ETIMEDOUT) {
+ cancel_delayed_work_sync(&udata->write_tmo);
+ schedule_delayed_work(&udata->write_tmo,
+ msecs_to_jiffies(WRITE_TMO_MS));
+ }
+
+ return ret;
}
struct ucsi_operations cros_ucsi_ops = {
@@ -123,6 +155,54 @@ static void cros_ucsi_work(struct work_struct *work)
ucsi_notify_common(udata->ucsi, cci);
}
+static void cros_ucsi_write_timeout(struct work_struct *work)
+{
+ struct cros_ucsi_data *udata =
+ container_of(work, struct cros_ucsi_data, write_tmo.work);
+ u32 cci;
+ u64 cmd;
+
+ if (cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci))) {
+ dev_err(udata->dev,
+ "Reading CCI failed; no write timeout recovery possible.");
+ return;
+ }
+
+ if (cci & UCSI_CCI_BUSY) {
+ udata->tmo_counter++;
+
+ if (udata->tmo_counter <= WRITE_TMO_CTR_MAX)
+ schedule_delayed_work(&udata->write_tmo,
+ msecs_to_jiffies(WRITE_TMO_MS));
+ else
+ dev_err(udata->dev,
+ "PPM unresponsive - too many write timeouts.");
+
+ return;
+ }
+
+ /* No longer busy means we can reset our timeout counter. */
+ udata->tmo_counter = 0;
+
+ /* Need to ack previous command which may have timed out. */
+ if (cci & UCSI_CCI_COMMAND_COMPLETE) {
+ cmd = UCSI_ACK_CC_CI | UCSI_ACK_COMMAND_COMPLETE;
+ cros_ucsi_async_control(udata->ucsi, &cmd);
+
+ /* Check again after a few seconds that the system has
+ * recovered to make sure our async write above was successful.
+ */
+ schedule_delayed_work(&udata->write_tmo,
+ msecs_to_jiffies(WRITE_TMO_MS));
+ return;
+ }
+
+ /* We recovered from a previous timeout. Treat this as a recovery from
+ * suspend and call resume.
+ */
+ ucsi_resume(udata->ucsi);
+}
+
static int cros_ucsi_event(struct notifier_block *nb,
unsigned long host_event, void *_notify)
{
@@ -167,6 +247,7 @@ static int cros_ucsi_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, udata);
INIT_WORK(&udata->work, cros_ucsi_work);
+ INIT_DELAYED_WORK(&udata->write_tmo, cros_ucsi_write_timeout);
init_completion(&udata->complete);
udata->ucsi = ucsi_create(dev, &cros_ucsi_ops);
--
2.47.0.338.g60cca15819-goog
