From: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx> commit 8e1ec117efdfd4b2f59f57bd0ad16b4edf5b963f upstream. Sometimes errors are seen, when doing DR swap, like: [ 24.672481] ucsi-stm32g0-i2c 0-0035: UCSI_GET_PDOS failed (-5) [ 24.720188] ucsi-stm32g0-i2c 0-0035: ucsi_handle_connector_change: GET_CONNECTOR_STATUS failed (-5) There may be some race, which lead to read CCI, before the command complete flag is set, hence returning -EIO. Similar fix has been done also in ucsi_acpi [1]. In case of a spurious or otherwise delayed notification it is possible that CCI still reports the previous completion. The UCSI spec is aware of this and provides two completion bits in CCI, one for normal commands and one for acks. As acks and commands alternate the notification handler can determine if the completion bit is from the current command. To fix this add the ACK_PENDING bit for ucsi_stm32g0 and only complete commands if the completion bit matches. [1] https://lore.kernel.org/lkml/20240121204123.275441-3-lk@xxxxxxx/ Fixes: 72849d4fcee7 ("usb: typec: ucsi: stm32g0: add support for stm32g0 controller") Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx> Link: https://lore.kernel.org/stable/20240612124656.2305603-1-fabrice.gasnier%40foss.st.com Cc: stable <stable@xxxxxxxxxx> Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20240612124656.2305603-1-fabrice.gasnier@xxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/typec/ucsi/ucsi_stm32g0.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) --- a/drivers/usb/typec/ucsi/ucsi_stm32g0.c +++ b/drivers/usb/typec/ucsi/ucsi_stm32g0.c @@ -64,6 +64,7 @@ struct ucsi_stm32g0 { struct completion complete; struct device *dev; unsigned long flags; +#define ACK_PENDING 2 const char *fw_name; struct ucsi *ucsi; bool suspended; @@ -395,9 +396,13 @@ static int ucsi_stm32g0_sync_write(struc size_t len) { struct ucsi_stm32g0 *g0 = ucsi_get_drvdata(ucsi); + bool ack = UCSI_COMMAND(*(u64 *)val) == UCSI_ACK_CC_CI; int ret; - set_bit(COMMAND_PENDING, &g0->flags); + if (ack) + set_bit(ACK_PENDING, &g0->flags); + else + set_bit(COMMAND_PENDING, &g0->flags); ret = ucsi_stm32g0_async_write(ucsi, offset, val, len); if (ret) @@ -405,9 +410,14 @@ static int ucsi_stm32g0_sync_write(struc if (!wait_for_completion_timeout(&g0->complete, msecs_to_jiffies(5000))) ret = -ETIMEDOUT; + else + return 0; out_clear_bit: - clear_bit(COMMAND_PENDING, &g0->flags); + if (ack) + clear_bit(ACK_PENDING, &g0->flags); + else + clear_bit(COMMAND_PENDING, &g0->flags); return ret; } @@ -428,8 +438,9 @@ static irqreturn_t ucsi_stm32g0_irq_hand if (UCSI_CCI_CONNECTOR(cci)) ucsi_connector_change(g0->ucsi, UCSI_CCI_CONNECTOR(cci)); - if (test_bit(COMMAND_PENDING, &g0->flags) && - cci & (UCSI_CCI_ACK_COMPLETE | UCSI_CCI_COMMAND_COMPLETE)) + if (cci & UCSI_CCI_ACK_COMPLETE && test_and_clear_bit(ACK_PENDING, &g0->flags)) + complete(&g0->complete); + if (cci & UCSI_CCI_COMMAND_COMPLETE && test_and_clear_bit(COMMAND_PENDING, &g0->flags)) complete(&g0->complete); return IRQ_HANDLED; Patches currently in stable-queue which might be from fabrice.gasnier@xxxxxxxxxxx are queue-6.1/usb-ucsi-stm32-fix-command-completion-handling.patch
