If firmware loading fails, the controller's pm_state is updated to MHI_PM_FW_DL_ERR unconditionally. This can corrupt the pm_state as the update is not done under the proper lock, and also does not validate the state transition. The firmware loading can fail due to a detected syserr, but if MHI_PM_FW_DL_ERR is unconditionally set as the pm_state, the handling of the syserr can break when it attempts to transition from syserr detect, to syserr process.
By grabbing the lock, we ensure we don't race with some other pm_state update. By using mhi_try_set_pm_state(), we check that the transition to MHI_PM_FW_DL_ERR is valid via the state machine logic. If it is not valid, then some other transition is occurring like syserr processing, and we assume that will resolve the firmware loading error.
Fixes: 12e050c77be0 ("bus: mhi: core: Move to an error state on any firmware load failure") Cc: stable@vger.kernel.org Signed-off-by: Jeffrey Hugo quic_jhugo@quicinc.com Reviewed-by: Carl Vanderlip quic_carlv@quicinc.com Reviewed-by: Manivannan Sadhasivam mani@kernel.org --- drivers/bus/mhi/host/boot.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/bus/mhi/host/boot.c b/drivers/bus/mhi/host/boot.c index 1c69fee..d2a19b07 100644 --- a/drivers/bus/mhi/host/boot.c +++ b/drivers/bus/mhi/host/boot.c @@ -391,6 +391,7 @@ void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl) { const struct firmware *firmware = NULL; struct device *dev = &mhi_cntrl->mhi_dev->dev; + enum mhi_pm_state new_state; const char *fw_name; void *buf; dma_addr_t dma_addr; @@ -508,14 +509,18 @@ void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl) }
error_fw_load: - mhi_cntrl->pm_state = MHI_PM_FW_DL_ERR; - wake_up_all(&mhi_cntrl->state_event); + write_lock_irq(&mhi_cntrl->pm_lock); + new_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_FW_DL_ERR); + write_unlock_irq(&mhi_cntrl->pm_lock); + if (new_state == MHI_PM_FW_DL_ERR) + wake_up_all(&mhi_cntrl->state_event); }
int mhi_download_amss_image(struct mhi_controller *mhi_cntrl) { struct image_info *image_info = mhi_cntrl->fbc_image; struct device *dev = &mhi_cntrl->mhi_dev->dev; + enum mhi_pm_state new_state; int ret;
if (!image_info) @@ -526,8 +531,11 @@ int mhi_download_amss_image(struct mhi_controller *mhi_cntrl) &image_info->mhi_buf[image_info->entries - 1]); if (ret) { dev_err(dev, "MHI did not load AMSS, ret:%d\n", ret); - mhi_cntrl->pm_state = MHI_PM_FW_DL_ERR; - wake_up_all(&mhi_cntrl->state_event); + write_lock_irq(&mhi_cntrl->pm_lock); + new_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_FW_DL_ERR); + write_unlock_irq(&mhi_cntrl->pm_lock); + if (new_state == MHI_PM_FW_DL_ERR) + wake_up_all(&mhi_cntrl->state_event); }
return ret;