On 2021-11-08 09:49 AM, Manivannan Sadhasivam wrote:
Some devices tend to trigger SYS_ERR interrupt while the host handling SYS_ERR state of the device during power up. This creates a race condition and causes a failure in booting up the device.
The issue is seen on the Sierra Wireless EM9191 modem during SYS_ERR handling in mhi_async_power_up(). Once the host detects that the device is in SYS_ERR state, it issues MHI_RESET and waits for the device to process the reset request. During this time, the device triggers SYS_ERR interrupt to the host and host starts handling SYS_ERR execution.
So by the time the device has completed reset, host starts SYS_ERR handling. This causes the race condition and the modem fails to boot.
Hence, register the IRQ handler only after handling the SYS_ERR check to avoid getting spurious IRQs from the device.
Cc: stable@vger.kernel.org Fixes: e18d4e9fa79b ("bus: mhi: core: Handle syserr during power_up") Reported-by: Aleksander Morgado aleksander@aleksander.es Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org
Changes in v2:
- Switched to "mhi_poll_reg_field" for detecting MHI reset in device.
drivers/bus/mhi/core/pm.c | 32 ++++++++++---------------------- 1 file changed, 10 insertions(+), 22 deletions(-)
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index fb99e3727155..3c347fe9b10d 100644 --- a/drivers/bus/mhi/core/pm.c +++ b/drivers/bus/mhi/core/pm.c @@ -1038,7 +1038,6 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) enum mhi_ee_type current_ee; enum dev_st_transition next_state; struct device *dev = &mhi_cntrl->mhi_dev->dev;
- u32 val;
u32 interval_us = 25000; /* poll register field every 25 milliseconds */
int ret;
dev_info(dev, "Requested to power ON\n"); @@ -1055,10 +1054,6 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) mutex_lock(&mhi_cntrl->pm_mutex); mhi_cntrl->pm_state = MHI_PM_DISABLE;
- ret = mhi_init_irq_setup(mhi_cntrl);
- if (ret)
goto error_setup_irq;- /* Setup BHI INTVEC */ write_lock_irq(&mhi_cntrl->pm_lock); mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
Let's also set the BHI INTVEC up _after_ the IRQ setup is done. I believe doing this before setting up IRQs may be racy.
@@ -1072,7 +1067,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) dev_err(dev, "%s is not a valid EE for power on\n", TO_MHI_EXEC_STR(current_ee)); ret = -EIO;
goto error_async_power_up;
goto error_setup_irq;}
state = mhi_get_mhi_state(mhi_cntrl);
@@ -1081,20 +1076,12 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
if (state == MHI_STATE_SYS_ERR) { mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);
ret = wait_event_timeout(mhi_cntrl->state_event,MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state) ||mhi_read_reg_field(mhi_cntrl,mhi_cntrl->regs,MHICTRL,MHICTRL_RESET_MASK,MHICTRL_RESET_SHIFT,&val) ||!val,msecs_to_jiffies(mhi_cntrl->timeout_ms));if (!ret) {ret = -EIO;
ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL,MHICTRL_RESET_MASK, MHICTRL_RESET_SHIFT, 0,msecs_to_jiffies(mhi_cntrl->timeout_ms));
Use "interval_us" as the last argument here since this API takes the polling interval value in microseconds as the last argument.
if (ret) { dev_info(dev, "Failed to reset MHI due to syserr state\n");
goto error_async_power_up;
goto error_setup_irq;}
/*
@@ -1104,6 +1091,10 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0); }
- ret = mhi_init_irq_setup(mhi_cntrl);
- if (ret)
goto error_setup_irq;- /* Transition to next state */ next_state = MHI_IN_PBL(current_ee) ? DEV_ST_TRANSITION_PBL : DEV_ST_TRANSITION_READY;
@@ -1116,9 +1107,6 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
return 0;
-error_async_power_up:
- mhi_deinit_free_irq(mhi_cntrl);
error_setup_irq: mhi_cntrl->pm_state = MHI_PM_DISABLE; mutex_unlock(&mhi_cntrl->pm_mutex);
Thanks, Bhaumik --- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project