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bus: mhi: core: Fix race while handling SYS_ERR at power up

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During SYS_ERR condition, as a response to the MHI_RESET from host, some
devices tend to issue BHI interrupt without clearing the SYS_ERR state in
the device. 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 the BHI
interrupt to the host without clearing SYS_ERR condition. So the host
starts handling the SYS_ERR condition again.

To fix this issue, let's register the IRQ handler only after handling the
SYS_ERR check to avoid getting spurious IRQs from the device.

Fixes: e18d4e9fa7 ("bus: mhi: core: Handle syserr during power_up")
Cc: stable@vger.kernel.org
Reported-by: Aleksander Morgado <aleksander@aleksander.es>
Tested-by: Aleksander Morgado <aleksander@aleksander.es>
Tested-by: Thomas Perrot <thomas.perrot@bootlin.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20211216081227.237749-8-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Manivannan Sadhasivam 2021-12-16 13:42:24 +05:30 committed by Greg Kroah-Hartman
parent 42c4668f7e
commit d651ce8e91
1 changed files with 12 additions and 23 deletions
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35
drivers/bus/mhi/core/pm.c
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@ -1053,7 +1053,7 @@ 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");
@ -1070,10 +1070,6 @@ 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);
@ -1087,7 +1083,7 @@ 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_exit;
}
state = mhi_get_mhi_state(mhi_cntrl);
@ -1096,20 +1092,12 @@ 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,
interval_us);
if (ret) {
dev_info(dev, "Failed to reset MHI due to syserr state\n");
goto error_async_power_up;
goto error_exit;
}
/*
@ -1119,6 +1107,10 @@ 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_exit;
/* Transition to next state */
next_state = MHI_IN_PBL(current_ee) ?
DEV_ST_TRANSITION_PBL : DEV_ST_TRANSITION_READY;
@ -1131,10 +1123,7 @@ 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:
error_exit:
mhi_cntrl->pm_state = MHI_PM_DISABLE;
mutex_unlock(&mhi_cntrl->pm_mutex);