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bus: mhi: core: Add support for forced PM resume

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For whatever reason, some devices like QCA6390, WCN6855 using ath11k
are not in M3 state during PM resume, but still functional. The
mhi_pm_resume should then not fail in those cases, and let the higher
level device specific stack continue resuming process.

Add an API mhi_pm_resume_force(), to force resuming irrespective of the
current MHI state. This fixes a regression with non functional ath11k WiFi
after suspend/resume cycle on some machines.

Bug report: https://bugzilla.kernel.org/show_bug.cgi?id=214179

Link: https://lore.kernel.org/regressions/871r5p0x2u.fsf@codeaurora.org/
Fixes: 020d3b26c0 ("bus: mhi: Early MHI resume failure in non M3 state")
Cc: stable@vger.kernel.org #5.13
Reported-by: Kalle Valo <kvalo@codeaurora.org>
Reported-by: Pengyu Ma <mapengyu@gmail.com>
Tested-by: Kalle Valo <kvalo@kernel.org>
Acked-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
[mani: Switched to API, added bug report, reported-by tags and CCed stable]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20211209131633.4168-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Loic Poulain 2021-12-09 18:46:33 +05:30 • committed by Greg Kroah-Hartman
parent 7c602f5d04
commit cab2d3fd68
3 changed files with 36 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

21
drivers/bus/mhi/core/pm.c
View file

@ -881,7 +881,7 @@ int mhi_pm_suspend(struct mhi_controller *mhi_cntrl)
}
EXPORT_SYMBOL_GPL(mhi_pm_suspend);
int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
static int __mhi_pm_resume(struct mhi_controller *mhi_cntrl, bool force)
{
struct mhi_chan *itr, *tmp;
struct device *dev = &mhi_cntrl->mhi_dev->dev;
@ -898,8 +898,12 @@ int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
return -EIO;
if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3)
return -EINVAL;
if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3) {
dev_warn(dev, "Resuming from non M3 state (%s)\n",
TO_MHI_STATE_STR(mhi_get_mhi_state(mhi_cntrl)));
if (!force)
return -EINVAL;
}
/* Notify clients about exiting LPM */
list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
@ -940,8 +944,19 @@ int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
return 0;
}
int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
{
return __mhi_pm_resume(mhi_cntrl, false);
}
EXPORT_SYMBOL_GPL(mhi_pm_resume);
int mhi_pm_resume_force(struct mhi_controller *mhi_cntrl)
{
return __mhi_pm_resume(mhi_cntrl, true);
}
EXPORT_SYMBOL_GPL(mhi_pm_resume_force);
int __mhi_device_get_sync(struct mhi_controller *mhi_cntrl)
{
int ret;

6
drivers/net/wireless/ath/ath11k/mhi.c
View file

@ -533,7 +533,11 @@ static int ath11k_mhi_set_state(struct ath11k_pci *ab_pci,
ret = mhi_pm_suspend(ab_pci->mhi_ctrl);
break;
case ATH11K_MHI_RESUME:
ret = mhi_pm_resume(ab_pci->mhi_ctrl);
/* Do force MHI resume as some devices like QCA6390, WCN6855
* are not in M3 state but they are functional. So just ignore
* the MHI state while resuming.
*/
ret = mhi_pm_resume_force(ab_pci->mhi_ctrl);
break;
case ATH11K_MHI_TRIGGER_RDDM:
ret = mhi_force_rddm_mode(ab_pci->mhi_ctrl);

13
include/linux/mhi.h
View file

@ -663,6 +663,19 @@ int mhi_pm_suspend(struct mhi_controller *mhi_cntrl);
*/
int mhi_pm_resume(struct mhi_controller *mhi_cntrl);
/**
* mhi_pm_resume_force - Force resume MHI from suspended state
* @mhi_cntrl: MHI controller
*
* Resume the device irrespective of its MHI state. As per the MHI spec, devices
* has to be in M3 state during resume. But some devices seem to be in a
* different MHI state other than M3 but they continue working fine if allowed.
* This API is intented to be used for such devices.
*
* Return: 0 if the resume succeeds, a negative error code otherwise
*/
int mhi_pm_resume_force(struct mhi_controller *mhi_cntrl);
/**
* mhi_download_rddm_image - Download ramdump image from device for
* debugging purpose.