Commit cab2d3fd authored by Loic Poulain's avatar Loic Poulain Committed by Greg Kroah-Hartman
Browse files

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

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: 020d3b26 ("bus: mhi: Early MHI resume failure in non M3 state")
Cc: stable@vger.kernel.org #5.13
Reported-by: default avatarKalle Valo <kvalo@codeaurora.org>
Reported-by: default avatarPengyu Ma <mapengyu@gmail.com>
Tested-by: default avatarKalle Valo <kvalo@kernel.org>
Acked-by: default avatarKalle Valo <kvalo@kernel.org>
Signed-off-by: default avatarLoic Poulain <loic.poulain@linaro.org>
[mani: Switched to API, added bug report, reported-by tags and CCed stable]
Signed-off-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20211209131633.4168-1-manivannan.sadhasivam@linaro.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7c602f5d

drivers/bus/mhi/core/pm.c

+18 −3
Original line number Diff line number Diff line
@@ -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)

	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;

drivers/net/wireless/ath/ath11k/mhi.c

+5 −1
Original line number Diff line number Diff line
@@ -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);

include/linux/mhi.h

+13 −0
Original line number Diff line number Diff line
@@ -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.