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From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: gregkh@linuxfoundation.org
Cc: mhi@lists.linux.dev, hemantk@codeaurora.org,
	bbhatt@codeaurora.org, loic.poulain@linaro.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
	kvalo@codeaurora.org, stable@vger.kernel.org,
	Pengyu Ma <mapengyu@gmail.com>, Kalle Valo <kvalo@kernel.org>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Subject: [PATCH 1/1] bus: mhi: core: Add support for forced PM resume
Date: Wed,  8 Dec 2021 14:27:35 +0530	[thread overview]
Message-ID: <20211208085735.196394-2-manivannan.sadhasivam@linaro.org> (raw)
In-Reply-To: <20211208085735.196394-1-manivannan.sadhasivam@linaro.org>

From: Loic Poulain <loic.poulain@linaro.org>

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 a new parameter to mhi_pm_resume, to force resuming, whatever the
current MHI state is. 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

Fixes: 020d3b26c07a ("bus: mhi: Early MHI resume failure in non M3 state")
Cc: stable@vger.kernel.org #5.13
Link: https://lore.kernel.org/regressions/871r5p0x2u.fsf@codeaurora.org/
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: Added comment, bug report, reported-by tags and CCed stable]
Link: https://lore.kernel.org/r/20211206161059.107007-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/bus/mhi/core/pm.c             | 10 +++++++---
 drivers/bus/mhi/pci_generic.c         |  2 +-
 drivers/net/wireless/ath/ath11k/mhi.c |  6 +++++-
 include/linux/mhi.h                   |  3 ++-
 4 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index fb99e3727155..8a486374d57a 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -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)
+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) {
diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
index 4c577a731709..3394819e8115 100644
--- a/drivers/bus/mhi/pci_generic.c
+++ b/drivers/bus/mhi/pci_generic.c
@@ -962,7 +962,7 @@ static int __maybe_unused mhi_pci_runtime_resume(struct device *dev)
 		return 0; /* Nothing to do at MHI level */
 
 	/* Exit M3, transition to M0 state */
-	err = mhi_pm_resume(mhi_cntrl);
+	err = mhi_pm_resume(mhi_cntrl, false);
 	if (err) {
 		dev_err(&pdev->dev, "failed to resume device: %d\n", err);
 		goto err_recovery;
diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c
index 26c7ae242db6..f1f2fa2d690d 100644
--- a/drivers/net/wireless/ath/ath11k/mhi.c
+++ b/drivers/net/wireless/ath/ath11k/mhi.c
@@ -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(ab_pci->mhi_ctrl, true);
 		break;
 	case ATH11K_MHI_TRIGGER_RDDM:
 		ret = mhi_force_rddm_mode(ab_pci->mhi_ctrl);
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 723985879035..102303288cee 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -660,8 +660,9 @@ int mhi_pm_suspend(struct mhi_controller *mhi_cntrl);
 /**
  * mhi_pm_resume - Resume MHI from suspended state
  * @mhi_cntrl: MHI controller
+ * @force: Force resuming to M0 irrespective of the device MHI state
  */
-int mhi_pm_resume(struct mhi_controller *mhi_cntrl);
+int mhi_pm_resume(struct mhi_controller *mhi_cntrl, bool force);
 
 /**
  * mhi_download_rddm_image - Download ramdump image from device for
-- 
2.25.1


       reply	other threads:[~2021-12-08  8:57 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20211208085735.196394-1-manivannan.sadhasivam@linaro.org>
2021-12-08  8:57 ` Manivannan Sadhasivam [this message]
2021-12-08  9:07   ` Greg KH
2021-12-08  9:40     ` Manivannan Sadhasivam

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