[PATCH] bus: mhi: core: Resume success on SYS_ERR

From: Loic Poulain <loic.poulain@linaro.org>
To: mani@kernel.org, hemantk@codeaurora.org
Cc: bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org,
	Loic Poulain <loic.poulain@linaro.org>
Subject: [PATCH] bus: mhi: core: Resume success on SYS_ERR
Date: Mon, 31 May 2021 10:30:13 +0200	[thread overview]
Message-ID: <1622449813-3850-1-git-send-email-loic.poulain@linaro.org> (raw)

When a crash occurs while in suspended state M3/D3hot, the host
only discovers SYS_ERR pm-state change on resume. Handle this
state as valid transition for resume procedure, giving a chance
to the MHI core to manage the state (sbl transition, etc...).

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
---
 drivers/bus/mhi/core/pm.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 704a5e2..e8eae4f 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -898,8 +898,27 @@ 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_SYS_ERR) {
+		/* If we are in SYS_ERR state, let MHI stack manages the error
+		 * and resume successfully.
+		 */
+		dev_warn(dev, "Entered error while suspended\n");
+
+		write_lock_irq(&mhi_cntrl->pm_lock);
+		cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_SYS_ERR_DETECT);
+		write_unlock_irq(&mhi_cntrl->pm_lock);
+
+		if (cur_state == MHI_PM_SYS_ERR_DETECT) {
+			mhi_pm_sys_err_handler(mhi_cntrl);
+			return 0;
+		}
+	}
+
+	if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3) {
+		dev_warn(dev, "Is not in M3 state, resume failed %d\n",
+			 mhi_get_mhi_state(mhi_cntrl));
 		return -EINVAL;
+	}
 
 	/* Notify clients about exiting LPM */
 	list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
-- 
2.7.4

