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From:   Bhaumik Bhatt <bbhatt@codeaurora.org>
To:     manivannan.sadhasivam@linaro.org
Cc:     linux-arm-msm@vger.kernel.org, hemantk@codeaurora.org,
        jhugo@codeaurora.org, linux-kernel@vger.kernel.org,
        Bhaumik Bhatt <bbhatt@codeaurora.org>
Subject: [PATCH v1 07/10] bus: mhi: core: Move to SYS_ERROR regardless of RDDM capability
Date:   Fri, 18 Sep 2020 19:02:32 -0700
Message-Id: <1600480955-16827-8-git-send-email-bbhatt@codeaurora.org>
In-Reply-To: <1600480955-16827-1-git-send-email-bbhatt@codeaurora.org>
References: <1600480955-16827-1-git-send-email-bbhatt@codeaurora.org>
Precedence: bulk

In some cases, the entry of device to RDDM execution environment
can occur after a significant amount of time has elapsed after the
SYS_ERROR state change event has arrived. This can result in scenarios
where users of the MHI bus are unaware of the error state of the
device. Hence, moving the MHI bus to a SYS_ERROR detected state will
prevent further client activity and wait for the RDDM entry.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
---
 drivers/bus/mhi/core/main.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 2cff5dd..1c8e332 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -376,6 +376,7 @@ irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *priv)
 	enum mhi_state state = MHI_STATE_MAX;
 	enum mhi_pm_state pm_state = 0;
 	enum mhi_ee_type ee = 0;
+	bool handle_rddm = false;
 
 	write_lock_irq(&mhi_cntrl->pm_lock);
 	if (!MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state)) {
@@ -400,6 +401,17 @@ irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *priv)
 	 /* If device supports RDDM don't bother processing SYS error */
 	if (mhi_cntrl->rddm_image) {
 		if (mhi_cntrl->ee == MHI_EE_RDDM && mhi_cntrl->ee != ee) {
+			/* prevent clients from queueing any more packets */
+			write_lock_irq(&mhi_cntrl->pm_lock);
+			pm_state = mhi_tryset_pm_state(mhi_cntrl,
+						       MHI_PM_SYS_ERR_DETECT);
+			if (pm_state == MHI_PM_SYS_ERR_DETECT)
+				handle_rddm = true;
+			write_unlock_irq(&mhi_cntrl->pm_lock);
+		}
+
+		if (handle_rddm) {
+			dev_err(dev, "RDDM event occurred!\n");
 			mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_EE_RDDM);
 			wake_up_all(&mhi_cntrl->state_event);
 		}
@@ -733,19 +745,15 @@ int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
 				break;
 			case MHI_STATE_SYS_ERR:
 			{
-				enum mhi_pm_state new_state;
-
-				/* skip SYS_ERROR handling if RDDM supported */
-				if (mhi_cntrl->ee == MHI_EE_RDDM ||
-				    mhi_cntrl->rddm_image)
-					break;
+				enum mhi_pm_state state = MHI_PM_STATE_MAX;
 
 				dev_dbg(dev, "System error detected\n");
 				write_lock_irq(&mhi_cntrl->pm_lock);
-				new_state = mhi_tryset_pm_state(mhi_cntrl,
+				if (mhi_cntrl->ee != MHI_EE_RDDM)
+					state = mhi_tryset_pm_state(mhi_cntrl,
 							MHI_PM_SYS_ERR_DETECT);
 				write_unlock_irq(&mhi_cntrl->pm_lock);
-				if (new_state == MHI_PM_SYS_ERR_DETECT)
+				if (state == MHI_PM_SYS_ERR_DETECT)
 					mhi_pm_sys_err_handler(mhi_cntrl);
 				break;
 			}
-- 
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