linux-kernel - [PATCH v1 3/7] bus: mhi: core: Handle EDL mode entry appropriately

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Date:   Mon, 29 Mar 2021 18:28:20 -0700
From:   Bhaumik Bhatt <bbhatt@...eaurora.org>
To:     manivannan.sadhasivam@...aro.org
Cc:     linux-arm-msm@...r.kernel.org, hemantk@...eaurora.org,
        jhugo@...eaurora.org, linux-kernel@...r.kernel.org,
        carl.yin@...ctel.com, naveen.kumar@...ctel.com,
        loic.poulain@...aro.org, abickett@...eaurora.org,
        Bhaumik Bhatt <bbhatt@...eaurora.org>
Subject: [PATCH v1 3/7] bus: mhi: core: Handle EDL mode entry appropriately

Device entering EDL or Emergency Download Mode will be in a
SYS_ERROR MHI state. This requires MHI host to proceed with the
EDL image download over BHI before device can enter an MHI READY
state and proceed with further bootup. Allow this to be handled
by relying on the execution environment check after SYS_ERROR
processing to determine whether to wait for an MHI READY or
download the EDL image over BHI after moving MHI PM state to
Power on Reset internally. This way handling is contained well
within the MHI core driver and helps pave the way for Flash
Programmer execution environment functionality.

Signed-off-by: Bhaumik Bhatt <bbhatt@...eaurora.org>
---
 drivers/bus/mhi/core/pm.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index fbe9447..b65222e 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -564,6 +564,7 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
 static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl)
 {
 	enum mhi_pm_state cur_state, prev_state;
+	enum dev_st_transition next_state;
 	struct mhi_event *mhi_event;
 	struct mhi_cmd_ctxt *cmd_ctxt;
 	struct mhi_cmd *mhi_cmd;
@@ -677,7 +678,23 @@ static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl)
 		er_ctxt->wp = er_ctxt->rbase;
 	}
 
-	mhi_ready_state_transition(mhi_cntrl);
+	/* Transition to next state */
+	if (MHI_IN_PBL(mhi_get_exec_env(mhi_cntrl))) {
+		write_lock_irq(&mhi_cntrl->pm_lock);
+		cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_POR);
+		write_unlock_irq(&mhi_cntrl->pm_lock);
+		if (cur_state != MHI_PM_POR) {
+			dev_err(dev, "Error moving to state %s from %s\n",
+				to_mhi_pm_state_str(MHI_PM_POR),
+				to_mhi_pm_state_str(cur_state));
+			goto exit_sys_error_transition;
+		}
+		next_state = DEV_ST_TRANSITION_PBL;
+	} else {
+		next_state = DEV_ST_TRANSITION_READY;
+	}
+
+	mhi_queue_state_transition(mhi_cntrl, next_state);
 
 exit_sys_error_transition:
 	dev_dbg(dev, "Exiting with PM state: %s, MHI state: %s\n",
-- 
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