linux-kernel - [PATCH] bus: mhi: ep: Power up/down MHI stack during MHI RESET

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Message-Id: <20220502043152.16675-1-manivannan.sadhasivam@linaro.org>
Date:   Mon,  2 May 2022 10:01:52 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     mhi@...ts.linux.dev
Cc:     linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        quic_hemantk@...cinc.com, quic_bbhatt@...cinc.com,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Subject: [PATCH] bus: mhi: ep: Power up/down MHI stack during MHI RESET

During graceful shutdown scenario, host will issue MHI RESET to the
endpoint device before initiating shutdown. In that case, it makes sense
to completely power down the MHI stack as sooner or later the access to
MMIO registers will be prohibited. Also, the stack needs to be powered
up in the case of SYS_ERR to recover the device.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
---
 drivers/bus/mhi/ep/main.c | 33 +++++++--------------------------
 1 file changed, 7 insertions(+), 26 deletions(-)

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index 40109a79017a..2de7ef20225a 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -977,7 +977,7 @@ static void mhi_ep_reset_worker(struct work_struct *work)
 	enum mhi_state cur_state;
 	int ret;
 
-	mhi_ep_abort_transfer(mhi_cntrl);
+	mhi_ep_power_down(mhi_cntrl);
 
 	spin_lock_bh(&mhi_cntrl->state_lock);
 	/* Reset MMIO to signal host that the MHI_RESET is completed in endpoint */
@@ -990,27 +990,8 @@ static void mhi_ep_reset_worker(struct work_struct *work)
 	 * issue reset during shutdown also and we don't need to do re-init in
 	 * that case.
 	 */
-	if (cur_state == MHI_STATE_SYS_ERR) {
-		mhi_ep_mmio_init(mhi_cntrl);
-
-		/* Set AMSS EE before signaling ready state */
-		mhi_ep_mmio_set_env(mhi_cntrl, MHI_EE_AMSS);
-
-		/* All set, notify the host that we are ready */
-		ret = mhi_ep_set_ready_state(mhi_cntrl);
-		if (ret)
-			return;
-
-		dev_dbg(dev, "READY state notification sent to the host\n");
-
-		ret = mhi_ep_enable(mhi_cntrl);
-		if (ret) {
-			dev_err(dev, "Failed to enable MHI endpoint: %d\n", ret);
-			return;
-		}
-
-		enable_irq(mhi_cntrl->irq);
-	}
+	if (cur_state == MHI_STATE_SYS_ERR)
+		mhi_ep_power_up(mhi_cntrl);
 }
 
 /*
@@ -1089,11 +1070,11 @@ EXPORT_SYMBOL_GPL(mhi_ep_power_up);
 
 void mhi_ep_power_down(struct mhi_ep_cntrl *mhi_cntrl)
 {
-	if (mhi_cntrl->enabled)
+	if (mhi_cntrl->enabled) {
 		mhi_ep_abort_transfer(mhi_cntrl);
-
-	kfree(mhi_cntrl->mhi_event);
-	disable_irq(mhi_cntrl->irq);
+		kfree(mhi_cntrl->mhi_event);
+		disable_irq(mhi_cntrl->irq);
+	}
 }
 EXPORT_SYMBOL_GPL(mhi_ep_power_down);
 
-- 
2.25.1