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From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: gregkh@linuxfoundation.org
Cc: hemantk@codeaurora.org, bbhatt@codeaurora.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	loic.poulain@linaro.org, stable@vger.kernel.org,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Subject: [PATCH 2/8] bus: mhi: core: Fix power down latency
Date: Mon, 21 Jun 2021 21:46:10 +0530	[thread overview]
Message-ID: <20210621161616.77524-3-manivannan.sadhasivam@linaro.org> (raw)
In-Reply-To: <20210621161616.77524-1-manivannan.sadhasivam@linaro.org>

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

On graceful power-down/disable transition, when an MHI reset is
performed, the MHI device loses its context, including interrupt
configuration. However, the current implementation is waiting for
event(irq) driven state change to confirm reset has been completed,
which never happens, and causes reset timeout, leading to unexpected
high latency of the mhi_power_down procedure (up to 45 seconds).

Fix that by moving to the recently introduced poll_reg_field method,
waiting for the reset bit to be cleared, in the same way as the
power_on procedure.

Cc: stable@vger.kernel.org
Fixes: a6e2e3522f29 ("bus: mhi: core: Add support for PM state transitions")
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Link: https://lore.kernel.org/r/1620029090-8975-1-git-send-email-loic.poulain@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/bus/mhi/core/pm.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index e2e59a341fef..704a5e225097 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -465,23 +465,15 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
 
 	/* Trigger MHI RESET so that the device will not access host memory */
 	if (!MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) {
-		u32 in_reset = -1;
-		unsigned long timeout = msecs_to_jiffies(mhi_cntrl->timeout_ms);
-
 		dev_dbg(dev, "Triggering MHI Reset in device\n");
 		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);
 
 		/* Wait for the reset bit to be cleared by the device */
-		ret = wait_event_timeout(mhi_cntrl->state_event,
-					 mhi_read_reg_field(mhi_cntrl,
-							    mhi_cntrl->regs,
-							    MHICTRL,
-							    MHICTRL_RESET_MASK,
-							    MHICTRL_RESET_SHIFT,
-							    &in_reset) ||
-					!in_reset, timeout);
-		if (!ret || in_reset)
-			dev_err(dev, "Device failed to exit MHI Reset state\n");
+		ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL,
+				 MHICTRL_RESET_MASK, MHICTRL_RESET_SHIFT, 0,
+				 25000);
+		if (ret)
+			dev_err(dev, "Device failed to clear MHI Reset\n");
 
 		/*
 		 * Device will clear BHI_INTVEC as a part of RESET processing,
-- 
2.25.1


  parent reply	other threads:[~2021-06-21 16:16 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-21 16:16 [PATCH 0/8] MHI patches for v5.14 Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 1/8] bus: mhi: core: Validate channel ID when processing command completions Manivannan Sadhasivam
2021-06-24 13:50   ` Greg KH
2021-06-24 14:32     ` Manivannan Sadhasivam
2021-06-24 14:39       ` Greg KH
2021-06-24 14:47         ` Manivannan Sadhasivam
2021-06-24 15:27           ` Greg KH
2021-06-24 15:56             ` Manivannan Sadhasivam
2021-06-21 16:16 ` Manivannan Sadhasivam [this message]
2021-06-21 16:16 ` [PATCH 3/8] bus: mhi: Wait for M2 state during system resume Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 4/8] bus: mhi: Add inbound buffers allocation flag Manivannan Sadhasivam
2021-06-24 13:51   ` Greg KH
2021-06-24 15:39     ` Loic Poulain
2021-06-24 16:48       ` Greg KH
2021-06-24 19:01         ` Loic Poulain
2021-06-21 16:16 ` [PATCH 5/8] bus: mhi: pci-generic: Add missing 'pci_disable_pcie_error_reporting()' calls Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 6/8] bus: mhi: core: Add support for processing priority of event ring Manivannan Sadhasivam
2021-06-24 13:53   ` Greg KH
2021-06-24 14:24     ` Manivannan Sadhasivam
2021-06-24 14:40       ` Greg KH
2021-06-24 14:50         ` Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 7/8] bus: mhi: pci_generic: Apply no-op for wake using sideband wake boolean Manivannan Sadhasivam
2021-06-24 13:54   ` Greg KH
2021-06-21 16:16 ` [PATCH 8/8] bus: mhi: pci_generic: Add Cinterion MV31-W PCIe to MHI Manivannan Sadhasivam
2021-06-24 13:54   ` Greg KH
2021-06-24 13:54 ` [PATCH 0/8] MHI patches for v5.14 Greg KH
2021-06-24 14:20   ` Manivannan Sadhasivam

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