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Commit 4e2f7cbc authored by Hemant Kumar's avatar Hemant Kumar Committed by Gerrit - the friendly Code Review server
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pci: msm: Add support to handle ep driver requested link down 



In case PCIe endpoint driver infers link down because of
completion timeout for config space access or if link fails
to enumerate, ep driver can request to handle the link down.
This allows to stream line the link down notification to ep
driver to initiate recovery operation.

Change-Id: I652e60e570c1e90c9f96d1c197e4b5501cd60a1e
Signed-off-by: default avatarHemant Kumar <hemantk@codeaurora.org>
parent ac3ef5b4

drivers/pci/controller/pci-msm.c

+51 −38
Original line number Diff line number Diff line
@@ -5034,41 +5034,22 @@ static irqreturn_t handle_wake_irq(int irq, void *data) 
	return IRQ_HANDLED;

}



static irqreturn_t handle_linkdown_irq(int irq, void *data)

static void msm_pcie_handle_linkdown(struct msm_pcie_dev_t *dev)

{

	struct msm_pcie_dev_t *dev = data;

	int i;



	dev->linkdown_counter++;



	PCIE_DBG(dev,

		"PCIe: No. %ld linkdown IRQ for RC%d.\n",

		dev->linkdown_counter, dev->rc_idx);

	if (dev->link_status == MSM_PCIE_LINK_DOWN)

		return;



	if (!dev->enumerated || dev->link_status != MSM_PCIE_LINK_ENABLED) {

		PCIE_DBG(dev,

			"PCIe:Linkdown IRQ for RC%d when the link is not enabled\n",

			dev->rc_idx);

	} else if (dev->suspending) {

		PCIE_DBG(dev,

			"PCIe:the link of RC%d is suspending.\n",

			dev->rc_idx);

	} else {

	dev->link_status = MSM_PCIE_LINK_DOWN;

	dev->shadow_en = false;



	/* PCIe registers dump on link down */

		if ((dev->rc_idx == 0) || (dev->rc_idx == 2)) {

			PCIE_DUMP(dev,

			"PCIe:Linkdown IRQ for RC%d Dumping PCIe registers\n",

	PCIE_DUMP(dev, "PCIe:Linkdown IRQ for RC%d Dumping PCIe registers\n",

		dev->rc_idx);

	pcie_phy_dump(dev);

	pcie_parf_dump(dev);

	pcie_dm_core_dump(dev);

		}



		if (dev->linkdown_panic)

			panic("User has chosen to panic on linkdown\n");



	/* assert PERST */

	if (!(msm_pcie_keep_resources_on & BIT(dev->rc_idx)))
@@ -5077,6 +5058,9 @@ static irqreturn_t handle_linkdown_irq(int irq, void *data) 


	PCIE_ERR(dev, "PCIe link is down for RC%d\n", dev->rc_idx);



	if (dev->linkdown_panic)

		panic("User has chosen to panic on linkdown\n");



	if (dev->num_ep > 1) {

		for (i = 0; i < MAX_DEVICE_NUM; i++) {

			dev->event_reg =
@@ -5089,6 +5073,27 @@ static irqreturn_t handle_linkdown_irq(int irq, void *data) 
	}

}



static irqreturn_t handle_linkdown_irq(int irq, void *data)

{

	struct msm_pcie_dev_t *dev = data;



	dev->linkdown_counter++;



	PCIE_DBG(dev,

		"PCIe: No. %ld linkdown IRQ for RC%d.\n",

		dev->linkdown_counter, dev->rc_idx);



	if (!dev->enumerated || dev->link_status != MSM_PCIE_LINK_ENABLED)

		PCIE_DBG(dev,

			"PCIe:Linkdown IRQ for RC%d when the link is not enabled\n",

			dev->rc_idx);

	else if (dev->suspending)

		PCIE_DBG(dev,

			"PCIe:the link of RC%d is suspending.\n",

			dev->rc_idx);

	else

		msm_pcie_handle_linkdown(dev);



	return IRQ_HANDLED;

}
@@ -7151,6 +7156,7 @@ int msm_pcie_pm_control(enum msm_pcie_pm_opt pm_opt, u32 busnr, void *user, 
	int ret = 0;

	struct pci_dev *dev;

	u32 rc_idx = 0;

	unsigned long flags;

	struct msm_pcie_dev_t *pcie_dev;



	PCIE_GEN_DBG("PCIe: pm_opt:%d;busnr:%d;options:%d\n",
@@ -7300,6 +7306,13 @@ int msm_pcie_pm_control(enum msm_pcie_pm_opt pm_opt, u32 busnr, void *user, 
		spin_unlock_irqrestore(&msm_pcie_dev[rc_idx].cfg_lock,

				msm_pcie_dev[rc_idx].irqsave_flags);

		break;

	case MSM_PCIE_HANDLE_LINKDOWN:

		PCIE_DBG(&msm_pcie_dev[rc_idx],

			"User of RC%d requests handling link down.\n", rc_idx);

		spin_lock_irqsave(&msm_pcie_dev[rc_idx].irq_lock, flags);

		msm_pcie_handle_linkdown(pcie_dev);

		spin_unlock_irqrestore(&msm_pcie_dev[rc_idx].irq_lock, flags);

		break;

	default:

		PCIE_ERR(&msm_pcie_dev[rc_idx],

			"PCIe: RC%d: unsupported pm operation:%d.\n",

include/linux/msm_pcie.h

+2 −1
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright (c) 2014-2019, The Linux Foundation. All rights reserved.*/

/* Copyright (c) 2014-2020, The Linux Foundation. All rights reserved.*/



#ifndef __MSM_PCIE_H

#define __MSM_PCIE_H
@@ -21,6 +21,7 @@ enum msm_pcie_pm_opt { 
	MSM_PCIE_RESUME,

	MSM_PCIE_DISABLE_PC,

	MSM_PCIE_ENABLE_PC,

	MSM_PCIE_HANDLE_LINKDOWN,

};



enum msm_pcie_event {