Commit 8562d4fe authored by Loic Poulain's avatar Loic Poulain Committed by Manivannan Sadhasivam
Browse files

mhi: pci_generic: Add health-check 



If the modem crashes for any reason, we may not be able to detect
it at MHI level (MHI registers not reachable anymore).

This patch implements a health-check mechanism to check regularly
that device is alive (MHI layer can communicate with). If device
is not alive (because a crash or unexpected reset), the recovery
procedure is triggered.

Tested successfully with Telit FN980m module.

Signed-off-by: default avatarLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: default avatarHemant Kumar <hemantk@codeaurora.org>
Signed-off-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
parent b012ee6b

drivers/bus/mhi/pci_generic.c

+35 −0
Original line number Diff line number Diff line
@@ -14,11 +14,15 @@ 
#include <linux/mhi.h>

#include <linux/module.h>

#include <linux/pci.h>

#include <linux/timer.h>

#include <linux/workqueue.h>



#define MHI_PCI_DEFAULT_BAR_NUM 0



#define MHI_POST_RESET_DELAY_MS 500



#define HEALTH_CHECK_PERIOD (HZ * 2)



/**

 * struct mhi_pci_dev_info - MHI PCI device specific information

 * @config: MHI controller configuration
@@ -189,6 +193,7 @@ struct mhi_pci_device { 
	struct mhi_controller mhi_cntrl;

	struct pci_saved_state *pci_state;

	struct work_struct recovery_work;

	struct timer_list health_check_timer;

	unsigned long status;

};
@@ -326,6 +331,8 @@ static void mhi_pci_recovery_work(struct work_struct *work) 


	dev_warn(&pdev->dev, "device recovery started\n");



	del_timer(&mhi_pdev->health_check_timer);



	/* Clean up MHI state */

	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {

		mhi_power_down(mhi_cntrl, false);
@@ -351,6 +358,7 @@ static void mhi_pci_recovery_work(struct work_struct *work) 
	dev_dbg(&pdev->dev, "Recovery completed\n");



	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);

	mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);

	return;



err_unprepare:
@@ -360,6 +368,21 @@ static void mhi_pci_recovery_work(struct work_struct *work) 
		dev_err(&pdev->dev, "Recovery failed\n");

}



static void health_check(struct timer_list *t)

{

	struct mhi_pci_device *mhi_pdev = from_timer(mhi_pdev, t, health_check_timer);

	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;



	if (!mhi_pci_is_alive(mhi_cntrl)) {

		dev_err(mhi_cntrl->cntrl_dev, "Device died\n");

		queue_work(system_long_wq, &mhi_pdev->recovery_work);

		return;

	}



	/* reschedule in two seconds */

	mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);

}



static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

{

	const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *) id->driver_data;
@@ -376,6 +399,7 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) 
		return -ENOMEM;



	INIT_WORK(&mhi_pdev->recovery_work, mhi_pci_recovery_work);

	timer_setup(&mhi_pdev->health_check_timer, health_check, 0);



	mhi_cntrl_config = info->config;

	mhi_cntrl = &mhi_pdev->mhi_cntrl;
@@ -427,6 +451,9 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) 


	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);



	/* start health check */

	mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);



	return 0;



err_unprepare:
@@ -442,6 +469,7 @@ static void mhi_pci_remove(struct pci_dev *pdev) 
	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);

	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;



	del_timer(&mhi_pdev->health_check_timer);

	cancel_work_sync(&mhi_pdev->recovery_work);



	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {
@@ -459,6 +487,8 @@ static void mhi_pci_reset_prepare(struct pci_dev *pdev) 


	dev_info(&pdev->dev, "reset\n");



	del_timer(&mhi_pdev->health_check_timer);



	/* Clean up MHI state */

	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {

		mhi_power_down(mhi_cntrl, false);
@@ -502,6 +532,7 @@ static void mhi_pci_reset_done(struct pci_dev *pdev) 
	}



	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);

	mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);

}



static pci_ers_result_t mhi_pci_error_detected(struct pci_dev *pdev,
@@ -562,6 +593,7 @@ static int __maybe_unused mhi_pci_suspend(struct device *dev) 
	struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);

	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;



	del_timer(&mhi_pdev->health_check_timer);

	cancel_work_sync(&mhi_pdev->recovery_work);



	/* Transition to M3 state */
@@ -597,6 +629,9 @@ static int __maybe_unused mhi_pci_resume(struct device *dev) 
		goto err_recovery;

	}



	/* Resume health check */

	mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);



	return 0;



err_recovery: