Commit 7389337f authored by Loic Poulain's avatar Loic Poulain Committed by Manivannan Sadhasivam
Browse files

mhi: pci_generic: Add suspend/resume/recovery procedure 



Add support for system wide suspend/resume. During suspend, MHI
device controller must be put in M3 state and PCI bus in D3 state.

Add a recovery procedure allowing to reinitialize the device in case
of error during resume steps, which can happen if device loses power
(and so its context) while system suspend.

Reviewed-by Hemant Kumar <hemantk@codeaurora.org>

Signed-off-by: default avatarLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
parent 8ccc3279

drivers/bus/mhi/pci_generic.c

+105 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/mhi.h>

#include <linux/module.h>

#include <linux/pci.h>

#include <linux/workqueue.h>



#define MHI_PCI_DEFAULT_BAR_NUM 0
@@ -186,6 +187,7 @@ enum mhi_pci_device_status { 
struct mhi_pci_device {

	struct mhi_controller mhi_cntrl;

	struct pci_saved_state *pci_state;

	struct work_struct recovery_work;

	unsigned long status;

};
@@ -313,6 +315,50 @@ static void mhi_pci_runtime_put(struct mhi_controller *mhi_cntrl) 
	/* no PM for now */

}



static void mhi_pci_recovery_work(struct work_struct *work)

{

	struct mhi_pci_device *mhi_pdev = container_of(work, struct mhi_pci_device,

						       recovery_work);

	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;

	struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev);

	int err;



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



	/* Clean up MHI state */

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

		mhi_power_down(mhi_cntrl, false);

		mhi_unprepare_after_power_down(mhi_cntrl);

	}



	/* Check if we can recover without full reset */

	pci_set_power_state(pdev, PCI_D0);

	pci_load_saved_state(pdev, mhi_pdev->pci_state);

	pci_restore_state(pdev);



	if (!mhi_pci_is_alive(mhi_cntrl))

		goto err_try_reset;



	err = mhi_prepare_for_power_up(mhi_cntrl);

	if (err)

		goto err_try_reset;



	err = mhi_sync_power_up(mhi_cntrl);

	if (err)

		goto err_unprepare;



	dev_dbg(&pdev->dev, "Recovery completed\n");



	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);

	return;



err_unprepare:

	mhi_unprepare_after_power_down(mhi_cntrl);

err_try_reset:

	if (pci_reset_function(pdev))

		dev_err(&pdev->dev, "Recovery failed\n");

}



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;
@@ -328,6 +374,8 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) 
	if (!mhi_pdev)

		return -ENOMEM;



	INIT_WORK(&mhi_pdev->recovery_work, mhi_pci_recovery_work);



	mhi_cntrl_config = info->config;

	mhi_cntrl = &mhi_pdev->mhi_cntrl;
@@ -391,6 +439,8 @@ 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;



	cancel_work_sync(&mhi_pdev->recovery_work);



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

		mhi_power_down(mhi_cntrl, true);

		mhi_unprepare_after_power_down(mhi_cntrl);
@@ -456,12 +506,67 @@ static const struct pci_error_handlers mhi_pci_err_handler = { 
	.reset_done = mhi_pci_reset_done,

};



static int  __maybe_unused mhi_pci_suspend(struct device *dev)

{

	struct pci_dev *pdev = to_pci_dev(dev);

	struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);

	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;



	cancel_work_sync(&mhi_pdev->recovery_work);



	/* Transition to M3 state */

	mhi_pm_suspend(mhi_cntrl);



	pci_save_state(pdev);

	pci_disable_device(pdev);

	pci_wake_from_d3(pdev, true);

	pci_set_power_state(pdev, PCI_D3hot);



	return 0;

}



static int __maybe_unused mhi_pci_resume(struct device *dev)

{

	struct pci_dev *pdev = to_pci_dev(dev);

	struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);

	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;

	int err;



	pci_set_power_state(pdev, PCI_D0);

	pci_restore_state(pdev);

	pci_set_master(pdev);



	err = pci_enable_device(pdev);

	if (err)

		goto err_recovery;



	/* Exit M3, transition to M0 state */

	err = mhi_pm_resume(mhi_cntrl);

	if (err) {

		dev_err(&pdev->dev, "failed to resume device: %d\n", err);

		goto err_recovery;

	}



	return 0;



err_recovery:

	/* The device may have loose power or crashed, try recovering it */

	queue_work(system_long_wq, &mhi_pdev->recovery_work);



	return err;

}



static const struct dev_pm_ops mhi_pci_pm_ops = {

	SET_SYSTEM_SLEEP_PM_OPS(mhi_pci_suspend, mhi_pci_resume)

};



static struct pci_driver mhi_pci_driver = {

	.name		= "mhi-pci-generic",

	.id_table	= mhi_pci_id_table,

	.probe		= mhi_pci_probe,

	.remove		= mhi_pci_remove,

	.err_handler	= &mhi_pci_err_handler,

	.driver.pm	= &mhi_pci_pm_ops

};

module_pci_driver(mhi_pci_driver);