From 8ccc3279fcad9736b58873b1ad597287ee52757a Mon Sep 17 00:00:00 2001 From: Loic Poulain Date: Mon, 4 Jan 2021 17:14:53 +0100 Subject: [PATCH] mhi: pci_generic: Add support for reset Add support for resetting the device, reset can be triggered in case of error or manually via sysfs (/sys/bus/pci/devices/*/reset). Signed-off-by: Loic Poulain Reviewed-by: Manivannan Sadhasivam Signed-off-by: Manivannan Sadhasivam --- drivers/bus/mhi/pci_generic.c | 121 ++++++++++++++++++++++++++++++---- 1 file changed, 108 insertions(+), 13 deletions(-) diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c index 778d13f0db2a..f0dfa625db16 100644 --- a/drivers/bus/mhi/pci_generic.c +++ b/drivers/bus/mhi/pci_generic.c @@ -8,6 +8,7 @@ * Copyright (C) 2020 Linaro Ltd */ +#include #include #include #include @@ -15,6 +16,7 @@ #define MHI_PCI_DEFAULT_BAR_NUM 0 +#define MHI_POST_RESET_DELAY_MS 500 /** * struct mhi_pci_dev_info - MHI PCI device specific information * @config: MHI controller configuration @@ -177,6 +179,16 @@ static const struct pci_device_id mhi_pci_id_table[] = { }; MODULE_DEVICE_TABLE(pci, mhi_pci_id_table); +enum mhi_pci_device_status { + MHI_PCI_DEV_STARTED, +}; + +struct mhi_pci_device { + struct mhi_controller mhi_cntrl; + struct pci_saved_state *pci_state; + unsigned long status; +}; + static int mhi_pci_read_reg(struct mhi_controller *mhi_cntrl, void __iomem *addr, u32 *out) { @@ -196,6 +208,20 @@ static void mhi_pci_status_cb(struct mhi_controller *mhi_cntrl, /* Nothing to do for now */ } +static bool mhi_pci_is_alive(struct mhi_controller *mhi_cntrl) +{ + struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev); + u16 vendor = 0; + + if (pci_read_config_word(pdev, PCI_VENDOR_ID, &vendor)) + return false; + + if (vendor == (u16) ~0 || vendor == 0) + return false; + + return true; +} + static int mhi_pci_claim(struct mhi_controller *mhi_cntrl, unsigned int bar_num, u64 dma_mask) { @@ -291,16 +317,20 @@ 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; const struct mhi_controller_config *mhi_cntrl_config; + struct mhi_pci_device *mhi_pdev; struct mhi_controller *mhi_cntrl; int err; dev_dbg(&pdev->dev, "MHI PCI device found: %s\n", info->name); - mhi_cntrl = mhi_alloc_controller(); - if (!mhi_cntrl) + /* mhi_pdev.mhi_cntrl must be zero-initialized */ + mhi_pdev = devm_kzalloc(&pdev->dev, sizeof(*mhi_pdev), GFP_KERNEL); + if (!mhi_pdev) return -ENOMEM; mhi_cntrl_config = info->config; + mhi_cntrl = &mhi_pdev->mhi_cntrl; + mhi_cntrl->cntrl_dev = &pdev->dev; mhi_cntrl->iova_start = 0; mhi_cntrl->iova_stop = (dma_addr_t)DMA_BIT_MASK(info->dma_data_width); @@ -315,17 +345,21 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) err = mhi_pci_claim(mhi_cntrl, info->bar_num, DMA_BIT_MASK(info->dma_data_width)); if (err) - goto err_release; + return err; err = mhi_pci_get_irqs(mhi_cntrl, mhi_cntrl_config); if (err) - goto err_release; + return err; - pci_set_drvdata(pdev, mhi_cntrl); + pci_set_drvdata(pdev, mhi_pdev); + + /* Have stored pci confspace at hand for restore in sudden PCI error */ + pci_save_state(pdev); + mhi_pdev->pci_state = pci_store_saved_state(pdev); err = mhi_register_controller(mhi_cntrl, mhi_cntrl_config); if (err) - goto err_release; + return err; /* MHI bus does not power up the controller by default */ err = mhi_prepare_for_power_up(mhi_cntrl); @@ -340,33 +374,94 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) goto err_unprepare; } + set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status); + return 0; err_unprepare: mhi_unprepare_after_power_down(mhi_cntrl); err_unregister: mhi_unregister_controller(mhi_cntrl); -err_release: - mhi_free_controller(mhi_cntrl); return err; } static void mhi_pci_remove(struct pci_dev *pdev) { - struct mhi_controller *mhi_cntrl = pci_get_drvdata(pdev); + struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev); + struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl; + + 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); + } - mhi_power_down(mhi_cntrl, true); - mhi_unprepare_after_power_down(mhi_cntrl); mhi_unregister_controller(mhi_cntrl); - mhi_free_controller(mhi_cntrl); } +static void mhi_pci_reset_prepare(struct pci_dev *pdev) +{ + struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev); + struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl; + + dev_info(&pdev->dev, "reset\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); + } + + /* cause internal device reset */ + mhi_soc_reset(mhi_cntrl); + + /* Be sure device reset has been executed */ + msleep(MHI_POST_RESET_DELAY_MS); +} + +static void mhi_pci_reset_done(struct pci_dev *pdev) +{ + struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev); + struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl; + int err; + + /* Restore initial known working PCI state */ + pci_load_saved_state(pdev, mhi_pdev->pci_state); + pci_restore_state(pdev); + + /* Is device status available ? */ + if (!mhi_pci_is_alive(mhi_cntrl)) { + dev_err(&pdev->dev, "reset failed\n"); + return; + } + + err = mhi_prepare_for_power_up(mhi_cntrl); + if (err) { + dev_err(&pdev->dev, "failed to prepare MHI controller\n"); + return; + } + + err = mhi_sync_power_up(mhi_cntrl); + if (err) { + dev_err(&pdev->dev, "failed to power up MHI controller\n"); + mhi_unprepare_after_power_down(mhi_cntrl); + return; + } + + set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status); +} + +static const struct pci_error_handlers mhi_pci_err_handler = { + .reset_prepare = mhi_pci_reset_prepare, + .reset_done = mhi_pci_reset_done, +}; + 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 + .remove = mhi_pci_remove, + .err_handler = &mhi_pci_err_handler, }; module_pci_driver(mhi_pci_driver);