mhi: pci_generic: Add support for reset (8ccc3279) · Commits · EulixOS / Software / Kernel

drivers/bus/mhi/pci_generic.c

+108 −13

Original line number	Diff line number	Diff line
		@@ -8,6 +8,7 @@
		* Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
		*/

		#include <linux/delay.h>
		#include <linux/device.h>
		#include <linux/mhi.h>
		#include <linux/module.h>
		@@ -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_pdev);

		pci_set_drvdata(pdev, mhi_cntrl);
		/* 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_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);