drivers/usb/host/xhci-pci-renesas.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (C) 2019-2020 Linaro Limited */

 #include <linux/acpi.h>
 #include <linux/firmware.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <asm/unaligned.h>

 #include "xhci.h"
 #include "xhci-trace.h"
 #include "xhci-pci.h"

 #define RENESAS_FW_VERSION				0x6C
 #define RENESAS_ROM_CONFIG				0xF0
 #define RENESAS_FW_STATUS				0xF4
 #define RENESAS_FW_STATUS_MSB				0xF5
 #define RENESAS_ROM_STATUS				0xF6
 #define RENESAS_ROM_STATUS_MSB				0xF7
 #define RENESAS_DATA0					0xF8
 #define RENESAS_DATA1					0xFC

 #define RENESAS_FW_VERSION_FIELD			GENMASK(23, 7)
 #define RENESAS_FW_VERSION_OFFSET			8

 #define RENESAS_FW_STATUS_DOWNLOAD_ENABLE		BIT(0)
 #define RENESAS_FW_STATUS_LOCK				BIT(1)
 #define RENESAS_FW_STATUS_RESULT			GENMASK(6, 4)
   #define RENESAS_FW_STATUS_INVALID			0
   #define RENESAS_FW_STATUS_SUCCESS			BIT(4)
   #define RENESAS_FW_STATUS_ERROR			BIT(5)
 #define RENESAS_FW_STATUS_SET_DATA0			BIT(8)
 #define RENESAS_FW_STATUS_SET_DATA1			BIT(9)

 #define RENESAS_ROM_STATUS_ACCESS			BIT(0)
 #define RENESAS_ROM_STATUS_ERASE			BIT(1)
 #define RENESAS_ROM_STATUS_RELOAD			BIT(2)
 #define RENESAS_ROM_STATUS_RESULT			GENMASK(6, 4)
   #define RENESAS_ROM_STATUS_NO_RESULT			0
   #define RENESAS_ROM_STATUS_SUCCESS			BIT(4)
   #define RENESAS_ROM_STATUS_ERROR			BIT(5)
 #define RENESAS_ROM_STATUS_SET_DATA0			BIT(8)
 #define RENESAS_ROM_STATUS_SET_DATA1			BIT(9)
 #define RENESAS_ROM_STATUS_ROM_EXISTS			BIT(15)

 #define RENESAS_ROM_ERASE_MAGIC				0x5A65726F
 #define RENESAS_ROM_WRITE_MAGIC				0x53524F4D

 #define RENESAS_RETRY	10000
 #define RENESAS_DELAY	10

 static int renesas_fw_download_image(struct pci_dev *dev,
 				     const u32 *fw, size_t step, bool rom)
 {
 	size_t i;
 	int err;
 	u8 fw_status;
 	bool data0_or_data1;
 	u32 status_reg;

 	if (rom)
 		status_reg = RENESAS_ROM_STATUS_MSB;
 	else
 		status_reg = RENESAS_FW_STATUS_MSB;

 	/*
 	 * The hardware does alternate between two 32-bit pages.
 	 * (This is because each row of the firmware is 8 bytes).
 	 *
 	 * for even steps we use DATA0, for odd steps DATA1.
 	 */
 	data0_or_data1 = (step & 1) == 1;

 	/* step+1. Read "Set DATAX" and confirm it is cleared. */
 	for (i = 0; i < RENESAS_RETRY; i++) {
 		err = pci_read_config_byte(dev, status_reg, &fw_status);
 		if (err) {
 			dev_err(&dev->dev, "Read Status failed: %d\n",
 				pcibios_err_to_errno(err));
 			return pcibios_err_to_errno(err);
 		}
 		if (!(fw_status & BIT(data0_or_data1)))
 			break;

 		udelay(RENESAS_DELAY);
 	}
 	if (i == RENESAS_RETRY) {
 		dev_err(&dev->dev, "Timeout for Set DATAX step: %zd\n", step);
 		return -ETIMEDOUT;
 	}

 	/*
 	 * step+2. Write FW data to "DATAX".
 	 * "LSB is left" => force little endian
 	 */
 	err = pci_write_config_dword(dev, data0_or_data1 ?
 				     RENESAS_DATA1 : RENESAS_DATA0,
 				     (__force u32)cpu_to_le32(fw[step]));
 	if (err) {
 		dev_err(&dev->dev, "Write to DATAX failed: %d\n",
 			pcibios_err_to_errno(err));
 		return pcibios_err_to_errno(err);
 	}

 	udelay(100);

 	/* step+3. Set "Set DATAX". */
 	err = pci_write_config_byte(dev, status_reg, BIT(data0_or_data1));
 	if (err) {
 		dev_err(&dev->dev, "Write config for DATAX failed: %d\n",
 			pcibios_err_to_errno(err));
 		return pcibios_err_to_errno(err);
 	}

 	return 0;
 }

 static int renesas_fw_verify(const void *fw_data,
 			     size_t length)
 {
 	u16 fw_version_pointer;
 	u16 fw_version;

 	/*
 	 * The Firmware's Data Format is describe in
 	 * "6.3 Data Format" R19UH0078EJ0500 Rev.5.00 page 124
 	 */

 	/*
 	 * The bootrom chips of the big brother have sizes up to 64k, let's
 	 * assume that's the biggest the firmware can get.
 	 */
 	if (length < 0x1000 || length >= 0x10000) {
 		pr_err("firmware is size %zd is not (4k - 64k).",
 			length);
 		return -EINVAL;
 	}

 	/* The First 2 bytes are fixed value (55aa). "LSB on Left" */
 	if (get_unaligned_le16(fw_data) != 0x55aa) {
 		pr_err("no valid firmware header found.");
 		return -EINVAL;
 	}

 	/* verify the firmware version position and print it. */
 	fw_version_pointer = get_unaligned_le16(fw_data + 4);
 	if (fw_version_pointer + 2 >= length) {
 		pr_err("fw ver pointer is outside of the firmware image");
 		return -EINVAL;
 	}

 	fw_version = get_unaligned_le16(fw_data + fw_version_pointer);
 	pr_err("got firmware version: %02x.", fw_version);

 	return 0;
 }

 static bool renesas_check_rom(struct pci_dev *pdev)
 {
 	u16 rom_status;
 	int retval;

 	/* Check if external ROM exists */
 	retval = pci_read_config_word(pdev, RENESAS_ROM_STATUS, &rom_status);
 	if (retval)
 		return false;

 	rom_status &= RENESAS_ROM_STATUS_ROM_EXISTS;
 	if (rom_status) {
 		dev_dbg(&pdev->dev, "External ROM exists\n");
 		return true; /* External ROM exists */
 	}

 	return false;
 }

 static int renesas_check_rom_state(struct pci_dev *pdev)
 {
 	u16 rom_state;
 	u32 version;
 	int err;

 	/* check FW version */
 	err = pci_read_config_dword(pdev, RENESAS_FW_VERSION, &version);
 	if (err)
 		return pcibios_err_to_errno(err);

 	version &= RENESAS_FW_VERSION_FIELD;
 	version = version >> RENESAS_FW_VERSION_OFFSET;
 	dev_dbg(&pdev->dev, "Found ROM version: %x\n", version);

 	/*
 	 * Test if ROM is present and loaded, if so we can skip everything
 	 */
 	err = pci_read_config_word(pdev, RENESAS_ROM_STATUS, &rom_state);
 	if (err)
 		return pcibios_err_to_errno(err);

 	if (rom_state & RENESAS_ROM_STATUS_ROM_EXISTS) {
 		/* ROM exists */
 		dev_dbg(&pdev->dev, "ROM exists\n");

 		/* Check the "Result Code" Bits (6:4) and act accordingly */
 		switch (rom_state & RENESAS_ROM_STATUS_RESULT) {
 		case RENESAS_ROM_STATUS_SUCCESS:
 			return 0;

 		case RENESAS_ROM_STATUS_NO_RESULT: /* No result yet */
 			dev_dbg(&pdev->dev, "Unknown ROM status ...\n");
 			return -ENOENT;

 		case RENESAS_ROM_STATUS_ERROR: /* Error State */
 		default: /* All other states are marked as "Reserved states" */
 			dev_err(&pdev->dev, "Invalid ROM..");
 			break;
 		}
 	}

 	return -EIO;
 }

 static int renesas_fw_check_running(struct pci_dev *pdev)
 {
 	u8 fw_state;
 	int err;

 	/*
 	 * Test if the device is actually needing the firmware. As most
 	 * BIOSes will initialize the device for us. If the device is
 	 * initialized.
 	 */
 	err = pci_read_config_byte(pdev, RENESAS_FW_STATUS, &fw_state);
 	if (err)
 		return pcibios_err_to_errno(err);

 	/*
 	 * Check if "FW Download Lock" is locked. If it is and the FW is
 	 * ready we can simply continue. If the FW is not ready, we have
 	 * to give up.
 	 */
 	if (fw_state & RENESAS_FW_STATUS_LOCK) {
 		dev_dbg(&pdev->dev, "FW Download Lock is engaged.");

 		if (fw_state & RENESAS_FW_STATUS_SUCCESS)
 			return 0;

 		dev_err(&pdev->dev,
 			"FW Download Lock is set and FW is not ready. Giving Up.");
 		return -EIO;
 	}

 	/*
 	 * Check if "FW Download Enable" is set. If someone (us?) tampered
 	 * with it and it can't be reset, we have to give up too... and
 	 * ask for a forgiveness and a reboot.
 	 */
 	if (fw_state & RENESAS_FW_STATUS_DOWNLOAD_ENABLE) {
 		dev_err(&pdev->dev,
 			"FW Download Enable is stale. Giving Up (poweroff/reboot needed).");
 		return -EIO;
 	}

 	/* Otherwise, Check the "Result Code" Bits (6:4) and act accordingly */
 	switch (fw_state & RENESAS_FW_STATUS_RESULT) {
 	case 0: /* No result yet */
 		dev_dbg(&pdev->dev, "FW is not ready/loaded yet.");

 		/* tell the caller, that this device needs the firmware. */
 		return 1;

 	case RENESAS_FW_STATUS_SUCCESS: /* Success, device should be working. */
 		dev_dbg(&pdev->dev, "FW is ready.");
 		return 0;

 	case RENESAS_FW_STATUS_ERROR: /* Error State */
 		dev_err(&pdev->dev,
 			"hardware is in an error state. Giving up (poweroff/reboot needed).");
 		return -ENODEV;

 	default: /* All other states are marked as "Reserved states" */
 		dev_err(&pdev->dev,
 			"hardware is in an invalid state %lx. Giving up (poweroff/reboot needed).",
 			(fw_state & RENESAS_FW_STATUS_RESULT) >> 4);
 		return -EINVAL;
 	}
 }

 static int renesas_fw_download(struct pci_dev *pdev,
 			       const struct firmware *fw)
 {
 	const u32 *fw_data = (const u32 *)fw->data;
 	size_t i;
 	int err;
 	u8 fw_status;

 	/*
 	 * For more information and the big picture: please look at the
 	 * "Firmware Download Sequence" in "7.1 FW Download Interface"
 	 * of R19UH0078EJ0500 Rev.5.00 page 131
 	 */

 	/*
 	 * 0. Set "FW Download Enable" bit in the
 	 * "FW Download Control & Status Register" at 0xF4
 	 */
 	err = pci_write_config_byte(pdev, RENESAS_FW_STATUS,
 				    RENESAS_FW_STATUS_DOWNLOAD_ENABLE);
 	if (err)
 		return pcibios_err_to_errno(err);

 	/* 1 - 10 follow one step after the other. */
 	for (i = 0; i < fw->size / 4; i++) {
 		err = renesas_fw_download_image(pdev, fw_data, i, false);
 		if (err) {
 			dev_err(&pdev->dev,
 				"Firmware Download Step %zd failed at position %zd bytes with (%d).",
 				i, i * 4, err);
 			return err;
 		}
 	}

 	/*
 	 * This sequence continues until the last data is written to
 	 * "DATA0" or "DATA1". Naturally, we wait until "SET DATA0/1"
 	 * is cleared by the hardware beforehand.
 	 */
 	for (i = 0; i < RENESAS_RETRY; i++) {
 		err = pci_read_config_byte(pdev, RENESAS_FW_STATUS_MSB,
 					   &fw_status);
 		if (err)
 			return pcibios_err_to_errno(err);
 		if (!(fw_status & (BIT(0) | BIT(1))))
 			break;

 		udelay(RENESAS_DELAY);
 	}
 	if (i == RENESAS_RETRY)
 		dev_warn(&pdev->dev, "Final Firmware Download step timed out.");

 	/*
 	 * 11. After finishing writing the last data of FW, the
 	 * System Software must clear "FW Download Enable"
 	 */
 	err = pci_write_config_byte(pdev, RENESAS_FW_STATUS, 0);
 	if (err)
 		return pcibios_err_to_errno(err);

 	/* 12. Read "Result Code" and confirm it is good. */
 	for (i = 0; i < RENESAS_RETRY; i++) {
 		err = pci_read_config_byte(pdev, RENESAS_FW_STATUS, &fw_status);
 		if (err)
 			return pcibios_err_to_errno(err);
 		if (fw_status & RENESAS_FW_STATUS_SUCCESS)
 			break;

 		udelay(RENESAS_DELAY);
 	}
 	if (i == RENESAS_RETRY) {
 		/* Timed out / Error - let's see if we can fix this */
 		err = renesas_fw_check_running(pdev);
 		switch (err) {
 		case 0: /*
 			 * we shouldn't end up here.
 			 * maybe it took a little bit longer.
 			 * But all should be well?
 			 */
 			break;

 		case 1: /* (No result yet! */
 			dev_err(&pdev->dev, "FW Load timedout");
 			return -ETIMEDOUT;

 		default:
 			return err;
 		}
 	}

 	return 0;
 }

 static void renesas_rom_erase(struct pci_dev *pdev)
 {
 	int retval, i;
 	u8 status;

 	dev_dbg(&pdev->dev, "Performing ROM Erase...\n");
 	retval = pci_write_config_dword(pdev, RENESAS_DATA0,
 					RENESAS_ROM_ERASE_MAGIC);
 	if (retval) {
 		dev_err(&pdev->dev, "ROM erase, magic word write failed: %d\n",
 			pcibios_err_to_errno(retval));
 		return;
 	}

 	retval = pci_read_config_byte(pdev, RENESAS_ROM_STATUS, &status);
 	if (retval) {
 		dev_err(&pdev->dev, "ROM status read failed: %d\n",
 			pcibios_err_to_errno(retval));
 		return;
 	}
 	status |= RENESAS_ROM_STATUS_ERASE;
 	retval = pci_write_config_byte(pdev, RENESAS_ROM_STATUS, status);
 	if (retval) {
 		dev_err(&pdev->dev, "ROM erase set word write failed\n");
 		return;
 	}

 	/* sleep a bit while ROM is erased */
 	msleep(20);

 	for (i = 0; i < RENESAS_RETRY; i++) {
 		retval = pci_read_config_byte(pdev, RENESAS_ROM_STATUS,
 					      &status);
 		status &= RENESAS_ROM_STATUS_ERASE;
 		if (!status)
 			break;

 		mdelay(RENESAS_DELAY);
 	}

 	if (i == RENESAS_RETRY)
 		dev_dbg(&pdev->dev, "Chip erase timedout: %x\n", status);

 	dev_dbg(&pdev->dev, "ROM Erase... Done success\n");
 }

 static bool renesas_setup_rom(struct pci_dev *pdev, const struct firmware *fw)
 {
 	const u32 *fw_data = (const u32 *)fw->data;
 	int err, i;
 	u8 status;

 	/* 2. Write magic word to Data0 */
 	err = pci_write_config_dword(pdev, RENESAS_DATA0,
 				     RENESAS_ROM_WRITE_MAGIC);
 	if (err)
 		return false;

 	/* 3. Set External ROM access */
 	err = pci_write_config_byte(pdev, RENESAS_ROM_STATUS,
 				    RENESAS_ROM_STATUS_ACCESS);
 	if (err)
 		goto remove_bypass;

 	/* 4. Check the result */
 	err = pci_read_config_byte(pdev, RENESAS_ROM_STATUS, &status);
 	if (err)
 		goto remove_bypass;
 	status &= GENMASK(6, 4);
 	if (status) {
 		dev_err(&pdev->dev,
 			"setting external rom failed: %x\n", status);
 		goto remove_bypass;
 	}

 	/* 5 to 16 Write FW to DATA0/1 while checking SetData0/1 */
 	for (i = 0; i < fw->size / 4; i++) {
 		err = renesas_fw_download_image(pdev, fw_data, i, true);
 		if (err) {
 			dev_err(&pdev->dev,
 				"ROM Download Step %d failed at position %d bytes with (%d)\n",
 				 i, i * 4, err);
 			goto remove_bypass;
 		}
 	}

 	/*
 	 * wait till DATA0/1 is cleared
 	 */
 	for (i = 0; i < RENESAS_RETRY; i++) {
 		err = pci_read_config_byte(pdev, RENESAS_ROM_STATUS_MSB,
 					   &status);
 		if (err)
 			goto remove_bypass;
 		if (!(status & (BIT(0) | BIT(1))))
 			break;

 		udelay(RENESAS_DELAY);
 	}
 	if (i == RENESAS_RETRY) {
 		dev_err(&pdev->dev, "Final Firmware ROM Download step timed out\n");
 		goto remove_bypass;
 	}

 	/* 17. Remove bypass */
 	err = pci_write_config_byte(pdev, RENESAS_ROM_STATUS, 0);
 	if (err)
 		return false;

 	udelay(10);

 	/* 18. check result */
 	for (i = 0; i < RENESAS_RETRY; i++) {
 		err = pci_read_config_byte(pdev, RENESAS_ROM_STATUS, &status);
 		if (err) {
 			dev_err(&pdev->dev, "Read ROM status failed:%d\n",
 				pcibios_err_to_errno(err));
 			return false;
 		}
 		status &= RENESAS_ROM_STATUS_RESULT;
 		if (status ==  RENESAS_ROM_STATUS_SUCCESS) {
 			dev_dbg(&pdev->dev, "Download ROM success\n");
 			break;
 		}
 		udelay(RENESAS_DELAY);
 	}
 	if (i == RENESAS_RETRY) { /* Timed out */
 		dev_err(&pdev->dev,
 			"Download to external ROM TO: %x\n", status);
 		return false;
 	}

 	dev_dbg(&pdev->dev, "Download to external ROM succeeded\n");

 	/* Last step set Reload */
 	err = pci_write_config_byte(pdev, RENESAS_ROM_STATUS,
 				    RENESAS_ROM_STATUS_RELOAD);
 	if (err) {
 		dev_err(&pdev->dev, "Set ROM execute failed: %d\n",
 			pcibios_err_to_errno(err));
 		return false;
 	}

 	/*
 	 * wait till Reload is cleared
 	 */
 	for (i = 0; i < RENESAS_RETRY; i++) {
 		err = pci_read_config_byte(pdev, RENESAS_ROM_STATUS, &status);
 		if (err)
 			return false;
 		if (!(status & RENESAS_ROM_STATUS_RELOAD))
 			break;

 		udelay(RENESAS_DELAY);
 	}
 	if (i == RENESAS_RETRY) {
 		dev_err(&pdev->dev, "ROM Exec timed out: %x\n", status);
 		return false;
 	}

 	return true;

 remove_bypass:
 	pci_write_config_byte(pdev, RENESAS_ROM_STATUS, 0);
 	return false;
 }

 static int renesas_load_fw(struct pci_dev *pdev, const struct firmware *fw)
 {
 	int err = 0;
 	bool rom;

 	/* Check if the device has external ROM */
 	rom = renesas_check_rom(pdev);
 	if (rom) {
 		/* perform chip erase first */
 		renesas_rom_erase(pdev);

 		/* lets try loading fw on ROM first */
 		rom = renesas_setup_rom(pdev, fw);
 		if (!rom) {
 			dev_dbg(&pdev->dev,
 				"ROM load failed, falling back on FW load\n");
 		} else {
 			dev_dbg(&pdev->dev,
 				"ROM load success\n");
 			goto exit;
 		}
 	}

 	err = renesas_fw_download(pdev, fw);

 exit:
 	if (err)
 		dev_err(&pdev->dev, "firmware failed to download (%d).", err);
 	return err;
 }

 int renesas_xhci_check_request_fw(struct pci_dev *pdev,
 				  const struct pci_device_id *id)
 {
 	struct xhci_driver_data *driver_data =
 			(struct xhci_driver_data *)id->driver_data;
 	const char *fw_name = driver_data->firmware;
 	const struct firmware *fw;
 	bool has_rom;
 	int err;

 	/* Check if device has ROM and loaded, if so skip everything */
 	has_rom = renesas_check_rom(pdev);
 	if (has_rom) {
 		err = renesas_check_rom_state(pdev);
 		if (!err)
 			return 0;
 		else if (err != -ENOENT)
 			has_rom = false;
 	}

 	err = renesas_fw_check_running(pdev);
 	/* Continue ahead, if the firmware is already running. */
 	if (!err)
 		return 0;

 	/* no firmware interface available */
 	if (err != 1)
 		return has_rom ? 0 : err;

 	pci_dev_get(pdev);
 	err = firmware_request_nowarn(&fw, fw_name, &pdev->dev);
 	pci_dev_put(pdev);
 	if (err) {
 		if (has_rom) {
 			dev_info(&pdev->dev, "failed to load firmware %s, fallback to ROM\n",
 				 fw_name);
 			return 0;
 		}
 		dev_err(&pdev->dev, "failed to load firmware %s: %d\n",
 			fw_name, err);
 		return err;
 	}

 	err = renesas_fw_verify(fw->data, fw->size);
 	if (err)
 		goto exit;

 	err = renesas_load_fw(pdev, fw);
 exit:
 	release_firmware(fw);
 	return err;
 }
 EXPORT_SYMBOL_GPL(renesas_xhci_check_request_fw);

 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/* Copyright (C) 2019-2020 Linaro Limited */

	#include <linux/acpi.h>
	#include <linux/firmware.h>
	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/slab.h>
	#include <asm/unaligned.h>

	#include "xhci.h"
	#include "xhci-trace.h"
	#include "xhci-pci.h"

	#define RENESAS_FW_VERSION 0x6C
	#define RENESAS_ROM_CONFIG 0xF0
	#define RENESAS_FW_STATUS 0xF4
	#define RENESAS_FW_STATUS_MSB 0xF5
	#define RENESAS_ROM_STATUS 0xF6
	#define RENESAS_ROM_STATUS_MSB 0xF7
	#define RENESAS_DATA0 0xF8
	#define RENESAS_DATA1 0xFC

	#define RENESAS_FW_VERSION_FIELD GENMASK(23, 7)
	#define RENESAS_FW_VERSION_OFFSET 8

	#define RENESAS_FW_STATUS_DOWNLOAD_ENABLE BIT(0)
	#define RENESAS_FW_STATUS_LOCK BIT(1)
	#define RENESAS_FW_STATUS_RESULT GENMASK(6, 4)
	#define RENESAS_FW_STATUS_INVALID 0
	#define RENESAS_FW_STATUS_SUCCESS BIT(4)
	#define RENESAS_FW_STATUS_ERROR BIT(5)
	#define RENESAS_FW_STATUS_SET_DATA0 BIT(8)
	#define RENESAS_FW_STATUS_SET_DATA1 BIT(9)

	#define RENESAS_ROM_STATUS_ACCESS BIT(0)
	#define RENESAS_ROM_STATUS_ERASE BIT(1)
	#define RENESAS_ROM_STATUS_RELOAD BIT(2)
	#define RENESAS_ROM_STATUS_RESULT GENMASK(6, 4)
	#define RENESAS_ROM_STATUS_NO_RESULT 0
	#define RENESAS_ROM_STATUS_SUCCESS BIT(4)
	#define RENESAS_ROM_STATUS_ERROR BIT(5)
	#define RENESAS_ROM_STATUS_SET_DATA0 BIT(8)
	#define RENESAS_ROM_STATUS_SET_DATA1 BIT(9)
	#define RENESAS_ROM_STATUS_ROM_EXISTS BIT(15)

	#define RENESAS_ROM_ERASE_MAGIC 0x5A65726F
	#define RENESAS_ROM_WRITE_MAGIC 0x53524F4D

	#define RENESAS_RETRY 10000
	#define RENESAS_DELAY 10

	static int renesas_fw_download_image(struct pci_dev *dev,
	const u32 *fw, size_t step, bool rom)
	{
	size_t i;
	int err;
	u8 fw_status;
	bool data0_or_data1;
	u32 status_reg;

	if (rom)
	status_reg = RENESAS_ROM_STATUS_MSB;
	else
	status_reg = RENESAS_FW_STATUS_MSB;

	/*
	* The hardware does alternate between two 32-bit pages.
	* (This is because each row of the firmware is 8 bytes).
	*
	* for even steps we use DATA0, for odd steps DATA1.
	*/
	data0_or_data1 = (step & 1) == 1;

	/* step+1. Read "Set DATAX" and confirm it is cleared. */
	for (i = 0; i < RENESAS_RETRY; i++) {
	err = pci_read_config_byte(dev, status_reg, &fw_status);
	if (err) {
	dev_err(&dev->dev, "Read Status failed: %d\n",
	pcibios_err_to_errno(err));
	return pcibios_err_to_errno(err);
	}
	if (!(fw_status & BIT(data0_or_data1)))
	break;

	udelay(RENESAS_DELAY);
	}
	if (i == RENESAS_RETRY) {
	dev_err(&dev->dev, "Timeout for Set DATAX step: %zd\n", step);
	return -ETIMEDOUT;
	}

	/*
	* step+2. Write FW data to "DATAX".
	* "LSB is left" => force little endian
	*/
	err = pci_write_config_dword(dev, data0_or_data1 ?
	RENESAS_DATA1 : RENESAS_DATA0,
	(__force u32)cpu_to_le32(fw[step]));
	if (err) {
	dev_err(&dev->dev, "Write to DATAX failed: %d\n",
	pcibios_err_to_errno(err));
	return pcibios_err_to_errno(err);
	}

	udelay(100);

	/* step+3. Set "Set DATAX". */
	err = pci_write_config_byte(dev, status_reg, BIT(data0_or_data1));
	if (err) {
	dev_err(&dev->dev, "Write config for DATAX failed: %d\n",
	pcibios_err_to_errno(err));
	return pcibios_err_to_errno(err);
	}

	return 0;
	}

	static int renesas_fw_verify(const void *fw_data,
	size_t length)
	{
	u16 fw_version_pointer;
	u16 fw_version;

	/*
	* The Firmware's Data Format is describe in
	* "6.3 Data Format" R19UH0078EJ0500 Rev.5.00 page 124
	*/

	/*
	* The bootrom chips of the big brother have sizes up to 64k, let's
	* assume that's the biggest the firmware can get.
	*/
	if (length < 0x1000 \|\| length >= 0x10000) {
	pr_err("firmware is size %zd is not (4k - 64k).",
	length);
	return -EINVAL;
	}

	/* The First 2 bytes are fixed value (55aa). "LSB on Left" */
	if (get_unaligned_le16(fw_data) != 0x55aa) {
	pr_err("no valid firmware header found.");
	return -EINVAL;
	}

	/* verify the firmware version position and print it. */
	fw_version_pointer = get_unaligned_le16(fw_data + 4);
	if (fw_version_pointer + 2 >= length) {
	pr_err("fw ver pointer is outside of the firmware image");
	return -EINVAL;
	}

	fw_version = get_unaligned_le16(fw_data + fw_version_pointer);
	pr_err("got firmware version: %02x.", fw_version);

	return 0;
	}

	static bool renesas_check_rom(struct pci_dev *pdev)
	{
	u16 rom_status;
	int retval;

	/* Check if external ROM exists */
	retval = pci_read_config_word(pdev, RENESAS_ROM_STATUS, &rom_status);
	if (retval)
	return false;

	rom_status &= RENESAS_ROM_STATUS_ROM_EXISTS;
	if (rom_status) {
	dev_dbg(&pdev->dev, "External ROM exists\n");
	return true; /* External ROM exists */
	}

	return false;
	}

	static int renesas_check_rom_state(struct pci_dev *pdev)
	{
	u16 rom_state;
	u32 version;
	int err;

	/* check FW version */
	err = pci_read_config_dword(pdev, RENESAS_FW_VERSION, &version);
	if (err)
	return pcibios_err_to_errno(err);

	version &= RENESAS_FW_VERSION_FIELD;
	version = version >> RENESAS_FW_VERSION_OFFSET;
	dev_dbg(&pdev->dev, "Found ROM version: %x\n", version);

	/*
	* Test if ROM is present and loaded, if so we can skip everything
	*/
	err = pci_read_config_word(pdev, RENESAS_ROM_STATUS, &rom_state);
	if (err)
	return pcibios_err_to_errno(err);

	if (rom_state & RENESAS_ROM_STATUS_ROM_EXISTS) {
	/* ROM exists */
	dev_dbg(&pdev->dev, "ROM exists\n");

	/* Check the "Result Code" Bits (6:4) and act accordingly */
	switch (rom_state & RENESAS_ROM_STATUS_RESULT) {
	case RENESAS_ROM_STATUS_SUCCESS:
	return 0;

	case RENESAS_ROM_STATUS_NO_RESULT: /* No result yet */
	dev_dbg(&pdev->dev, "Unknown ROM status ...\n");
	return -ENOENT;

	case RENESAS_ROM_STATUS_ERROR: /* Error State */
	default: /* All other states are marked as "Reserved states" */
	dev_err(&pdev->dev, "Invalid ROM..");
	break;
	}
	}

	return -EIO;
	}

	static int renesas_fw_check_running(struct pci_dev *pdev)
	{
	u8 fw_state;
	int err;

	/*
	* Test if the device is actually needing the firmware. As most
	* BIOSes will initialize the device for us. If the device is
	* initialized.
	*/
	err = pci_read_config_byte(pdev, RENESAS_FW_STATUS, &fw_state);
	if (err)
	return pcibios_err_to_errno(err);

	/*
	* Check if "FW Download Lock" is locked. If it is and the FW is
	* ready we can simply continue. If the FW is not ready, we have
	* to give up.
	*/
	if (fw_state & RENESAS_FW_STATUS_LOCK) {
	dev_dbg(&pdev->dev, "FW Download Lock is engaged.");

	if (fw_state & RENESAS_FW_STATUS_SUCCESS)
	return 0;

	dev_err(&pdev->dev,
	"FW Download Lock is set and FW is not ready. Giving Up.");
	return -EIO;
	}

	/*
	* Check if "FW Download Enable" is set. If someone (us?) tampered
	* with it and it can't be reset, we have to give up too... and
	* ask for a forgiveness and a reboot.
	*/
	if (fw_state & RENESAS_FW_STATUS_DOWNLOAD_ENABLE) {
	dev_err(&pdev->dev,
	"FW Download Enable is stale. Giving Up (poweroff/reboot needed).");
	return -EIO;
	}

	/* Otherwise, Check the "Result Code" Bits (6:4) and act accordingly */
	switch (fw_state & RENESAS_FW_STATUS_RESULT) {
	case 0: /* No result yet */
	dev_dbg(&pdev->dev, "FW is not ready/loaded yet.");

	/* tell the caller, that this device needs the firmware. */
	return 1;

	case RENESAS_FW_STATUS_SUCCESS: /* Success, device should be working. */
	dev_dbg(&pdev->dev, "FW is ready.");
	return 0;

	case RENESAS_FW_STATUS_ERROR: /* Error State */
	dev_err(&pdev->dev,
	"hardware is in an error state. Giving up (poweroff/reboot needed).");
	return -ENODEV;

	default: /* All other states are marked as "Reserved states" */
	dev_err(&pdev->dev,
	"hardware is in an invalid state %lx. Giving up (poweroff/reboot needed).",
	(fw_state & RENESAS_FW_STATUS_RESULT) >> 4);
	return -EINVAL;
	}
	}

	static int renesas_fw_download(struct pci_dev *pdev,
	const struct firmware *fw)
	{
	const u32 fw_data = (const u32 )fw->data;
	size_t i;
	int err;
	u8 fw_status;

	/*
	* For more information and the big picture: please look at the
	* "Firmware Download Sequence" in "7.1 FW Download Interface"
	* of R19UH0078EJ0500 Rev.5.00 page 131
	*/

	/*
	* 0. Set "FW Download Enable" bit in the
	* "FW Download Control & Status Register" at 0xF4
	*/
	err = pci_write_config_byte(pdev, RENESAS_FW_STATUS,
	RENESAS_FW_STATUS_DOWNLOAD_ENABLE);
	if (err)
	return pcibios_err_to_errno(err);

	/* 1 - 10 follow one step after the other. */
	for (i = 0; i < fw->size / 4; i++) {
	err = renesas_fw_download_image(pdev, fw_data, i, false);
	if (err) {
	dev_err(&pdev->dev,
	"Firmware Download Step %zd failed at position %zd bytes with (%d).",
	i, i * 4, err);
	return err;
	}
	}

	/*
	* This sequence continues until the last data is written to
	* "DATA0" or "DATA1". Naturally, we wait until "SET DATA0/1"
	* is cleared by the hardware beforehand.
	*/
	for (i = 0; i < RENESAS_RETRY; i++) {
	err = pci_read_config_byte(pdev, RENESAS_FW_STATUS_MSB,
	&fw_status);
	if (err)
	return pcibios_err_to_errno(err);
	if (!(fw_status & (BIT(0) \| BIT(1))))
	break;

	udelay(RENESAS_DELAY);
	}
	if (i == RENESAS_RETRY)
	dev_warn(&pdev->dev, "Final Firmware Download step timed out.");

	/*
	* 11. After finishing writing the last data of FW, the
	* System Software must clear "FW Download Enable"
	*/
	err = pci_write_config_byte(pdev, RENESAS_FW_STATUS, 0);
	if (err)
	return pcibios_err_to_errno(err);

	/* 12. Read "Result Code" and confirm it is good. */
	for (i = 0; i < RENESAS_RETRY; i++) {
	err = pci_read_config_byte(pdev, RENESAS_FW_STATUS, &fw_status);
	if (err)
	return pcibios_err_to_errno(err);
	if (fw_status & RENESAS_FW_STATUS_SUCCESS)
	break;

	udelay(RENESAS_DELAY);
	}
	if (i == RENESAS_RETRY) {
	/* Timed out / Error - let's see if we can fix this */
	err = renesas_fw_check_running(pdev);
	switch (err) {
	case 0: /*
	* we shouldn't end up here.
	* maybe it took a little bit longer.
	* But all should be well?
	*/
	break;

	case 1: /* (No result yet! */
	dev_err(&pdev->dev, "FW Load timedout");
	return -ETIMEDOUT;

	default:
	return err;
	}
	}

	return 0;
	}

	static void renesas_rom_erase(struct pci_dev *pdev)
	{
	int retval, i;
	u8 status;

	dev_dbg(&pdev->dev, "Performing ROM Erase...\n");
	retval = pci_write_config_dword(pdev, RENESAS_DATA0,
	RENESAS_ROM_ERASE_MAGIC);
	if (retval) {
	dev_err(&pdev->dev, "ROM erase, magic word write failed: %d\n",
	pcibios_err_to_errno(retval));
	return;
	}

	retval = pci_read_config_byte(pdev, RENESAS_ROM_STATUS, &status);
	if (retval) {
	dev_err(&pdev->dev, "ROM status read failed: %d\n",
	pcibios_err_to_errno(retval));
	return;
	}
	status \|= RENESAS_ROM_STATUS_ERASE;
	retval = pci_write_config_byte(pdev, RENESAS_ROM_STATUS, status);
	if (retval) {
	dev_err(&pdev->dev, "ROM erase set word write failed\n");
	return;
	}

	/* sleep a bit while ROM is erased */
	msleep(20);

	for (i = 0; i < RENESAS_RETRY; i++) {
	retval = pci_read_config_byte(pdev, RENESAS_ROM_STATUS,
	&status);
	status &= RENESAS_ROM_STATUS_ERASE;
	if (!status)
	break;

	mdelay(RENESAS_DELAY);
	}

	if (i == RENESAS_RETRY)
	dev_dbg(&pdev->dev, "Chip erase timedout: %x\n", status);

	dev_dbg(&pdev->dev, "ROM Erase... Done success\n");
	}

	static bool renesas_setup_rom(struct pci_dev pdev, const struct firmware fw)
	{
	const u32 fw_data = (const u32 )fw->data;
	int err, i;
	u8 status;

	/* 2. Write magic word to Data0 */
	err = pci_write_config_dword(pdev, RENESAS_DATA0,
	RENESAS_ROM_WRITE_MAGIC);
	if (err)
	return false;

	/* 3. Set External ROM access */
	err = pci_write_config_byte(pdev, RENESAS_ROM_STATUS,
	RENESAS_ROM_STATUS_ACCESS);
	if (err)
	goto remove_bypass;

	/* 4. Check the result */
	err = pci_read_config_byte(pdev, RENESAS_ROM_STATUS, &status);
	if (err)
	goto remove_bypass;
	status &= GENMASK(6, 4);
	if (status) {
	dev_err(&pdev->dev,
	"setting external rom failed: %x\n", status);
	goto remove_bypass;
	}

	/* 5 to 16 Write FW to DATA0/1 while checking SetData0/1 */
	for (i = 0; i < fw->size / 4; i++) {
	err = renesas_fw_download_image(pdev, fw_data, i, true);
	if (err) {
	dev_err(&pdev->dev,
	"ROM Download Step %d failed at position %d bytes with (%d)\n",
	i, i * 4, err);
	goto remove_bypass;
	}
	}

	/*
	* wait till DATA0/1 is cleared
	*/
	for (i = 0; i < RENESAS_RETRY; i++) {
	err = pci_read_config_byte(pdev, RENESAS_ROM_STATUS_MSB,
	&status);
	if (err)
	goto remove_bypass;
	if (!(status & (BIT(0) \| BIT(1))))
	break;

	udelay(RENESAS_DELAY);
	}
	if (i == RENESAS_RETRY) {
	dev_err(&pdev->dev, "Final Firmware ROM Download step timed out\n");
	goto remove_bypass;
	}

	/* 17. Remove bypass */
	err = pci_write_config_byte(pdev, RENESAS_ROM_STATUS, 0);
	if (err)
	return false;

	udelay(10);

	/* 18. check result */
	for (i = 0; i < RENESAS_RETRY; i++) {
	err = pci_read_config_byte(pdev, RENESAS_ROM_STATUS, &status);
	if (err) {
	dev_err(&pdev->dev, "Read ROM status failed:%d\n",
	pcibios_err_to_errno(err));
	return false;
	}
	status &= RENESAS_ROM_STATUS_RESULT;
	if (status == RENESAS_ROM_STATUS_SUCCESS) {
	dev_dbg(&pdev->dev, "Download ROM success\n");
	break;
	}
	udelay(RENESAS_DELAY);
	}
	if (i == RENESAS_RETRY) { /* Timed out */
	dev_err(&pdev->dev,
	"Download to external ROM TO: %x\n", status);
	return false;
	}

	dev_dbg(&pdev->dev, "Download to external ROM succeeded\n");

	/* Last step set Reload */
	err = pci_write_config_byte(pdev, RENESAS_ROM_STATUS,
	RENESAS_ROM_STATUS_RELOAD);
	if (err) {
	dev_err(&pdev->dev, "Set ROM execute failed: %d\n",
	pcibios_err_to_errno(err));
	return false;
	}

	/*
	* wait till Reload is cleared
	*/
	for (i = 0; i < RENESAS_RETRY; i++) {
	err = pci_read_config_byte(pdev, RENESAS_ROM_STATUS, &status);
	if (err)
	return false;
	if (!(status & RENESAS_ROM_STATUS_RELOAD))
	break;

	udelay(RENESAS_DELAY);
	}
	if (i == RENESAS_RETRY) {
	dev_err(&pdev->dev, "ROM Exec timed out: %x\n", status);
	return false;
	}

	return true;

	remove_bypass:
	pci_write_config_byte(pdev, RENESAS_ROM_STATUS, 0);
	return false;
	}

	static int renesas_load_fw(struct pci_dev pdev, const struct firmware fw)
	{
	int err = 0;
	bool rom;

	/* Check if the device has external ROM */
	rom = renesas_check_rom(pdev);
	if (rom) {
	/* perform chip erase first */
	renesas_rom_erase(pdev);

	/* lets try loading fw on ROM first */
	rom = renesas_setup_rom(pdev, fw);
	if (!rom) {
	dev_dbg(&pdev->dev,
	"ROM load failed, falling back on FW load\n");
	} else {
	dev_dbg(&pdev->dev,
	"ROM load success\n");
	goto exit;
	}
	}

	err = renesas_fw_download(pdev, fw);

	exit:
	if (err)
	dev_err(&pdev->dev, "firmware failed to download (%d).", err);
	return err;
	}

	int renesas_xhci_check_request_fw(struct pci_dev *pdev,
	const struct pci_device_id *id)
	{
	struct xhci_driver_data *driver_data =
	(struct xhci_driver_data *)id->driver_data;
	const char *fw_name = driver_data->firmware;
	const struct firmware *fw;
	bool has_rom;
	int err;

	/* Check if device has ROM and loaded, if so skip everything */
	has_rom = renesas_check_rom(pdev);
	if (has_rom) {
	err = renesas_check_rom_state(pdev);
	if (!err)
	return 0;
	else if (err != -ENOENT)
	has_rom = false;
	}

	err = renesas_fw_check_running(pdev);
	/* Continue ahead, if the firmware is already running. */
	if (!err)
	return 0;

	/* no firmware interface available */
	if (err != 1)
	return has_rom ? 0 : err;

	pci_dev_get(pdev);
	err = firmware_request_nowarn(&fw, fw_name, &pdev->dev);
	pci_dev_put(pdev);
	if (err) {
	if (has_rom) {
	dev_info(&pdev->dev, "failed to load firmware %s, fallback to ROM\n",
	fw_name);
	return 0;
	}
	dev_err(&pdev->dev, "failed to load firmware %s: %d\n",
	fw_name, err);
	return err;
	}

	err = renesas_fw_verify(fw->data, fw->size);
	if (err)
	goto exit;

	err = renesas_load_fw(pdev, fw);
	exit:
	release_firmware(fw);
	return err;
	}
	EXPORT_SYMBOL_GPL(renesas_xhci_check_request_fw);

	MODULE_LICENSE("GPL v2");