drivers/thunderbolt/dma_port.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Thunderbolt DMA configuration based mailbox support
  *
  * Copyright (C) 2017, Intel Corporation
  * Authors: Michael Jamet <michael.jamet@intel.com>
  *          Mika Westerberg <mika.westerberg@linux.intel.com>
  */

 #include <linux/delay.h>
 #include <linux/slab.h>

 #include "dma_port.h"
 #include "tb_regs.h"

 #define DMA_PORT_CAP			0x3e

 #define MAIL_DATA			1
 #define MAIL_DATA_DWORDS		16

 #define MAIL_IN				17
 #define MAIL_IN_CMD_SHIFT		28
 #define MAIL_IN_CMD_MASK		GENMASK(31, 28)
 #define MAIL_IN_CMD_FLASH_WRITE		0x0
 #define MAIL_IN_CMD_FLASH_UPDATE_AUTH	0x1
 #define MAIL_IN_CMD_FLASH_READ		0x2
 #define MAIL_IN_CMD_POWER_CYCLE		0x4
 #define MAIL_IN_DWORDS_SHIFT		24
 #define MAIL_IN_DWORDS_MASK		GENMASK(27, 24)
 #define MAIL_IN_ADDRESS_SHIFT		2
 #define MAIL_IN_ADDRESS_MASK		GENMASK(23, 2)
 #define MAIL_IN_CSS			BIT(1)
 #define MAIL_IN_OP_REQUEST		BIT(0)

 #define MAIL_OUT			18
 #define MAIL_OUT_STATUS_RESPONSE	BIT(29)
 #define MAIL_OUT_STATUS_CMD_SHIFT	4
 #define MAIL_OUT_STATUS_CMD_MASK	GENMASK(7, 4)
 #define MAIL_OUT_STATUS_MASK		GENMASK(3, 0)
 #define MAIL_OUT_STATUS_COMPLETED	0
 #define MAIL_OUT_STATUS_ERR_AUTH	1
 #define MAIL_OUT_STATUS_ERR_ACCESS	2

 #define DMA_PORT_TIMEOUT		5000 /* ms */
 #define DMA_PORT_RETRIES		3

 /**
  * struct tb_dma_port - DMA control port
  * @sw: Switch the DMA port belongs to
  * @port: Switch port number where DMA capability is found
  * @base: Start offset of the mailbox registers
  * @buf: Temporary buffer to store a single block
  */
 struct tb_dma_port {
 	struct tb_switch *sw;
 	u8 port;
 	u32 base;
 	u8 *buf;
 };

 /*
  * When the switch is in safe mode it supports very little functionality
  * so we don't validate that much here.
  */
 static bool dma_port_match(const struct tb_cfg_request *req,
 			   const struct ctl_pkg *pkg)
 {
 	u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);

 	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
 		return true;
 	if (pkg->frame.eof != req->response_type)
 		return false;
 	if (route != tb_cfg_get_route(req->request))
 		return false;
 	if (pkg->frame.size != req->response_size)
 		return false;

 	return true;
 }

 static bool dma_port_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
 {
 	memcpy(req->response, pkg->buffer, req->response_size);
 	return true;
 }

 static int dma_port_read(struct tb_ctl *ctl, void *buffer, u64 route,
 			 u32 port, u32 offset, u32 length, int timeout_msec)
 {
 	struct cfg_read_pkg request = {
 		.header = tb_cfg_make_header(route),
 		.addr = {
 			.seq = 1,
 			.port = port,
 			.space = TB_CFG_PORT,
 			.offset = offset,
 			.length = length,
 		},
 	};
 	struct tb_cfg_request *req;
 	struct cfg_write_pkg reply;
 	struct tb_cfg_result res;

 	req = tb_cfg_request_alloc();
 	if (!req)
 		return -ENOMEM;

 	req->match = dma_port_match;
 	req->copy = dma_port_copy;
 	req->request = &request;
 	req->request_size = sizeof(request);
 	req->request_type = TB_CFG_PKG_READ;
 	req->response = &reply;
 	req->response_size = 12 + 4 * length;
 	req->response_type = TB_CFG_PKG_READ;

 	res = tb_cfg_request_sync(ctl, req, timeout_msec);

 	tb_cfg_request_put(req);

 	if (res.err)
 		return res.err;

 	memcpy(buffer, &reply.data, 4 * length);
 	return 0;
 }

 static int dma_port_write(struct tb_ctl *ctl, const void *buffer, u64 route,
 			  u32 port, u32 offset, u32 length, int timeout_msec)
 {
 	struct cfg_write_pkg request = {
 		.header = tb_cfg_make_header(route),
 		.addr = {
 			.seq = 1,
 			.port = port,
 			.space = TB_CFG_PORT,
 			.offset = offset,
 			.length = length,
 		},
 	};
 	struct tb_cfg_request *req;
 	struct cfg_read_pkg reply;
 	struct tb_cfg_result res;

 	memcpy(&request.data, buffer, length * 4);

 	req = tb_cfg_request_alloc();
 	if (!req)
 		return -ENOMEM;

 	req->match = dma_port_match;
 	req->copy = dma_port_copy;
 	req->request = &request;
 	req->request_size = 12 + 4 * length;
 	req->request_type = TB_CFG_PKG_WRITE;
 	req->response = &reply;
 	req->response_size = sizeof(reply);
 	req->response_type = TB_CFG_PKG_WRITE;

 	res = tb_cfg_request_sync(ctl, req, timeout_msec);

 	tb_cfg_request_put(req);

 	return res.err;
 }

 static int dma_find_port(struct tb_switch *sw)
 {
 	static const int ports[] = { 3, 5, 7 };
 	int i;

 	/*
 	 * The DMA (NHI) port is either 3, 5 or 7 depending on the
 	 * controller. Try all of them.
 	 */
 	for (i = 0; i < ARRAY_SIZE(ports); i++) {
 		u32 type;
 		int ret;

 		ret = dma_port_read(sw->tb->ctl, &type, tb_route(sw), ports[i],
 				    2, 1, DMA_PORT_TIMEOUT);
 		if (!ret && (type & 0xffffff) == TB_TYPE_NHI)
 			return ports[i];
 	}

 	return -ENODEV;
 }

 /**
  * dma_port_alloc() - Finds DMA control port from a switch pointed by route
  * @sw: Switch from where find the DMA port
  *
  * Function checks if the switch NHI port supports DMA configuration
  * based mailbox capability and if it does, allocates and initializes
  * DMA port structure. Returns %NULL if the capabity was not found.
  *
  * The DMA control port is functional also when the switch is in safe
  * mode.
  */
 struct tb_dma_port *dma_port_alloc(struct tb_switch *sw)
 {
 	struct tb_dma_port *dma;
 	int port;

 	port = dma_find_port(sw);
 	if (port < 0)
 		return NULL;

 	dma = kzalloc(sizeof(*dma), GFP_KERNEL);
 	if (!dma)
 		return NULL;

 	dma->buf = kmalloc_array(MAIL_DATA_DWORDS, sizeof(u32), GFP_KERNEL);
 	if (!dma->buf) {
 		kfree(dma);
 		return NULL;
 	}

 	dma->sw = sw;
 	dma->port = port;
 	dma->base = DMA_PORT_CAP;

 	return dma;
 }

 /**
  * dma_port_free() - Release DMA control port structure
  * @dma: DMA control port
  */
 void dma_port_free(struct tb_dma_port *dma)
 {
 	if (dma) {
 		kfree(dma->buf);
 		kfree(dma);
 	}
 }

 static int dma_port_wait_for_completion(struct tb_dma_port *dma,
 					unsigned int timeout)
 {
 	unsigned long end = jiffies + msecs_to_jiffies(timeout);
 	struct tb_switch *sw = dma->sw;

 	do {
 		int ret;
 		u32 in;

 		ret = dma_port_read(sw->tb->ctl, &in, tb_route(sw), dma->port,
 				    dma->base + MAIL_IN, 1, 50);
 		if (ret) {
 			if (ret != -ETIMEDOUT)
 				return ret;
 		} else if (!(in & MAIL_IN_OP_REQUEST)) {
 			return 0;
 		}

 		usleep_range(50, 100);
 	} while (time_before(jiffies, end));

 	return -ETIMEDOUT;
 }

 static int status_to_errno(u32 status)
 {
 	switch (status & MAIL_OUT_STATUS_MASK) {
 	case MAIL_OUT_STATUS_COMPLETED:
 		return 0;
 	case MAIL_OUT_STATUS_ERR_AUTH:
 		return -EINVAL;
 	case MAIL_OUT_STATUS_ERR_ACCESS:
 		return -EACCES;
 	}

 	return -EIO;
 }

 static int dma_port_request(struct tb_dma_port *dma, u32 in,
 			    unsigned int timeout)
 {
 	struct tb_switch *sw = dma->sw;
 	u32 out;
 	int ret;

 	ret = dma_port_write(sw->tb->ctl, &in, tb_route(sw), dma->port,
 			     dma->base + MAIL_IN, 1, DMA_PORT_TIMEOUT);
 	if (ret)
 		return ret;

 	ret = dma_port_wait_for_completion(dma, timeout);
 	if (ret)
 		return ret;

 	ret = dma_port_read(sw->tb->ctl, &out, tb_route(sw), dma->port,
 			    dma->base + MAIL_OUT, 1, DMA_PORT_TIMEOUT);
 	if (ret)
 		return ret;

 	return status_to_errno(out);
 }

 static int dma_port_flash_read_block(struct tb_dma_port *dma, u32 address,
 				     void *buf, u32 size)
 {
 	struct tb_switch *sw = dma->sw;
 	u32 in, dwaddress, dwords;
 	int ret;

 	dwaddress = address / 4;
 	dwords = size / 4;

 	in = MAIL_IN_CMD_FLASH_READ << MAIL_IN_CMD_SHIFT;
 	if (dwords < MAIL_DATA_DWORDS)
 		in |= (dwords << MAIL_IN_DWORDS_SHIFT) & MAIL_IN_DWORDS_MASK;
 	in |= (dwaddress << MAIL_IN_ADDRESS_SHIFT) & MAIL_IN_ADDRESS_MASK;
 	in |= MAIL_IN_OP_REQUEST;

 	ret = dma_port_request(dma, in, DMA_PORT_TIMEOUT);
 	if (ret)
 		return ret;

 	return dma_port_read(sw->tb->ctl, buf, tb_route(sw), dma->port,
 			     dma->base + MAIL_DATA, dwords, DMA_PORT_TIMEOUT);
 }

 static int dma_port_flash_write_block(struct tb_dma_port *dma, u32 address,
 				      const void *buf, u32 size)
 {
 	struct tb_switch *sw = dma->sw;
 	u32 in, dwaddress, dwords;
 	int ret;

 	dwords = size / 4;

 	/* Write the block to MAIL_DATA registers */
 	ret = dma_port_write(sw->tb->ctl, buf, tb_route(sw), dma->port,
 			    dma->base + MAIL_DATA, dwords, DMA_PORT_TIMEOUT);

 	in = MAIL_IN_CMD_FLASH_WRITE << MAIL_IN_CMD_SHIFT;

 	/* CSS header write is always done to the same magic address */
 	if (address >= DMA_PORT_CSS_ADDRESS) {
 		dwaddress = DMA_PORT_CSS_ADDRESS;
 		in |= MAIL_IN_CSS;
 	} else {
 		dwaddress = address / 4;
 	}

 	in |= ((dwords - 1) << MAIL_IN_DWORDS_SHIFT) & MAIL_IN_DWORDS_MASK;
 	in |= (dwaddress << MAIL_IN_ADDRESS_SHIFT) & MAIL_IN_ADDRESS_MASK;
 	in |= MAIL_IN_OP_REQUEST;

 	return dma_port_request(dma, in, DMA_PORT_TIMEOUT);
 }

 /**
  * dma_port_flash_read() - Read from active flash region
  * @dma: DMA control port
  * @address: Address relative to the start of active region
  * @buf: Buffer where the data is read
  * @size: Size of the buffer
  */
 int dma_port_flash_read(struct tb_dma_port *dma, unsigned int address,
 			void *buf, size_t size)
 {
 	unsigned int retries = DMA_PORT_RETRIES;

 	do {
 		unsigned int offset;
 		size_t nbytes;
 		int ret;

 		offset = address & 3;
 		nbytes = min_t(size_t, size + offset, MAIL_DATA_DWORDS * 4);

 		ret = dma_port_flash_read_block(dma, address, dma->buf,
 						ALIGN(nbytes, 4));
 		if (ret) {
 			if (ret == -ETIMEDOUT) {
 				if (retries--)
 					continue;
 				ret = -EIO;
 			}
 			return ret;
 		}

 		nbytes -= offset;
 		memcpy(buf, dma->buf + offset, nbytes);

 		size -= nbytes;
 		address += nbytes;
 		buf += nbytes;
 	} while (size > 0);

 	return 0;
 }

 /**
  * dma_port_flash_write() - Write to non-active flash region
  * @dma: DMA control port
  * @address: Address relative to the start of non-active region
  * @buf: Data to write
  * @size: Size of the buffer
  *
  * Writes block of data to the non-active flash region of the switch. If
  * the address is given as %DMA_PORT_CSS_ADDRESS the block is written
  * using CSS command.
  */
 int dma_port_flash_write(struct tb_dma_port *dma, unsigned int address,
 			 const void *buf, size_t size)
 {
 	unsigned int retries = DMA_PORT_RETRIES;
 	unsigned int offset;

 	if (address >= DMA_PORT_CSS_ADDRESS) {
 		offset = 0;
 		if (size > DMA_PORT_CSS_MAX_SIZE)
 			return -E2BIG;
 	} else {
 		offset = address & 3;
 		address = address & ~3;
 	}

 	do {
 		u32 nbytes = min_t(u32, size, MAIL_DATA_DWORDS * 4);
 		int ret;

 		memcpy(dma->buf + offset, buf, nbytes);

 		ret = dma_port_flash_write_block(dma, address, buf, nbytes);
 		if (ret) {
 			if (ret == -ETIMEDOUT) {
 				if (retries--)
 					continue;
 				ret = -EIO;
 			}
 			return ret;
 		}

 		size -= nbytes;
 		address += nbytes;
 		buf += nbytes;
 	} while (size > 0);

 	return 0;
 }

 /**
  * dma_port_flash_update_auth() - Starts flash authenticate cycle
  * @dma: DMA control port
  *
  * Starts the flash update authentication cycle. If the image in the
  * non-active area was valid, the switch starts upgrade process where
  * active and non-active area get swapped in the end. Caller should call
  * dma_port_flash_update_auth_status() to get status of this command.
  * This is because if the switch in question is root switch the
  * thunderbolt host controller gets reset as well.
  */
 int dma_port_flash_update_auth(struct tb_dma_port *dma)
 {
 	u32 in;

 	in = MAIL_IN_CMD_FLASH_UPDATE_AUTH << MAIL_IN_CMD_SHIFT;
 	in |= MAIL_IN_OP_REQUEST;

 	return dma_port_request(dma, in, 150);
 }

 /**
  * dma_port_flash_update_auth_status() - Reads status of update auth command
  * @dma: DMA control port
  * @status: Status code of the operation
  *
  * The function checks if there is status available from the last update
  * auth command. Returns %0 if there is no status and no further
  * action is required. If there is status, %1 is returned instead and
  * @status holds the failure code.
  *
  * Negative return means there was an error reading status from the
  * switch.
  */
 int dma_port_flash_update_auth_status(struct tb_dma_port *dma, u32 *status)
 {
 	struct tb_switch *sw = dma->sw;
 	u32 out, cmd;
 	int ret;

 	ret = dma_port_read(sw->tb->ctl, &out, tb_route(sw), dma->port,
 			    dma->base + MAIL_OUT, 1, DMA_PORT_TIMEOUT);
 	if (ret)
 		return ret;

 	/* Check if the status relates to flash update auth */
 	cmd = (out & MAIL_OUT_STATUS_CMD_MASK) >> MAIL_OUT_STATUS_CMD_SHIFT;
 	if (cmd == MAIL_IN_CMD_FLASH_UPDATE_AUTH) {
 		if (status)
 			*status = out & MAIL_OUT_STATUS_MASK;

 		/* Reset is needed in any case */
 		return 1;
 	}

 	return 0;
 }

 /**
  * dma_port_power_cycle() - Power cycles the switch
  * @dma: DMA control port
  *
  * Triggers power cycle to the switch.
  */
 int dma_port_power_cycle(struct tb_dma_port *dma)
 {
 	u32 in;

 	in = MAIL_IN_CMD_POWER_CYCLE << MAIL_IN_CMD_SHIFT;
 	in |= MAIL_IN_OP_REQUEST;

 	return dma_port_request(dma, in, 150);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Thunderbolt DMA configuration based mailbox support
	*
	* Copyright (C) 2017, Intel Corporation
	* Authors: Michael Jamet <michael.jamet@intel.com>
	* Mika Westerberg <mika.westerberg@linux.intel.com>
	*/

	#include <linux/delay.h>
	#include <linux/slab.h>

	#include "dma_port.h"
	#include "tb_regs.h"

	#define DMA_PORT_CAP 0x3e

	#define MAIL_DATA 1
	#define MAIL_DATA_DWORDS 16

	#define MAIL_IN 17
	#define MAIL_IN_CMD_SHIFT 28
	#define MAIL_IN_CMD_MASK GENMASK(31, 28)
	#define MAIL_IN_CMD_FLASH_WRITE 0x0
	#define MAIL_IN_CMD_FLASH_UPDATE_AUTH 0x1
	#define MAIL_IN_CMD_FLASH_READ 0x2
	#define MAIL_IN_CMD_POWER_CYCLE 0x4
	#define MAIL_IN_DWORDS_SHIFT 24
	#define MAIL_IN_DWORDS_MASK GENMASK(27, 24)
	#define MAIL_IN_ADDRESS_SHIFT 2
	#define MAIL_IN_ADDRESS_MASK GENMASK(23, 2)
	#define MAIL_IN_CSS BIT(1)
	#define MAIL_IN_OP_REQUEST BIT(0)

	#define MAIL_OUT 18
	#define MAIL_OUT_STATUS_RESPONSE BIT(29)
	#define MAIL_OUT_STATUS_CMD_SHIFT 4
	#define MAIL_OUT_STATUS_CMD_MASK GENMASK(7, 4)
	#define MAIL_OUT_STATUS_MASK GENMASK(3, 0)
	#define MAIL_OUT_STATUS_COMPLETED 0
	#define MAIL_OUT_STATUS_ERR_AUTH 1
	#define MAIL_OUT_STATUS_ERR_ACCESS 2

	#define DMA_PORT_TIMEOUT 5000 /* ms */
	#define DMA_PORT_RETRIES 3

	/**
	* struct tb_dma_port - DMA control port
	* @sw: Switch the DMA port belongs to
	* @port: Switch port number where DMA capability is found
	* @base: Start offset of the mailbox registers
	* @buf: Temporary buffer to store a single block
	*/
	struct tb_dma_port {
	struct tb_switch *sw;
	u8 port;
	u32 base;
	u8 *buf;
	};

	/*
	* When the switch is in safe mode it supports very little functionality
	* so we don't validate that much here.
	*/
	static bool dma_port_match(const struct tb_cfg_request *req,
	const struct ctl_pkg *pkg)
	{
	u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);

	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
	return true;
	if (pkg->frame.eof != req->response_type)
	return false;
	if (route != tb_cfg_get_route(req->request))
	return false;
	if (pkg->frame.size != req->response_size)
	return false;

	return true;
	}

	static bool dma_port_copy(struct tb_cfg_request req, const struct ctl_pkg pkg)
	{
	memcpy(req->response, pkg->buffer, req->response_size);
	return true;
	}

	static int dma_port_read(struct tb_ctl ctl, void buffer, u64 route,
	u32 port, u32 offset, u32 length, int timeout_msec)
	{
	struct cfg_read_pkg request = {
	.header = tb_cfg_make_header(route),
	.addr = {
	.seq = 1,
	.port = port,
	.space = TB_CFG_PORT,
	.offset = offset,
	.length = length,
	},
	};
	struct tb_cfg_request *req;
	struct cfg_write_pkg reply;
	struct tb_cfg_result res;

	req = tb_cfg_request_alloc();
	if (!req)
	return -ENOMEM;

	req->match = dma_port_match;
	req->copy = dma_port_copy;
	req->request = &request;
	req->request_size = sizeof(request);
	req->request_type = TB_CFG_PKG_READ;
	req->response = &reply;
	req->response_size = 12 + 4 * length;
	req->response_type = TB_CFG_PKG_READ;

	res = tb_cfg_request_sync(ctl, req, timeout_msec);

	tb_cfg_request_put(req);

	if (res.err)
	return res.err;

	memcpy(buffer, &reply.data, 4 * length);
	return 0;
	}

	static int dma_port_write(struct tb_ctl ctl, const void buffer, u64 route,
	u32 port, u32 offset, u32 length, int timeout_msec)
	{
	struct cfg_write_pkg request = {
	.header = tb_cfg_make_header(route),
	.addr = {
	.seq = 1,
	.port = port,
	.space = TB_CFG_PORT,
	.offset = offset,
	.length = length,
	},
	};
	struct tb_cfg_request *req;
	struct cfg_read_pkg reply;
	struct tb_cfg_result res;

	memcpy(&request.data, buffer, length * 4);

	req = tb_cfg_request_alloc();
	if (!req)
	return -ENOMEM;

	req->match = dma_port_match;
	req->copy = dma_port_copy;
	req->request = &request;
	req->request_size = 12 + 4 * length;
	req->request_type = TB_CFG_PKG_WRITE;
	req->response = &reply;
	req->response_size = sizeof(reply);
	req->response_type = TB_CFG_PKG_WRITE;

	res = tb_cfg_request_sync(ctl, req, timeout_msec);

	tb_cfg_request_put(req);

	return res.err;
	}

	static int dma_find_port(struct tb_switch *sw)
	{
	static const int ports[] = { 3, 5, 7 };
	int i;

	/*
	* The DMA (NHI) port is either 3, 5 or 7 depending on the
	* controller. Try all of them.
	*/
	for (i = 0; i < ARRAY_SIZE(ports); i++) {
	u32 type;
	int ret;

	ret = dma_port_read(sw->tb->ctl, &type, tb_route(sw), ports[i],
	2, 1, DMA_PORT_TIMEOUT);
	if (!ret && (type & 0xffffff) == TB_TYPE_NHI)
	return ports[i];
	}

	return -ENODEV;
	}

	/**
	* dma_port_alloc() - Finds DMA control port from a switch pointed by route
	* @sw: Switch from where find the DMA port
	*
	* Function checks if the switch NHI port supports DMA configuration
	* based mailbox capability and if it does, allocates and initializes
	* DMA port structure. Returns %NULL if the capabity was not found.
	*
	* The DMA control port is functional also when the switch is in safe
	* mode.
	*/
	struct tb_dma_port dma_port_alloc(struct tb_switch sw)
	{
	struct tb_dma_port *dma;
	int port;

	port = dma_find_port(sw);
	if (port < 0)
	return NULL;

	dma = kzalloc(sizeof(*dma), GFP_KERNEL);
	if (!dma)
	return NULL;

	dma->buf = kmalloc_array(MAIL_DATA_DWORDS, sizeof(u32), GFP_KERNEL);
	if (!dma->buf) {
	kfree(dma);
	return NULL;
	}

	dma->sw = sw;
	dma->port = port;
	dma->base = DMA_PORT_CAP;

	return dma;
	}

	/**
	* dma_port_free() - Release DMA control port structure
	* @dma: DMA control port
	*/
	void dma_port_free(struct tb_dma_port *dma)
	{
	if (dma) {
	kfree(dma->buf);
	kfree(dma);
	}
	}

	static int dma_port_wait_for_completion(struct tb_dma_port *dma,
	unsigned int timeout)
	{
	unsigned long end = jiffies + msecs_to_jiffies(timeout);
	struct tb_switch *sw = dma->sw;

	do {
	int ret;
	u32 in;

	ret = dma_port_read(sw->tb->ctl, &in, tb_route(sw), dma->port,
	dma->base + MAIL_IN, 1, 50);
	if (ret) {
	if (ret != -ETIMEDOUT)
	return ret;
	} else if (!(in & MAIL_IN_OP_REQUEST)) {
	return 0;
	}

	usleep_range(50, 100);
	} while (time_before(jiffies, end));

	return -ETIMEDOUT;
	}

	static int status_to_errno(u32 status)
	{
	switch (status & MAIL_OUT_STATUS_MASK) {
	case MAIL_OUT_STATUS_COMPLETED:
	return 0;
	case MAIL_OUT_STATUS_ERR_AUTH:
	return -EINVAL;
	case MAIL_OUT_STATUS_ERR_ACCESS:
	return -EACCES;
	}

	return -EIO;
	}

	static int dma_port_request(struct tb_dma_port *dma, u32 in,
	unsigned int timeout)
	{
	struct tb_switch *sw = dma->sw;
	u32 out;
	int ret;

	ret = dma_port_write(sw->tb->ctl, &in, tb_route(sw), dma->port,
	dma->base + MAIL_IN, 1, DMA_PORT_TIMEOUT);
	if (ret)
	return ret;

	ret = dma_port_wait_for_completion(dma, timeout);
	if (ret)
	return ret;

	ret = dma_port_read(sw->tb->ctl, &out, tb_route(sw), dma->port,
	dma->base + MAIL_OUT, 1, DMA_PORT_TIMEOUT);
	if (ret)
	return ret;

	return status_to_errno(out);
	}

	static int dma_port_flash_read_block(struct tb_dma_port *dma, u32 address,
	void *buf, u32 size)
	{
	struct tb_switch *sw = dma->sw;
	u32 in, dwaddress, dwords;
	int ret;

	dwaddress = address / 4;
	dwords = size / 4;

	in = MAIL_IN_CMD_FLASH_READ << MAIL_IN_CMD_SHIFT;
	if (dwords < MAIL_DATA_DWORDS)
	in \|= (dwords << MAIL_IN_DWORDS_SHIFT) & MAIL_IN_DWORDS_MASK;
	in \|= (dwaddress << MAIL_IN_ADDRESS_SHIFT) & MAIL_IN_ADDRESS_MASK;
	in \|= MAIL_IN_OP_REQUEST;

	ret = dma_port_request(dma, in, DMA_PORT_TIMEOUT);
	if (ret)
	return ret;

	return dma_port_read(sw->tb->ctl, buf, tb_route(sw), dma->port,
	dma->base + MAIL_DATA, dwords, DMA_PORT_TIMEOUT);
	}

	static int dma_port_flash_write_block(struct tb_dma_port *dma, u32 address,
	const void *buf, u32 size)
	{
	struct tb_switch *sw = dma->sw;
	u32 in, dwaddress, dwords;
	int ret;

	dwords = size / 4;

	/* Write the block to MAIL_DATA registers */
	ret = dma_port_write(sw->tb->ctl, buf, tb_route(sw), dma->port,
	dma->base + MAIL_DATA, dwords, DMA_PORT_TIMEOUT);

	in = MAIL_IN_CMD_FLASH_WRITE << MAIL_IN_CMD_SHIFT;

	/* CSS header write is always done to the same magic address */
	if (address >= DMA_PORT_CSS_ADDRESS) {
	dwaddress = DMA_PORT_CSS_ADDRESS;
	in \|= MAIL_IN_CSS;
	} else {
	dwaddress = address / 4;
	}

	in \|= ((dwords - 1) << MAIL_IN_DWORDS_SHIFT) & MAIL_IN_DWORDS_MASK;
	in \|= (dwaddress << MAIL_IN_ADDRESS_SHIFT) & MAIL_IN_ADDRESS_MASK;
	in \|= MAIL_IN_OP_REQUEST;

	return dma_port_request(dma, in, DMA_PORT_TIMEOUT);
	}

	/**
	* dma_port_flash_read() - Read from active flash region
	* @dma: DMA control port
	* @address: Address relative to the start of active region
	* @buf: Buffer where the data is read
	* @size: Size of the buffer
	*/
	int dma_port_flash_read(struct tb_dma_port *dma, unsigned int address,
	void *buf, size_t size)
	{
	unsigned int retries = DMA_PORT_RETRIES;

	do {
	unsigned int offset;
	size_t nbytes;
	int ret;

	offset = address & 3;
	nbytes = min_t(size_t, size + offset, MAIL_DATA_DWORDS * 4);

	ret = dma_port_flash_read_block(dma, address, dma->buf,
	ALIGN(nbytes, 4));
	if (ret) {
	if (ret == -ETIMEDOUT) {
	if (retries--)
	continue;
	ret = -EIO;
	}
	return ret;
	}

	nbytes -= offset;
	memcpy(buf, dma->buf + offset, nbytes);

	size -= nbytes;
	address += nbytes;
	buf += nbytes;
	} while (size > 0);

	return 0;
	}

	/**
	* dma_port_flash_write() - Write to non-active flash region
	* @dma: DMA control port
	* @address: Address relative to the start of non-active region
	* @buf: Data to write
	* @size: Size of the buffer
	*
	* Writes block of data to the non-active flash region of the switch. If
	* the address is given as %DMA_PORT_CSS_ADDRESS the block is written
	* using CSS command.
	*/
	int dma_port_flash_write(struct tb_dma_port *dma, unsigned int address,
	const void *buf, size_t size)
	{
	unsigned int retries = DMA_PORT_RETRIES;
	unsigned int offset;

	if (address >= DMA_PORT_CSS_ADDRESS) {
	offset = 0;
	if (size > DMA_PORT_CSS_MAX_SIZE)
	return -E2BIG;
	} else {
	offset = address & 3;
	address = address & ~3;
	}

	do {
	u32 nbytes = min_t(u32, size, MAIL_DATA_DWORDS * 4);
	int ret;

	memcpy(dma->buf + offset, buf, nbytes);

	ret = dma_port_flash_write_block(dma, address, buf, nbytes);
	if (ret) {
	if (ret == -ETIMEDOUT) {
	if (retries--)
	continue;
	ret = -EIO;
	}
	return ret;
	}

	size -= nbytes;
	address += nbytes;
	buf += nbytes;
	} while (size > 0);

	return 0;
	}

	/**
	* dma_port_flash_update_auth() - Starts flash authenticate cycle
	* @dma: DMA control port
	*
	* Starts the flash update authentication cycle. If the image in the
	* non-active area was valid, the switch starts upgrade process where
	* active and non-active area get swapped in the end. Caller should call
	* dma_port_flash_update_auth_status() to get status of this command.
	* This is because if the switch in question is root switch the
	* thunderbolt host controller gets reset as well.
	*/
	int dma_port_flash_update_auth(struct tb_dma_port *dma)
	{
	u32 in;

	in = MAIL_IN_CMD_FLASH_UPDATE_AUTH << MAIL_IN_CMD_SHIFT;
	in \|= MAIL_IN_OP_REQUEST;

	return dma_port_request(dma, in, 150);
	}

	/**
	* dma_port_flash_update_auth_status() - Reads status of update auth command
	* @dma: DMA control port
	* @status: Status code of the operation
	*
	* The function checks if there is status available from the last update
	* auth command. Returns %0 if there is no status and no further
	* action is required. If there is status, %1 is returned instead and
	* @status holds the failure code.
	*
	* Negative return means there was an error reading status from the
	* switch.
	*/
	int dma_port_flash_update_auth_status(struct tb_dma_port dma, u32 status)
	{
	struct tb_switch *sw = dma->sw;
	u32 out, cmd;
	int ret;

	ret = dma_port_read(sw->tb->ctl, &out, tb_route(sw), dma->port,
	dma->base + MAIL_OUT, 1, DMA_PORT_TIMEOUT);
	if (ret)
	return ret;

	/* Check if the status relates to flash update auth */
	cmd = (out & MAIL_OUT_STATUS_CMD_MASK) >> MAIL_OUT_STATUS_CMD_SHIFT;
	if (cmd == MAIL_IN_CMD_FLASH_UPDATE_AUTH) {
	if (status)
	*status = out & MAIL_OUT_STATUS_MASK;

	/* Reset is needed in any case */
	return 1;
	}

	return 0;
	}

	/**
	* dma_port_power_cycle() - Power cycles the switch
	* @dma: DMA control port
	*
	* Triggers power cycle to the switch.
	*/
	int dma_port_power_cycle(struct tb_dma_port *dma)
	{
	u32 in;

	in = MAIL_IN_CMD_POWER_CYCLE << MAIL_IN_CMD_SHIFT;
	in \|= MAIL_IN_OP_REQUEST;

	return dma_port_request(dma, in, 150);
	}