/*
 * Copyright 2013-2016 Freescale Semiconductor Inc.
 *
 * I/O services to send MC commands to the MC hardware
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the above-listed copyright holders nor the
 *       names of any contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * ALTERNATIVELY, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") as published by the Free Software
 * Foundation, either version 2 of that License or (at your option) any
 * later version.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/io-64-nonatomic-hi-lo.h>
#include "../include/mc.h"

#include "dpmcp.h"

/**
 * Timeout in milliseconds to wait for the completion of an MC command
 */
#define MC_CMD_COMPLETION_TIMEOUT_MS	500

/*
 * usleep_range() min and max values used to throttle down polling
 * iterations while waiting for MC command completion
 */
#define MC_CMD_COMPLETION_POLLING_MIN_SLEEP_USECS    10
#define MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS    500

static enum mc_cmd_status mc_cmd_hdr_read_status(struct mc_command *cmd)
{
	struct mc_cmd_header *hdr = (struct mc_cmd_header *)&cmd->header;

	return (enum mc_cmd_status)hdr->status;
}

static u16 mc_cmd_hdr_read_cmdid(struct mc_command *cmd)
{
	struct mc_cmd_header *hdr = (struct mc_cmd_header *)&cmd->header;
	u16 cmd_id = le16_to_cpu(hdr->cmd_id);

	return cmd_id;
}

static int mc_status_to_error(enum mc_cmd_status status)
{
	static const int mc_status_to_error_map[] = {
		[MC_CMD_STATUS_OK] = 0,
		[MC_CMD_STATUS_AUTH_ERR] = -EACCES,
		[MC_CMD_STATUS_NO_PRIVILEGE] = -EPERM,
		[MC_CMD_STATUS_DMA_ERR] = -EIO,
		[MC_CMD_STATUS_CONFIG_ERR] = -ENXIO,
		[MC_CMD_STATUS_TIMEOUT] = -ETIMEDOUT,
		[MC_CMD_STATUS_NO_RESOURCE] = -ENAVAIL,
		[MC_CMD_STATUS_NO_MEMORY] = -ENOMEM,
		[MC_CMD_STATUS_BUSY] = -EBUSY,
		[MC_CMD_STATUS_UNSUPPORTED_OP] = -ENOTSUPP,
		[MC_CMD_STATUS_INVALID_STATE] = -ENODEV,
	};

	if (WARN_ON((u32)status >= ARRAY_SIZE(mc_status_to_error_map)))
		return -EINVAL;

	return mc_status_to_error_map[status];
}

static const char *mc_status_to_string(enum mc_cmd_status status)
{
	static const char *const status_strings[] = {
		[MC_CMD_STATUS_OK] = "Command completed successfully",
		[MC_CMD_STATUS_READY] = "Command ready to be processed",
		[MC_CMD_STATUS_AUTH_ERR] = "Authentication error",
		[MC_CMD_STATUS_NO_PRIVILEGE] = "No privilege",
		[MC_CMD_STATUS_DMA_ERR] = "DMA or I/O error",
		[MC_CMD_STATUS_CONFIG_ERR] = "Configuration error",
		[MC_CMD_STATUS_TIMEOUT] = "Operation timed out",
		[MC_CMD_STATUS_NO_RESOURCE] = "No resources",
		[MC_CMD_STATUS_NO_MEMORY] = "No memory available",
		[MC_CMD_STATUS_BUSY] = "Device is busy",
		[MC_CMD_STATUS_UNSUPPORTED_OP] = "Unsupported operation",
		[MC_CMD_STATUS_INVALID_STATE] = "Invalid state"
	};

	if ((unsigned int)status >= ARRAY_SIZE(status_strings))
		return "Unknown MC error";

	return status_strings[status];
}

/**
 * mc_write_command - writes a command to a Management Complex (MC) portal
 *
 * @portal: pointer to an MC portal
 * @cmd: pointer to a filled command
 */
static inline void mc_write_command(struct mc_command __iomem *portal,
				    struct mc_command *cmd)
{
	int i;

	/* copy command parameters into the portal */
	for (i = 0; i < MC_CMD_NUM_OF_PARAMS; i++)
		/*
		 * Data is already in the expected LE byte-order. Do an
		 * extra LE -> CPU conversion so that the CPU -> LE done in
		 * the device io write api puts it back in the right order.
		 */
		writeq_relaxed(le64_to_cpu(cmd->params[i]), &portal->params[i]);

	/* submit the command by writing the header */
	writeq(le64_to_cpu(cmd->header), &portal->header);
}

/**
 * mc_read_response - reads the response for the last MC command from a
 * Management Complex (MC) portal
 *
 * @portal: pointer to an MC portal
 * @resp: pointer to command response buffer
 *
 * Returns MC_CMD_STATUS_OK on Success; Error code otherwise.
 */
static inline enum mc_cmd_status mc_read_response(struct mc_command __iomem *
						  portal,
						  struct mc_command *resp)
{
	int i;
	enum mc_cmd_status status;

	/* Copy command response header from MC portal: */
	resp->header = cpu_to_le64(readq_relaxed(&portal->header));
	status = mc_cmd_hdr_read_status(resp);
	if (status != MC_CMD_STATUS_OK)
		return status;

	/* Copy command response data from MC portal: */
	for (i = 0; i < MC_CMD_NUM_OF_PARAMS; i++)
		/*
		 * Data is expected to be in LE byte-order. Do an
		 * extra CPU -> LE to revert the LE -> CPU done in
		 * the device io read api.
		 */
		resp->params[i] =
			cpu_to_le64(readq_relaxed(&portal->params[i]));

	return status;
}

/**
 * Waits for the completion of an MC command doing preemptible polling.
 * uslepp_range() is called between polling iterations.
 *
 * @mc_io: MC I/O object to be used
 * @cmd: command buffer to receive MC response
 * @mc_status: MC command completion status
 */
static int mc_polling_wait_preemptible(struct fsl_mc_io *mc_io,
				       struct mc_command *cmd,
				       enum mc_cmd_status *mc_status)
{
	enum mc_cmd_status status;
	unsigned long jiffies_until_timeout =
		jiffies + msecs_to_jiffies(MC_CMD_COMPLETION_TIMEOUT_MS);

	/*
	 * Wait for response from the MC hardware:
	 */
	for (;;) {
		status = mc_read_response(mc_io->portal_virt_addr, cmd);
		if (status != MC_CMD_STATUS_READY)
			break;

		/*
		 * TODO: When MC command completion interrupts are supported
		 * call wait function here instead of usleep_range()
		 */
		usleep_range(MC_CMD_COMPLETION_POLLING_MIN_SLEEP_USECS,
			     MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS);

		if (time_after_eq(jiffies, jiffies_until_timeout)) {
			dev_dbg(mc_io->dev,
				"MC command timed out (portal: %pa, dprc handle: %#x, command: %#x)\n",
				 &mc_io->portal_phys_addr,
				 (unsigned int)mc_cmd_hdr_read_token(cmd),
				 (unsigned int)mc_cmd_hdr_read_cmdid(cmd));

			return -ETIMEDOUT;
		}
	}

	*mc_status = status;
	return 0;
}

/**
 * Waits for the completion of an MC command doing atomic polling.
 * udelay() is called between polling iterations.
 *
 * @mc_io: MC I/O object to be used
 * @cmd: command buffer to receive MC response
 * @mc_status: MC command completion status
 */
static int mc_polling_wait_atomic(struct fsl_mc_io *mc_io,
				  struct mc_command *cmd,
				  enum mc_cmd_status *mc_status)
{
	enum mc_cmd_status status;
	unsigned long timeout_usecs = MC_CMD_COMPLETION_TIMEOUT_MS * 1000;

	BUILD_BUG_ON((MC_CMD_COMPLETION_TIMEOUT_MS * 1000) %
		     MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS != 0);

	for (;;) {
		status = mc_read_response(mc_io->portal_virt_addr, cmd);
		if (status != MC_CMD_STATUS_READY)
			break;

		udelay(MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS);
		timeout_usecs -= MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS;
		if (timeout_usecs == 0) {
			dev_dbg(mc_io->dev,
				"MC command timed out (portal: %pa, dprc handle: %#x, command: %#x)\n",
				 &mc_io->portal_phys_addr,
				 (unsigned int)mc_cmd_hdr_read_token(cmd),
				 (unsigned int)mc_cmd_hdr_read_cmdid(cmd));

			return -ETIMEDOUT;
		}
	}

	*mc_status = status;
	return 0;
}

/**
 * Sends a command to the MC device using the given MC I/O object
 *
 * @mc_io: MC I/O object to be used
 * @cmd: command to be sent
 *
 * Returns '0' on Success; Error code otherwise.
 */
int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd)
{
	int error;
	enum mc_cmd_status status;
	unsigned long irq_flags = 0;

	if (WARN_ON(in_irq() &&
		    !(mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)))
		return -EINVAL;

	if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)
		spin_lock_irqsave(&mc_io->spinlock, irq_flags);
	else
		mutex_lock(&mc_io->mutex);

	/*
	 * Send command to the MC hardware:
	 */
	mc_write_command(mc_io->portal_virt_addr, cmd);

	/*
	 * Wait for response from the MC hardware:
	 */
	if (!(mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL))
		error = mc_polling_wait_preemptible(mc_io, cmd, &status);
	else
		error = mc_polling_wait_atomic(mc_io, cmd, &status);

	if (error < 0)
		goto common_exit;

	if (status != MC_CMD_STATUS_OK) {
		dev_dbg(mc_io->dev,
			"MC command failed: portal: %pa, dprc handle: %#x, command: %#x, status: %s (%#x)\n",
			 &mc_io->portal_phys_addr,
			 (unsigned int)mc_cmd_hdr_read_token(cmd),
			 (unsigned int)mc_cmd_hdr_read_cmdid(cmd),
			 mc_status_to_string(status),
			 (unsigned int)status);

		error = mc_status_to_error(status);
		goto common_exit;
	}

	error = 0;
common_exit:
	if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)
		spin_unlock_irqrestore(&mc_io->spinlock, irq_flags);
	else
		mutex_unlock(&mc_io->mutex);

	return error;
}
EXPORT_SYMBOL(mc_send_command);