// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
/*
 * Copyright 2013-2016 Freescale Semiconductor Inc.
 *
 * I/O services to send MC commands to the MC hardware
 *
 */

#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 <linux/fsl/mc.h>

#include "fsl-mc-private.h"

/*
 * Timeout in milliseconds to wait for the completion of an MC command
 */
#define MC_CMD_COMPLETION_TIMEOUT_MS    15000

/*
 * 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 fsl_mc_command *cmd)
{
        struct mc_cmd_header *hdr = (struct mc_cmd_header *)&cmd->header;

        return (enum mc_cmd_status)hdr->status;
}

u16 mc_cmd_hdr_read_cmdid(struct fsl_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 ((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 fsl_mc_command __iomem *portal,
                                    struct fsl_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 fsl_mc_command __iomem
                                                  *portal,
                                                  struct fsl_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;
}

/**
 * mc_polling_wait_preemptible() - 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 fsl_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;
}

/**
 * mc_polling_wait_atomic() - 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 fsl_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;
}

/**
 * mc_send_command() - 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 fsl_mc_command *cmd)
{
        int error;
        enum mc_cmd_status status;
        unsigned long irq_flags = 0;

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

        if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)
                raw_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)
                raw_spin_unlock_irqrestore(&mc_io->spinlock, irq_flags);
        else
                mutex_unlock(&mc_io->mutex);

        return error;
}
EXPORT_SYMBOL_GPL(mc_send_command);