mmc: refactor bus operations

[deliverable/linux.git] / drivers / mmc / core / core.c

/*
 *  linux/drivers/mmc/core/core.c
 *
 *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
 *  SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
 *  Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
 *  MMCv4 support Copyright (C) 2006 Philip Langdale, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/pagemap.h>
#include <linux/err.h>
#include <asm/scatterlist.h>
#include <linux/scatterlist.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sd.h>

#include "core.h"
#include "sysfs.h"

#include "mmc_ops.h"
#include "sd_ops.h"

extern int mmc_attach_mmc(struct mmc_host *host, u32 ocr);
extern int mmc_attach_sd(struct mmc_host *host, u32 ocr);

/**
 *      mmc_request_done - finish processing an MMC request
 *      @host: MMC host which completed request
 *      @mrq: MMC request which request
 *
 *      MMC drivers should call this function when they have completed
 *      their processing of a request.
 */
void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
{
        struct mmc_command *cmd = mrq->cmd;
        int err = cmd->error;

        pr_debug("%s: req done (CMD%u): %d/%d/%d: %08x %08x %08x %08x\n",
                 mmc_hostname(host), cmd->opcode, err,
                 mrq->data ? mrq->data->error : 0,
                 mrq->stop ? mrq->stop->error : 0,
                 cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3]);

        if (err && cmd->retries) {
                cmd->retries--;
                cmd->error = 0;
                host->ops->request(host, mrq);
        } else if (mrq->done) {
                mrq->done(mrq);
        }
}

EXPORT_SYMBOL(mmc_request_done);

/**
 *      mmc_start_request - start a command on a host
 *      @host: MMC host to start command on
 *      @mrq: MMC request to start
 *
 *      Queue a command on the specified host.  We expect the
 *      caller to be holding the host lock with interrupts disabled.
 */
void
mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
#ifdef CONFIG_MMC_DEBUG
        unsigned int i, sz;
#endif

        pr_debug("%s: starting CMD%u arg %08x flags %08x\n",
                 mmc_hostname(host), mrq->cmd->opcode,
                 mrq->cmd->arg, mrq->cmd->flags);

        WARN_ON(!host->claimed);

        mrq->cmd->error = 0;
        mrq->cmd->mrq = mrq;
        if (mrq->data) {
                BUG_ON(mrq->data->blksz > host->max_blk_size);
                BUG_ON(mrq->data->blocks > host->max_blk_count);
                BUG_ON(mrq->data->blocks * mrq->data->blksz >
                        host->max_req_size);

#ifdef CONFIG_MMC_DEBUG
                sz = 0;
                for (i = 0;i < mrq->data->sg_len;i++)
                        sz += mrq->data->sg[i].length;
                BUG_ON(sz != mrq->data->blocks * mrq->data->blksz);
#endif

                mrq->cmd->data = mrq->data;
                mrq->data->error = 0;
                mrq->data->mrq = mrq;
                if (mrq->stop) {
                        mrq->data->stop = mrq->stop;
                        mrq->stop->error = 0;
                        mrq->stop->mrq = mrq;
                }
        }
        host->ops->request(host, mrq);
}

EXPORT_SYMBOL(mmc_start_request);

static void mmc_wait_done(struct mmc_request *mrq)
{
        complete(mrq->done_data);
}

int mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
        DECLARE_COMPLETION_ONSTACK(complete);

        mrq->done_data = &complete;
        mrq->done = mmc_wait_done;

        mmc_start_request(host, mrq);

        wait_for_completion(&complete);

        return 0;
}

EXPORT_SYMBOL(mmc_wait_for_req);

/**
 *      mmc_wait_for_cmd - start a command and wait for completion
 *      @host: MMC host to start command
 *      @cmd: MMC command to start
 *      @retries: maximum number of retries
 *
 *      Start a new MMC command for a host, and wait for the command
 *      to complete.  Return any error that occurred while the command
 *      was executing.  Do not attempt to parse the response.
 */
int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries)
{
        struct mmc_request mrq;

        BUG_ON(!host->claimed);

        memset(&mrq, 0, sizeof(struct mmc_request));

        memset(cmd->resp, 0, sizeof(cmd->resp));
        cmd->retries = retries;

        mrq.cmd = cmd;
        cmd->data = NULL;

        mmc_wait_for_req(host, &mrq);

        return cmd->error;
}

EXPORT_SYMBOL(mmc_wait_for_cmd);

/**
 *      mmc_set_data_timeout - set the timeout for a data command
 *      @data: data phase for command
 *      @card: the MMC card associated with the data transfer
 *      @write: flag to differentiate reads from writes
 */
void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card,
                          int write)
{
        unsigned int mult;

        /*
         * SD cards use a 100 multiplier rather than 10
         */
        mult = mmc_card_sd(card) ? 100 : 10;

        /*
         * Scale up the multiplier (and therefore the timeout) by
         * the r2w factor for writes.
         */
        if (write)
                mult <<= card->csd.r2w_factor;

        data->timeout_ns = card->csd.tacc_ns * mult;
        data->timeout_clks = card->csd.tacc_clks * mult;

        /*
         * SD cards also have an upper limit on the timeout.
         */
        if (mmc_card_sd(card)) {
                unsigned int timeout_us, limit_us;

                timeout_us = data->timeout_ns / 1000;
                timeout_us += data->timeout_clks * 1000 /
                        (card->host->ios.clock / 1000);

                if (write)
                        limit_us = 250000;
                else
                        limit_us = 100000;

                /*
                 * SDHC cards always use these fixed values.
                 */
                if (timeout_us > limit_us || mmc_card_blockaddr(card)) {
                        data->timeout_ns = limit_us * 1000;
                        data->timeout_clks = 0;
                }
        }
}
EXPORT_SYMBOL(mmc_set_data_timeout);

/**
 *      __mmc_claim_host - exclusively claim a host
 *      @host: mmc host to claim
 *      @card: mmc card to claim host for
 *
 *      Claim a host for a set of operations.  If a valid card
 *      is passed and this wasn't the last card selected, select
 *      the card before returning.
 *
 *      Note: you should use mmc_card_claim_host or mmc_claim_host.
 */
void mmc_claim_host(struct mmc_host *host)
{
        DECLARE_WAITQUEUE(wait, current);
        unsigned long flags;

        add_wait_queue(&host->wq, &wait);
        spin_lock_irqsave(&host->lock, flags);
        while (1) {
                set_current_state(TASK_UNINTERRUPTIBLE);
                if (!host->claimed)
                        break;
                spin_unlock_irqrestore(&host->lock, flags);
                schedule();
                spin_lock_irqsave(&host->lock, flags);
        }
        set_current_state(TASK_RUNNING);
        host->claimed = 1;
        spin_unlock_irqrestore(&host->lock, flags);
        remove_wait_queue(&host->wq, &wait);
}

EXPORT_SYMBOL(mmc_claim_host);

/**
 *      mmc_release_host - release a host
 *      @host: mmc host to release
 *
 *      Release a MMC host, allowing others to claim the host
 *      for their operations.
 */
void mmc_release_host(struct mmc_host *host)
{
        unsigned long flags;

        BUG_ON(!host->claimed);

        spin_lock_irqsave(&host->lock, flags);
        host->claimed = 0;
        spin_unlock_irqrestore(&host->lock, flags);

        wake_up(&host->wq);
}

EXPORT_SYMBOL(mmc_release_host);

/*
 * Internal function that does the actual ios call to the host driver,
 * optionally printing some debug output.
 */
static inline void mmc_set_ios(struct mmc_host *host)
{
        struct mmc_ios *ios = &host->ios;

        pr_debug("%s: clock %uHz busmode %u powermode %u cs %u Vdd %u "
                "width %u timing %u\n",
                 mmc_hostname(host), ios->clock, ios->bus_mode,
                 ios->power_mode, ios->chip_select, ios->vdd,
                 ios->bus_width, ios->timing);

        host->ops->set_ios(host, ios);
}

/*
 * Control chip select pin on a host.
 */
void mmc_set_chip_select(struct mmc_host *host, int mode)
{
        host->ios.chip_select = mode;
        mmc_set_ios(host);
}

/*
 * Sets the host clock to the highest possible frequency that
 * is below "hz".
 */
void mmc_set_clock(struct mmc_host *host, unsigned int hz)
{
        WARN_ON(hz < host->f_min);

        if (hz > host->f_max)
                hz = host->f_max;

        host->ios.clock = hz;
        mmc_set_ios(host);
}

/*
 * Change the bus mode (open drain/push-pull) of a host.
 */
void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode)
{
        host->ios.bus_mode = mode;
        mmc_set_ios(host);
}

/*
 * Change data bus width of a host.
 */
void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
{
        host->ios.bus_width = width;
        mmc_set_ios(host);
}

/*
 * Mask off any voltages we don't support and select
 * the lowest voltage
 */
u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
{
        int bit;

        ocr &= host->ocr_avail;

        bit = ffs(ocr);
        if (bit) {
                bit -= 1;

                ocr &= 3 << bit;

                host->ios.vdd = bit;
                mmc_set_ios(host);
        } else {
                ocr = 0;
        }

        return ocr;
}

/*
 * Select timing parameters for host.
 */
void mmc_set_timing(struct mmc_host *host, unsigned int timing)
{
        host->ios.timing = timing;
        mmc_set_ios(host);
}

/*
 * Apply power to the MMC stack.  This is a two-stage process.
 * First, we enable power to the card without the clock running.
 * We then wait a bit for the power to stabilise.  Finally,
 * enable the bus drivers and clock to the card.
 *
 * We must _NOT_ enable the clock prior to power stablising.
 *
 * If a host does all the power sequencing itself, ignore the
 * initial MMC_POWER_UP stage.
 */
static void mmc_power_up(struct mmc_host *host)
{
        int bit = fls(host->ocr_avail) - 1;

        host->ios.vdd = bit;
        host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
        host->ios.chip_select = MMC_CS_DONTCARE;
        host->ios.power_mode = MMC_POWER_UP;
        host->ios.bus_width = MMC_BUS_WIDTH_1;
        host->ios.timing = MMC_TIMING_LEGACY;
        mmc_set_ios(host);

        mmc_delay(1);

        host->ios.clock = host->f_min;
        host->ios.power_mode = MMC_POWER_ON;
        mmc_set_ios(host);

        mmc_delay(2);
}

static void mmc_power_off(struct mmc_host *host)
{
        host->ios.clock = 0;
        host->ios.vdd = 0;
        host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
        host->ios.chip_select = MMC_CS_DONTCARE;
        host->ios.power_mode = MMC_POWER_OFF;
        host->ios.bus_width = MMC_BUS_WIDTH_1;
        host->ios.timing = MMC_TIMING_LEGACY;
        mmc_set_ios(host);
}

/*
 * Assign a mmc bus handler to a host. Only one bus handler may control a
 * host at any given time.
 */
void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops)
{
        unsigned long flags;

        BUG_ON(!host);
        BUG_ON(!ops);

        BUG_ON(!host->claimed);

        spin_lock_irqsave(&host->lock, flags);

        BUG_ON(host->bus_ops);
        BUG_ON(host->bus_refs);

        host->bus_ops = ops;
        host->bus_refs = 1;
        host->bus_dead = 0;

        spin_unlock_irqrestore(&host->lock, flags);
}

/*
 * Remove the current bus handler from a host. Assumes that there are
 * no interesting cards left, so the bus is powered down.
 */
void mmc_detach_bus(struct mmc_host *host)
{
        unsigned long flags;

        BUG_ON(!host);

        BUG_ON(!host->claimed);
        BUG_ON(!host->bus_ops);

        spin_lock_irqsave(&host->lock, flags);

        host->bus_dead = 1;

        spin_unlock_irqrestore(&host->lock, flags);

        mmc_power_off(host);

        mmc_bus_put(host);
}

/*
 * Cleanup when the last reference to the bus operator is dropped.
 */
void __mmc_release_bus(struct mmc_host *host)
{
        BUG_ON(!host);
        BUG_ON(host->bus_refs);
        BUG_ON(!host->bus_dead);

        host->bus_ops = NULL;
}

/**
 *      mmc_detect_change - process change of state on a MMC socket
 *      @host: host which changed state.
 *      @delay: optional delay to wait before detection (jiffies)
 *
 *      All we know is that card(s) have been inserted or removed
 *      from the socket(s).  We don't know which socket or cards.
 */
void mmc_detect_change(struct mmc_host *host, unsigned long delay)
{
#ifdef CONFIG_MMC_DEBUG
        unsigned long flags;
        spin_lock_irqsave(&host->lock, flags);
        BUG_ON(host->removed);
        spin_unlock_irqrestore(&host->lock, flags);
#endif

        mmc_schedule_delayed_work(&host->detect, delay);
}

EXPORT_SYMBOL(mmc_detect_change);


static void mmc_rescan(struct work_struct *work)
{
        struct mmc_host *host =
                container_of(work, struct mmc_host, detect.work);
        u32 ocr;
        int err;

        mmc_bus_get(host);

        if (host->bus_ops == NULL) {
                /*
                 * Only we can add a new handler, so it's safe to
                 * release the lock here.
                 */
                mmc_bus_put(host);

                mmc_claim_host(host);

                mmc_power_up(host);
                mmc_go_idle(host);

                mmc_send_if_cond(host, host->ocr_avail);

                err = mmc_send_app_op_cond(host, 0, &ocr);
                if (err == MMC_ERR_NONE) {
                        if (mmc_attach_sd(host, ocr))
                                mmc_power_off(host);
                } else {
                        /*
                         * If we fail to detect any SD cards then try
                         * searching for MMC cards.
                         */
                        err = mmc_send_op_cond(host, 0, &ocr);
                        if (err == MMC_ERR_NONE) {
                                if (mmc_attach_mmc(host, ocr))
                                        mmc_power_off(host);
                        } else {
                                mmc_power_off(host);
                                mmc_release_host(host);
                        }
                }
        } else {
                if (host->bus_ops->detect && !host->bus_dead)
                        host->bus_ops->detect(host);

                mmc_bus_put(host);
        }
}


/**
 *      mmc_alloc_host - initialise the per-host structure.
 *      @extra: sizeof private data structure
 *      @dev: pointer to host device model structure
 *
 *      Initialise the per-host structure.
 */
struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
{
        struct mmc_host *host;

        host = mmc_alloc_host_sysfs(extra, dev);
        if (host) {
                spin_lock_init(&host->lock);
                init_waitqueue_head(&host->wq);
                INIT_DELAYED_WORK(&host->detect, mmc_rescan);

                /*
                 * By default, hosts do not support SGIO or large requests.
                 * They have to set these according to their abilities.
                 */
                host->max_hw_segs = 1;
                host->max_phys_segs = 1;
                host->max_seg_size = PAGE_CACHE_SIZE;

                host->max_req_size = PAGE_CACHE_SIZE;
                host->max_blk_size = 512;
                host->max_blk_count = PAGE_CACHE_SIZE / 512;
        }

        return host;
}

EXPORT_SYMBOL(mmc_alloc_host);

/**
 *      mmc_add_host - initialise host hardware
 *      @host: mmc host
 */
int mmc_add_host(struct mmc_host *host)
{
        int ret;

        ret = mmc_add_host_sysfs(host);
        if (ret == 0) {
                mmc_power_off(host);
                mmc_detect_change(host, 0);
        }

        return ret;
}

EXPORT_SYMBOL(mmc_add_host);

/**
 *      mmc_remove_host - remove host hardware
 *      @host: mmc host
 *
 *      Unregister and remove all cards associated with this host,
 *      and power down the MMC bus.
 */
void mmc_remove_host(struct mmc_host *host)
{
#ifdef CONFIG_MMC_DEBUG
        unsigned long flags;
        spin_lock_irqsave(&host->lock, flags);
        host->removed = 1;
        spin_unlock_irqrestore(&host->lock, flags);
#endif

        mmc_flush_scheduled_work();

        mmc_bus_get(host);
        if (host->bus_ops && !host->bus_dead) {
                if (host->bus_ops->remove)
                        host->bus_ops->remove(host);

                mmc_claim_host(host);
                mmc_detach_bus(host);
                mmc_release_host(host);
        }
        mmc_bus_put(host);

        BUG_ON(host->card);

        mmc_power_off(host);
        mmc_remove_host_sysfs(host);
}

EXPORT_SYMBOL(mmc_remove_host);

/**
 *      mmc_free_host - free the host structure
 *      @host: mmc host
 *
 *      Free the host once all references to it have been dropped.
 */
void mmc_free_host(struct mmc_host *host)
{
        mmc_free_host_sysfs(host);
}

EXPORT_SYMBOL(mmc_free_host);

#ifdef CONFIG_PM

/**
 *      mmc_suspend_host - suspend a host
 *      @host: mmc host
 *      @state: suspend mode (PM_SUSPEND_xxx)
 */
int mmc_suspend_host(struct mmc_host *host, pm_message_t state)
{
        mmc_flush_scheduled_work();

        mmc_bus_get(host);
        if (host->bus_ops && !host->bus_dead) {
                if (host->bus_ops->suspend)
                        host->bus_ops->suspend(host);
                if (!host->bus_ops->resume) {
                        if (host->bus_ops->remove)
                                host->bus_ops->remove(host);

                        mmc_claim_host(host);
                        mmc_detach_bus(host);
                        mmc_release_host(host);
                }
        }
        mmc_bus_put(host);

        mmc_power_off(host);

        return 0;
}

EXPORT_SYMBOL(mmc_suspend_host);

/**
 *      mmc_resume_host - resume a previously suspended host
 *      @host: mmc host
 */
int mmc_resume_host(struct mmc_host *host)
{
        mmc_bus_get(host);
        if (host->bus_ops && !host->bus_dead) {
                mmc_power_up(host);
                BUG_ON(!host->bus_ops->resume);
                host->bus_ops->resume(host);
        }
        mmc_bus_put(host);

        /*
         * We add a slight delay here so that resume can progress
         * in parallel.
         */
        mmc_detect_change(host, 1);

        return 0;
}

EXPORT_SYMBOL(mmc_resume_host);

#endif

MODULE_LICENSE("GPL");