ext4: Don't use ext4_dec_count() if not needed

[linux-2.6/mini2440.git] / drivers / mmc / core / sd.c

/*
 *  linux/drivers/mmc/core/sd.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.
 *
 * 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/err.h>

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

#include "core.h"
#include "sysfs.h"
#include "bus.h"
#include "mmc_ops.h"
#include "sd_ops.h"

static const unsigned int tran_exp[] = {
        10000,          100000,         1000000,        10000000,
        0,              0,              0,              0
};

static const unsigned char tran_mant[] = {
        0,      10,     12,     13,     15,     20,     25,     30,
        35,     40,     45,     50,     55,     60,     70,     80,
};

static const unsigned int tacc_exp[] = {
        1,      10,     100,    1000,   10000,  100000, 1000000, 10000000,
};

static const unsigned int tacc_mant[] = {
        0,      10,     12,     13,     15,     20,     25,     30,
        35,     40,     45,     50,     55,     60,     70,     80,
};

#define UNSTUFF_BITS(resp,start,size)                                   \
        ({                                                              \
                const int __size = size;                                \
                const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1; \
                const int __off = 3 - ((start) / 32);                   \
                const int __shft = (start) & 31;                        \
                u32 __res;                                              \
                                                                        \
                __res = resp[__off] >> __shft;                          \
                if (__size + __shft > 32)                               \
                        __res |= resp[__off-1] << ((32 - __shft) % 32); \
                __res & __mask;                                         \
        })

/*
 * Given the decoded CSD structure, decode the raw CID to our CID structure.
 */
static void mmc_decode_cid(struct mmc_card *card)
{
        u32 *resp = card->raw_cid;

        memset(&card->cid, 0, sizeof(struct mmc_cid));

        /*
         * SD doesn't currently have a version field so we will
         * have to assume we can parse this.
         */
        card->cid.manfid                = UNSTUFF_BITS(resp, 120, 8);
        card->cid.oemid                 = UNSTUFF_BITS(resp, 104, 16);
        card->cid.prod_name[0]          = UNSTUFF_BITS(resp, 96, 8);
        card->cid.prod_name[1]          = UNSTUFF_BITS(resp, 88, 8);
        card->cid.prod_name[2]          = UNSTUFF_BITS(resp, 80, 8);
        card->cid.prod_name[3]          = UNSTUFF_BITS(resp, 72, 8);
        card->cid.prod_name[4]          = UNSTUFF_BITS(resp, 64, 8);
        card->cid.hwrev                 = UNSTUFF_BITS(resp, 60, 4);
        card->cid.fwrev                 = UNSTUFF_BITS(resp, 56, 4);
        card->cid.serial                = UNSTUFF_BITS(resp, 24, 32);
        card->cid.year                  = UNSTUFF_BITS(resp, 12, 8);
        card->cid.month                 = UNSTUFF_BITS(resp, 8, 4);

        card->cid.year += 2000; /* SD cards year offset */
}

/*
 * Given a 128-bit response, decode to our card CSD structure.
 */
static int mmc_decode_csd(struct mmc_card *card)
{
        struct mmc_csd *csd = &card->csd;
        unsigned int e, m, csd_struct;
        u32 *resp = card->raw_csd;

        csd_struct = UNSTUFF_BITS(resp, 126, 2);

        switch (csd_struct) {
        case 0:
                m = UNSTUFF_BITS(resp, 115, 4);
                e = UNSTUFF_BITS(resp, 112, 3);
                csd->tacc_ns     = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
                csd->tacc_clks   = UNSTUFF_BITS(resp, 104, 8) * 100;

                m = UNSTUFF_BITS(resp, 99, 4);
                e = UNSTUFF_BITS(resp, 96, 3);
                csd->max_dtr      = tran_exp[e] * tran_mant[m];
                csd->cmdclass     = UNSTUFF_BITS(resp, 84, 12);

                e = UNSTUFF_BITS(resp, 47, 3);
                m = UNSTUFF_BITS(resp, 62, 12);
                csd->capacity     = (1 + m) << (e + 2);

                csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
                csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
                csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
                csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
                csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
                csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
                csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
                break;
        case 1:
                /*
                 * This is a block-addressed SDHC card. Most
                 * interesting fields are unused and have fixed
                 * values. To avoid getting tripped by buggy cards,
                 * we assume those fixed values ourselves.
                 */
                mmc_card_set_blockaddr(card);

                csd->tacc_ns     = 0; /* Unused */
                csd->tacc_clks   = 0; /* Unused */

                m = UNSTUFF_BITS(resp, 99, 4);
                e = UNSTUFF_BITS(resp, 96, 3);
                csd->max_dtr      = tran_exp[e] * tran_mant[m];
                csd->cmdclass     = UNSTUFF_BITS(resp, 84, 12);

                m = UNSTUFF_BITS(resp, 48, 22);
                csd->capacity     = (1 + m) << 10;

                csd->read_blkbits = 9;
                csd->read_partial = 0;
                csd->write_misalign = 0;
                csd->read_misalign = 0;
                csd->r2w_factor = 4; /* Unused */
                csd->write_blkbits = 9;
                csd->write_partial = 0;
                break;
        default:
                printk(KERN_ERR "%s: unrecognised CSD structure version %d\n",
                        mmc_hostname(card->host), csd_struct);
                return -EINVAL;
        }

        return 0;
}

/*
 * Given a 64-bit response, decode to our card SCR structure.
 */
static int mmc_decode_scr(struct mmc_card *card)
{
        struct sd_scr *scr = &card->scr;
        unsigned int scr_struct;
        u32 resp[4];

        resp[3] = card->raw_scr[1];
        resp[2] = card->raw_scr[0];

        scr_struct = UNSTUFF_BITS(resp, 60, 4);
        if (scr_struct != 0) {
                printk(KERN_ERR "%s: unrecognised SCR structure version %d\n",
                        mmc_hostname(card->host), scr_struct);
                return -EINVAL;
        }

        scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
        scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);

        return 0;
}

/*
 * Fetches and decodes switch information
 */
static int mmc_read_switch(struct mmc_card *card)
{
        int err;
        u8 *status;

        if (card->scr.sda_vsn < SCR_SPEC_VER_1)
                return 0;

        if (!(card->csd.cmdclass & CCC_SWITCH)) {
                printk(KERN_WARNING "%s: card lacks mandatory switch "
                        "function, performance might suffer.\n",
                        mmc_hostname(card->host));
                return 0;
        }

        err = -EIO;

        status = kmalloc(64, GFP_KERNEL);
        if (!status) {
                printk(KERN_ERR "%s: could not allocate a buffer for "
                        "switch capabilities.\n", mmc_hostname(card->host));
                return -ENOMEM;
        }

        err = mmc_sd_switch(card, 0, 0, 1, status);
        if (err) {
                /*
                 * We all hosts that cannot perform the command
                 * to fail more gracefully
                 */
                if (err != -EINVAL)
                        goto out;

                printk(KERN_WARNING "%s: problem reading switch "
                        "capabilities, performance might suffer.\n",
                        mmc_hostname(card->host));
                err = 0;

                goto out;
        }

        if (status[13] & 0x02)
                card->sw_caps.hs_max_dtr = 50000000;

out:
        kfree(status);

        return err;
}

/*
 * Test if the card supports high-speed mode and, if so, switch to it.
 */
static int mmc_switch_hs(struct mmc_card *card)
{
        int err;
        u8 *status;

        if (card->scr.sda_vsn < SCR_SPEC_VER_1)
                return 0;

        if (!(card->csd.cmdclass & CCC_SWITCH))
                return 0;

        if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
                return 0;

        if (card->sw_caps.hs_max_dtr == 0)
                return 0;

        err = -EIO;

        status = kmalloc(64, GFP_KERNEL);
        if (!status) {
                printk(KERN_ERR "%s: could not allocate a buffer for "
                        "switch capabilities.\n", mmc_hostname(card->host));
                return -ENOMEM;
        }

        err = mmc_sd_switch(card, 1, 0, 1, status);
        if (err)
                goto out;

        if ((status[16] & 0xF) != 1) {
                printk(KERN_WARNING "%s: Problem switching card "
                        "into high-speed mode!\n",
                        mmc_hostname(card->host));
        } else {
                mmc_card_set_highspeed(card);
                mmc_set_timing(card->host, MMC_TIMING_SD_HS);
        }

out:
        kfree(status);

        return err;
}

/*
 * Handle the detection and initialisation of a card.
 *
 * In the case of a resume, "curcard" will contain the card
 * we're trying to reinitialise.
 */
static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
        struct mmc_card *oldcard)
{
        struct mmc_card *card;
        int err;
        u32 cid[4];
        unsigned int max_dtr;

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

        /*
         * Since we're changing the OCR value, we seem to
         * need to tell some cards to go back to the idle
         * state.  We wait 1ms to give cards time to
         * respond.
         */
        mmc_go_idle(host);

        /*
         * If SD_SEND_IF_COND indicates an SD 2.0
         * compliant card and we should set bit 30
         * of the ocr to indicate that we can handle
         * block-addressed SDHC cards.
         */
        err = mmc_send_if_cond(host, ocr);
        if (!err)
                ocr |= 1 << 30;

        err = mmc_send_app_op_cond(host, ocr, NULL);
        if (err)
                goto err;

        /*
         * For SPI, enable CRC as appropriate.
         */
        if (mmc_host_is_spi(host)) {
                err = mmc_spi_set_crc(host, use_spi_crc);
                if (err)
                        goto err;
        }

        /*
         * Fetch CID from card.
         */
        if (mmc_host_is_spi(host))
                err = mmc_send_cid(host, cid);
        else
                err = mmc_all_send_cid(host, cid);
        if (err)
                goto err;

        if (oldcard) {
                if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0) {
                        err = -ENOENT;
                        goto err;
                }

                card = oldcard;
        } else {
                /*
                 * Allocate card structure.
                 */
                card = mmc_alloc_card(host);
                if (IS_ERR(card)) {
                        err = PTR_ERR(card);
                        goto err;
                }

                card->type = MMC_TYPE_SD;
                memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
        }

        /*
         * For native busses:  get card RCA and quit open drain mode.
         */
        if (!mmc_host_is_spi(host)) {
                err = mmc_send_relative_addr(host, &card->rca);
                if (err)
                        goto free_card;

                mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
        }

        if (!oldcard) {
                /*
                 * Fetch CSD from card.
                 */
                err = mmc_send_csd(card, card->raw_csd);
                if (err)
                        goto free_card;

                err = mmc_decode_csd(card);
                if (err)
                        goto free_card;

                mmc_decode_cid(card);
        }

        /*
         * Select card, as all following commands rely on that.
         */
        if (!mmc_host_is_spi(host)) {
                err = mmc_select_card(card);
                if (err)
                        goto free_card;
        }

        if (!oldcard) {
                /*
                 * Fetch SCR from card.
                 */
                err = mmc_app_send_scr(card, card->raw_scr);
                if (err)
                        goto free_card;

                err = mmc_decode_scr(card);
                if (err < 0)
                        goto free_card;

                /*
                 * Fetch switch information from card.
                 */
                err = mmc_read_switch(card);
                if (err)
                        goto free_card;
        }

        /*
         * Attempt to change to high-speed (if supported)
         */
        err = mmc_switch_hs(card);
        if (err)
                goto free_card;

        /*
         * Compute bus speed.
         */
        max_dtr = (unsigned int)-1;

        if (mmc_card_highspeed(card)) {
                if (max_dtr > card->sw_caps.hs_max_dtr)
                        max_dtr = card->sw_caps.hs_max_dtr;
        } else if (max_dtr > card->csd.max_dtr) {
                max_dtr = card->csd.max_dtr;
        }

        mmc_set_clock(host, max_dtr);

        /*
         * Switch to wider bus (if supported).
         */
        if ((host->caps & MMC_CAP_4_BIT_DATA) &&
                (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
                err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
                if (err)
                        goto free_card;

                mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
        }

        /*
         * Check if read-only switch is active.
         */
        if (!oldcard) {
                if (!host->ops->get_ro) {
                        printk(KERN_WARNING "%s: host does not "
                                "support reading read-only "
                                "switch. assuming write-enable.\n",
                                mmc_hostname(host));
                } else {
                        if (host->ops->get_ro(host))
                                mmc_card_set_readonly(card);
                }
        }

        if (!oldcard)
                host->card = card;

        return 0;

free_card:
        if (!oldcard)
                mmc_remove_card(card);
err:

        return err;
}

/*
 * Host is being removed. Free up the current card.
 */
static void mmc_sd_remove(struct mmc_host *host)
{
        BUG_ON(!host);
        BUG_ON(!host->card);

        mmc_remove_card(host->card);
        host->card = NULL;
}

/*
 * Card detection callback from host.
 */
static void mmc_sd_detect(struct mmc_host *host)
{
        int err;

        BUG_ON(!host);
        BUG_ON(!host->card);

        mmc_claim_host(host);

        /*
         * Just check if our card has been removed.
         */
        err = mmc_send_status(host->card, NULL);

        mmc_release_host(host);

        if (err) {
                mmc_sd_remove(host);

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

MMC_ATTR_FN(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
        card->raw_cid[2], card->raw_cid[3]);
MMC_ATTR_FN(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
        card->raw_csd[2], card->raw_csd[3]);
MMC_ATTR_FN(scr, "%08x%08x\n", card->raw_scr[0], card->raw_scr[1]);
MMC_ATTR_FN(date, "%02d/%04d\n", card->cid.month, card->cid.year);
MMC_ATTR_FN(fwrev, "0x%x\n", card->cid.fwrev);
MMC_ATTR_FN(hwrev, "0x%x\n", card->cid.hwrev);
MMC_ATTR_FN(manfid, "0x%06x\n", card->cid.manfid);
MMC_ATTR_FN(name, "%s\n", card->cid.prod_name);
MMC_ATTR_FN(oemid, "0x%04x\n", card->cid.oemid);
MMC_ATTR_FN(serial, "0x%08x\n", card->cid.serial);

static struct device_attribute mmc_sd_dev_attrs[] = {
        MMC_ATTR_RO(cid),
        MMC_ATTR_RO(csd),
        MMC_ATTR_RO(scr),
        MMC_ATTR_RO(date),
        MMC_ATTR_RO(fwrev),
        MMC_ATTR_RO(hwrev),
        MMC_ATTR_RO(manfid),
        MMC_ATTR_RO(name),
        MMC_ATTR_RO(oemid),
        MMC_ATTR_RO(serial),
        __ATTR_NULL,
};

/*
 * Adds sysfs entries as relevant.
 */
static int mmc_sd_sysfs_add(struct mmc_host *host, struct mmc_card *card)
{
        int ret;

        ret = mmc_add_attrs(card, mmc_sd_dev_attrs);
        if (ret < 0)
                return ret;

        return 0;
}

/*
 * Removes the sysfs entries added by mmc_sysfs_add().
 */
static void mmc_sd_sysfs_remove(struct mmc_host *host, struct mmc_card *card)
{
        mmc_remove_attrs(card, mmc_sd_dev_attrs);
}

#ifdef CONFIG_MMC_UNSAFE_RESUME

/*
 * Suspend callback from host.
 */
static void mmc_sd_suspend(struct mmc_host *host)
{
        BUG_ON(!host);
        BUG_ON(!host->card);

        mmc_claim_host(host);
        if (!mmc_host_is_spi(host))
                mmc_deselect_cards(host);
        host->card->state &= ~MMC_STATE_HIGHSPEED;
        mmc_release_host(host);
}

/*
 * Resume callback from host.
 *
 * This function tries to determine if the same card is still present
 * and, if so, restore all state to it.
 */
static void mmc_sd_resume(struct mmc_host *host)
{
        int err;

        BUG_ON(!host);
        BUG_ON(!host->card);

        mmc_claim_host(host);
        err = mmc_sd_init_card(host, host->ocr, host->card);
        mmc_release_host(host);

        if (err) {
                mmc_sd_remove(host);

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

}

#else

#define mmc_sd_suspend NULL
#define mmc_sd_resume NULL

#endif

static const struct mmc_bus_ops mmc_sd_ops = {
        .remove = mmc_sd_remove,
        .detect = mmc_sd_detect,
        .sysfs_add = mmc_sd_sysfs_add,
        .sysfs_remove = mmc_sd_sysfs_remove,
        .suspend = mmc_sd_suspend,
        .resume = mmc_sd_resume,
};

/*
 * Starting point for SD card init.
 */
int mmc_attach_sd(struct mmc_host *host, u32 ocr)
{
        int err;

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

        mmc_attach_bus(host, &mmc_sd_ops);

        /*
         * We need to get OCR a different way for SPI.
         */
        if (mmc_host_is_spi(host)) {
                mmc_go_idle(host);

                err = mmc_spi_read_ocr(host, 0, &ocr);
                if (err)
                        goto err;
        }

        /*
         * Sanity check the voltages that the card claims to
         * support.
         */
        if (ocr & 0x7F) {
                printk(KERN_WARNING "%s: card claims to support voltages "
                       "below the defined range. These will be ignored.\n",
                       mmc_hostname(host));
                ocr &= ~0x7F;
        }

        if (ocr & MMC_VDD_165_195) {
                printk(KERN_WARNING "%s: SD card claims to support the "
                       "incompletely defined 'low voltage range'. This "
                       "will be ignored.\n", mmc_hostname(host));
                ocr &= ~MMC_VDD_165_195;
        }

        host->ocr = mmc_select_voltage(host, ocr);

        /*
         * Can we support the voltage(s) of the card(s)?
         */
        if (!host->ocr) {
                err = -EINVAL;
                goto err;
        }

        /*
         * Detect and init the card.
         */
        err = mmc_sd_init_card(host, host->ocr, NULL);
        if (err)
                goto err;

        mmc_release_host(host);

        err = mmc_add_card(host->card);
        if (err)
                goto remove_card;

        return 0;

remove_card:
        mmc_remove_card(host->card);
        host->card = NULL;
        mmc_claim_host(host);
err:
        mmc_detach_bus(host);
        mmc_release_host(host);

        printk(KERN_ERR "%s: error %d whilst initialising SD card\n",
                mmc_hostname(host), err);

        return err;
}