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[netbsd-mini2440.git] / sys / arch / arm / xscale / pxa2x0_mci.c

/*      $NetBSD: pxa2x0_mci.c,v 1.2 2009/05/11 08:27:03 nonaka Exp $    */
/*      $OpenBSD: pxa2x0_mmc.c,v 1.5 2009/02/23 18:09:55 miod Exp $     */

/*
 * Copyright (c) 2007 Uwe Stuehler <uwe@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*-
 * Copyright (c) 2007-2009 NONAKA Kimihiro <nonaka@netbsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

/*
 * MMC/SD/SDIO controller driver for Intel PXA2xx processors
 *
 * Power management is beyond control of the processor's SD/SDIO/MMC
 * block, so this driver depends on the attachment driver to provide
 * us with some callback functions via the "tag" member in our softc.
 * Bus power management calls are then dispatched to the attachment
 * driver.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: pxa2x0_mci.c,v 1.2 2009/05/11 08:27:03 nonaka Exp $");

#include <sys/param.h>
#include <sys/device.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/bus.h>
#include <sys/mutex.h>
#include <sys/condvar.h>

#include <machine/intr.h>

#include <dev/sdmmc/sdmmcvar.h>
#include <dev/sdmmc/sdmmcchip.h>

#include <arm/xscale/pxa2x0cpu.h>
#include <arm/xscale/pxa2x0reg.h>
#include <arm/xscale/pxa2x0var.h>
#include <arm/xscale/pxa2x0_dmac.h>
#include <arm/xscale/pxa2x0_gpio.h>
#include <arm/xscale/pxa2x0_mci.h>

#ifdef PXAMCI_DEBUG
int pxamci_debug = 1;
#define DPRINTF(n,s)    do { if ((n) <= pxamci_debug) printf s; } while (0)
#else
#define DPRINTF(n,s)    do {} while (0)
#endif

#ifndef DEBUG
#define STOPCLK_TIMO    2       /* ms */
#define EXECCMD_TIMO    2       /* ms */
#else
#define STOPCLK_TIMO    2       /* ms */
#define EXECCMD_TIMO    5       /* ms */
#endif

static int      pxamci_host_reset(sdmmc_chipset_handle_t);
static uint32_t pxamci_host_ocr(sdmmc_chipset_handle_t);
static int      pxamci_host_maxblklen(sdmmc_chipset_handle_t);
static int      pxamci_card_detect(sdmmc_chipset_handle_t);
static int      pxamci_write_protect(sdmmc_chipset_handle_t);
static int      pxamci_bus_power(sdmmc_chipset_handle_t, uint32_t);
static int      pxamci_bus_clock(sdmmc_chipset_handle_t, int);
static int      pxamci_bus_width(sdmmc_chipset_handle_t, int);
static void     pxamci_exec_command(sdmmc_chipset_handle_t,
                    struct sdmmc_command *);
static void     pxamci_card_enable_intr(sdmmc_chipset_handle_t, int);
static void     pxamci_card_intr_ack(sdmmc_chipset_handle_t);

static struct sdmmc_chip_functions pxamci_chip_functions = {
        /* host controller reset */
        .host_reset             = pxamci_host_reset,

        /* host controller capabilities */
        .host_ocr               = pxamci_host_ocr,
        .host_maxblklen         = pxamci_host_maxblklen,

        /* card detection */
        .card_detect            = pxamci_card_detect,

        /* write protect */
        .write_protect          = pxamci_write_protect,

        /* bus power, clock frequency, width */
        .bus_power              = pxamci_bus_power,
        .bus_clock              = pxamci_bus_clock,
        .bus_width              = pxamci_bus_width,

        /* command execution */
        .exec_command           = pxamci_exec_command,

        /* card interrupt */
        .card_enable_intr       = pxamci_card_enable_intr,
        .card_intr_ack          = pxamci_card_intr_ack,
};

static int      pxamci_intr(void *);
static void     pxamci_intr_cmd(struct pxamci_softc *);
static void     pxamci_intr_data(struct pxamci_softc *);
static void     pxamci_intr_done(struct pxamci_softc *);
static void     pxamci_dmac_iintr(struct dmac_xfer *, int);
static void     pxamci_dmac_ointr(struct dmac_xfer *, int);

static void     pxamci_stop_clock(struct pxamci_softc *);

#define CSR_READ_1(sc, reg) \
        bus_space_read_1((sc)->sc_iot, (sc)->sc_ioh, (reg))
#define CSR_WRITE_1(sc, reg, val) \
        bus_space_write_1((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
#define CSR_READ_4(sc, reg) \
        bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg))
#define CSR_WRITE_4(sc, reg, val) \
        bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
#define CSR_SET_4(sc, reg, val) \
        CSR_WRITE_4(sc, reg, CSR_READ_4(sc, reg) | (val))
#define CSR_CLR_4(sc, reg, val) \
        CSR_WRITE_4(sc, reg, CSR_READ_4(sc, reg) & ~(val))

static void
pxamci_enable_intr(struct pxamci_softc *sc, uint32_t mask)
{
        int s;

        s = splsdmmc();
        sc->sc_imask &= ~mask;
        CSR_WRITE_4(sc, MMC_I_MASK, sc->sc_imask);
        splx(s);
}

static void
pxamci_disable_intr(struct pxamci_softc *sc, uint32_t mask)
{
        int s;

        s = splsdmmc();
        sc->sc_imask |= mask;
        CSR_WRITE_4(sc, MMC_I_MASK, sc->sc_imask);
        splx(s);
}

int
pxamci_attach_sub(device_t self, struct pxaip_attach_args *pxa)
{
        struct pxamci_softc *sc = device_private(self);
        struct sdmmcbus_attach_args saa;

        sc->sc_dev = self;

        aprint_normal(": MMC/SD Controller\n");
        aprint_naive("\n");

        /* Enable the clocks to the MMC controller. */
        pxa2x0_clkman_config(CKEN_MMC, 1);

        sc->sc_iot = pxa->pxa_iot;
        if (bus_space_map(sc->sc_iot, PXA2X0_MMC_BASE, PXA2X0_MMC_SIZE, 0,
            &sc->sc_ioh)) {
                aprint_error_dev(sc->sc_dev, "couldn't map registers\n");
                goto out;
        }

        /*
         * Establish the card detection and MMC interrupt handlers and
         * mask all interrupts until we are prepared to handle them.
         */
        pxamci_disable_intr(sc, MMC_I_ALL);
        sc->sc_ih = pxa2x0_intr_establish(PXA2X0_INT_MMC, IPL_SDMMC,
            pxamci_intr, sc);
        if (sc->sc_ih == NULL) {
                aprint_error_dev(sc->sc_dev,
                    "couldn't establish MMC interrupt\n");
                goto free_map;
        }

        /*
         * Reset the host controller and unmask normal interrupts.
         */
        (void) pxamci_host_reset(sc);

        /* Setup bus clock */
        if (CPU_IS_PXA270) {
                sc->sc_clkmin = PXA270_MMC_CLKRT_MIN / 1000;
                sc->sc_clkmax = PXA270_MMC_CLKRT_MAX / 1000;
        } else {
                sc->sc_clkmin = PXA250_MMC_CLKRT_MIN / 1000;
                sc->sc_clkmax = PXA250_MMC_CLKRT_MAX / 1000;
        }
        sc->sc_clkbase = sc->sc_clkmin;
        pxamci_bus_clock(sc, sc->sc_clkbase);

        /* Setup max block length */
        if (CPU_IS_PXA270) {
                sc->sc_maxblklen = 2048;
        } else {
                sc->sc_maxblklen = 512;
        }

        /* Set default bus width */
        sc->sc_buswidth = 1;

        /* setting DMA */
#if 1   /* XXX */
        SET(sc->sc_caps, PMC_CAPS_NO_DMA);      /* disable DMA */
#endif
        if (!ISSET(sc->sc_caps, PMC_CAPS_NO_DMA)) {
                aprint_normal_dev(sc->sc_dev, "using DMA transfer\n");

                sc->sc_rxdr.ds_addr = PXA2X0_MMC_BASE + MMC_RXFIFO;
                sc->sc_rxdr.ds_len = 1;
                sc->sc_rxdx = pxa2x0_dmac_allocate_xfer(M_NOWAIT);
                if (sc->sc_rxdx == NULL) {
                        aprint_error_dev(sc->sc_dev,
                            "couldn't alloc rx dma xfer\n");
                        goto free_intr;
                }
                sc->sc_rxdx->dx_cookie = sc;
                sc->sc_rxdx->dx_priority = DMAC_PRIORITY_NORMAL;
                sc->sc_rxdx->dx_dev_width = DMAC_DEV_WIDTH_1;
                sc->sc_rxdx->dx_burst_size = DMAC_BURST_SIZE_32;
                sc->sc_rxdx->dx_done = pxamci_dmac_iintr;
                sc->sc_rxdx->dx_peripheral = DMAC_PERIPH_MMCRX;
                sc->sc_rxdx->dx_flow = DMAC_FLOW_CTRL_SRC;
                sc->sc_rxdx->dx_loop_notify = DMAC_DONT_LOOP;
                sc->sc_rxdx->dx_desc[DMAC_DESC_SRC].xd_addr_hold = true;
                sc->sc_rxdx->dx_desc[DMAC_DESC_SRC].xd_nsegs = 1;
                sc->sc_rxdx->dx_desc[DMAC_DESC_SRC].xd_dma_segs = &sc->sc_rxdr;
                sc->sc_rxdx->dx_desc[DMAC_DESC_DST].xd_addr_hold = false;

                sc->sc_txdr.ds_addr = PXA2X0_MMC_BASE + MMC_TXFIFO;
                sc->sc_txdr.ds_len = 1;
                sc->sc_txdx = pxa2x0_dmac_allocate_xfer(M_NOWAIT);
                if (sc->sc_txdx == NULL) {
                        aprint_error_dev(sc->sc_dev,
                            "couldn't alloc tx dma xfer\n");
                        goto free_xfer;
                }
                sc->sc_txdx->dx_cookie = sc;
                sc->sc_txdx->dx_priority = DMAC_PRIORITY_NORMAL;
                sc->sc_txdx->dx_dev_width = DMAC_DEV_WIDTH_1;
                sc->sc_txdx->dx_burst_size = DMAC_BURST_SIZE_32;
                sc->sc_txdx->dx_done = pxamci_dmac_ointr;
                sc->sc_txdx->dx_peripheral = DMAC_PERIPH_MMCTX;
                sc->sc_txdx->dx_flow = DMAC_FLOW_CTRL_DEST;
                sc->sc_txdx->dx_loop_notify = DMAC_DONT_LOOP;
                sc->sc_txdx->dx_desc[DMAC_DESC_DST].xd_addr_hold = true;
                sc->sc_txdx->dx_desc[DMAC_DESC_DST].xd_nsegs = 1;
                sc->sc_txdx->dx_desc[DMAC_DESC_DST].xd_dma_segs = &sc->sc_txdr;
                sc->sc_txdx->dx_desc[DMAC_DESC_SRC].xd_addr_hold = false;
        }

        /*
         * Attach the generic SD/MMC bus driver.  (The bus driver must
         * not invoke any chipset functions before it is attached.)
         */
        memset(&saa, 0, sizeof(saa));
        saa.saa_busname = "sdmmc";
        saa.saa_sct = &pxamci_chip_functions;
        saa.saa_sch = sc;
        saa.saa_dmat = pxa->pxa_dmat;
        saa.saa_clkmin = sc->sc_clkmin;
        saa.saa_clkmax = sc->sc_clkmax;
        saa.saa_caps = 0;
        if (!ISSET(sc->sc_caps, PMC_CAPS_NO_DMA))
                SET(saa.saa_caps, SMC_CAPS_DMA);
#if notyet
        if (CPU_IS_PXA270 && ISSET(sc->sc_caps, PMC_CAPS_4BIT))
                SET(saa.saa_caps, SMC_CAPS_4BIT_MODE);
#endif

        sc->sc_sdmmc = config_found(sc->sc_dev, &saa, NULL);
        if (sc->sc_sdmmc == NULL) {
                aprint_error_dev(sc->sc_dev, "couldn't attach bus\n");
                goto free_xfer;
        }
        return 0;

free_xfer:
        if (!ISSET(sc->sc_caps, PMC_CAPS_NO_DMA)) {
                if (sc->sc_rxdx)
                        pxa2x0_dmac_free_xfer(sc->sc_rxdx);
                if (sc->sc_txdx)
                        pxa2x0_dmac_free_xfer(sc->sc_txdx);
        }
free_intr:
        pxa2x0_intr_disestablish(sc->sc_ih);
        sc->sc_ih = NULL;
free_map:
        bus_space_unmap(sc->sc_iot, sc->sc_ioh, PXA2X0_MMC_SIZE);
out:
        pxa2x0_clkman_config(CKEN_MMC, 0);
        return 1;
}

/*
 * Notify card attach/detach event.
 */
void
pxamci_card_detect_event(struct pxamci_softc *sc)
{

        sdmmc_needs_discover(sc->sc_sdmmc);
}

/*
 * Reset the host controller.  Called during initialization, when
 * cards are removed, upon resume, and during error recovery.
 */
static int
pxamci_host_reset(sdmmc_chipset_handle_t sch)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;
        int s;

        s = splsdmmc();

        CSR_WRITE_4(sc, MMC_SPI, 0);
        CSR_WRITE_4(sc, MMC_RESTO, 0x7f);
        CSR_WRITE_4(sc, MMC_I_MASK, sc->sc_imask);

        /* Make sure to initialize the card before the next command. */
        CLR(sc->sc_flags, PMF_CARDINITED);

        splx(s);

        return 0;
}

static uint32_t
pxamci_host_ocr(sdmmc_chipset_handle_t sch)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;
        int rv;

        if (__predict_true(sc->sc_tag.get_ocr != NULL)) {
                rv = (*sc->sc_tag.get_ocr)(sc->sc_tag.cookie);
                return rv;
        }

        DPRINTF(0,("%s: driver lacks get_ocr() function.\n",
            device_xname(sc->sc_dev)));
        return ENXIO;
}

static int
pxamci_host_maxblklen(sdmmc_chipset_handle_t sch)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;

        return sc->sc_maxblklen;
}

static int
pxamci_card_detect(sdmmc_chipset_handle_t sch)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;

        if (__predict_true(sc->sc_tag.card_detect != NULL)) {
                return (*sc->sc_tag.card_detect)(sc->sc_tag.cookie);
        }

        DPRINTF(0,("%s: driver lacks card_detect() function.\n",
            device_xname(sc->sc_dev)));
        return 1;       /* always detect */
}

static int
pxamci_write_protect(sdmmc_chipset_handle_t sch)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;

        if (__predict_true(sc->sc_tag.write_protect != NULL)) {
                return (*sc->sc_tag.write_protect)(sc->sc_tag.cookie);
        }

        DPRINTF(0,("%s: driver lacks write_protect() function.\n",
            device_xname(sc->sc_dev)));
        return 0;       /* non-protect */
}

/*
 * Set or change SD bus voltage and enable or disable SD bus power.
 * Return zero on success.
 */
static int
pxamci_bus_power(sdmmc_chipset_handle_t sch, uint32_t ocr)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;

        /*
         * Bus power management is beyond control of the SD/SDIO/MMC
         * block of the PXA2xx processors, so we have to hand this
         * task off to the attachment driver.
         */
        if (__predict_true(sc->sc_tag.set_power != NULL)) {
                return (*sc->sc_tag.set_power)(sc->sc_tag.cookie, ocr);
        }

        DPRINTF(0,("%s: driver lacks set_power() function\n",
            device_xname(sc->sc_dev)));
        return ENXIO;
}

/*
 * Set or change MMCLK frequency or disable the MMC clock.
 * Return zero on success.
 */
static int
pxamci_bus_clock(sdmmc_chipset_handle_t sch, int freq)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;
        int actfreq;
        int div;
        int rv = 0;
        int s;

        s = splsdmmc();

        /*
         * Stop MMC clock before changing the frequency.
         */
        pxamci_stop_clock(sc);

        /* Just stop the clock. */
        if (freq == 0)
                goto out;

        /*
         * PXA27x Errata...
         *
         * <snip>
         * E40. SDIO: SDIO Devices Not Working at 19.5 Mbps
         *
         * SD/SDIO controller can only support up to 9.75 Mbps data
         * transfer rate for SDIO card.
         * </snip>
         *
         * If we don't limit the frequency, CRC errors will be
         * reported by the controller after we set the bus speed.
         * XXX slow down incrementally.
         */
        if (CPU_IS_PXA270) {
                if (freq > 9750) {
                        freq = 9750;
                }
        }

        /*
         * Pick the smallest divider that produces a frequency not
         * more than `freq' KHz.
         */
        actfreq = sc->sc_clkmax;
        for (div = 0; div < 7; actfreq /= 2, div++) {
                if (actfreq <= freq)
                        break;
        }
        if (div == 7) {
                aprint_error_dev(sc->sc_dev,
                    "unsupported bus frequency of %d KHz\n", freq);
                rv = 1;
                goto out;
        }

        DPRINTF(1,("%s: freq = %d, actfreq = %d, div = %d\n",
            device_xname(sc->sc_dev), freq, actfreq, div));

        sc->sc_clkbase = actfreq;
        sc->sc_clkrt = div;

        CSR_WRITE_4(sc, MMC_CLKRT, sc->sc_clkrt);
        CSR_WRITE_4(sc, MMC_STRPCL, STRPCL_START);

 out:
        splx(s);

        return rv;
}

static int
pxamci_bus_width(sdmmc_chipset_handle_t sch, int width)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;
        int rv = 0;
        int s;

        s = splsdmmc();

        switch (width) {
        case 1:
                break;
        case 4:
                if (CPU_IS_PXA270)
                        break;
                /*FALLTHROUGH*/
        default:
                DPRINTF(0,("%s: unsupported bus width (%d)\n",
                    device_xname(sc->sc_dev), width));
                rv = 1;
                goto out;
        }

        sc->sc_buswidth = width;

 out:
        splx(s);

        return rv;
}

static void
pxamci_exec_command(sdmmc_chipset_handle_t sch, struct sdmmc_command *cmd)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;
        uint32_t cmdat;
        int error;
        int timo;
        int s;

        DPRINTF(1,("%s: start cmd %d arg=%#x data=%p dlen=%d flags=%#x\n"
            "proc=%p \"%s\"\n", device_xname(sc->sc_dev), cmd->c_opcode,
            cmd->c_arg, cmd->c_data, cmd->c_datalen, cmd->c_flags));

        s = splsdmmc();

        /* Stop the bus clock (MMCLK). [15.8.3] */
        pxamci_stop_clock(sc);

        /* Set the command and argument. */
        CSR_WRITE_4(sc, MMC_CMD, cmd->c_opcode & CMD_MASK);
        CSR_WRITE_4(sc, MMC_ARGH, (cmd->c_arg >> 16) & ARGH_MASK);
        CSR_WRITE_4(sc, MMC_ARGL, cmd->c_arg & ARGL_MASK);

        /* Response type */
        if (!ISSET(cmd->c_flags, SCF_RSP_PRESENT))
                cmdat = CMDAT_RESPONSE_FORMAT_NO;
        else if (ISSET(cmd->c_flags, SCF_RSP_136))
                cmdat = CMDAT_RESPONSE_FORMAT_R2;
        else if (!ISSET(cmd->c_flags, SCF_RSP_CRC))
                cmdat = CMDAT_RESPONSE_FORMAT_R3;
        else
                cmdat = CMDAT_RESPONSE_FORMAT_R1;

        if (ISSET(cmd->c_flags, SCF_RSP_BSY))
                cmdat |= CMDAT_BUSY;
        if (!ISSET(cmd->c_flags, SCF_CMD_READ))
                cmdat |= CMDAT_WRITE;
        if (sc->sc_buswidth == 4)
                cmdat |= CMDAT_SD_4DAT;

        /* Fragment the data into proper blocks. */
        if (cmd->c_datalen > 0) {
                int blklen = MIN(cmd->c_datalen, cmd->c_blklen);
                int numblk = cmd->c_datalen / blklen;

                if (cmd->c_datalen % blklen > 0) {
                        /* XXX: Split this command. (1.7.4) */
                        aprint_error_dev(sc->sc_dev,
                            "data not a multiple of %u bytes\n", blklen);
                        cmd->c_error = EINVAL;
                        goto out;
                }

                /* Check limit imposed by block count. */
                if (numblk > NOB_MASK) {
                        aprint_error_dev(sc->sc_dev, "too much data\n");
                        cmd->c_error = EINVAL;
                        goto out;
                }

                CSR_WRITE_4(sc, MMC_BLKLEN, blklen);
                CSR_WRITE_4(sc, MMC_NOB, numblk);
                CSR_WRITE_4(sc, MMC_RDTO, RDTO_MASK);

                cmdat |= CMDAT_DATA_EN;

                /* setting DMA */
                if (!ISSET(sc->sc_caps, PMC_CAPS_NO_DMA)) {
                        struct dmac_xfer_desc *dx_desc;

                        cmdat |= CMDAT_MMC_DMA_EN;

                        if (ISSET(cmd->c_flags, SCF_CMD_READ)) {
                                dx_desc = &sc->sc_rxdx->dx_desc[DMAC_DESC_DST];
                                dx_desc->xd_nsegs = cmd->c_dmamap->dm_nsegs;
                                dx_desc->xd_dma_segs = cmd->c_dmamap->dm_segs;
                                error = pxa2x0_dmac_start_xfer(sc->sc_rxdx);
                        } else {
                                dx_desc = &sc->sc_txdx->dx_desc[DMAC_DESC_SRC];
                                dx_desc->xd_nsegs = cmd->c_dmamap->dm_nsegs;
                                dx_desc->xd_dma_segs = cmd->c_dmamap->dm_segs;
                                /* workaround for erratum #91 */
                                error = 0;
                                if (!CPU_IS_PXA270) {
                                        error =
                                            pxa2x0_dmac_start_xfer(sc->sc_txdx);
                                }
                        }
                        if (error) {
                                aprint_error_dev(sc->sc_dev,
                                    "couldn't start dma xfer. (error=%d)\n",
                                    error);
                                cmd->c_error = EIO;
                                goto err;
                        }
                } else {
                        cmd->c_resid = cmd->c_datalen;
                        cmd->c_buf = cmd->c_data;

                        pxamci_enable_intr(sc, MMC_I_RXFIFO_RD_REQ
                                               | MMC_I_TXFIFO_WR_REQ
                                               | MMC_I_DAT_ERR);
                }
        }

        sc->sc_cmd = cmd;

        /*
         * "After reset, the MMC card must be initialized by sending
         * 80 clocks to it on the MMCLK signal." [15.4.3.2]
         */
        if (!ISSET(sc->sc_flags, PMF_CARDINITED)) {
                DPRINTF(1,("%s: first command\n", device_xname(sc->sc_dev)));
                cmdat |= CMDAT_INIT;
                SET(sc->sc_flags, PMF_CARDINITED);
        }

        /* Begin the transfer and start the bus clock. */
        CSR_WRITE_4(sc, MMC_CMDAT, cmdat);
        CSR_WRITE_4(sc, MMC_CLKRT, sc->sc_clkrt);
        CSR_WRITE_4(sc, MMC_STRPCL, STRPCL_START);

        /* Wait for it to complete */
        pxamci_enable_intr(sc, MMC_I_END_CMD_RES|MMC_I_RES_ERR);
        for (timo = EXECCMD_TIMO; (sc->sc_cmd == cmd) && (timo > 0); timo--) {
                tsleep(sc, PWAIT, "mmcmd", hz);
        }

        /* If it completed in time, SCF_ITSDONE is already set. */
        if (sc->sc_cmd == cmd) {
                cmd->c_error = ETIMEDOUT;
err:
                SET(cmd->c_flags, SCF_ITSDONE);
                sc->sc_cmd = NULL;
                goto out;
        }

out:
        splx(s);

        DPRINTF(1,("%s: cmd %d done (flags=%08x error=%d)\n",
          device_xname(sc->sc_dev), cmd->c_opcode, cmd->c_flags, cmd->c_error));
}

static void
pxamci_card_enable_intr(sdmmc_chipset_handle_t sch, int enable)
{
        struct pxamci_softc *sc = (struct pxamci_softc *)sch;

        if (enable) {
                pxamci_enable_intr(sc, MMC_I_SDIO_INT);
        } else {
                pxamci_disable_intr(sc, MMC_I_SDIO_INT);
        }
}

static void
pxamci_card_intr_ack(sdmmc_chipset_handle_t sch)
{

        /* Nothing to do */
}

static void
pxamci_stop_clock(struct pxamci_softc *sc)
{
        int timo = STOPCLK_TIMO;

        if (ISSET(CSR_READ_4(sc, MMC_STAT), STAT_CLK_EN)) {
                CSR_CLR_4(sc, MMC_I_MASK, MMC_I_CLK_IS_OFF);
                CSR_WRITE_4(sc, MMC_STRPCL, STRPCL_STOP);
                while (ISSET(CSR_READ_4(sc, MMC_STAT), STAT_CLK_EN)
                    && (timo-- > 0)) {
                        tsleep(sc, PWAIT, "mmclk", hz);
                }
        }
        if (timo == 0)
                aprint_error_dev(sc->sc_dev, "clock stop timeout\n");
}

/*
 * SD/MMC controller interrput handler
 */
static int
pxamci_intr(void *arg)
{
        struct pxamci_softc *sc = arg;
        int status;
#ifdef PXAMCI_DEBUG
        int ostatus;

        ostatus =
#endif
        status = CSR_READ_4(sc, MMC_I_REG) & ~CSR_READ_4(sc, MMC_I_MASK);
        DPRINTF(9,("%s: intr status = %08x\n", device_xname(sc->sc_dev),
            status));

        /*
         * Notify the process waiting in pxamci_clock_stop() when
         * the clock has really stopped.
         */
        if (ISSET(status, MMC_I_CLK_IS_OFF)) {
                DPRINTF(2,("%s: clock is now off\n", device_xname(sc->sc_dev)));
                wakeup(sc);
                pxamci_disable_intr(sc, MMC_I_CLK_IS_OFF);
                CLR(status, MMC_I_CLK_IS_OFF);
        }

        if (sc->sc_cmd == NULL)
                goto end;

        if (ISSET(status, MMC_I_RES_ERR)) {
                DPRINTF(9, ("%s: handling MMC_I_RES_ERR\n",
                    device_xname(sc->sc_dev)));
                pxamci_disable_intr(sc, MMC_I_RES_ERR);
                CLR(status, MMC_I_RES_ERR|MMC_I_END_CMD_RES);
                if (!ISSET(sc->sc_caps, PMC_CAPS_NO_DMA)
                 && (sc->sc_cmd->c_datalen > 0)) {
                        if (ISSET(sc->sc_cmd->c_flags, SCF_CMD_READ)) {
                                pxa2x0_dmac_abort_xfer(sc->sc_rxdx);
                        } else {
                                pxa2x0_dmac_abort_xfer(sc->sc_txdx);
                        }
                }
                sc->sc_cmd->c_error = ENOEXEC;
                pxamci_intr_done(sc);
                goto end;
        }

        if (ISSET(status, MMC_I_END_CMD_RES)) {
                DPRINTF(9,("%s: handling MMC_I_END_CMD_RES\n",
                    device_xname(sc->sc_dev)));
                pxamci_intr_cmd(sc);
                pxamci_disable_intr(sc, MMC_I_END_CMD_RES);
                CLR(status, MMC_I_END_CMD_RES);
                /* ignore programming done condition */
                if (ISSET(status, MMC_I_PRG_DONE)) {
                        pxamci_disable_intr(sc, MMC_I_PRG_DONE);
                        CLR(status, MMC_I_PRG_DONE);
                }
                if (sc->sc_cmd == NULL)
                        goto end;
        }

        if (ISSET(status, MMC_I_DAT_ERR)) {
                DPRINTF(9, ("%s: handling MMC_I_DAT_ERR\n",
                    device_xname(sc->sc_dev)));
                sc->sc_cmd->c_error = EIO;
                pxamci_intr_done(sc);
                pxamci_disable_intr(sc, MMC_I_DAT_ERR);
                CLR(status, MMC_I_DAT_ERR);
                if (!ISSET(sc->sc_caps, PMC_CAPS_NO_DMA)) {
                        if (ISSET(sc->sc_cmd->c_flags, SCF_CMD_READ)) {
                                pxa2x0_dmac_abort_xfer(sc->sc_rxdx);
                        } else {
                                pxa2x0_dmac_abort_xfer(sc->sc_txdx);
                        }
                }
                /* ignore transmission done condition */
                if (ISSET(status, MMC_I_DATA_TRAN_DONE)) {
                        pxamci_disable_intr(sc, MMC_I_DATA_TRAN_DONE);
                        CLR(status, MMC_I_DATA_TRAN_DONE);
                }
                goto end;
        }

        if (ISSET(status, MMC_I_DATA_TRAN_DONE)) {
                DPRINTF(9,("%s: handling MMC_I_DATA_TRAN_DONE\n",
                    device_xname(sc->sc_dev)));
                pxamci_intr_done(sc);
                pxamci_disable_intr(sc, MMC_I_DATA_TRAN_DONE);
                CLR(status, MMC_I_DATA_TRAN_DONE);
        }

        if (ISSET(status, MMC_I_TXFIFO_WR_REQ|MMC_I_RXFIFO_RD_REQ)) {
                DPRINTF(9,("%s: handling MMC_I_xxFIFO_xx_REQ\n",
                    device_xname(sc->sc_dev)));
                pxamci_intr_data(sc);
                CLR(status, MMC_I_TXFIFO_WR_REQ|MMC_I_RXFIFO_RD_REQ);
        }

        if (ISSET(status, STAT_SDIO_INT)) {
                DPRINTF(9,("%s: handling STAT_SDIO_INT\n",
                    device_xname(sc->sc_dev)));
                sdmmc_card_intr(sc->sc_sdmmc);
                CLR(status, STAT_SDIO_INT);
        }

end:
        /* Avoid further unhandled interrupts. */
        if (status != 0) {
                pxamci_disable_intr(sc, status);
#ifdef PXAMCI_DEBUG
                aprint_error_dev(sc->sc_dev,
                    "unhandled interrupt 0x%x out of 0x%x\n", status, ostatus);
#endif
        }
        return 1;
}

static void
pxamci_intr_cmd(struct pxamci_softc *sc)
{
        struct sdmmc_command *cmd = sc->sc_cmd;
        uint32_t status;
        int error;
        int i;

        KASSERT(sc->sc_cmd != NULL);

#define STAT_ERR        (STAT_READ_TIME_OUT \
                         | STAT_TIMEOUT_RESPONSE \
                         | STAT_CRC_WRITE_ERROR \
                         | STAT_CRC_READ_ERROR \
                         | STAT_SPI_READ_ERROR_TOKEN)

        if (ISSET(cmd->c_flags, SCF_RSP_136)) {
                for (i = 3; i >= 0; i--) {
                        uint32_t h = CSR_READ_4(sc, MMC_RES) & 0xffff;
                        uint32_t l = CSR_READ_4(sc, MMC_RES) & 0xffff;
                        cmd->c_resp[i] = (h << 16) | l;
                }
                cmd->c_error = 0;
        } else if (ISSET(cmd->c_flags, SCF_RSP_PRESENT)) {
                /*
                 * Grrr... The processor manual is not clear about
                 * the layout of the response FIFO.  It just states
                 * that the FIFO is 16 bits wide, has a depth of 8,
                 * and that the CRC is not copied into the FIFO.
                 *
                 * A 16-bit word in the FIFO is filled from highest
                 * to lowest bit as the response comes in.  The two
                 * start bits and the 6 command index bits are thus
                 * stored in the upper 8 bits of the first 16-bit
                 * word that we read back from the FIFO.
                 *
                 * Since the sdmmc(4) framework expects the host
                 * controller to discard the first 8 bits of the
                 * response, what we must do is discard the upper
                 * byte of the first 16-bit word.
                 */
                uint32_t h = CSR_READ_4(sc, MMC_RES) & 0xffff;
                uint32_t m = CSR_READ_4(sc, MMC_RES) & 0xffff;
                uint32_t l = CSR_READ_4(sc, MMC_RES) & 0xffff;
                cmd->c_resp[0] = (h << 24) | (m << 8) | (l >> 8);
                for (i = 1; i < 4; i++)
                        cmd->c_resp[i] = 0;
                cmd->c_error = 0;
        }

        status = CSR_READ_4(sc, MMC_STAT);

        if (!ISSET(cmd->c_flags, SCF_RSP_PRESENT))
                CLR(status, STAT_TIMEOUT_RESPONSE);

        /* XXX only for R6, not for R2 */
        if (!ISSET(cmd->c_flags, SCF_RSP_IDX))
                CLR(status, STAT_RES_CRC_ERR);

        if (ISSET(status, STAT_TIMEOUT_RESPONSE))
                cmd->c_error = ETIMEDOUT;
        else if (ISSET(status, STAT_RES_CRC_ERR)
              && ISSET(cmd->c_flags, SCF_RSP_CRC)
              && CPU_IS_PXA270) {
                /* workaround for erratum #42 */
                if (ISSET(cmd->c_flags, SCF_RSP_136)
                 && (cmd->c_resp[0] & 0x80000000U)) {
                        DPRINTF(1,("%s: ignore CRC error\n",
                            device_xname(sc->sc_dev)));
                } else
                        cmd->c_error = EIO;
        } else if (ISSET(status, STAT_ERR))
                cmd->c_error = EIO;

        if (cmd->c_error == 0 && cmd->c_datalen > 0) {
                /* workaround for erratum #91 */
                if (!ISSET(sc->sc_caps, PMC_CAPS_NO_DMA)
                 && CPU_IS_PXA270
                 && !ISSET(cmd->c_flags, SCF_CMD_READ)) {
                        error = pxa2x0_dmac_start_xfer(sc->sc_txdx);
                        if (error) {
                                aprint_error_dev(sc->sc_dev,
                                    "couldn't start dma xfer. (error=%d)\n",
                                    error);
                                cmd->c_error = EIO;
                                pxamci_intr_done(sc);
                                return;
                        }
                        pxamci_enable_intr(sc,
                            MMC_I_DATA_TRAN_DONE|MMC_I_DAT_ERR);
                }
        } else {
                pxamci_intr_done(sc);
        }
}

static void
pxamci_intr_data(struct pxamci_softc *sc)
{
        struct sdmmc_command *cmd = sc->sc_cmd;
        int intr;
        int n;

        DPRINTF(1,("%s: pxamci_intr_data: cmd = %p, resid = %d\n",
            device_xname(sc->sc_dev), cmd, cmd->c_resid));

        n = MIN(32, cmd->c_resid);
        cmd->c_resid -= n;

        if (ISSET(cmd->c_flags, SCF_CMD_READ)) {
                intr = MMC_I_RXFIFO_RD_REQ;
                while (n-- > 0)
                        *cmd->c_buf++ = CSR_READ_1(sc, MMC_RXFIFO);
        } else {
                int short_xfer = n < 32;

                intr = MMC_I_TXFIFO_WR_REQ;
                while (n-- > 0)
                        CSR_WRITE_1(sc, MMC_TXFIFO, *cmd->c_buf++);
                if (short_xfer)
                        CSR_WRITE_4(sc, MMC_PRTBUF, 1);
        }

        if (cmd->c_resid > 0) {
                pxamci_enable_intr(sc, intr);
        } else {
                pxamci_disable_intr(sc, intr);
                pxamci_enable_intr(sc, MMC_I_DATA_TRAN_DONE);
        }
}

/*
 * Wake up the process sleeping in pxamci_exec_command().
 */
static void
pxamci_intr_done(struct pxamci_softc *sc)
{

        DPRINTF(1,("%s: pxamci_intr_done: mmc status = %#x\n",
            device_xname(sc->sc_dev), CSR_READ_4(sc, MMC_STAT)));

        pxamci_disable_intr(sc, MMC_I_TXFIFO_WR_REQ|MMC_I_RXFIFO_RD_REQ|
            MMC_I_DATA_TRAN_DONE|MMC_I_END_CMD_RES|MMC_I_RES_ERR|MMC_I_DAT_ERR);
        SET(sc->sc_cmd->c_flags, SCF_ITSDONE);
        sc->sc_cmd = NULL;
        wakeup(sc);
}

static void
pxamci_dmac_iintr(struct dmac_xfer *dx, int status)
{
        struct pxamci_softc *sc = dx->dx_cookie;

        if (status) {
                aprint_error_dev(sc->sc_dev, "pxamci_dmac_iintr: "
                    "non-zero completion status %d\n", status);
        }
}

static void
pxamci_dmac_ointr(struct dmac_xfer *dx, int status)
{
        struct pxamci_softc *sc = dx->dx_cookie;

        if (status) {
                aprint_error_dev(sc->sc_dev, "pxamci_dmac_ointr: "
                    "non-zero completion status %d\n", status);
        }
}