backtrace: replace timer with tasklet + completions

[linux-2.6/mini2440.git] / drivers / mmc / host / au1xmmc.c

/*
 * linux/drivers/mmc/host/au1xmmc.c - AU1XX0 MMC driver
 *
 *  Copyright (c) 2005, Advanced Micro Devices, Inc.
 *
 *  Developed with help from the 2.4.30 MMC AU1XXX controller including
 *  the following copyright notices:
 *     Copyright (c) 2003-2004 Embedded Edge, LLC.
 *     Portions Copyright (C) 2002 Embedix, Inc
 *     Copyright 2002 Hewlett-Packard Company

 *  2.6 version of this driver inspired by:
 *     (drivers/mmc/wbsd.c) Copyright (C) 2004-2005 Pierre Ossman,
 *     All Rights Reserved.
 *     (drivers/mmc/pxa.c) Copyright (C) 2003 Russell King,
 *     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.
 */

/* Why is a timer used to detect insert events?
 *
 * From the AU1100 MMC application guide:
 * If the Au1100-based design is intended to support both MultiMediaCards
 * and 1- or 4-data bit SecureDigital cards, then the solution is to
 * connect a weak (560KOhm) pull-up resistor to connector pin 1.
 * In doing so, a MMC card never enters SPI-mode communications,
 * but now the SecureDigital card-detect feature of CD/DAT3 is ineffective
 * (the low to high transition will not occur).
 *
 * So we use the timer to check the status manually.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>

#include <linux/mmc/host.h>
#include <asm/io.h>
#include <asm/mach-au1x00/au1000.h>
#include <asm/mach-au1x00/au1xxx_dbdma.h>
#include <asm/mach-au1x00/au1100_mmc.h>

#include <au1xxx.h>
#include "au1xmmc.h"

#define DRIVER_NAME "au1xxx-mmc"

/* Set this to enable special debugging macros */

#ifdef DEBUG
#define DBG(fmt, idx, args...) printk("au1xx(%d): DEBUG: " fmt, idx, ##args)
#else
#define DBG(fmt, idx, args...)
#endif

const struct {
        u32 iobase;
        u32 tx_devid, rx_devid;
        u16 bcsrpwr;
        u16 bcsrstatus;
        u16 wpstatus;
} au1xmmc_card_table[] = {
        { SD0_BASE, DSCR_CMD0_SDMS_TX0, DSCR_CMD0_SDMS_RX0,
          BCSR_BOARD_SD0PWR, BCSR_INT_SD0INSERT, BCSR_STATUS_SD0WP },
#ifndef CONFIG_MIPS_DB1200
        { SD1_BASE, DSCR_CMD0_SDMS_TX1, DSCR_CMD0_SDMS_RX1,
          BCSR_BOARD_DS1PWR, BCSR_INT_SD1INSERT, BCSR_STATUS_SD1WP }
#endif
};

#define AU1XMMC_CONTROLLER_COUNT (ARRAY_SIZE(au1xmmc_card_table))

/* This array stores pointers for the hosts (used by the IRQ handler) */
struct au1xmmc_host *au1xmmc_hosts[AU1XMMC_CONTROLLER_COUNT];
static int dma = 1;

#ifdef MODULE
module_param(dma, bool, 0);
MODULE_PARM_DESC(dma, "Use DMA engine for data transfers (0 = disabled)");
#endif

static inline void IRQ_ON(struct au1xmmc_host *host, u32 mask)
{
        u32 val = au_readl(HOST_CONFIG(host));
        val |= mask;
        au_writel(val, HOST_CONFIG(host));
        au_sync();
}

static inline void FLUSH_FIFO(struct au1xmmc_host *host)
{
        u32 val = au_readl(HOST_CONFIG2(host));

        au_writel(val | SD_CONFIG2_FF, HOST_CONFIG2(host));
        au_sync_delay(1);

        /* SEND_STOP will turn off clock control - this re-enables it */
        val &= ~SD_CONFIG2_DF;

        au_writel(val, HOST_CONFIG2(host));
        au_sync();
}

static inline void IRQ_OFF(struct au1xmmc_host *host, u32 mask)
{
        u32 val = au_readl(HOST_CONFIG(host));
        val &= ~mask;
        au_writel(val, HOST_CONFIG(host));
        au_sync();
}

static inline void SEND_STOP(struct au1xmmc_host *host)
{

        /* We know the value of CONFIG2, so avoid a read we don't need */
        u32 mask = SD_CONFIG2_EN;

        WARN_ON(host->status != HOST_S_DATA);
        host->status = HOST_S_STOP;

        au_writel(mask | SD_CONFIG2_DF, HOST_CONFIG2(host));
        au_sync();

        /* Send the stop commmand */
        au_writel(STOP_CMD, HOST_CMD(host));
}

static void au1xmmc_set_power(struct au1xmmc_host *host, int state)
{

        u32 val = au1xmmc_card_table[host->id].bcsrpwr;

        bcsr->board &= ~val;
        if (state) bcsr->board |= val;

        au_sync_delay(1);
}

static inline int au1xmmc_card_inserted(struct au1xmmc_host *host)
{
        return (bcsr->sig_status & au1xmmc_card_table[host->id].bcsrstatus)
                ? 1 : 0;
}

static int au1xmmc_card_readonly(struct mmc_host *mmc)
{
        struct au1xmmc_host *host = mmc_priv(mmc);
        return (bcsr->status & au1xmmc_card_table[host->id].wpstatus)
                ? 1 : 0;
}

static void au1xmmc_finish_request(struct au1xmmc_host *host)
{

        struct mmc_request *mrq = host->mrq;

        host->mrq = NULL;
        host->flags &= HOST_F_ACTIVE;

        host->dma.len = 0;
        host->dma.dir = 0;

        host->pio.index  = 0;
        host->pio.offset = 0;
        host->pio.len = 0;

        host->status = HOST_S_IDLE;

        bcsr->disk_leds |= (1 << 8);

        mmc_request_done(host->mmc, mrq);
}

static void au1xmmc_tasklet_finish(unsigned long param)
{
        struct au1xmmc_host *host = (struct au1xmmc_host *) param;
        au1xmmc_finish_request(host);
}

static int au1xmmc_send_command(struct au1xmmc_host *host, int wait,
                                struct mmc_command *cmd, struct mmc_data *data)
{
        u32 mmccmd = (cmd->opcode << SD_CMD_CI_SHIFT);

        switch (mmc_resp_type(cmd)) {
        case MMC_RSP_NONE:
                break;
        case MMC_RSP_R1:
                mmccmd |= SD_CMD_RT_1;
                break;
        case MMC_RSP_R1B:
                mmccmd |= SD_CMD_RT_1B;
                break;
        case MMC_RSP_R2:
                mmccmd |= SD_CMD_RT_2;
                break;
        case MMC_RSP_R3:
                mmccmd |= SD_CMD_RT_3;
                break;
        default:
                printk(KERN_INFO "au1xmmc: unhandled response type %02x\n",
                        mmc_resp_type(cmd));
                return -EINVAL;
        }

        if (data) {
                if (data->flags & MMC_DATA_READ) {
                        if (data->blocks > 1)
                                mmccmd |= SD_CMD_CT_4;
                        else
                                mmccmd |= SD_CMD_CT_2;
                } else if (data->flags & MMC_DATA_WRITE) {
                        if (data->blocks > 1)
                                mmccmd |= SD_CMD_CT_3;
                        else
                                mmccmd |= SD_CMD_CT_1;
                }
        }

        au_writel(cmd->arg, HOST_CMDARG(host));
        au_sync();

        if (wait)
                IRQ_OFF(host, SD_CONFIG_CR);

        au_writel((mmccmd | SD_CMD_GO), HOST_CMD(host));
        au_sync();

        /* Wait for the command to go on the line */

        while(1) {
                if (!(au_readl(HOST_CMD(host)) & SD_CMD_GO))
                        break;
        }

        /* Wait for the command to come back */

        if (wait) {
                u32 status = au_readl(HOST_STATUS(host));

                while(!(status & SD_STATUS_CR))
                        status = au_readl(HOST_STATUS(host));

                /* Clear the CR status */
                au_writel(SD_STATUS_CR, HOST_STATUS(host));

                IRQ_ON(host, SD_CONFIG_CR);
        }

        return 0;
}

static void au1xmmc_data_complete(struct au1xmmc_host *host, u32 status)
{

        struct mmc_request *mrq = host->mrq;
        struct mmc_data *data;
        u32 crc;

        WARN_ON(host->status != HOST_S_DATA && host->status != HOST_S_STOP);

        if (host->mrq == NULL)
                return;

        data = mrq->cmd->data;

        if (status == 0)
                status = au_readl(HOST_STATUS(host));

        /* The transaction is really over when the SD_STATUS_DB bit is clear */

        while((host->flags & HOST_F_XMIT) && (status & SD_STATUS_DB))
                status = au_readl(HOST_STATUS(host));

        data->error = 0;
        dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len, host->dma.dir);

        /* Process any errors */

        crc = (status & (SD_STATUS_WC | SD_STATUS_RC));
        if (host->flags & HOST_F_XMIT)
                crc |= ((status & 0x07) == 0x02) ? 0 : 1;

        if (crc)
                data->error = -EILSEQ;

        /* Clear the CRC bits */
        au_writel(SD_STATUS_WC | SD_STATUS_RC, HOST_STATUS(host));

        data->bytes_xfered = 0;

        if (!data->error) {
                if (host->flags & HOST_F_DMA) {
                        u32 chan = DMA_CHANNEL(host);

                        chan_tab_t *c = *((chan_tab_t **) chan);
                        au1x_dma_chan_t *cp = c->chan_ptr;
                        data->bytes_xfered = cp->ddma_bytecnt;
                }
                else
                        data->bytes_xfered =
                                (data->blocks * data->blksz) -
                                host->pio.len;
        }

        au1xmmc_finish_request(host);
}

static void au1xmmc_tasklet_data(unsigned long param)
{
        struct au1xmmc_host *host = (struct au1xmmc_host *) param;

        u32 status = au_readl(HOST_STATUS(host));
        au1xmmc_data_complete(host, status);
}

#define AU1XMMC_MAX_TRANSFER 8

static void au1xmmc_send_pio(struct au1xmmc_host *host)
{

        struct mmc_data *data = 0;
        int sg_len, max, count = 0;
        unsigned char *sg_ptr;
        u32 status = 0;
        struct scatterlist *sg;

        data = host->mrq->data;

        if (!(host->flags & HOST_F_XMIT))
                return;

        /* This is the pointer to the data buffer */
        sg = &data->sg[host->pio.index];
        sg_ptr = sg_virt(sg) + host->pio.offset;

        /* This is the space left inside the buffer */
        sg_len = data->sg[host->pio.index].length - host->pio.offset;

        /* Check to if we need less then the size of the sg_buffer */

        max = (sg_len > host->pio.len) ? host->pio.len : sg_len;
        if (max > AU1XMMC_MAX_TRANSFER) max = AU1XMMC_MAX_TRANSFER;

        for(count = 0; count < max; count++ ) {
                unsigned char val;

                status = au_readl(HOST_STATUS(host));

                if (!(status & SD_STATUS_TH))
                        break;

                val = *sg_ptr++;

                au_writel((unsigned long) val, HOST_TXPORT(host));
                au_sync();
        }

        host->pio.len -= count;
        host->pio.offset += count;

        if (count == sg_len) {
                host->pio.index++;
                host->pio.offset = 0;
        }

        if (host->pio.len == 0) {
                IRQ_OFF(host, SD_CONFIG_TH);

                if (host->flags & HOST_F_STOP)
                        SEND_STOP(host);

                tasklet_schedule(&host->data_task);
        }
}

static void au1xmmc_receive_pio(struct au1xmmc_host *host)
{

        struct mmc_data *data = 0;
        int sg_len = 0, max = 0, count = 0;
        unsigned char *sg_ptr = 0;
        u32 status = 0;
        struct scatterlist *sg;

        data = host->mrq->data;

        if (!(host->flags & HOST_F_RECV))
                return;

        max = host->pio.len;

        if (host->pio.index < host->dma.len) {
                sg = &data->sg[host->pio.index];
                sg_ptr = sg_virt(sg) + host->pio.offset;

                /* This is the space left inside the buffer */
                sg_len = sg_dma_len(&data->sg[host->pio.index]) - host->pio.offset;

                /* Check to if we need less then the size of the sg_buffer */
                if (sg_len < max) max = sg_len;
        }

        if (max > AU1XMMC_MAX_TRANSFER)
                max = AU1XMMC_MAX_TRANSFER;

        for(count = 0; count < max; count++ ) {
                u32 val;
                status = au_readl(HOST_STATUS(host));

                if (!(status & SD_STATUS_NE))
                        break;

                if (status & SD_STATUS_RC) {
                        DBG("RX CRC Error [%d + %d].\n", host->id,
                                        host->pio.len, count);
                        break;
                }

                if (status & SD_STATUS_RO) {
                        DBG("RX Overrun [%d + %d]\n", host->id,
                                        host->pio.len, count);
                        break;
                }
                else if (status & SD_STATUS_RU) {
                        DBG("RX Underrun [%d + %d]\n", host->id,
                                        host->pio.len,  count);
                        break;
                }

                val = au_readl(HOST_RXPORT(host));

                if (sg_ptr)
                        *sg_ptr++ = (unsigned char) (val & 0xFF);
        }

        host->pio.len -= count;
        host->pio.offset += count;

        if (sg_len && count == sg_len) {
                host->pio.index++;
                host->pio.offset = 0;
        }

        if (host->pio.len == 0) {
                //IRQ_OFF(host, SD_CONFIG_RA | SD_CONFIG_RF);
                IRQ_OFF(host, SD_CONFIG_NE);

                if (host->flags & HOST_F_STOP)
                        SEND_STOP(host);

                tasklet_schedule(&host->data_task);
        }
}

/* static void au1xmmc_cmd_complete
   This is called when a command has been completed - grab the response
   and check for errors.  Then start the data transfer if it is indicated.
*/

static void au1xmmc_cmd_complete(struct au1xmmc_host *host, u32 status)
{

        struct mmc_request *mrq = host->mrq;
        struct mmc_command *cmd;
        int trans;

        if (!host->mrq)
                return;

        cmd = mrq->cmd;
        cmd->error = 0;

        if (cmd->flags & MMC_RSP_PRESENT) {
                if (cmd->flags & MMC_RSP_136) {
                        u32 r[4];
                        int i;

                        r[0] = au_readl(host->iobase + SD_RESP3);
                        r[1] = au_readl(host->iobase + SD_RESP2);
                        r[2] = au_readl(host->iobase + SD_RESP1);
                        r[3] = au_readl(host->iobase + SD_RESP0);

                        /* The CRC is omitted from the response, so really
                         * we only got 120 bytes, but the engine expects
                         * 128 bits, so we have to shift things up
                         */

                        for(i = 0; i < 4; i++) {
                                cmd->resp[i] = (r[i] & 0x00FFFFFF) << 8;
                                if (i != 3)
                                        cmd->resp[i] |= (r[i + 1] & 0xFF000000) >> 24;
                        }
                } else {
                        /* Techincally, we should be getting all 48 bits of
                         * the response (SD_RESP1 + SD_RESP2), but because
                         * our response omits the CRC, our data ends up
                         * being shifted 8 bits to the right.  In this case,
                         * that means that the OSR data starts at bit 31,
                         * so we can just read RESP0 and return that
                         */
                        cmd->resp[0] = au_readl(host->iobase + SD_RESP0);
                }
        }

        /* Figure out errors */

        if (status & (SD_STATUS_SC | SD_STATUS_WC | SD_STATUS_RC))
                cmd->error = -EILSEQ;

        trans = host->flags & (HOST_F_XMIT | HOST_F_RECV);

        if (!trans || cmd->error) {

                IRQ_OFF(host, SD_CONFIG_TH | SD_CONFIG_RA|SD_CONFIG_RF);
                tasklet_schedule(&host->finish_task);
                return;
        }

        host->status = HOST_S_DATA;

        if (host->flags & HOST_F_DMA) {
                u32 channel = DMA_CHANNEL(host);

                /* Start the DMA as soon as the buffer gets something in it */

                if (host->flags & HOST_F_RECV) {
                        u32 mask = SD_STATUS_DB | SD_STATUS_NE;

                        while((status & mask) != mask)
                                status = au_readl(HOST_STATUS(host));
                }

                au1xxx_dbdma_start(channel);
        }
}

static void au1xmmc_set_clock(struct au1xmmc_host *host, int rate)
{

        unsigned int pbus = get_au1x00_speed();
        unsigned int divisor;
        u32 config;

        /* From databook:
           divisor = ((((cpuclock / sbus_divisor) / 2) / mmcclock) / 2) - 1
        */

        pbus /= ((au_readl(SYS_POWERCTRL) & 0x3) + 2);
        pbus /= 2;

        divisor = ((pbus / rate) / 2) - 1;

        config = au_readl(HOST_CONFIG(host));

        config &= ~(SD_CONFIG_DIV);
        config |= (divisor & SD_CONFIG_DIV) | SD_CONFIG_DE;

        au_writel(config, HOST_CONFIG(host));
        au_sync();
}

static int
au1xmmc_prepare_data(struct au1xmmc_host *host, struct mmc_data *data)
{

        int datalen = data->blocks * data->blksz;

        if (dma != 0)
                host->flags |= HOST_F_DMA;

        if (data->flags & MMC_DATA_READ)
                host->flags |= HOST_F_RECV;
        else
                host->flags |= HOST_F_XMIT;

        if (host->mrq->stop)
                host->flags |= HOST_F_STOP;

        host->dma.dir = DMA_BIDIRECTIONAL;

        host->dma.len = dma_map_sg(mmc_dev(host->mmc), data->sg,
                                   data->sg_len, host->dma.dir);

        if (host->dma.len == 0)
                return -ETIMEDOUT;

        au_writel(data->blksz - 1, HOST_BLKSIZE(host));

        if (host->flags & HOST_F_DMA) {
                int i;
                u32 channel = DMA_CHANNEL(host);

                au1xxx_dbdma_stop(channel);

                for(i = 0; i < host->dma.len; i++) {
                        u32 ret = 0, flags = DDMA_FLAGS_NOIE;
                        struct scatterlist *sg = &data->sg[i];
                        int sg_len = sg->length;

                        int len = (datalen > sg_len) ? sg_len : datalen;

                        if (i == host->dma.len - 1)
                                flags = DDMA_FLAGS_IE;

                        if (host->flags & HOST_F_XMIT){
                                ret = au1xxx_dbdma_put_source_flags(channel,
                                        (void *) sg_virt(sg), len, flags);
                        }
                        else {
                                ret = au1xxx_dbdma_put_dest_flags(channel,
                                        (void *) sg_virt(sg),
                                        len, flags);
                        }

                        if (!ret)
                                goto dataerr;

                        datalen -= len;
                }
        }
        else {
                host->pio.index = 0;
                host->pio.offset = 0;
                host->pio.len = datalen;

                if (host->flags & HOST_F_XMIT)
                        IRQ_ON(host, SD_CONFIG_TH);
                else
                        IRQ_ON(host, SD_CONFIG_NE);
                        //IRQ_ON(host, SD_CONFIG_RA|SD_CONFIG_RF);
        }

        return 0;

 dataerr:
        dma_unmap_sg(mmc_dev(host->mmc),data->sg,data->sg_len,host->dma.dir);
        return -ETIMEDOUT;
}

/* static void au1xmmc_request
   This actually starts a command or data transaction
*/

static void au1xmmc_request(struct mmc_host* mmc, struct mmc_request* mrq)
{

        struct au1xmmc_host *host = mmc_priv(mmc);
        unsigned int flags = 0;
        int ret = 0;

        WARN_ON(irqs_disabled());
        WARN_ON(host->status != HOST_S_IDLE);

        host->mrq = mrq;
        host->status = HOST_S_CMD;

        bcsr->disk_leds &= ~(1 << 8);

        if (mrq->data) {
                FLUSH_FIFO(host);
                flags = mrq->data->flags;
                ret = au1xmmc_prepare_data(host, mrq->data);
        }

        if (!ret)
                ret = au1xmmc_send_command(host, 0, mrq->cmd, mrq->data);

        if (ret) {
                mrq->cmd->error = ret;
                au1xmmc_finish_request(host);
        }
}

static void au1xmmc_reset_controller(struct au1xmmc_host *host)
{

        /* Apply the clock */
        au_writel(SD_ENABLE_CE, HOST_ENABLE(host));
        au_sync_delay(1);

        au_writel(SD_ENABLE_R | SD_ENABLE_CE, HOST_ENABLE(host));
        au_sync_delay(5);

        au_writel(~0, HOST_STATUS(host));
        au_sync();

        au_writel(0, HOST_BLKSIZE(host));
        au_writel(0x001fffff, HOST_TIMEOUT(host));
        au_sync();

        au_writel(SD_CONFIG2_EN, HOST_CONFIG2(host));
        au_sync();

        au_writel(SD_CONFIG2_EN | SD_CONFIG2_FF, HOST_CONFIG2(host));
        au_sync_delay(1);

        au_writel(SD_CONFIG2_EN, HOST_CONFIG2(host));
        au_sync();

        /* Configure interrupts */
        au_writel(AU1XMMC_INTERRUPTS, HOST_CONFIG(host));
        au_sync();
}


static void au1xmmc_set_ios(struct mmc_host* mmc, struct mmc_ios* ios)
{
        struct au1xmmc_host *host = mmc_priv(mmc);

        if (ios->power_mode == MMC_POWER_OFF)
                au1xmmc_set_power(host, 0);
        else if (ios->power_mode == MMC_POWER_ON) {
                au1xmmc_set_power(host, 1);
        }

        if (ios->clock && ios->clock != host->clock) {
                au1xmmc_set_clock(host, ios->clock);
                host->clock = ios->clock;
        }
}

static void au1xmmc_dma_callback(int irq, void *dev_id)
{
        struct au1xmmc_host *host = (struct au1xmmc_host *) dev_id;

        /* Avoid spurious interrupts */

        if (!host->mrq)
                return;

        if (host->flags & HOST_F_STOP)
                SEND_STOP(host);

        tasklet_schedule(&host->data_task);
}

#define STATUS_TIMEOUT (SD_STATUS_RAT | SD_STATUS_DT)
#define STATUS_DATA_IN  (SD_STATUS_NE)
#define STATUS_DATA_OUT (SD_STATUS_TH)

static irqreturn_t au1xmmc_irq(int irq, void *dev_id)
{

        u32 status;
        int i, ret = 0;

        disable_irq(AU1100_SD_IRQ);

        for(i = 0; i < AU1XMMC_CONTROLLER_COUNT; i++) {
                struct au1xmmc_host * host = au1xmmc_hosts[i];
                u32 handled = 1;

                status = au_readl(HOST_STATUS(host));

                if (host->mrq && (status & STATUS_TIMEOUT)) {
                        if (status & SD_STATUS_RAT)
                                host->mrq->cmd->error = -ETIMEDOUT;

                        else if (status & SD_STATUS_DT)
                                host->mrq->data->error = -ETIMEDOUT;

                        /* In PIO mode, interrupts might still be enabled */
                        IRQ_OFF(host, SD_CONFIG_NE | SD_CONFIG_TH);

                        //IRQ_OFF(host, SD_CONFIG_TH|SD_CONFIG_RA|SD_CONFIG_RF);
                        tasklet_schedule(&host->finish_task);
                }
#if 0
                else if (status & SD_STATUS_DD) {

                        /* Sometimes we get a DD before a NE in PIO mode */

                        if (!(host->flags & HOST_F_DMA) &&
                                        (status & SD_STATUS_NE))
                                au1xmmc_receive_pio(host);
                        else {
                                au1xmmc_data_complete(host, status);
                                //tasklet_schedule(&host->data_task);
                        }
                }
#endif
                else if (status & (SD_STATUS_CR)) {
                        if (host->status == HOST_S_CMD)
                                au1xmmc_cmd_complete(host,status);
                }
                else if (!(host->flags & HOST_F_DMA)) {
                        if ((host->flags & HOST_F_XMIT) &&
                            (status & STATUS_DATA_OUT))
                                au1xmmc_send_pio(host);
                        else if ((host->flags & HOST_F_RECV) &&
                            (status & STATUS_DATA_IN))
                                au1xmmc_receive_pio(host);
                }
                else if (status & 0x203FBC70) {
                        DBG("Unhandled status %8.8x\n", host->id, status);
                        handled = 0;
                }

                au_writel(status, HOST_STATUS(host));
                au_sync();

                ret |= handled;
        }

        enable_irq(AU1100_SD_IRQ);
        return ret;
}

static void au1xmmc_poll_event(unsigned long arg)
{
        struct au1xmmc_host *host = (struct au1xmmc_host *) arg;

        int card = au1xmmc_card_inserted(host);
        int controller = (host->flags & HOST_F_ACTIVE) ? 1 : 0;

        if (card != controller) {
                host->flags &= ~HOST_F_ACTIVE;
                if (card) host->flags |= HOST_F_ACTIVE;
                mmc_detect_change(host->mmc, 0);
        }

        if (host->mrq != NULL) {
                u32 status = au_readl(HOST_STATUS(host));
                DBG("PENDING - %8.8x\n", host->id, status);
        }

        mod_timer(&host->timer, jiffies + AU1XMMC_DETECT_TIMEOUT);
}

static dbdev_tab_t au1xmmc_mem_dbdev =
{
        DSCR_CMD0_ALWAYS, DEV_FLAGS_ANYUSE, 0, 8, 0x00000000, 0, 0
};

static void au1xmmc_init_dma(struct au1xmmc_host *host)
{

        u32 rxchan, txchan;

        int txid = au1xmmc_card_table[host->id].tx_devid;
        int rxid = au1xmmc_card_table[host->id].rx_devid;

        /* DSCR_CMD0_ALWAYS has a stride of 32 bits, we need a stride
           of 8 bits.  And since devices are shared, we need to create
           our own to avoid freaking out other devices
        */

        int memid = au1xxx_ddma_add_device(&au1xmmc_mem_dbdev);

        txchan = au1xxx_dbdma_chan_alloc(memid, txid,
                                         au1xmmc_dma_callback, (void *) host);

        rxchan = au1xxx_dbdma_chan_alloc(rxid, memid,
                                         au1xmmc_dma_callback, (void *) host);

        au1xxx_dbdma_set_devwidth(txchan, 8);
        au1xxx_dbdma_set_devwidth(rxchan, 8);

        au1xxx_dbdma_ring_alloc(txchan, AU1XMMC_DESCRIPTOR_COUNT);
        au1xxx_dbdma_ring_alloc(rxchan, AU1XMMC_DESCRIPTOR_COUNT);

        host->tx_chan = txchan;
        host->rx_chan = rxchan;
}

static const struct mmc_host_ops au1xmmc_ops = {
        .request        = au1xmmc_request,
        .set_ios        = au1xmmc_set_ios,
        .get_ro         = au1xmmc_card_readonly,
};

static int __devinit au1xmmc_probe(struct platform_device *pdev)
{

        int i, ret = 0;

        /* THe interrupt is shared among all controllers */
        ret = request_irq(AU1100_SD_IRQ, au1xmmc_irq, IRQF_DISABLED, "MMC", 0);

        if (ret) {
                printk(DRIVER_NAME "ERROR: Couldn't get int %d: %d\n",
                                AU1100_SD_IRQ, ret);
                return -ENXIO;
        }

        disable_irq(AU1100_SD_IRQ);

        for(i = 0; i < AU1XMMC_CONTROLLER_COUNT; i++) {
                struct mmc_host *mmc = mmc_alloc_host(sizeof(struct au1xmmc_host), &pdev->dev);
                struct au1xmmc_host *host = 0;

                if (!mmc) {
                        printk(DRIVER_NAME "ERROR: no mem for host %d\n", i);
                        au1xmmc_hosts[i] = 0;
                        continue;
                }

                mmc->ops = &au1xmmc_ops;

                mmc->f_min =   450000;
                mmc->f_max = 24000000;

                mmc->max_seg_size = AU1XMMC_DESCRIPTOR_SIZE;
                mmc->max_phys_segs = AU1XMMC_DESCRIPTOR_COUNT;

                mmc->max_blk_size = 2048;
                mmc->max_blk_count = 512;

                mmc->ocr_avail = AU1XMMC_OCR;

                host = mmc_priv(mmc);
                host->mmc = mmc;

                host->id = i;
                host->iobase = au1xmmc_card_table[host->id].iobase;
                host->clock = 0;
                host->power_mode = MMC_POWER_OFF;

                host->flags = au1xmmc_card_inserted(host) ? HOST_F_ACTIVE : 0;
                host->status = HOST_S_IDLE;

                init_timer(&host->timer);

                host->timer.function = au1xmmc_poll_event;
                host->timer.data = (unsigned long) host;
                host->timer.expires = jiffies + AU1XMMC_DETECT_TIMEOUT;

                tasklet_init(&host->data_task, au1xmmc_tasklet_data,
                                (unsigned long) host);

                tasklet_init(&host->finish_task, au1xmmc_tasklet_finish,
                                (unsigned long) host);

                spin_lock_init(&host->lock);

                if (dma != 0)
                        au1xmmc_init_dma(host);

                au1xmmc_reset_controller(host);

                mmc_add_host(mmc);
                au1xmmc_hosts[i] = host;

                add_timer(&host->timer);

                printk(KERN_INFO DRIVER_NAME ": MMC Controller %d set up at %8.8X (mode=%s)\n",
                       host->id, host->iobase, dma ? "dma" : "pio");
        }

        enable_irq(AU1100_SD_IRQ);

        return 0;
}

static int __devexit au1xmmc_remove(struct platform_device *pdev)
{

        int i;

        disable_irq(AU1100_SD_IRQ);

        for(i = 0; i < AU1XMMC_CONTROLLER_COUNT; i++) {
                struct au1xmmc_host *host = au1xmmc_hosts[i];
                if (!host) continue;

                tasklet_kill(&host->data_task);
                tasklet_kill(&host->finish_task);

                del_timer_sync(&host->timer);
                au1xmmc_set_power(host, 0);

                mmc_remove_host(host->mmc);

                au1xxx_dbdma_chan_free(host->tx_chan);
                au1xxx_dbdma_chan_free(host->rx_chan);

                au_writel(0x0, HOST_ENABLE(host));
                au_sync();
        }

        free_irq(AU1100_SD_IRQ, 0);
        return 0;
}

static struct platform_driver au1xmmc_driver = {
        .probe         = au1xmmc_probe,
        .remove        = au1xmmc_remove,
        .suspend       = NULL,
        .resume        = NULL,
        .driver        = {
                .name  = DRIVER_NAME,
                .owner = THIS_MODULE,
        },
};

static int __init au1xmmc_init(void)
{
        return platform_driver_register(&au1xmmc_driver);
}

static void __exit au1xmmc_exit(void)
{
        platform_driver_unregister(&au1xmmc_driver);
}

module_init(au1xmmc_init);
module_exit(au1xmmc_exit);

#ifdef MODULE
MODULE_AUTHOR("Advanced Micro Devices, Inc");
MODULE_DESCRIPTION("MMC/SD driver for the Alchemy Au1XXX");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:au1xxx-mmc");
#endif