[ARM] 3456/1: AT91RM9200 support for 2.6 (MMC/SD driver)

Patch from Andrew Victor

This patch adds support for the MMC/SD card interface on the Atmel
AT91RM9200 processor.

Original driver was by Nick Randell, but a number of people have
subsequently worked on it. It's currently maintained by Malcolm Noyes.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 997 insertions, 0 deletions

diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 7cc162e8978b..0330168e50cd 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -91,4 +91,12 @@ config MMC_AU1X
 
           If unsure, say N.
 
+config MMC_AT91RM9200
+        tristate "AT91RM9200 SD/MMC Card Interface support"
+        depends on ARCH_AT91RM9200 && MMC
+        help
+          This selects the AT91RM9200 MCI controller.
+
+          If unsure, say N.
+
 endmenu
diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile
index c7c34aadfc92..5d2b9ab59c41 100644
--- a/drivers/mmc/Makefile
+++ b/drivers/mmc/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_MMC_SDHCI)		+= sdhci.o
 obj-$(CONFIG_MMC_WBSD)          += wbsd.o
 obj-$(CONFIG_MMC_AU1X)          += au1xmmc.o
 obj-$(CONFIG_MMC_OMAP)          += omap.o
+obj-$(CONFIG_MMC_AT91RM9200)    += at91_mci.o
 
 mmc_core-y := mmc.o mmc_queue.o mmc_sysfs.o
 
diff --git a/drivers/mmc/at91_mci.c b/drivers/mmc/at91_mci.c
new file mode 100644
index 000000000000..6061c2d101a0
--- /dev/null
+++ b/drivers/mmc/at91_mci.c
@@ -0,0 +1,988 @@
+/*
+ *  linux/drivers/mmc/at91_mci.c - ATMEL AT91RM9200 MCI Driver
+ *
+ *  Copyright (C) 2005 Cougar Creek Computing Devices Ltd, All Rights Reserved
+ *
+ *  Copyright (C) 2006 Malcolm Noyes
+ *
+ * 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.
+ */
+
+/*
+   This is the AT91RM9200 MCI driver that has been tested with both MMC cards
+   and SD-cards.  Boards that support write protect are now supported.
+   The CCAT91SBC001 board does not support SD cards.
+
+   The three entry points are at91_mci_request, at91_mci_set_ios
+   and at91_mci_get_ro.
+
+   SET IOS
+     This configures the device to put it into the correct mode and clock speed
+     required.
+
+   MCI REQUEST
+     MCI request processes the commands sent in the mmc_request structure. This
+     can consist of a processing command and a stop command in the case of
+     multiple block transfers.
+
+     There are three main types of request, commands, reads and writes.
+
+     Commands are straight forward. The command is submitted to the controller and
+     the request function returns. When the controller generates an interrupt to indicate
+     the command is finished, the response to the command are read and the mmc_request_done
+     function called to end the request.
+
+     Reads and writes work in a similar manner to normal commands but involve the PDC (DMA)
+     controller to manage the transfers.
+
+     A read is done from the controller directly to the scatterlist passed in from the request.
+     Due to a bug in the controller, when a read is completed, all the words are byte
+     swapped in the scatterlist buffers.
+
+     The sequence of read interrupts is: ENDRX, RXBUFF, CMDRDY
+
+     A write is slightly different in that the bytes to write are read from the scatterlist
+     into a dma memory buffer (this is in case the source buffer should be read only). The
+     entire write buffer is then done from this single dma memory buffer.
+
+     The sequence of write interrupts is: ENDTX, TXBUFE, NOTBUSY, CMDRDY
+
+   GET RO
+     Gets the status of the write protect pin, if available.
+*/
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/dma-mapping.h>
+#include <linux/clk.h>
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/protocol.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/mach/mmc.h>
+#include <asm/arch/board.h>
+#include <asm/arch/gpio.h>
+#include <asm/arch/at91rm9200_mci.h>
+#include <asm/arch/at91rm9200_pdc.h>
+
+#define DRIVER_NAME "at91_mci"
+
+#undef  SUPPORT_4WIRE
+
+#ifdef CONFIG_MMC_DEBUG
+#define DBG(fmt...)     \
+        printk(fmt)
+#else
+#define DBG(fmt...)     do { } while (0)
+#endif
+
+static struct clk *mci_clk;
+
+#define FL_SENT_COMMAND (1 << 0)
+#define FL_SENT_STOP (1 << 1)
+
+
+
+/*
+ * Read from a MCI register.
+ */
+static inline unsigned long at91_mci_read(unsigned int reg)
+{
+        void __iomem *mci_base = (void __iomem *)AT91_VA_BASE_MCI;
+
+        return __raw_readl(mci_base + reg);
+}
+
+/*
+ * Write to a MCI register.
+ */
+static inline void at91_mci_write(unsigned int reg, unsigned long value)
+{
+        void __iomem *mci_base = (void __iomem *)AT91_VA_BASE_MCI;
+
+        __raw_writel(value, mci_base + reg);
+}
+
+/*
+ * Low level type for this driver
+ */
+struct at91mci_host
+{
+        struct mmc_host *mmc;
+        struct mmc_command *cmd;
+        struct mmc_request *request;
+
+        struct at91_mmc_data *board;
+        int present;
+
+        /*
+         * Flag indicating when the command has been sent. This is used to
+         * work out whether or not to send the stop
+         */
+        unsigned int flags;
+        /* flag for current bus settings */
+        u32 bus_mode;
+
+        /* DMA buffer used for transmitting */
+        unsigned int* buffer;
+        dma_addr_t physical_address;
+        unsigned int total_length;
+
+        /* Latest in the scatterlist that has been enabled for transfer, but not freed */
+        int in_use_index;
+
+        /* Latest in the scatterlist that has been enabled for transfer */
+        int transfer_index;
+};
+
+/*
+ * Copy from sg to a dma block - used for transfers
+ */
+static inline void at91mci_sg_to_dma(struct at91mci_host *host, struct mmc_data *data)
+{
+        unsigned int len, i, size;
+        unsigned *dmabuf = host->buffer;
+
+        size = host->total_length;
+        len = data->sg_len;
+
+        /*
+         * Just loop through all entries. Size might not
+         * be the entire list though so make sure that
+         * we do not transfer too much.
+         */
+        for (i = 0; i < len; i++) {
+                struct scatterlist *sg;
+                int amount;
+                int index;
+                unsigned int *sgbuffer;
+
+                sg = &data->sg[i];
+
+                sgbuffer = kmap_atomic(sg->page, KM_BIO_SRC_IRQ) + sg->offset;
+                amount = min(size, sg->length);
+                size -= amount;
+                amount /= 4;
+
+                for (index = 0; index < amount; index++)
+                        *dmabuf++ = swab32(sgbuffer[index]);
+
+                kunmap_atomic(sgbuffer, KM_BIO_SRC_IRQ);
+
+                if (size == 0)
+                        break;
+        }
+
+        /*
+         * Check that we didn't get a request to transfer
+         * more data than can fit into the SG list.
+         */
+        BUG_ON(size != 0);
+}
+
+/*
+ * Prepare a dma read
+ */
+static void at91mci_pre_dma_read(struct at91mci_host *host)
+{
+        int i;
+        struct scatterlist *sg;
+        struct mmc_command *cmd;
+        struct mmc_data *data;
+
+        DBG("pre dma read\n");
+
+        cmd = host->cmd;
+        if (!cmd) {
+                DBG("no command\n");
+                return;
+        }
+
+        data = cmd->data;
+        if (!data) {
+                DBG("no data\n");
+                return;
+        }
+
+        for (i = 0; i < 2; i++) {
+                /* nothing left to transfer */
+                if (host->transfer_index >= data->sg_len) {
+                        DBG("Nothing left to transfer (index = %d)\n", host->transfer_index);
+                        break;
+                }
+
+                /* Check to see if this needs filling */
+                if (i == 0) {
+                        if (at91_mci_read(AT91_PDC_RCR) != 0) {
+                                DBG("Transfer active in current\n");
+                                continue;
+                        }
+                }
+                else {
+                        if (at91_mci_read(AT91_PDC_RNCR) != 0) {
+                                DBG("Transfer active in next\n");
+                                continue;
+                        }
+                }
+
+                /* Setup the next transfer */
+                DBG("Using transfer index %d\n", host->transfer_index);
+
+                sg = &data->sg[host->transfer_index++];
+                DBG("sg = %p\n", sg);
+
+                sg->dma_address = dma_map_page(NULL, sg->page, sg->offset, sg->length, DMA_FROM_DEVICE);
+
+                DBG("dma address = %08X, length = %d\n", sg->dma_address, sg->length);
+
+                if (i == 0) {
+                        at91_mci_write(AT91_PDC_RPR, sg->dma_address);
+                        at91_mci_write(AT91_PDC_RCR, sg->length / 4);
+                }
+                else {
+                        at91_mci_write(AT91_PDC_RNPR, sg->dma_address);
+                        at91_mci_write(AT91_PDC_RNCR, sg->length / 4);
+                }
+        }
+
+        DBG("pre dma read done\n");
+}
+
+/*
+ * Handle after a dma read
+ */
+static void at91mci_post_dma_read(struct at91mci_host *host)
+{
+        struct mmc_command *cmd;
+        struct mmc_data *data;
+
+        DBG("post dma read\n");
+
+        cmd = host->cmd;
+        if (!cmd) {
+                DBG("no command\n");
+                return;
+        }
+
+        data = cmd->data;
+        if (!data) {
+                DBG("no data\n");
+                return;
+        }
+
+        while (host->in_use_index < host->transfer_index) {
+                unsigned int *buffer;
+                int index;
+                int len;
+
+                struct scatterlist *sg;
+
+                DBG("finishing index %d\n", host->in_use_index);
+
+                sg = &data->sg[host->in_use_index++];
+
+                DBG("Unmapping page %08X\n", sg->dma_address);
+
+                dma_unmap_page(NULL, sg->dma_address, sg->length, DMA_FROM_DEVICE);
+
+                /* Swap the contents of the buffer */
+                buffer = kmap_atomic(sg->page, KM_BIO_SRC_IRQ) + sg->offset;
+                DBG("buffer = %p, length = %d\n", buffer, sg->length);
+
+                data->bytes_xfered += sg->length;
+
+                len = sg->length / 4;
+
+                for (index = 0; index < len; index++) {
+                        buffer[index] = swab32(buffer[index]);
+                }
+                kunmap_atomic(buffer, KM_BIO_SRC_IRQ);
+                flush_dcache_page(sg->page);
+        }
+
+        /* Is there another transfer to trigger? */
+        if (host->transfer_index < data->sg_len)
+                at91mci_pre_dma_read(host);
+        else {
+                at91_mci_write(AT91_MCI_IER, AT91_MCI_RXBUFF);
+                at91_mci_write(AT91_PDC_PTCR, AT91_PDC_RXTDIS | AT91_PDC_TXTDIS);
+        }
+
+        DBG("post dma read done\n");
+}
+
+/*
+ * Handle transmitted data
+ */
+static void at91_mci_handle_transmitted(struct at91mci_host *host)
+{
+        struct mmc_command *cmd;
+        struct mmc_data *data;
+
+        DBG("Handling the transmit\n");
+
+        /* Disable the transfer */
+        at91_mci_write(AT91_PDC_PTCR, AT91_PDC_RXTDIS | AT91_PDC_TXTDIS);
+
+        /* Now wait for cmd ready */
+        at91_mci_write(AT91_MCI_IDR, AT91_MCI_TXBUFE);
+        at91_mci_write(AT91_MCI_IER, AT91_MCI_NOTBUSY);
+
+        cmd = host->cmd;
+        if (!cmd) return;
+
+        data = cmd->data;
+        if (!data) return;
+
+        data->bytes_xfered = host->total_length;
+}
+
+/*
+ * Enable the controller
+ */
+static void at91_mci_enable(void)
+{
+        at91_mci_write(AT91_MCI_CR, AT91_MCI_MCIEN);
+        at91_mci_write(AT91_MCI_IDR, 0xFFFFFFFF);
+        at91_mci_write(AT91_MCI_DTOR, AT91_MCI_DTOMUL_1M | AT91_MCI_DTOCYC);
+        at91_mci_write(AT91_MCI_MR, 0x834A);
+        at91_mci_write(AT91_MCI_SDCR, 0x0);
+}
+
+/*
+ * Disable the controller
+ */
+static void at91_mci_disable(void)
+{
+        at91_mci_write(AT91_MCI_CR, AT91_MCI_MCIDIS | AT91_MCI_SWRST);
+}
+
+/*
+ * Send a command
+ * return the interrupts to enable
+ */
+static unsigned int at91_mci_send_command(struct at91mci_host *host, struct mmc_command *cmd)
+{
+        unsigned int cmdr, mr;
+        unsigned int block_length;
+        struct mmc_data *data = cmd->data;
+
+        unsigned int blocks;
+        unsigned int ier = 0;
+
+        host->cmd = cmd;
+
+        /* Not sure if this is needed */
+#if 0
+        if ((at91_mci_read(AT91_MCI_SR) & AT91_MCI_RTOE) && (cmd->opcode == 1)) {
+                DBG("Clearing timeout\n");
+                at91_mci_write(AT91_MCI_ARGR, 0);
+                at91_mci_write(AT91_MCI_CMDR, AT91_MCI_OPDCMD);
+                while (!(at91_mci_read(AT91_MCI_SR) & AT91_MCI_CMDRDY)) {
+                        /* spin */
+                        DBG("Clearing: SR = %08X\n", at91_mci_read(AT91_MCI_SR));
+                }
+        }
+#endif
+        cmdr = cmd->opcode;
+
+        if (mmc_resp_type(cmd) == MMC_RSP_NONE)
+                cmdr |= AT91_MCI_RSPTYP_NONE;
+        else {
+                /* if a response is expected then allow maximum response latancy */
+                cmdr |= AT91_MCI_MAXLAT;
+                /* set 136 bit response for R2, 48 bit response otherwise */
+                if (mmc_resp_type(cmd) == MMC_RSP_R2)
+                        cmdr |= AT91_MCI_RSPTYP_136;
+                else
+                        cmdr |= AT91_MCI_RSPTYP_48;
+        }
+
+        if (data) {
+                block_length = 1 << data->blksz_bits;
+                blocks = data->blocks;
+
+                /* always set data start - also set direction flag for read */
+                if (data->flags & MMC_DATA_READ)
+                        cmdr |= (AT91_MCI_TRDIR | AT91_MCI_TRCMD_START);
+                else if (data->flags & MMC_DATA_WRITE)
+                        cmdr |= AT91_MCI_TRCMD_START;
+
+                if (data->flags & MMC_DATA_STREAM)
+                        cmdr |= AT91_MCI_TRTYP_STREAM;
+                if (data->flags & MMC_DATA_MULTI)
+                        cmdr |= AT91_MCI_TRTYP_MULTIPLE;
+        }
+        else {
+                block_length = 0;
+                blocks = 0;
+        }
+
+        if (cmd->opcode == MMC_STOP_TRANSMISSION)
+                cmdr |= AT91_MCI_TRCMD_STOP;
+
+        if (host->bus_mode == MMC_BUSMODE_OPENDRAIN)
+                cmdr |= AT91_MCI_OPDCMD;
+
+        /*
+         * Set the arguments and send the command
+         */
+        DBG("Sending command %d as %08X, arg = %08X, blocks = %d, length = %d (MR = %08lX)\n",
+                cmd->opcode, cmdr, cmd->arg, blocks, block_length, at91_mci_read(AT91_MCI_MR));
+
+        if (!data) {
+                at91_mci_write(AT91_PDC_PTCR, AT91_PDC_TXTDIS | AT91_PDC_RXTDIS);
+                at91_mci_write(AT91_PDC_RPR, 0);
+                at91_mci_write(AT91_PDC_RCR, 0);
+                at91_mci_write(AT91_PDC_RNPR, 0);
+                at91_mci_write(AT91_PDC_RNCR, 0);
+                at91_mci_write(AT91_PDC_TPR, 0);
+                at91_mci_write(AT91_PDC_TCR, 0);
+                at91_mci_write(AT91_PDC_TNPR, 0);
+                at91_mci_write(AT91_PDC_TNCR, 0);
+
+                at91_mci_write(AT91_MCI_ARGR, cmd->arg);
+                at91_mci_write(AT91_MCI_CMDR, cmdr);
+                return AT91_MCI_CMDRDY;
+        }
+
+        mr = at91_mci_read(AT91_MCI_MR) & 0x7fff;       /* zero block length and PDC mode */
+        at91_mci_write(AT91_MCI_MR, mr | (block_length << 16) | AT91_MCI_PDCMODE);
+
+        /*
+         * Disable the PDC controller
+         */
+        at91_mci_write(AT91_PDC_PTCR, AT91_PDC_RXTDIS | AT91_PDC_TXTDIS);
+
+        if (cmdr & AT91_MCI_TRCMD_START) {
+                data->bytes_xfered = 0;
+                host->transfer_index = 0;
+                host->in_use_index = 0;
+                if (cmdr & AT91_MCI_TRDIR) {
+                        /*
+                         * Handle a read
+                         */
+                        host->buffer = NULL;
+                        host->total_length = 0;
+
+                        at91mci_pre_dma_read(host);
+                        ier = AT91_MCI_ENDRX /* | AT91_MCI_RXBUFF */;
+                }
+                else {
+                        /*
+                         * Handle a write
+                         */
+                        host->total_length = block_length * blocks;
+                        host->buffer = dma_alloc_coherent(NULL,
+                                                  host->total_length,
+                                                  &host->physical_address, GFP_KERNEL);
+
+                        at91mci_sg_to_dma(host, data);
+
+                        DBG("Transmitting %d bytes\n", host->total_length);
+
+                        at91_mci_write(AT91_PDC_TPR, host->physical_address);
+                        at91_mci_write(AT91_PDC_TCR, host->total_length / 4);
+                        ier = AT91_MCI_TXBUFE;
+                }
+        }
+
+        /*
+         * Send the command and then enable the PDC - not the other way round as
+         * the data sheet says
+         */
+
+        at91_mci_write(AT91_MCI_ARGR, cmd->arg);
+        at91_mci_write(AT91_MCI_CMDR, cmdr);
+
+        if (cmdr & AT91_MCI_TRCMD_START) {
+                if (cmdr & AT91_MCI_TRDIR)
+                        at91_mci_write(AT91_PDC_PTCR, AT91_PDC_RXTEN);
+                else
+                        at91_mci_write(AT91_PDC_PTCR, AT91_PDC_TXTEN);
+        }
+        return ier;
+}
+
+/*
+ * Wait for a command to complete
+ */
+static void at91mci_process_command(struct at91mci_host *host, struct mmc_command *cmd)
+{
+        unsigned int ier;
+
+        ier = at91_mci_send_command(host, cmd);
+
+        DBG("setting ier to %08X\n", ier);
+
+        /* Stop on errors or the required value */
+        at91_mci_write(AT91_MCI_IER, 0xffff0000 | ier);
+}
+
+/*
+ * Process the next step in the request
+ */
+static void at91mci_process_next(struct at91mci_host *host)
+{
+        if (!(host->flags & FL_SENT_COMMAND)) {
+                host->flags |= FL_SENT_COMMAND;
+                at91mci_process_command(host, host->request->cmd);
+        }
+        else if ((!(host->flags & FL_SENT_STOP)) && host->request->stop) {
+                host->flags |= FL_SENT_STOP;
+                at91mci_process_command(host, host->request->stop);
+        }
+        else
+                mmc_request_done(host->mmc, host->request);
+}
+
+/*
+ * Handle a command that has been completed
+ */
+static void at91mci_completed_command(struct at91mci_host *host)
+{
+        struct mmc_command *cmd = host->cmd;
+        unsigned int status;
+
+        at91_mci_write(AT91_MCI_IDR, 0xffffffff);
+
+        cmd->resp[0] = at91_mci_read(AT91_MCI_RSPR(0));
+        cmd->resp[1] = at91_mci_read(AT91_MCI_RSPR(1));
+        cmd->resp[2] = at91_mci_read(AT91_MCI_RSPR(2));
+        cmd->resp[3] = at91_mci_read(AT91_MCI_RSPR(3));
+
+        if (host->buffer) {
+                dma_free_coherent(NULL, host->total_length, host->buffer, host->physical_address);
+                host->buffer = NULL;
+        }
+
+        status = at91_mci_read(AT91_MCI_SR);
+
+        DBG("Status = %08X [%08X %08X %08X %08X]\n",
+                 status, cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3]);
+
+        if (status & (AT91_MCI_RINDE | AT91_MCI_RDIRE | AT91_MCI_RCRCE |
+                        AT91_MCI_RENDE | AT91_MCI_RTOE | AT91_MCI_DCRCE |
+                        AT91_MCI_DTOE | AT91_MCI_OVRE | AT91_MCI_UNRE)) {
+                if ((status & AT91_MCI_RCRCE) &&
+                        ((cmd->opcode == MMC_SEND_OP_COND) || (cmd->opcode == SD_APP_OP_COND))) {
+                        cmd->error = MMC_ERR_NONE;
+                }
+                else {
+                        if (status & (AT91_MCI_RTOE | AT91_MCI_DTOE))
+                                cmd->error = MMC_ERR_TIMEOUT;
+                        else if (status & (AT91_MCI_RCRCE | AT91_MCI_DCRCE))
+                                cmd->error = MMC_ERR_BADCRC;
+                        else if (status & (AT91_MCI_OVRE | AT91_MCI_UNRE))
+                                cmd->error = MMC_ERR_FIFO;
+                        else
+                                cmd->error = MMC_ERR_FAILED;
+
+                        DBG("Error detected and set to %d (cmd = %d, retries = %d)\n",
+                                 cmd->error, cmd->opcode, cmd->retries);
+                }
+        }
+        else
+                cmd->error = MMC_ERR_NONE;
+
+        at91mci_process_next(host);
+}
+
+/*
+ * Handle an MMC request
+ */
+static void at91_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+        struct at91mci_host *host = mmc_priv(mmc);
+        host->request = mrq;
+        host->flags = 0;
+
+        at91mci_process_next(host);
+}
+
+/*
+ * Set the IOS
+ */
+static void at91_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+        int clkdiv;
+        struct at91mci_host *host = mmc_priv(mmc);
+        unsigned long at91_master_clock = clk_get_rate(mci_clk);
+
+        DBG("Clock %uHz, busmode %u, powermode %u, Vdd %u\n",
+                ios->clock, ios->bus_mode, ios->power_mode, ios->vdd);
+
+        if (host)
+                host->bus_mode = ios->bus_mode;
+        else
+                printk("MMC: No host for bus_mode\n");
+
+        if (ios->clock == 0) {
+                /* Disable the MCI controller */
+                at91_mci_write(AT91_MCI_CR, AT91_MCI_MCIDIS);
+                clkdiv = 0;
+        }
+        else {
+                /* Enable the MCI controller */
+                at91_mci_write(AT91_MCI_CR, AT91_MCI_MCIEN);
+
+                if ((at91_master_clock % (ios->clock * 2)) == 0)
+                        clkdiv = ((at91_master_clock / ios->clock) / 2) - 1;
+                else
+                        clkdiv = (at91_master_clock / ios->clock) / 2;
+
+                DBG("clkdiv = %d. mcck = %ld\n", clkdiv,
+                        at91_master_clock / (2 * (clkdiv + 1)));
+        }
+        if (ios->bus_width == MMC_BUS_WIDTH_4 && host->board->wire4) {
+                DBG("MMC: Setting controller bus width to 4\n");
+                at91_mci_write(AT91_MCI_SDCR, at91_mci_read(AT91_MCI_SDCR) | AT91_MCI_SDCBUS);
+        }
+        else {
+                DBG("MMC: Setting controller bus width to 1\n");
+                at91_mci_write(AT91_MCI_SDCR, at91_mci_read(AT91_MCI_SDCR) & ~AT91_MCI_SDCBUS);
+        }
+
+        /* Set the clock divider */
+        at91_mci_write(AT91_MCI_MR, (at91_mci_read(AT91_MCI_MR) & ~AT91_MCI_CLKDIV) | clkdiv);
+
+        /* maybe switch power to the card */
+        if (host && host->board->vcc_pin) {
+                switch (ios->power_mode) {
+                        case MMC_POWER_OFF:
+                                at91_set_gpio_output(host->board->vcc_pin, 0);
+                                break;
+                        case MMC_POWER_UP:
+                        case MMC_POWER_ON:
+                                at91_set_gpio_output(host->board->vcc_pin, 1);
+                                break;
+                }
+        }
+}
+
+/*
+ * Handle an interrupt
+ */
+static irqreturn_t at91_mci_irq(int irq, void *devid, struct pt_regs *regs)
+{
+        struct at91mci_host *host = devid;
+        int completed = 0;
+
+        unsigned int int_status;
+
+        if (host == NULL)
+                return IRQ_HANDLED;
+
+        int_status = at91_mci_read(AT91_MCI_SR);
+        DBG("MCI irq: status = %08X, %08lX, %08lX\n", int_status, at91_mci_read(AT91_MCI_IMR),
+                int_status & at91_mci_read(AT91_MCI_IMR));
+
+        if ((int_status & at91_mci_read(AT91_MCI_IMR)) & 0xffff0000)
+                completed = 1;
+
+        int_status &= at91_mci_read(AT91_MCI_IMR);
+
+        if (int_status & AT91_MCI_UNRE)
+                DBG("MMC: Underrun error\n");
+        if (int_status & AT91_MCI_OVRE)
+                DBG("MMC: Overrun error\n");
+        if (int_status & AT91_MCI_DTOE)
+                DBG("MMC: Data timeout\n");
+        if (int_status & AT91_MCI_DCRCE)
+                DBG("MMC: CRC error in data\n");
+        if (int_status & AT91_MCI_RTOE)
+                DBG("MMC: Response timeout\n");
+        if (int_status & AT91_MCI_RENDE)
+                DBG("MMC: Response end bit error\n");
+        if (int_status & AT91_MCI_RCRCE)
+                DBG("MMC: Response CRC error\n");
+        if (int_status & AT91_MCI_RDIRE)
+                DBG("MMC: Response direction error\n");
+        if (int_status & AT91_MCI_RINDE)
+                DBG("MMC: Response index error\n");
+
+        /* Only continue processing if no errors */
+        if (!completed) {
+                if (int_status & AT91_MCI_TXBUFE) {
+                        DBG("TX buffer empty\n");
+                        at91_mci_handle_transmitted(host);
+                }
+
+                if (int_status & AT91_MCI_RXBUFF) {
+                        DBG("RX buffer full\n");
+                        at91_mci_write(AT91_MCI_IER, AT91_MCI_CMDRDY);
+                }
+
+                if (int_status & AT91_MCI_ENDTX) {
+                        DBG("Transmit has ended\n");
+                }
+
+                if (int_status & AT91_MCI_ENDRX) {
+                        DBG("Receive has ended\n");
+                        at91mci_post_dma_read(host);
+                }
+
+                if (int_status & AT91_MCI_NOTBUSY) {
+                        DBG("Card is ready\n");
+                        at91_mci_write(AT91_MCI_IER, AT91_MCI_CMDRDY);
+                }
+
+                if (int_status & AT91_MCI_DTIP) {
+                        DBG("Data transfer in progress\n");
+                }
+
+                if (int_status & AT91_MCI_BLKE) {
+                        DBG("Block transfer has ended\n");
+                }
+
+                if (int_status & AT91_MCI_TXRDY) {
+                        DBG("Ready to transmit\n");
+                }
+
+                if (int_status & AT91_MCI_RXRDY) {
+                        DBG("Ready to receive\n");
+                }
+
+                if (int_status & AT91_MCI_CMDRDY) {
+                        DBG("Command ready\n");
+                        completed = 1;
+                }
+        }
+        at91_mci_write(AT91_MCI_IDR, int_status);
+
+        if (completed) {
+                DBG("Completed command\n");
+                at91_mci_write(AT91_MCI_IDR, 0xffffffff);
+                at91mci_completed_command(host);
+        }
+
+        return IRQ_HANDLED;
+}
+
+static irqreturn_t at91_mmc_det_irq(int irq, void *_host, struct pt_regs *regs)
+{
+        struct at91mci_host *host = _host;
+        int present = !at91_get_gpio_value(irq);
+
+        /*
+         * we expect this irq on both insert and remove,
+         * and use a short delay to debounce.
+         */
+        if (present != host->present) {
+                host->present = present;
+                DBG("%s: card %s\n", mmc_hostname(host->mmc),
+                        present ? "insert" : "remove");
+                if (!present) {
+                        DBG("****** Resetting SD-card bus width ******\n");
+                        at91_mci_write(AT91_MCI_SDCR, 0);
+                }
+                mmc_detect_change(host->mmc, msecs_to_jiffies(100));
+        }
+        return IRQ_HANDLED;
+}
+
+int at91_mci_get_ro(struct mmc_host *mmc)
+{
+        int read_only = 0;
+        struct at91mci_host *host = mmc_priv(mmc);
+
+        if (host->board->wp_pin) {
+                read_only = at91_get_gpio_value(host->board->wp_pin);
+                printk(KERN_WARNING "%s: card is %s\n", mmc_hostname(mmc),
+                                (read_only ? "read-only" : "read-write") );
+        }
+        else {
+                printk(KERN_WARNING "%s: host does not support reading read-only "
+                                "switch.  Assuming write-enable.\n", mmc_hostname(mmc));
+        }
+        return read_only;
+}
+
+static struct mmc_host_ops at91_mci_ops = {
+        .request        = at91_mci_request,
+        .set_ios        = at91_mci_set_ios,
+        .get_ro         = at91_mci_get_ro,
+};
+
+/*
+ * Probe for the device
+ */
+static int at91_mci_probe(struct platform_device *pdev)
+{
+        struct mmc_host *mmc;
+        struct at91mci_host *host;
+        int ret;
+
+        DBG("Probe MCI devices\n");
+        at91_mci_disable();
+        at91_mci_enable();
+
+        mmc = mmc_alloc_host(sizeof(struct at91mci_host), &pdev->dev);
+        if (!mmc) {
+                DBG("Failed to allocate mmc host\n");
+                return -ENOMEM;
+        }
+
+        mmc->ops = &at91_mci_ops;
+        mmc->f_min = 375000;
+        mmc->f_max = 25000000;
+        mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
+
+        host = mmc_priv(mmc);
+        host->mmc = mmc;
+        host->buffer = NULL;
+        host->bus_mode = 0;
+        host->board = pdev->dev.platform_data;
+        if (host->board->wire4) {
+#ifdef SUPPORT_4WIRE
+                mmc->caps |= MMC_CAP_4_BIT_DATA;
+#else
+                printk("MMC: 4 wire bus mode not supported by this driver - using 1 wire\n");
+#endif
+        }
+
+        /*
+         * Get Clock
+         */
+        mci_clk = clk_get(&pdev->dev, "mci_clk");
+        if (!mci_clk) {
+                printk(KERN_ERR "AT91 MMC: no clock defined.\n");
+                return -ENODEV;
+        }
+        clk_enable(mci_clk);                    /* Enable the peripheral clock */
+
+        /*
+         * Allocate the MCI interrupt
+         */
+        ret = request_irq(AT91_ID_MCI, at91_mci_irq, SA_SHIRQ, DRIVER_NAME, host);
+        if (ret) {
+                DBG("Failed to request MCI interrupt\n");
+                return ret;
+        }
+
+        platform_set_drvdata(pdev, mmc);
+
+        /*
+         * Add host to MMC layer
+         */
+        if (host->board->det_pin)
+                host->present = !at91_get_gpio_value(host->board->det_pin);
+        else
+                host->present = -1;
+
+        mmc_add_host(mmc);
+
+        /*
+         * monitor card insertion/removal if we can
+         */
+        if (host->board->det_pin) {
+                ret = request_irq(host->board->det_pin, at91_mmc_det_irq,
+                                SA_SAMPLE_RANDOM, DRIVER_NAME, host);
+                if (ret)
+                        DBG("couldn't allocate MMC detect irq\n");
+        }
+
+        DBG(KERN_INFO "Added MCI driver\n");
+
+        return 0;
+}
+
+/*
+ * Remove a device
+ */
+static int at91_mci_remove(struct platform_device *pdev)
+{
+        struct mmc_host *mmc = platform_get_drvdata(pdev);
+        struct at91mci_host *host;
+
+        if (!mmc)
+                return -1;
+
+        host = mmc_priv(mmc);
+
+        if (host->present != -1) {
+                free_irq(host->board->det_pin, host);
+                cancel_delayed_work(&host->mmc->detect);
+        }
+
+        mmc_remove_host(mmc);
+        at91_mci_disable();
+        free_irq(AT91_ID_MCI, host);
+        mmc_free_host(mmc);
+
+        clk_disable(mci_clk);                           /* Disable the peripheral clock */
+        clk_put(mci_clk);
+
+        platform_set_drvdata(pdev, NULL);
+
+        DBG("Removed\n");
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int at91_mci_suspend(struct platform_device *pdev, pm_message_t state)
+{
+        struct mmc_host *mmc = platform_get_drvdata(pdev);
+        int ret = 0;
+
+        if (mmc)
+                ret = mmc_suspend_host(mmc, state);
+
+        return ret;
+}
+
+static int at91_mci_resume(struct platform_device *pdev)
+{
+        struct mmc_host *mmc = platform_get_drvdata(pdev);
+        int ret = 0;
+
+        if (mmc)
+                ret = mmc_resume_host(mmc);
+
+        return ret;
+}
+#else
+#define at91_mci_suspend        NULL
+#define at91_mci_resume         NULL
+#endif
+
+static struct platform_driver at91_mci_driver = {
+        .probe          = at91_mci_probe,
+        .remove         = at91_mci_remove,
+        .suspend        = at91_mci_suspend,
+        .resume         = at91_mci_resume,
+        .driver         = {
+                .name   = DRIVER_NAME,
+                .owner  = THIS_MODULE,
+        },
+};
+
+static int __init at91_mci_init(void)
+{
+        return platform_driver_register(&at91_mci_driver);
+}
+
+static void __exit at91_mci_exit(void)
+{
+        platform_driver_unregister(&at91_mci_driver);
+}
+
+module_init(at91_mci_init);
+module_exit(at91_mci_exit);
+
+MODULE_DESCRIPTION("AT91 Multimedia Card Interface driver");
+MODULE_AUTHOR("Nick Randell");
+MODULE_LICENSE("GPL");