atmel-mci: support multiple mmc slots

The Atmel MCI controller can drive multiple cards through separate sets
of pins, but only one at a time. This patch adds support for
multiplexing access to the controller so that multiple card slots can be
used as if they were hooked up to separate mmc controllers.

The atmel-mci driver registers each slot as a separate mmc_host. Both
access the same common controller state, but they also have some state
on their own for card detection/write protect handling, and separate
shadows of the MR and SDCR registers.

When one of the slots receives a request from the mmc core, the common
controller state is checked. If it's idle, the request is submitted
immediately. If not, the request is added to a queue. When a request is
done, the queue is checked and if there is a queued request, it is
submitted before the completion callback is called.

This patch also includes a few cleanups and fixes, including a locking
overhaul. I had to change the locking extensively in any case, so I
might as well try to get it right. The driver no longer takes any
irq-safe locks, which may or may not improve the overall system
performance.

This patch also adds a bit of documentation of the internal data
structures.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>

1 files changed, 614 insertions, 308 deletions

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 8170905a0401..d8ab35175a53 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -42,20 +42,86 @@ enum {
 };
 
 enum atmel_mci_state {
-        STATE_SENDING_CMD = 0,
+        STATE_IDLE = 0,
+        STATE_SENDING_CMD,
         STATE_SENDING_DATA,
         STATE_DATA_BUSY,
         STATE_SENDING_STOP,
         STATE_DATA_ERROR,
 };
 
+/**
+ * struct atmel_mci - MMC controller state shared between all slots
+ * @lock: Spinlock protecting the queue and associated data.
+ * @regs: Pointer to MMIO registers.
+ * @sg: Scatterlist entry currently being processed by PIO code, if any.
+ * @pio_offset: Offset into the current scatterlist entry.
+ * @cur_slot: The slot which is currently using the controller.
+ * @mrq: The request currently being processed on @cur_slot,
+ *      or NULL if the controller is idle.
+ * @cmd: The command currently being sent to the card, or NULL.
+ * @data: The data currently being transferred, or NULL if no data
+ *      transfer is in progress.
+ * @cmd_status: Snapshot of SR taken upon completion of the current
+ *      command. Only valid when EVENT_CMD_COMPLETE is pending.
+ * @data_status: Snapshot of SR taken upon completion of the current
+ *      data transfer. Only valid when EVENT_DATA_COMPLETE or
+ *      EVENT_DATA_ERROR is pending.
+ * @stop_cmdr: Value to be loaded into CMDR when the stop command is
+ *      to be sent.
+ * @tasklet: Tasklet running the request state machine.
+ * @pending_events: Bitmask of events flagged by the interrupt handler
+ *      to be processed by the tasklet.
+ * @completed_events: Bitmask of events which the state machine has
+ *      processed.
+ * @state: Tasklet state.
+ * @queue: List of slots waiting for access to the controller.
+ * @need_clock_update: Update the clock rate before the next request.
+ * @need_reset: Reset controller before next request.
+ * @mode_reg: Value of the MR register.
+ * @bus_hz: The rate of @mck in Hz. This forms the basis for MMC bus
+ *      rate and timeout calculations.
+ * @mapbase: Physical address of the MMIO registers.
+ * @mck: The peripheral bus clock hooked up to the MMC controller.
+ * @pdev: Platform device associated with the MMC controller.
+ * @slot: Slots sharing this MMC controller.
+ *
+ * Locking
+ * =======
+ *
+ * @lock is a softirq-safe spinlock protecting @queue as well as
+ * @cur_slot, @mrq and @state. These must always be updated
+ * at the same time while holding @lock.
+ *
+ * @lock also protects mode_reg and need_clock_update since these are
+ * used to synchronize mode register updates with the queue
+ * processing.
+ *
+ * The @mrq field of struct atmel_mci_slot is also protected by @lock,
+ * and must always be written at the same time as the slot is added to
+ * @queue.
+ *
+ * @pending_events and @completed_events are accessed using atomic bit
+ * operations, so they don't need any locking.
+ *
+ * None of the fields touched by the interrupt handler need any
+ * locking. However, ordering is important: Before EVENT_DATA_ERROR or
+ * EVENT_DATA_COMPLETE is set in @pending_events, all data-related
+ * interrupts must be disabled and @data_status updated with a
+ * snapshot of SR. Similarly, before EVENT_CMD_COMPLETE is set, the
+ * CMDRDY interupt must be disabled and @cmd_status updated with a
+ * snapshot of SR, and before EVENT_XFER_COMPLETE can be set, the
+ * bytes_xfered field of @data must be written. This is ensured by
+ * using barriers.
+ */
 struct atmel_mci {
-        struct mmc_host         *mmc;
+        spinlock_t              lock;
         void __iomem            *regs;
 
         struct scatterlist      *sg;
         unsigned int            pio_offset;
 
+        struct atmel_mci_slot   *cur_slot;
         struct mmc_request      *mrq;
         struct mmc_command      *cmd;
         struct mmc_data         *data;
@@ -64,25 +130,59 @@ struct atmel_mci {
         u32                     data_status;
         u32                     stop_cmdr;
 
-        u32                     mode_reg;
-        u32                     sdc_reg;
-
         struct tasklet_struct   tasklet;
         unsigned long           pending_events;
         unsigned long           completed_events;
         enum atmel_mci_state    state;
+        struct list_head        queue;
 
-        int                     present;
-        int                     detect_pin;
-        int                     wp_pin;
-
-        /* For detect pin debouncing */
-        struct timer_list       detect_timer;
-
+        bool                    need_clock_update;
+        bool                    need_reset;
+        u32                     mode_reg;
         unsigned long           bus_hz;
         unsigned long           mapbase;
         struct clk              *mck;
         struct platform_device  *pdev;
+
+        struct atmel_mci_slot   *slot[ATMEL_MCI_MAX_NR_SLOTS];
+};
+
+/**
+ * struct atmel_mci_slot - MMC slot state
+ * @mmc: The mmc_host representing this slot.
+ * @host: The MMC controller this slot is using.
+ * @sdc_reg: Value of SDCR to be written before using this slot.
+ * @mrq: mmc_request currently being processed or waiting to be
+ *      processed, or NULL when the slot is idle.
+ * @queue_node: List node for placing this node in the @queue list of
+ *      &struct atmel_mci.
+ * @clock: Clock rate configured by set_ios(). Protected by host->lock.
+ * @flags: Random state bits associated with the slot.
+ * @detect_pin: GPIO pin used for card detection, or negative if not
+ *      available.
+ * @wp_pin: GPIO pin used for card write protect sending, or negative
+ *      if not available.
+ * @detect_timer: Timer used for debouncing @detect_pin interrupts.
+ */
+struct atmel_mci_slot {
+        struct mmc_host         *mmc;
+        struct atmel_mci        *host;
+
+        u32                     sdc_reg;
+
+        struct mmc_request      *mrq;
+        struct list_head        queue_node;
+
+        unsigned int            clock;
+        unsigned long           flags;
+#define ATMCI_CARD_PRESENT      0
+#define ATMCI_CARD_NEED_INIT    1
+#define ATMCI_SHUTDOWN          2
+
+        int                     detect_pin;
+        int                     wp_pin;
+
+        struct timer_list       detect_timer;
 };
 
 #define atmci_test_and_clear_pending(host, event)               \
@@ -98,14 +198,15 @@ struct atmel_mci {
  */
 static int atmci_req_show(struct seq_file *s, void *v)
 {
-        struct atmel_mci        *host = s->private;
-        struct mmc_request      *mrq = host->mrq;
+        struct atmel_mci_slot   *slot = s->private;
+        struct mmc_request      *mrq;
         struct mmc_command      *cmd;
         struct mmc_command      *stop;
         struct mmc_data         *data;
 
         /* Make sure we get a consistent snapshot */
-        spin_lock_irq(&host->mmc->lock);
+        spin_lock_bh(&slot->host->lock);
+        mrq = slot->mrq;
 
         if (mrq) {
                 cmd = mrq->cmd;
@@ -130,7 +231,7 @@ static int atmci_req_show(struct seq_file *s, void *v)
                                 stop->resp[2], stop->error);
         }
 
-        spin_unlock_irq(&host->mmc->lock);
+        spin_unlock_bh(&slot->host->lock);
 
         return 0;
 }
@@ -193,12 +294,16 @@ static int atmci_regs_show(struct seq_file *s, void *v)
         if (!buf)
                 return -ENOMEM;
 
-        /* Grab a more or less consistent snapshot */
-        spin_lock_irq(&host->mmc->lock);
+        /*
+         * Grab a more or less consistent snapshot. Note that we're
+         * not disabling interrupts, so IMR and SR may not be
+         * consistent.
+         */
+        spin_lock_bh(&host->lock);
         clk_enable(host->mck);
         memcpy_fromio(buf, host->regs, MCI_REGS_SIZE);
         clk_disable(host->mck);
-        spin_unlock_irq(&host->mmc->lock);
+        spin_unlock_bh(&host->lock);
 
         seq_printf(s, "MR:\t0x%08x%s%s CLKDIV=%u\n",
                         buf[MCI_MR / 4],
@@ -236,13 +341,13 @@ static const struct file_operations atmci_regs_fops = {
         .release        = single_release,
 };
 
-static void atmci_init_debugfs(struct atmel_mci *host)
+static void atmci_init_debugfs(struct atmel_mci_slot *slot)
 {
-        struct mmc_host *mmc;
-        struct dentry   *root;
-        struct dentry   *node;
+        struct mmc_host         *mmc = slot->mmc;
+        struct atmel_mci        *host = slot->host;
+        struct dentry           *root;
+        struct dentry           *node;
 
-        mmc = host->mmc;
         root = mmc->debugfs_root;
         if (!root)
                 return;
@@ -254,7 +359,7 @@ static void atmci_init_debugfs(struct atmel_mci *host)
         if (!node)
                 goto err;
 
-        node = debugfs_create_file("req", S_IRUSR, root, host, &atmci_req_fops);
+        node = debugfs_create_file("req", S_IRUSR, root, slot, &atmci_req_fops);
         if (!node)
                 goto err;
 
@@ -275,8 +380,7 @@ static void atmci_init_debugfs(struct atmel_mci *host)
         return;
 
 err:
-        dev_err(&host->pdev->dev,
-                "failed to initialize debugfs for controller\n");
+        dev_err(&mmc->class_dev, "failed to initialize debugfs for slot\n");
 }
 
 static inline unsigned int ns_to_clocks(struct atmel_mci *host,
@@ -286,7 +390,7 @@ static inline unsigned int ns_to_clocks(struct atmel_mci *host,
 }
 
 static void atmci_set_timeout(struct atmel_mci *host,
-                              struct mmc_data *data)
+                struct atmel_mci_slot *slot, struct mmc_data *data)
 {
         static unsigned dtomul_to_shift[] = {
                 0, 4, 7, 8, 10, 12, 16, 20
@@ -309,7 +413,7 @@ static void atmci_set_timeout(struct atmel_mci *host,
                 dtocyc = 15;
         }
 
-        dev_vdbg(&host->mmc->class_dev, "setting timeout to %u cycles\n",
+        dev_vdbg(&slot->mmc->class_dev, "setting timeout to %u cycles\n",
                         dtocyc << dtomul_to_shift[dtomul]);
         mci_writel(host, DTOR, (MCI_DTOMUL(dtomul) | MCI_DTOCYC(dtocyc)));
 }
@@ -362,13 +466,12 @@ static u32 atmci_prepare_command(struct mmc_host *mmc,
 }
 
 static void atmci_start_command(struct atmel_mci *host,
-                                struct mmc_command *cmd,
-                                u32 cmd_flags)
+                struct mmc_command *cmd, u32 cmd_flags)
 {
         WARN_ON(host->cmd);
         host->cmd = cmd;
 
-        dev_vdbg(&host->mmc->class_dev,
+        dev_vdbg(&host->pdev->dev,
                         "start command: ARGR=0x%08x CMDR=0x%08x\n",
                         cmd->arg, cmd_flags);
 
@@ -376,32 +479,19 @@ static void atmci_start_command(struct atmel_mci *host,
         mci_writel(host, CMDR, cmd_flags);
 }
 
-static void send_stop_cmd(struct mmc_host *mmc, struct mmc_data *data)
+static void send_stop_cmd(struct atmel_mci *host, struct mmc_data *data)
 {
-        struct atmel_mci *host = mmc_priv(mmc);
-
         atmci_start_command(host, data->stop, host->stop_cmdr);
         mci_writel(host, IER, MCI_CMDRDY);
 }
 
-static void atmci_request_end(struct mmc_host *mmc, struct mmc_request *mrq)
-{
-        struct atmel_mci *host = mmc_priv(mmc);
-
-        WARN_ON(host->cmd || host->data);
-        host->mrq = NULL;
-
-        mmc_request_done(mmc, mrq);
-}
-
 /*
  * Returns a mask of interrupt flags to be enabled after the whole
  * request has been prepared.
  */
-static u32 atmci_submit_data(struct mmc_host *mmc, struct mmc_data *data)
+static u32 atmci_submit_data(struct atmel_mci *host, struct mmc_data *data)
 {
-        struct atmel_mci        *host = mmc_priv(mmc);
-        u32                     iflags;
+        u32 iflags;
 
         data->error = -EINPROGRESS;
 
@@ -409,10 +499,19 @@ static u32 atmci_submit_data(struct mmc_host *mmc, struct mmc_data *data)
         host->sg = NULL;
         host->data = data;
 
-        dev_vdbg(&mmc->class_dev, "BLKR=0x%08x\n",
-                        MCI_BCNT(data->blocks) | MCI_BLKLEN(data->blksz));
-
         iflags = ATMCI_DATA_ERROR_FLAGS;
+
+        /*
+         * Errata: MMC data write operation with less than 12
+         * bytes is impossible.
+         *
+         * Errata: MCI Transmit Data Register (TDR) FIFO
+         * corruption when length is not multiple of 4.
+         */
+        if (data->blocks * data->blksz < 12
+                        || (data->blocks * data->blksz) & 3)
+                host->need_reset = true;
+
         host->sg = data->sg;
         host->pio_offset = 0;
         if (data->flags & MMC_DATA_READ)
@@ -423,62 +522,62 @@ static u32 atmci_submit_data(struct mmc_host *mmc, struct mmc_data *data)
         return iflags;
 }
 
-static void atmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
+static void atmci_start_request(struct atmel_mci *host,
+                struct atmel_mci_slot *slot)
 {
-        struct atmel_mci        *host = mmc_priv(mmc);
-        struct mmc_data         *data;
+        struct mmc_request      *mrq;
         struct mmc_command      *cmd;
+        struct mmc_data         *data;
         u32                     iflags;
-        u32                     cmdflags = 0;
-
-        iflags = mci_readl(host, IMR);
-        if (iflags)
-                dev_warn(&mmc->class_dev, "WARNING: IMR=0x%08x\n",
-                                mci_readl(host, IMR));
-
-        WARN_ON(host->mrq != NULL);
-
-        /*
-         * We may "know" the card is gone even though there's still an
-         * electrical connection. If so, we really need to communicate
-         * this to the MMC core since there won't be any more
-         * interrupts as the card is completely removed. Otherwise,
-         * the MMC core might believe the card is still there even
-         * though the card was just removed very slowly.
-         */
-        if (!host->present) {
-                mrq->cmd->error = -ENOMEDIUM;
-                mmc_request_done(mmc, mrq);
-                return;
-        }
+        u32                     cmdflags;
 
+        mrq = slot->mrq;
+        host->cur_slot = slot;
         host->mrq = mrq;
+
         host->pending_events = 0;
         host->completed_events = 0;
-        host->state = STATE_SENDING_CMD;
 
-        /* We don't support multiple blocks of weird lengths. */
+        if (host->need_reset) {
+                mci_writel(host, CR, MCI_CR_SWRST);
+                mci_writel(host, CR, MCI_CR_MCIEN);
+                mci_writel(host, MR, host->mode_reg);
+                host->need_reset = false;
+        }
+        mci_writel(host, SDCR, slot->sdc_reg);
+
+        iflags = mci_readl(host, IMR);
+        if (iflags)
+                dev_warn(&slot->mmc->class_dev, "WARNING: IMR=0x%08x\n",
+                                iflags);
+
+        if (unlikely(test_and_clear_bit(ATMCI_CARD_NEED_INIT, &slot->flags))) {
+                /* Send init sequence (74 clock cycles) */
+                mci_writel(host, CMDR, MCI_CMDR_SPCMD_INIT);
+                while (!(mci_readl(host, SR) & MCI_CMDRDY))
+                        cpu_relax();
+        }
         data = mrq->data;
         if (data) {
-                if (data->blocks > 1 && data->blksz & 3)
-                        goto fail;
-                atmci_set_timeout(host, data);
+                atmci_set_timeout(host, slot, data);
 
                 /* Must set block count/size before sending command */
                 mci_writel(host, BLKR, MCI_BCNT(data->blocks)
                                 | MCI_BLKLEN(data->blksz));
+                dev_vdbg(&slot->mmc->class_dev, "BLKR=0x%08x\n",
+                        MCI_BCNT(data->blocks) | MCI_BLKLEN(data->blksz));
         }
 
         iflags = MCI_CMDRDY;
         cmd = mrq->cmd;
-        cmdflags = atmci_prepare_command(mmc, cmd);
+        cmdflags = atmci_prepare_command(slot->mmc, cmd);
         atmci_start_command(host, cmd, cmdflags);
 
         if (data)
-                iflags |= atmci_submit_data(mmc, data);
+                iflags |= atmci_submit_data(host, data);
 
         if (mrq->stop) {
-                host->stop_cmdr = atmci_prepare_command(mmc, mrq->stop);
+                host->stop_cmdr = atmci_prepare_command(slot->mmc, mrq->stop);
                 host->stop_cmdr |= MCI_CMDR_STOP_XFER;
                 if (!(data->flags & MMC_DATA_WRITE))
                         host->stop_cmdr |= MCI_CMDR_TRDIR_READ;
@@ -495,65 +594,156 @@ static void atmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
          * prepared yet.)
          */
         mci_writel(host, IER, iflags);
+}
 
-        return;
+static void atmci_queue_request(struct atmel_mci *host,
+                struct atmel_mci_slot *slot, struct mmc_request *mrq)
+{
+        dev_vdbg(&slot->mmc->class_dev, "queue request: state=%d\n",
+                        host->state);
+
+        spin_lock_bh(&host->lock);
+        slot->mrq = mrq;
+        if (host->state == STATE_IDLE) {
+                host->state = STATE_SENDING_CMD;
+                atmci_start_request(host, slot);
+        } else {
+                list_add_tail(&slot->queue_node, &host->queue);
+        }
+        spin_unlock_bh(&host->lock);
+}
 
-fail:
-        host->mrq = NULL;
-        mrq->cmd->error = -EINVAL;
-        mmc_request_done(mmc, mrq);
+static void atmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+        struct atmel_mci_slot   *slot = mmc_priv(mmc);
+        struct atmel_mci        *host = slot->host;
+        struct mmc_data         *data;
+
+        WARN_ON(slot->mrq);
+
+        /*
+         * We may "know" the card is gone even though there's still an
+         * electrical connection. If so, we really need to communicate
+         * this to the MMC core since there won't be any more
+         * interrupts as the card is completely removed. Otherwise,
+         * the MMC core might believe the card is still there even
+         * though the card was just removed very slowly.
+         */
+        if (!test_bit(ATMCI_CARD_PRESENT, &slot->flags)) {
+                mrq->cmd->error = -ENOMEDIUM;
+                mmc_request_done(mmc, mrq);
+                return;
+        }
+
+        /* We don't support multiple blocks of weird lengths. */
+        data = mrq->data;
+        if (data && data->blocks > 1 && data->blksz & 3) {
+                mrq->cmd->error = -EINVAL;
+                mmc_request_done(mmc, mrq);
+        }
+
+        atmci_queue_request(host, slot, mrq);
 }
 
 static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
-        struct atmel_mci        *host = mmc_priv(mmc);
+        struct atmel_mci_slot   *slot = mmc_priv(mmc);
+        struct atmel_mci        *host = slot->host;
+        unsigned int            i;
 
-        host->sdc_reg &= ~MCI_SDCBUS_MASK;
+        slot->sdc_reg &= ~MCI_SDCBUS_MASK;
         switch (ios->bus_width) {
         case MMC_BUS_WIDTH_1:
-                host->sdc_reg |= MCI_SDCBUS_1BIT;
+                slot->sdc_reg |= MCI_SDCBUS_1BIT;
                 break;
         case MMC_BUS_WIDTH_4:
-                host->sdc_reg = MCI_SDCBUS_4BIT;
+                slot->sdc_reg = MCI_SDCBUS_4BIT;
                 break;
         }
 
         if (ios->clock) {
+                unsigned int clock_min = ~0U;
                 u32 clkdiv;
 
-                if (!host->mode_reg)
+                spin_lock_bh(&host->lock);
+                if (!host->mode_reg) {
                         clk_enable(host->mck);
+                        mci_writel(host, CR, MCI_CR_SWRST);
+                        mci_writel(host, CR, MCI_CR_MCIEN);
+                }
 
-                /* Set clock rate */
-                clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * ios->clock) - 1;
+                /*
+                 * Use mirror of ios->clock to prevent race with mmc
+                 * core ios update when finding the minimum.
+                 */
+                slot->clock = ios->clock;
+                for (i = 0; i < ATMEL_MCI_MAX_NR_SLOTS; i++) {
+                        if (host->slot[i] && host->slot[i]->clock
+                                        && host->slot[i]->clock < clock_min)
+                                clock_min = host->slot[i]->clock;
+                }
+
+                /* Calculate clock divider */
+                clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * clock_min) - 1;
                 if (clkdiv > 255) {
                         dev_warn(&mmc->class_dev,
                                 "clock %u too slow; using %lu\n",
-                                ios->clock, host->bus_hz / (2 * 256));
+                                clock_min, host->bus_hz / (2 * 256));
                         clkdiv = 255;
                 }
 
+                /*
+                 * WRPROOF and RDPROOF prevent overruns/underruns by
+                 * stopping the clock when the FIFO is full/empty.
+                 * This state is not expected to last for long.
+                 */
                 host->mode_reg = MCI_MR_CLKDIV(clkdiv) | MCI_MR_WRPROOF
                                         | MCI_MR_RDPROOF;
 
-                mci_writel(host, CR, MCI_CR_MCIEN);
-                mci_writel(host, MR, host->mode_reg);
-                mci_writel(host, SDCR, host->sdc_reg);
+                if (list_empty(&host->queue))
+                        mci_writel(host, MR, host->mode_reg);
+                else
+                        host->need_clock_update = true;
+
+                spin_unlock_bh(&host->lock);
         } else {
-                mci_writel(host, CR, MCI_CR_MCIDIS);
-                if (host->mode_reg) {
-                        mci_readl(host, MR);
-                        clk_disable(host->mck);
+                bool any_slot_active = false;
+
+                spin_lock_bh(&host->lock);
+                slot->clock = 0;
+                for (i = 0; i < ATMEL_MCI_MAX_NR_SLOTS; i++) {
+                        if (host->slot[i] && host->slot[i]->clock) {
+                                any_slot_active = true;
+                                break;
+                        }
                 }
-                host->mode_reg = 0;
+                if (!any_slot_active) {
+                        mci_writel(host, CR, MCI_CR_MCIDIS);
+                        if (host->mode_reg) {
+                                mci_readl(host, MR);
+                                clk_disable(host->mck);
+                        }
+                        host->mode_reg = 0;
+                }
+                spin_unlock_bh(&host->lock);
         }
 
         switch (ios->power_mode) {
+        case MMC_POWER_UP:
+                set_bit(ATMCI_CARD_NEED_INIT, &slot->flags);
+                break;
         default:
                 /*
                  * TODO: None of the currently available AVR32-based
                  * boards allow MMC power to be turned off. Implement
                  * power control when this can be tested properly.
+                 *
+                 * We also need to hook this into the clock management
+                 * somehow so that newly inserted cards aren't
+                 * subjected to a fast clock before we have a chance
+                 * to figure out what the maximum rate is. Currently,
+                 * there's no way to avoid this, and there never will
+                 * be for boards that don't support power control.
                  */
                 break;
         }
@@ -561,28 +751,77 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 static int atmci_get_ro(struct mmc_host *mmc)
 {
-        int                     read_only = 0;
-        struct atmel_mci        *host = mmc_priv(mmc);
+        int                     read_only = -ENOSYS;
+        struct atmel_mci_slot   *slot = mmc_priv(mmc);
 
-        if (gpio_is_valid(host->wp_pin)) {
-                read_only = gpio_get_value(host->wp_pin);
+        if (gpio_is_valid(slot->wp_pin)) {
+                read_only = gpio_get_value(slot->wp_pin);
                 dev_dbg(&mmc->class_dev, "card is %s\n",
                                 read_only ? "read-only" : "read-write");
-        } else {
-                dev_dbg(&mmc->class_dev,
-                        "no pin for checking read-only switch."
-                        " Assuming write-enable.\n");
         }
 
         return read_only;
 }
 
-static struct mmc_host_ops atmci_ops = {
+static int atmci_get_cd(struct mmc_host *mmc)
+{
+        int                     present = -ENOSYS;
+        struct atmel_mci_slot   *slot = mmc_priv(mmc);
+
+        if (gpio_is_valid(slot->detect_pin)) {
+                present = !gpio_get_value(slot->detect_pin);
+                dev_dbg(&mmc->class_dev, "card is %spresent\n",
+                                present ? "" : "not ");
+        }
+
+        return present;
+}
+
+static const struct mmc_host_ops atmci_ops = {
         .request        = atmci_request,
         .set_ios        = atmci_set_ios,
         .get_ro         = atmci_get_ro,
+        .get_cd         = atmci_get_cd,
 };
 
+/* Called with host->lock held */
+static void atmci_request_end(struct atmel_mci *host, struct mmc_request *mrq)
+        __releases(&host->lock)
+        __acquires(&host->lock)
+{
+        struct atmel_mci_slot   *slot = NULL;
+        struct mmc_host         *prev_mmc = host->cur_slot->mmc;
+
+        WARN_ON(host->cmd || host->data);
+
+        /*
+         * Update the MMC clock rate if necessary. This may be
+         * necessary if set_ios() is called when a different slot is
+         * busy transfering data.
+         */
+        if (host->need_clock_update)
+                mci_writel(host, MR, host->mode_reg);
+
+        host->cur_slot->mrq = NULL;
+        host->mrq = NULL;
+        if (!list_empty(&host->queue)) {
+                slot = list_entry(host->queue.next,
+                                struct atmel_mci_slot, queue_node);
+                list_del(&slot->queue_node);
+                dev_vdbg(&host->pdev->dev, "list not empty: %s is next\n",
+                                mmc_hostname(slot->mmc));
+                host->state = STATE_SENDING_CMD;
+                atmci_start_request(host, slot);
+        } else {
+                dev_vdbg(&host->pdev->dev, "list empty\n");
+                host->state = STATE_IDLE;
+        }
+
+        spin_unlock(&host->lock);
+        mmc_request_done(prev_mmc, mrq);
+        spin_lock(&host->lock);
+}
+
 static void atmci_command_complete(struct atmel_mci *host,
                         struct mmc_command *cmd)
 {
@@ -604,7 +843,7 @@ static void atmci_command_complete(struct atmel_mci *host,
                 cmd->error = 0;
 
         if (cmd->error) {
-                dev_dbg(&host->mmc->class_dev,
+                dev_dbg(&host->pdev->dev,
                         "command error: status=0x%08x\n", status);
 
                 if (cmd->data) {
@@ -618,81 +857,102 @@ static void atmci_command_complete(struct atmel_mci *host,
 
 static void atmci_detect_change(unsigned long data)
 {
-        struct atmel_mci *host = (struct atmel_mci *)data;
-        struct mmc_request *mrq = host->mrq;
-        int present;
+        struct atmel_mci_slot   *slot = (struct atmel_mci_slot *)data;
+        bool                    present;
+        bool                    present_old;
 
         /*
-         * atmci_remove() sets detect_pin to -1 before freeing the
-         * interrupt. We must not re-enable the interrupt if it has
-         * been freed.
+         * atmci_cleanup_slot() sets the ATMCI_SHUTDOWN flag before
+         * freeing the interrupt. We must not re-enable the interrupt
+         * if it has been freed, and if we're shutting down, it
+         * doesn't really matter whether the card is present or not.
          */
         smp_rmb();
-        if (!gpio_is_valid(host->detect_pin))
+        if (test_bit(ATMCI_SHUTDOWN, &slot->flags))
                 return;
 
-        enable_irq(gpio_to_irq(host->detect_pin));
-        present = !gpio_get_value(host->detect_pin);
+        enable_irq(gpio_to_irq(slot->detect_pin));
+        present = !gpio_get_value(slot->detect_pin);
+        present_old = test_bit(ATMCI_CARD_PRESENT, &slot->flags);
 
-        dev_vdbg(&host->pdev->dev, "detect change: %d (was %d)\n",
-                        present, host->present);
+        dev_vdbg(&slot->mmc->class_dev, "detect change: %d (was %d)\n",
+                        present, present_old);
 
-        if (present != host->present) {
-                dev_dbg(&host->mmc->class_dev, "card %s\n",
+        if (present != present_old) {
+                struct atmel_mci        *host = slot->host;
+                struct mmc_request      *mrq;
+
+                dev_dbg(&slot->mmc->class_dev, "card %s\n",
                         present ? "inserted" : "removed");
-                host->present = present;
 
-                /* Reset controller if card is gone */
-                if (!present) {
-                        mci_writel(host, CR, MCI_CR_SWRST);
-                        mci_writel(host, IDR, ~0UL);
-                        mci_writel(host, CR, MCI_CR_MCIEN);
-                }
+                spin_lock(&host->lock);
+
+                if (!present)
+                        clear_bit(ATMCI_CARD_PRESENT, &slot->flags);
+                else
+                        set_bit(ATMCI_CARD_PRESENT, &slot->flags);
 
                 /* Clean up queue if present */
+                mrq = slot->mrq;
                 if (mrq) {
-                        /*
-                         * Reset controller to terminate any ongoing
-                         * commands or data transfers.
-                         */
-                        mci_writel(host, CR, MCI_CR_SWRST);
-                        mci_readl(host, SR);
-
-                        host->data = NULL;
-                        host->cmd = NULL;
-
-                        switch (host->state) {
-                        case STATE_SENDING_CMD:
-                                mrq->cmd->error = -ENOMEDIUM;
-                                if (!mrq->data)
+                        if (mrq == host->mrq) {
+                                /*
+                                 * Reset controller to terminate any ongoing
+                                 * commands or data transfers.
+                                 */
+                                mci_writel(host, CR, MCI_CR_SWRST);
+                                mci_writel(host, CR, MCI_CR_MCIEN);
+                                mci_writel(host, MR, host->mode_reg);
+
+                                host->data = NULL;
+                                host->cmd = NULL;
+
+                                switch (host->state) {
+                                case STATE_IDLE:
                                         break;
-                                /* fall through */
-                        case STATE_SENDING_DATA:
-                                mrq->data->error = -ENOMEDIUM;
-                                break;
-                        case STATE_DATA_BUSY:
-                        case STATE_DATA_ERROR:
-                                if (mrq->data->error == -EINPROGRESS)
+                                case STATE_SENDING_CMD:
+                                        mrq->cmd->error = -ENOMEDIUM;
+                                        if (!mrq->data)
+                                                break;
+                                        /* fall through */
+                                case STATE_SENDING_DATA:
                                         mrq->data->error = -ENOMEDIUM;
-                                if (!mrq->stop)
                                         break;
-                                /* fall through */
-                        case STATE_SENDING_STOP:
-                                mrq->stop->error = -ENOMEDIUM;
-                                break;
-                        }
+                                case STATE_DATA_BUSY:
+                                case STATE_DATA_ERROR:
+                                        if (mrq->data->error == -EINPROGRESS)
+                                                mrq->data->error = -ENOMEDIUM;
+                                        if (!mrq->stop)
+                                                break;
+                                        /* fall through */
+                                case STATE_SENDING_STOP:
+                                        mrq->stop->error = -ENOMEDIUM;
+                                        break;
+                                }
 
-                        atmci_request_end(host->mmc, mrq);
+                                atmci_request_end(host, mrq);
+                        } else {
+                                list_del(&slot->queue_node);
+                                mrq->cmd->error = -ENOMEDIUM;
+                                if (mrq->data)
+                                        mrq->data->error = -ENOMEDIUM;
+                                if (mrq->stop)
+                                        mrq->stop->error = -ENOMEDIUM;
+
+                                spin_unlock(&host->lock);
+                                mmc_request_done(slot->mmc, mrq);
+                                spin_lock(&host->lock);
+                        }
                 }
+                spin_unlock(&host->lock);
 
-                mmc_detect_change(host->mmc, 0);
+                mmc_detect_change(slot->mmc, 0);
         }
 }
 
 static void atmci_tasklet_func(unsigned long priv)
 {
-        struct mmc_host         *mmc = (struct mmc_host *)priv;
-        struct atmel_mci        *host = mmc_priv(mmc);
+        struct atmel_mci        *host = (struct atmel_mci *)priv;
         struct mmc_request      *mrq = host->mrq;
         struct mmc_data         *data = host->data;
         struct mmc_command      *cmd = host->cmd;
@@ -700,9 +960,11 @@ static void atmci_tasklet_func(unsigned long priv)
         enum atmel_mci_state    prev_state;
         u32                     status;
 
+        spin_lock(&host->lock);
+
         state = host->state;
 
-        dev_vdbg(&mmc->class_dev,
+        dev_vdbg(&host->pdev->dev,
                 "tasklet: state %u pending/completed/mask %lx/%lx/%x\n",
                 state, host->pending_events, host->completed_events,
                 mci_readl(host, IMR));
@@ -711,6 +973,9 @@ static void atmci_tasklet_func(unsigned long priv)
                 prev_state = state;
 
                 switch (state) {
+                case STATE_IDLE:
+                        break;
+
                 case STATE_SENDING_CMD:
                         if (!atmci_test_and_clear_pending(host,
                                                 EVENT_CMD_COMPLETE))
@@ -720,8 +985,8 @@ static void atmci_tasklet_func(unsigned long priv)
                         atmci_set_completed(host, EVENT_CMD_COMPLETE);
                         atmci_command_complete(host, mrq->cmd);
                         if (!mrq->data || cmd->error) {
-                                atmci_request_end(mmc, host->mrq);
-                                break;
+                                atmci_request_end(host, host->mrq);
+                                goto unlock;
                         }
 
                         prev_state = state = STATE_SENDING_DATA;
@@ -731,7 +996,7 @@ static void atmci_tasklet_func(unsigned long priv)
                         if (atmci_test_and_clear_pending(host,
                                                 EVENT_DATA_ERROR)) {
                                 if (data->stop)
-                                        send_stop_cmd(host->mmc, data);
+                                        send_stop_cmd(host, data);
                                 state = STATE_DATA_ERROR;
                                 break;
                         }
@@ -754,15 +1019,15 @@ static void atmci_tasklet_func(unsigned long priv)
                         status = host->data_status;
                         if (unlikely(status & ATMCI_DATA_ERROR_FLAGS)) {
                                 if (status & MCI_DTOE) {
-                                        dev_dbg(&mmc->class_dev,
+                                        dev_dbg(&host->pdev->dev,
                                                         "data timeout error\n");
                                         data->error = -ETIMEDOUT;
                                 } else if (status & MCI_DCRCE) {
-                                        dev_dbg(&mmc->class_dev,
+                                        dev_dbg(&host->pdev->dev,
                                                         "data CRC error\n");
                                         data->error = -EILSEQ;
                                 } else {
-                                        dev_dbg(&mmc->class_dev,
+                                        dev_dbg(&host->pdev->dev,
                                                 "data FIFO error (status=%08x)\n",
                                                 status);
                                         data->error = -EIO;
@@ -773,14 +1038,13 @@ static void atmci_tasklet_func(unsigned long priv)
                         }
 
                         if (!data->stop) {
-                                atmci_request_end(mmc, host->mrq);
-                                prev_state = state;
-                                break;
+                                atmci_request_end(host, host->mrq);
+                                goto unlock;
                         }
 
                         prev_state = state = STATE_SENDING_STOP;
                         if (!data->error)
-                                send_stop_cmd(host->mmc, data);
+                                send_stop_cmd(host, data);
                         /* fall through */
 
                 case STATE_SENDING_STOP:
@@ -790,9 +1054,8 @@ static void atmci_tasklet_func(unsigned long priv)
 
                         host->cmd = NULL;
                         atmci_command_complete(host, mrq->stop);
-                        atmci_request_end(mmc, host->mrq);
-                        prev_state = state;
-                        break;
+                        atmci_request_end(host, host->mrq);
+                        goto unlock;
 
                 case STATE_DATA_ERROR:
                         if (!atmci_test_and_clear_pending(host,
@@ -805,6 +1068,9 @@ static void atmci_tasklet_func(unsigned long priv)
         } while (state != prev_state);
 
         host->state = state;
+
+unlock:
+        spin_unlock(&host->lock);
 }
 
 static void atmci_read_data_pio(struct atmel_mci *host)
@@ -854,9 +1120,11 @@ static void atmci_read_data_pio(struct atmel_mci *host)
                         mci_writel(host, IDR, (MCI_NOTBUSY | MCI_RXRDY
                                                 | ATMCI_DATA_ERROR_FLAGS));
                         host->data_status = status;
+                        data->bytes_xfered += nbytes;
+                        smp_wmb();
                         atmci_set_pending(host, EVENT_DATA_ERROR);
                         tasklet_schedule(&host->tasklet);
-                        break;
+                        return;
                 }
         } while (status & MCI_RXRDY);
 
@@ -869,6 +1137,7 @@ done:
         mci_writel(host, IDR, MCI_RXRDY);
         mci_writel(host, IER, MCI_NOTBUSY);
         data->bytes_xfered += nbytes;
+        smp_wmb();
         atmci_set_pending(host, EVENT_XFER_COMPLETE);
 }
 
@@ -922,9 +1191,11 @@ static void atmci_write_data_pio(struct atmel_mci *host)
                         mci_writel(host, IDR, (MCI_NOTBUSY | MCI_TXRDY
                                                 | ATMCI_DATA_ERROR_FLAGS));
                         host->data_status = status;
+                        data->bytes_xfered += nbytes;
+                        smp_wmb();
                         atmci_set_pending(host, EVENT_DATA_ERROR);
                         tasklet_schedule(&host->tasklet);
-                        break;
+                        return;
                 }
         } while (status & MCI_TXRDY);
 
@@ -937,29 +1208,26 @@ done:
         mci_writel(host, IDR, MCI_TXRDY);
         mci_writel(host, IER, MCI_NOTBUSY);
         data->bytes_xfered += nbytes;
+        smp_wmb();
         atmci_set_pending(host, EVENT_XFER_COMPLETE);
 }
 
-static void atmci_cmd_interrupt(struct mmc_host *mmc, u32 status)
+static void atmci_cmd_interrupt(struct atmel_mci *host, u32 status)
 {
-        struct atmel_mci        *host = mmc_priv(mmc);
-
         mci_writel(host, IDR, MCI_CMDRDY);
 
         host->cmd_status = status;
+        smp_wmb();
         atmci_set_pending(host, EVENT_CMD_COMPLETE);
         tasklet_schedule(&host->tasklet);
 }
 
 static irqreturn_t atmci_interrupt(int irq, void *dev_id)
 {
-        struct mmc_host         *mmc = dev_id;
-        struct atmel_mci        *host = mmc_priv(mmc);
+        struct atmel_mci        *host = dev_id;
         u32                     status, mask, pending;
         unsigned int            pass_count = 0;
 
-        spin_lock(&mmc->lock);
-
         do {
                 status = mci_readl(host, SR);
                 mask = mci_readl(host, IMR);
@@ -971,7 +1239,9 @@ static irqreturn_t atmci_interrupt(int irq, void *dev_id)
                         mci_writel(host, IDR, ATMCI_DATA_ERROR_FLAGS
                                         | MCI_RXRDY | MCI_TXRDY);
                         pending &= mci_readl(host, IMR);
+
                         host->data_status = status;
+                        smp_wmb();
                         atmci_set_pending(host, EVENT_DATA_ERROR);
                         tasklet_schedule(&host->tasklet);
                 }
@@ -979,6 +1249,7 @@ static irqreturn_t atmci_interrupt(int irq, void *dev_id)
                         mci_writel(host, IDR,
                                         ATMCI_DATA_ERROR_FLAGS | MCI_NOTBUSY);
                         host->data_status = status;
+                        smp_wmb();
                         atmci_set_pending(host, EVENT_DATA_COMPLETE);
                         tasklet_schedule(&host->tasklet);
                 }
@@ -988,18 +1259,15 @@ static irqreturn_t atmci_interrupt(int irq, void *dev_id)
                         atmci_write_data_pio(host);
 
                 if (pending & MCI_CMDRDY)
-                        atmci_cmd_interrupt(mmc, status);
+                        atmci_cmd_interrupt(host, status);
         } while (pass_count++ < 5);
 
-        spin_unlock(&mmc->lock);
-
         return pass_count ? IRQ_HANDLED : IRQ_NONE;
 }
 
 static irqreturn_t atmci_detect_interrupt(int irq, void *dev_id)
 {
-        struct mmc_host         *mmc = dev_id;
-        struct atmel_mci        *host = mmc_priv(mmc);
+        struct atmel_mci_slot   *slot = dev_id;
 
         /*
          * Disable interrupts until the pin has stabilized and check
@@ -1007,21 +1275,122 @@ static irqreturn_t atmci_detect_interrupt(int irq, void *dev_id)
          * middle of the timer routine when this interrupt triggers.
          */
         disable_irq_nosync(irq);
-        mod_timer(&host->detect_timer, jiffies + msecs_to_jiffies(20));
+        mod_timer(&slot->detect_timer, jiffies + msecs_to_jiffies(20));
 
         return IRQ_HANDLED;
 }
 
+static int __init atmci_init_slot(struct atmel_mci *host,
+                struct mci_slot_pdata *slot_data, unsigned int id,
+                u32 sdc_reg)
+{
+        struct mmc_host                 *mmc;
+        struct atmel_mci_slot           *slot;
+
+        mmc = mmc_alloc_host(sizeof(struct atmel_mci_slot), &host->pdev->dev);
+        if (!mmc)
+                return -ENOMEM;
+
+        slot = mmc_priv(mmc);
+        slot->mmc = mmc;
+        slot->host = host;
+        slot->detect_pin = slot_data->detect_pin;
+        slot->wp_pin = slot_data->wp_pin;
+        slot->sdc_reg = sdc_reg;
+
+        mmc->ops = &atmci_ops;
+        mmc->f_min = DIV_ROUND_UP(host->bus_hz, 512);
+        mmc->f_max = host->bus_hz / 2;
+        mmc->ocr_avail  = MMC_VDD_32_33 | MMC_VDD_33_34;
+        if (slot_data->bus_width >= 4)
+                mmc->caps |= MMC_CAP_4_BIT_DATA;
+
+        mmc->max_hw_segs = 64;
+        mmc->max_phys_segs = 64;
+        mmc->max_req_size = 32768 * 512;
+        mmc->max_blk_size = 32768;
+        mmc->max_blk_count = 512;
+
+        /* Assume card is present initially */
+        set_bit(ATMCI_CARD_PRESENT, &slot->flags);
+        if (gpio_is_valid(slot->detect_pin)) {
+                if (gpio_request(slot->detect_pin, "mmc_detect")) {
+                        dev_dbg(&mmc->class_dev, "no detect pin available\n");
+                        slot->detect_pin = -EBUSY;
+                } else if (gpio_get_value(slot->detect_pin)) {
+                        clear_bit(ATMCI_CARD_PRESENT, &slot->flags);
+                }
+        }
+
+        if (!gpio_is_valid(slot->detect_pin))
+                mmc->caps |= MMC_CAP_NEEDS_POLL;
+
+        if (gpio_is_valid(slot->wp_pin)) {
+                if (gpio_request(slot->wp_pin, "mmc_wp")) {
+                        dev_dbg(&mmc->class_dev, "no WP pin available\n");
+                        slot->wp_pin = -EBUSY;
+                }
+        }
+
+        host->slot[id] = slot;
+        mmc_add_host(mmc);
+
+        if (gpio_is_valid(slot->detect_pin)) {
+                int ret;
+
+                setup_timer(&slot->detect_timer, atmci_detect_change,
+                                (unsigned long)slot);
+
+                ret = request_irq(gpio_to_irq(slot->detect_pin),
+                                atmci_detect_interrupt,
+                                IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+                                "mmc-detect", slot);
+                if (ret) {
+                        dev_dbg(&mmc->class_dev,
+                                "could not request IRQ %d for detect pin\n",
+                                gpio_to_irq(slot->detect_pin));
+                        gpio_free(slot->detect_pin);
+                        slot->detect_pin = -EBUSY;
+                }
+        }
+
+        atmci_init_debugfs(slot);
+
+        return 0;
+}
+
+static void __exit atmci_cleanup_slot(struct atmel_mci_slot *slot,
+                unsigned int id)
+{
+        /* Debugfs stuff is cleaned up by mmc core */
+
+        set_bit(ATMCI_SHUTDOWN, &slot->flags);
+        smp_wmb();
+
+        mmc_remove_host(slot->mmc);
+
+        if (gpio_is_valid(slot->detect_pin)) {
+                int pin = slot->detect_pin;
+
+                free_irq(gpio_to_irq(pin), slot);
+                del_timer_sync(&slot->detect_timer);
+                gpio_free(pin);
+        }
+        if (gpio_is_valid(slot->wp_pin))
+                gpio_free(slot->wp_pin);
+
+        slot->host->slot[id] = NULL;
+        mmc_free_host(slot->mmc);
+}
+
 static int __init atmci_probe(struct platform_device *pdev)
 {
         struct mci_platform_data        *pdata;
-        struct mci_slot_pdata           *slot;
-        struct atmel_mci *host;
-        struct mmc_host *mmc;
-        struct resource *regs;
-        u32 sdc_reg;
-        int irq;
-        int ret;
+        struct atmel_mci                *host;
+        struct resource                 *regs;
+        unsigned int                    nr_slots;
+        int                             irq;
+        int                             ret;
 
         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         if (!regs)
@@ -1033,27 +1402,13 @@ static int __init atmci_probe(struct platform_device *pdev)
         if (irq < 0)
                 return irq;
 
-        /* TODO: Allow using several slots at once */
-        if (pdata->slot[0].bus_width) {
-                sdc_reg = MCI_SDCSEL_SLOT_A;
-                slot = &pdata->slot[0];
-        } else if (pdata->slot[1].bus_width) {
-                sdc_reg = MCI_SDCSEL_SLOT_B;
-                slot = &pdata->slot[1];
-        } else {
-                return -EINVAL;
-        }
-
-        mmc = mmc_alloc_host(sizeof(struct atmel_mci), &pdev->dev);
-        if (!mmc)
+        host = kzalloc(sizeof(struct atmel_mci), GFP_KERNEL);
+        if (!host)
                 return -ENOMEM;
 
-        host = mmc_priv(mmc);
         host->pdev = pdev;
-        host->mmc = mmc;
-        host->detect_pin = slot->detect_pin;
-        host->wp_pin = slot->wp_pin;
-        host->sdc_reg = sdc_reg;
+        spin_lock_init(&host->lock);
+        INIT_LIST_HEAD(&host->queue);
 
         host->mck = clk_get(&pdev->dev, "mci_clk");
         if (IS_ERR(host->mck)) {
@@ -1073,123 +1428,74 @@ static int __init atmci_probe(struct platform_device *pdev)
 
         host->mapbase = regs->start;
 
-        mmc->ops = &atmci_ops;
-        mmc->f_min = (host->bus_hz + 511) / 512;
-        mmc->f_max = host->bus_hz / 2;
-        mmc->ocr_avail  = MMC_VDD_32_33 | MMC_VDD_33_34;
-        if (slot->bus_width >= 4)
-                mmc->caps |= MMC_CAP_4_BIT_DATA;
-
-        mmc->max_hw_segs = 64;
-        mmc->max_phys_segs = 64;
-        mmc->max_req_size = 32768 * 512;
-        mmc->max_blk_size = 32768;
-        mmc->max_blk_count = 512;
-
-        tasklet_init(&host->tasklet, atmci_tasklet_func, (unsigned long)mmc);
+        tasklet_init(&host->tasklet, atmci_tasklet_func, (unsigned long)host);
 
-        ret = request_irq(irq, atmci_interrupt, 0, pdev->dev.bus_id, mmc);
+        ret = request_irq(irq, atmci_interrupt, 0, pdev->dev.bus_id, host);
         if (ret)
                 goto err_request_irq;
 
-        /* Assume card is present if we don't have a detect pin */
-        host->present = 1;
-        if (gpio_is_valid(host->detect_pin)) {
-                if (gpio_request(host->detect_pin, "mmc_detect")) {
-                        dev_dbg(&mmc->class_dev, "no detect pin available\n");
-                        host->detect_pin = -1;
-                } else {
-                        host->present = !gpio_get_value(host->detect_pin);
-                }
-        }
-
-        if (!gpio_is_valid(host->detect_pin))
-                mmc->caps |= MMC_CAP_NEEDS_POLL;
-
-        if (gpio_is_valid(host->wp_pin)) {
-                if (gpio_request(host->wp_pin, "mmc_wp")) {
-                        dev_dbg(&mmc->class_dev, "no WP pin available\n");
-                        host->wp_pin = -1;
-                }
-        }
-
         platform_set_drvdata(pdev, host);
 
-        mmc_add_host(mmc);
-
-        if (gpio_is_valid(host->detect_pin)) {
-                setup_timer(&host->detect_timer, atmci_detect_change,
-                                (unsigned long)host);
-
-                ret = request_irq(gpio_to_irq(host->detect_pin),
-                                atmci_detect_interrupt,
-                                IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
-                                "mmc-detect", mmc);
-                if (ret) {
-                        dev_dbg(&mmc->class_dev,
-                                "could not request IRQ %d for detect pin\n",
-                                gpio_to_irq(host->detect_pin));
-                        gpio_free(host->detect_pin);
-                        host->detect_pin = -1;
-                }
+        /* We need at least one slot to succeed */
+        nr_slots = 0;
+        ret = -ENODEV;
+        if (pdata->slot[0].bus_width) {
+                ret = atmci_init_slot(host, &pdata->slot[0],
+                                MCI_SDCSEL_SLOT_A, 0);
+                if (!ret)
+                        nr_slots++;
+        }
+        if (pdata->slot[1].bus_width) {
+                ret = atmci_init_slot(host, &pdata->slot[1],
+                                MCI_SDCSEL_SLOT_B, 1);
+                if (!ret)
+                        nr_slots++;
         }
 
-        dev_info(&mmc->class_dev,
-                        "Atmel MCI controller at 0x%08lx irq %d\n",
-                        host->mapbase, irq);
+        if (!nr_slots)
+                goto err_init_slot;
 
-        atmci_init_debugfs(host);
+        dev_info(&pdev->dev,
+                        "Atmel MCI controller at 0x%08lx irq %d, %u slots\n",
+                        host->mapbase, irq, nr_slots);
 
         return 0;
 
+err_init_slot:
+        free_irq(irq, host);
 err_request_irq:
         iounmap(host->regs);
 err_ioremap:
         clk_put(host->mck);
 err_clk_get:
-        mmc_free_host(mmc);
+        kfree(host);
         return ret;
 }
 
 static int __exit atmci_remove(struct platform_device *pdev)
 {
-        struct atmel_mci *host = platform_get_drvdata(pdev);
+        struct atmel_mci        *host = platform_get_drvdata(pdev);
+        unsigned int            i;
 
         platform_set_drvdata(pdev, NULL);
 
-        if (host) {
-                /* Debugfs stuff is cleaned up by mmc core */
-
-                if (gpio_is_valid(host->detect_pin)) {
-                        int pin = host->detect_pin;
-
-                        /* Make sure the timer doesn't enable the interrupt */
-                        host->detect_pin = -1;
-                        smp_wmb();
-
-                        free_irq(gpio_to_irq(pin), host->mmc);
-                        del_timer_sync(&host->detect_timer);
-                        gpio_free(pin);
-                }
-
-                mmc_remove_host(host->mmc);
-
-                clk_enable(host->mck);
-                mci_writel(host, IDR, ~0UL);
-                mci_writel(host, CR, MCI_CR_MCIDIS);
-                mci_readl(host, SR);
-                clk_disable(host->mck);
+        for (i = 0; i < ATMEL_MCI_MAX_NR_SLOTS; i++) {
+                if (host->slot[i])
+                        atmci_cleanup_slot(host->slot[i], i);
+        }
 
-                if (gpio_is_valid(host->wp_pin))
-                        gpio_free(host->wp_pin);
+        clk_enable(host->mck);
+        mci_writel(host, IDR, ~0UL);
+        mci_writel(host, CR, MCI_CR_MCIDIS);
+        mci_readl(host, SR);
+        clk_disable(host->mck);
 
-                free_irq(platform_get_irq(pdev, 0), host->mmc);
-                iounmap(host->regs);
+        free_irq(platform_get_irq(pdev, 0), host);
+        iounmap(host->regs);
 
-                clk_put(host->mck);
+        clk_put(host->mck);
+        kfree(host);
 
-                mmc_free_host(host->mmc);
-        }
         return 0;
 }