spi: atmel: Refactor spi-atmel to use SPI framework queue

Replace the deprecated master->transfer with transfer_one_message()
and allow the SPI subsystem handle all the queuing of messages.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Tested-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 220 insertions, 458 deletions

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index b96f9a89cdc6..b0842f751016 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -189,6 +189,8 @@
  */
 #define DMA_MIN_BYTES   16
 
+#define SPI_DMA_TIMEOUT         (msecs_to_jiffies(1000))
+
 struct atmel_spi_dma {
         struct dma_chan                 *chan_rx;
         struct dma_chan                 *chan_tx;
@@ -220,17 +222,13 @@ struct atmel_spi {
         int                     irq;
         struct clk              *clk;
         struct platform_device  *pdev;
-        struct spi_device       *stay;
 
-        u8                      stopping;
-        struct list_head        queue;
-        struct tasklet_struct   tasklet;
         struct spi_transfer     *current_transfer;
         unsigned long           current_remaining_bytes;
-        struct spi_transfer     *next_transfer;
-        unsigned long           next_remaining_bytes;
         int                     done_status;
 
+        struct completion       xfer_completion;
+
         /* scratch buffer */
         void                    *buffer;
         dma_addr_t              buffer_dma;
@@ -241,6 +239,9 @@ struct atmel_spi {
         bool                    use_pdc;
         /* dmaengine data */
         struct atmel_spi_dma    dma;
+
+        bool                    keep_cs;
+        bool                    cs_active;
 };
 
 /* Controller-specific per-slave state */
@@ -376,17 +377,6 @@ static inline bool atmel_spi_use_dma(struct atmel_spi *as,
         return as->use_dma && xfer->len >= DMA_MIN_BYTES;
 }
 
-static inline int atmel_spi_xfer_is_last(struct spi_message *msg,
-                                        struct spi_transfer *xfer)
-{
-        return msg->transfers.prev == &xfer->transfer_list;
-}
-
-static inline int atmel_spi_xfer_can_be_chained(struct spi_transfer *xfer)
-{
-        return xfer->delay_usecs == 0 && !xfer->cs_change;
-}
-
 static int atmel_spi_dma_slave_config(struct atmel_spi *as,
                                 struct dma_slave_config *slave_config,
                                 u8 bits_per_word)
@@ -513,23 +503,20 @@ static void dma_callback(void *data)
         struct spi_master       *master = data;
         struct atmel_spi        *as = spi_master_get_devdata(master);
 
-        /* trigger SPI tasklet */
-        tasklet_schedule(&as->tasklet);
+        complete(&as->xfer_completion);
 }
 
 /*
  * Next transfer using PIO.
- * lock is held, spi tasklet is blocked
  */
 static void atmel_spi_next_xfer_pio(struct spi_master *master,
                                 struct spi_transfer *xfer)
 {
         struct atmel_spi        *as = spi_master_get_devdata(master);
+        unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
 
         dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
 
-        as->current_remaining_bytes = xfer->len;
-
         /* Make sure data is not remaining in RDR */
         spi_readl(as, RDR);
         while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
@@ -537,13 +524,14 @@ static void atmel_spi_next_xfer_pio(struct spi_master *master,
                 cpu_relax();
         }
 
-        if (xfer->tx_buf)
+        if (xfer->tx_buf) {
                 if (xfer->bits_per_word > 8)
-                        spi_writel(as, TDR, *(u16 *)(xfer->tx_buf));
+                        spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
                 else
-                        spi_writel(as, TDR, *(u8 *)(xfer->tx_buf));
-        else
+                        spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
+        } else {
                 spi_writel(as, TDR, 0);
+        }
 
         dev_dbg(master->dev.parent,
                 "  start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
@@ -556,7 +544,6 @@ static void atmel_spi_next_xfer_pio(struct spi_master *master,
 
 /*
  * Submit next transfer for DMA.
- * lock is held, spi tasklet is blocked
  */
 static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
                                 struct spi_transfer *xfer,
@@ -747,71 +734,37 @@ static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
  * lock is held, spi irq is blocked
  */
 static void atmel_spi_pdc_next_xfer(struct spi_master *master,
-                                struct spi_message *msg)
+                                        struct spi_message *msg,
+                                        struct spi_transfer *xfer)
 {
         struct atmel_spi        *as = spi_master_get_devdata(master);
-        struct spi_transfer     *xfer;
-        u32                     len, remaining;
-        u32                     ieval;
+        u32                     len;
         dma_addr_t              tx_dma, rx_dma;
 
-        if (!as->current_transfer)
-                xfer = list_entry(msg->transfers.next,
-                                struct spi_transfer, transfer_list);
-        else if (!as->next_transfer)
-                xfer = list_entry(as->current_transfer->transfer_list.next,
-                                struct spi_transfer, transfer_list);
-        else
-                xfer = NULL;
-
-        if (xfer) {
-                spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
-
-                len = xfer->len;
-                atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
-                remaining = xfer->len - len;
-
-                spi_writel(as, RPR, rx_dma);
-                spi_writel(as, TPR, tx_dma);
-
-                if (msg->spi->bits_per_word > 8)
-                        len >>= 1;
-                spi_writel(as, RCR, len);
-                spi_writel(as, TCR, len);
-
-                atmel_spi_set_xfer_speed(as, msg->spi, xfer);
-
-                dev_dbg(&msg->spi->dev,
-                        "  start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
-                        xfer, xfer->len, xfer->tx_buf,
-                        (unsigned long long)xfer->tx_dma, xfer->rx_buf,
-                        (unsigned long long)xfer->rx_dma);
-        } else {
-                xfer = as->next_transfer;
-                remaining = as->next_remaining_bytes;
-        }
+        spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 
-        as->current_transfer = xfer;
-        as->current_remaining_bytes = remaining;
+        len = as->current_remaining_bytes;
+        atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
+        as->current_remaining_bytes -= len;
 
-        if (remaining > 0)
-                len = remaining;
-        else if (!atmel_spi_xfer_is_last(msg, xfer)
-                        && atmel_spi_xfer_can_be_chained(xfer)) {
-                xfer = list_entry(xfer->transfer_list.next,
-                                struct spi_transfer, transfer_list);
-                len = xfer->len;
-        } else
-                xfer = NULL;
+        spi_writel(as, RPR, rx_dma);
+        spi_writel(as, TPR, tx_dma);
 
-        as->next_transfer = xfer;
+        if (msg->spi->bits_per_word > 8)
+                len >>= 1;
+        spi_writel(as, RCR, len);
+        spi_writel(as, TCR, len);
 
-        if (xfer) {
-                u32     total;
+        dev_dbg(&msg->spi->dev,
+                "  start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
+                xfer, xfer->len, xfer->tx_buf,
+                (unsigned long long)xfer->tx_dma, xfer->rx_buf,
+                (unsigned long long)xfer->rx_dma);
 
-                total = len;
+        if (as->current_remaining_bytes) {
+                len = as->current_remaining_bytes;
                 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
-                as->next_remaining_bytes = total - len;
+                as->current_remaining_bytes -= len;
 
                 spi_writel(as, RNPR, rx_dma);
                 spi_writel(as, TNPR, tx_dma);
@@ -826,11 +779,6 @@ static void atmel_spi_pdc_next_xfer(struct spi_master *master,
                         xfer, xfer->len, xfer->tx_buf,
                         (unsigned long long)xfer->tx_dma, xfer->rx_buf,
                         (unsigned long long)xfer->rx_dma);
-                ieval = SPI_BIT(ENDRX) | SPI_BIT(OVRES);
-        } else {
-                spi_writel(as, RNCR, 0);
-                spi_writel(as, TNCR, 0);
-                ieval = SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES);
         }
 
         /* REVISIT: We're waiting for ENDRX before we start the next
@@ -843,84 +791,11 @@ static void atmel_spi_pdc_next_xfer(struct spi_master *master,
          *
          * It should be doable, though. Just not now...
          */
-        spi_writel(as, IER, ieval);
+        spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 }
 
 /*
- * Choose way to submit next transfer and start it.
- * lock is held, spi tasklet is blocked
- */
-static void atmel_spi_dma_next_xfer(struct spi_master *master,
-                                struct spi_message *msg)
-{
-        struct atmel_spi        *as = spi_master_get_devdata(master);
-        struct spi_transfer     *xfer;
-        u32     remaining, len;
-
-        remaining = as->current_remaining_bytes;
-        if (remaining) {
-                xfer = as->current_transfer;
-                len = remaining;
-        } else {
-                if (!as->current_transfer)
-                        xfer = list_entry(msg->transfers.next,
-                                struct spi_transfer, transfer_list);
-                else
-                        xfer = list_entry(
-                                as->current_transfer->transfer_list.next,
-                                        struct spi_transfer, transfer_list);
-
-                as->current_transfer = xfer;
-                len = xfer->len;
-                atmel_spi_set_xfer_speed(as, msg->spi, xfer);
-        }
-
-        if (atmel_spi_use_dma(as, xfer)) {
-                u32 total = len;
-                if (!atmel_spi_next_xfer_dma_submit(master, xfer, &len)) {
-                        as->current_remaining_bytes = total - len;
-                        return;
-                } else {
-                        dev_err(&msg->spi->dev, "unable to use DMA, fallback to PIO\n");
-                }
-        }
-
-        /* use PIO if error appened using DMA */
-        atmel_spi_next_xfer_pio(master, xfer);
-}
-
-static void atmel_spi_next_message(struct spi_master *master)
-{
-        struct atmel_spi        *as = spi_master_get_devdata(master);
-        struct spi_message      *msg;
-        struct spi_device       *spi;
-
-        BUG_ON(as->current_transfer);
-
-        msg = list_entry(as->queue.next, struct spi_message, queue);
-        spi = msg->spi;
-
-        dev_dbg(master->dev.parent, "start message %p for %s\n",
-                        msg, dev_name(&spi->dev));
-
-        /* select chip if it's not still active */
-        if (as->stay) {
-                if (as->stay != spi) {
-                        cs_deactivate(as, as->stay);
-                        cs_activate(as, spi);
-                }
-                as->stay = NULL;
-        } else
-                cs_activate(as, spi);
-
-        if (as->use_pdc)
-                atmel_spi_pdc_next_xfer(master, msg);
-        else
-                atmel_spi_dma_next_xfer(master, msg);
-}
-
-/*
  * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
  *  - The buffer is either valid for CPU access, else NULL
  *  - If the buffer is valid, so is its DMA address
@@ -975,41 +850,7 @@ static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 }
 
-static void
-atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
-                struct spi_message *msg, int stay)
-{
-        if (!stay || as->done_status < 0)
-                cs_deactivate(as, msg->spi);
-        else
-                as->stay = msg->spi;
-
-        list_del(&msg->queue);
-        msg->status = as->done_status;
-
-        dev_dbg(master->dev.parent,
-                "xfer complete: %u bytes transferred\n",
-                msg->actual_length);
-
-        atmel_spi_unlock(as);
-        msg->complete(msg->context);
-        atmel_spi_lock(as);
-
-        as->current_transfer = NULL;
-        as->next_transfer = NULL;
-        as->done_status = 0;
-
-        /* continue if needed */
-        if (list_empty(&as->queue) || as->stopping) {
-                if (as->use_pdc)
-                        atmel_spi_disable_pdc_transfer(as);
-        } else {
-                atmel_spi_next_message(master);
-        }
-}
-
 /* Called from IRQ
- * lock is held
  *
  * Must update "current_remaining_bytes" to keep track of data
  * to transfer.
@@ -1017,9 +858,7 @@ atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
 static void
 atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
 {
-        u8              *txp;
         u8              *rxp;
-        u16             *txp16;
         u16             *rxp16;
         unsigned long   xfer_pos = xfer->len - as->current_remaining_bytes;
 
@@ -1041,96 +880,12 @@ atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
         } else {
                 as->current_remaining_bytes--;
         }
-
-        if (as->current_remaining_bytes) {
-                if (xfer->tx_buf) {
-                        if (xfer->bits_per_word > 8) {
-                                txp16 = (u16 *)(((u8 *)xfer->tx_buf)
-                                                        + xfer_pos + 2);
-                                spi_writel(as, TDR, *txp16);
-                        } else {
-                                txp = ((u8 *)xfer->tx_buf) + xfer_pos + 1;
-                                spi_writel(as, TDR, *txp);
-                        }
-                } else {
-                        spi_writel(as, TDR, 0);
-                }
-        }
-}
-
-/* Tasklet
- * Called from DMA callback + pio transfer and overrun IRQ.
- */
-static void atmel_spi_tasklet_func(unsigned long data)
-{
-        struct spi_master       *master = (struct spi_master *)data;
-        struct atmel_spi        *as = spi_master_get_devdata(master);
-        struct spi_message      *msg;
-        struct spi_transfer     *xfer;
-
-        dev_vdbg(master->dev.parent, "atmel_spi_tasklet_func\n");
-
-        atmel_spi_lock(as);
-
-        xfer = as->current_transfer;
-
-        if (xfer == NULL)
-                /* already been there */
-                goto tasklet_out;
-
-        msg = list_entry(as->queue.next, struct spi_message, queue);
-
-        if (as->current_remaining_bytes == 0) {
-                if (as->done_status < 0) {
-                        /* error happened (overrun) */
-                        if (atmel_spi_use_dma(as, xfer))
-                                atmel_spi_stop_dma(as);
-                } else {
-                        /* only update length if no error */
-                        msg->actual_length += xfer->len;
-                }
-
-                if (atmel_spi_use_dma(as, xfer))
-                        if (!msg->is_dma_mapped)
-                                atmel_spi_dma_unmap_xfer(master, xfer);
-
-                if (xfer->delay_usecs)
-                        udelay(xfer->delay_usecs);
-
-                if (atmel_spi_xfer_is_last(msg, xfer) || as->done_status < 0) {
-                        /* report completed (or erroneous) message */
-                        atmel_spi_msg_done(master, as, msg, xfer->cs_change);
-                } else {
-                        if (xfer->cs_change) {
-                                cs_deactivate(as, msg->spi);
-                                udelay(1);
-                                cs_activate(as, msg->spi);
-                        }
-
-                        /*
-                         * Not done yet. Submit the next transfer.
-                         *
-                         * FIXME handle protocol options for xfer
-                         */
-                        atmel_spi_dma_next_xfer(master, msg);
-                }
-        } else {
-                /*
-                 * Keep going, we still have data to send in
-                 * the current transfer.
-                 */
-                atmel_spi_dma_next_xfer(master, msg);
-        }
-
-tasklet_out:
-        atmel_spi_unlock(as);
 }
 
 /* Interrupt
  *
  * No need for locking in this Interrupt handler: done_status is the
- * only information modified. What we need is the update of this field
- * before tasklet runs. This is ensured by using barrier.
+ * only information modified.
  */
 static irqreturn_t
 atmel_spi_pio_interrupt(int irq, void *dev_id)
@@ -1158,8 +913,6 @@ atmel_spi_pio_interrupt(int irq, void *dev_id)
                  *
                  * We will also not process any remaning transfers in
                  * the message.
-                 *
-                 * All actions are done in tasklet with done_status indication
                  */
                 as->done_status = -EIO;
                 smp_wmb();
@@ -1167,7 +920,7 @@ atmel_spi_pio_interrupt(int irq, void *dev_id)
                 /* Clear any overrun happening while cleaning up */
                 spi_readl(as, SR);
 
-                tasklet_schedule(&as->tasklet);
+                complete(&as->xfer_completion);
 
         } else if (pending & SPI_BIT(RDRF)) {
                 atmel_spi_lock(as);
@@ -1176,11 +929,10 @@ atmel_spi_pio_interrupt(int irq, void *dev_id)
                         ret = IRQ_HANDLED;
                         xfer = as->current_transfer;
                         atmel_spi_pump_pio_data(as, xfer);
-                        if (!as->current_remaining_bytes) {
-                                /* no more data to xfer, kick tasklet */
+                        if (!as->current_remaining_bytes)
                                 spi_writel(as, IDR, pending);
-                                tasklet_schedule(&as->tasklet);
-                        }
+
+                        complete(&as->xfer_completion);
                 }
 
                 atmel_spi_unlock(as);
@@ -1198,116 +950,35 @@ atmel_spi_pdc_interrupt(int irq, void *dev_id)
 {
         struct spi_master       *master = dev_id;
         struct atmel_spi        *as = spi_master_get_devdata(master);
-        struct spi_message      *msg;
-        struct spi_transfer     *xfer;
         u32                     status, pending, imr;
         int                     ret = IRQ_NONE;
 
-        atmel_spi_lock(as);
-
-        xfer = as->current_transfer;
-        msg = list_entry(as->queue.next, struct spi_message, queue);
-
         imr = spi_readl(as, IMR);
         status = spi_readl(as, SR);
         pending = status & imr;
 
         if (pending & SPI_BIT(OVRES)) {
-                int timeout;
 
                 ret = IRQ_HANDLED;
 
                 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
                                      | SPI_BIT(OVRES)));
 
-                /*
-                 * When we get an overrun, we disregard the current
-                 * transfer. Data will not be copied back from any
-                 * bounce buffer and msg->actual_len will not be
-                 * updated with the last xfer.
-                 *
-                 * We will also not process any remaning transfers in
-                 * the message.
-                 *
-                 * First, stop the transfer and unmap the DMA buffers.
-                 */
-                spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
-                if (!msg->is_dma_mapped)
-                        atmel_spi_dma_unmap_xfer(master, xfer);
-
-                /* REVISIT: udelay in irq is unfriendly */
-                if (xfer->delay_usecs)
-                        udelay(xfer->delay_usecs);
-
-                dev_warn(master->dev.parent, "overrun (%u/%u remaining)\n",
-                         spi_readl(as, TCR), spi_readl(as, RCR));
-
-                /*
-                 * Clean up DMA registers and make sure the data
-                 * registers are empty.
-                 */
-                spi_writel(as, RNCR, 0);
-                spi_writel(as, TNCR, 0);
-                spi_writel(as, RCR, 0);
-                spi_writel(as, TCR, 0);
-                for (timeout = 1000; timeout; timeout--)
-                        if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
-                                break;
-                if (!timeout)
-                        dev_warn(master->dev.parent,
-                                 "timeout waiting for TXEMPTY");
-                while (spi_readl(as, SR) & SPI_BIT(RDRF))
-                        spi_readl(as, RDR);
-
                 /* Clear any overrun happening while cleaning up */
                 spi_readl(as, SR);
 
                 as->done_status = -EIO;
-                atmel_spi_msg_done(master, as, msg, 0);
+
+                complete(&as->xfer_completion);
+
         } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
                 ret = IRQ_HANDLED;
 
                 spi_writel(as, IDR, pending);
 
-                if (as->current_remaining_bytes == 0) {
-                        msg->actual_length += xfer->len;
-
-                        if (!msg->is_dma_mapped)
-                                atmel_spi_dma_unmap_xfer(master, xfer);
-
-                        /* REVISIT: udelay in irq is unfriendly */
-                        if (xfer->delay_usecs)
-                                udelay(xfer->delay_usecs);
-
-                        if (atmel_spi_xfer_is_last(msg, xfer)) {
-                                /* report completed message */
-                                atmel_spi_msg_done(master, as, msg,
-                                                xfer->cs_change);
-                        } else {
-                                if (xfer->cs_change) {
-                                        cs_deactivate(as, msg->spi);
-                                        udelay(1);
-                                        cs_activate(as, msg->spi);
-                                }
-
-                                /*
-                                 * Not done yet. Submit the next transfer.
-                                 *
-                                 * FIXME handle protocol options for xfer
-                                 */
-                                atmel_spi_pdc_next_xfer(master, msg);
-                        }
-                } else {
-                        /*
-                         * Keep going, we still have data to send in
-                         * the current transfer.
-                         */
-                        atmel_spi_pdc_next_xfer(master, msg);
-                }
+                complete(&as->xfer_completion);
         }
 
-        atmel_spi_unlock(as);
-
         return ret;
 }
 
@@ -1322,9 +993,6 @@ static int atmel_spi_setup(struct spi_device *spi)
 
         as = spi_master_get_devdata(spi->master);
 
-        if (as->stopping)
-                return -ESHUTDOWN;
-
         if (spi->chip_select > spi->master->num_chipselect) {
                 dev_dbg(&spi->dev,
                                 "setup: invalid chipselect %u (%u defined)\n",
@@ -1376,12 +1044,6 @@ static int atmel_spi_setup(struct spi_device *spi)
                 asd->npcs_pin = npcs_pin;
                 spi->controller_state = asd;
                 gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
-        } else {
-                atmel_spi_lock(as);
-                if (as->stay == spi)
-                        as->stay = NULL;
-                cs_deactivate(as, spi);
-                atmel_spi_unlock(as);
         }
 
         asd->csr = csr;
@@ -1396,97 +1058,218 @@ static int atmel_spi_setup(struct spi_device *spi)
         return 0;
 }
 
-static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
+static int atmel_spi_one_transfer(struct spi_master *master,
+                                        struct spi_message *msg,
+                                        struct spi_transfer *xfer)
 {
         struct atmel_spi        *as;
-        struct spi_transfer     *xfer;
-        struct device           *controller = spi->master->dev.parent;
+        struct spi_device       *spi = msg->spi;
         u8                      bits;
+        u32                     len;
         struct atmel_spi_device *asd;
+        int                     timeout;
+        int                     ret;
 
-        as = spi_master_get_devdata(spi->master);
-
-        dev_dbg(controller, "new message %p submitted for %s\n",
-                        msg, dev_name(&spi->dev));
+        as = spi_master_get_devdata(master);
 
-        if (unlikely(list_empty(&msg->transfers)))
+        if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
+                dev_dbg(&spi->dev, "missing rx or tx buf\n");
                 return -EINVAL;
+        }
 
-        if (as->stopping)
-                return -ESHUTDOWN;
+        if (xfer->bits_per_word) {
+                asd = spi->controller_state;
+                bits = (asd->csr >> 4) & 0xf;
+                if (bits != xfer->bits_per_word - 8) {
+                        dev_dbg(&spi->dev,
+                        "you can't yet change bits_per_word in transfers\n");
+                        return -ENOPROTOOPT;
+                }
+        }
 
-        list_for_each_entry(xfer, &msg->transfers, transfer_list) {
-                if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
-                        dev_dbg(&spi->dev, "missing rx or tx buf\n");
+        if (xfer->bits_per_word > 8) {
+                if (xfer->len % 2) {
+                        dev_dbg(&spi->dev,
+                        "buffer len should be 16 bits aligned\n");
                         return -EINVAL;
                 }
+        }
+
+        /*
+         * DMA map early, for performance (empties dcache ASAP) and
+         * better fault reporting.
+         */
+        if ((!msg->is_dma_mapped)
+                && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) {
+                if (atmel_spi_dma_map_xfer(as, xfer) < 0)
+                        return -ENOMEM;
+        }
 
-                if (xfer->bits_per_word) {
-                        asd = spi->controller_state;
-                        bits = (asd->csr >> 4) & 0xf;
-                        if (bits != xfer->bits_per_word - 8) {
-                                dev_dbg(&spi->dev,
-                                        "you can't yet change bits_per_word in transfers\n");
-                                return -ENOPROTOOPT;
+        atmel_spi_set_xfer_speed(as, msg->spi, xfer);
+
+        as->done_status = 0;
+        as->current_transfer = xfer;
+        as->current_remaining_bytes = xfer->len;
+        while (as->current_remaining_bytes) {
+                reinit_completion(&as->xfer_completion);
+
+                if (as->use_pdc) {
+                        atmel_spi_pdc_next_xfer(master, msg, xfer);
+                } else if (atmel_spi_use_dma(as, xfer)) {
+                        len = as->current_remaining_bytes;
+                        ret = atmel_spi_next_xfer_dma_submit(master,
+                                                                xfer, &len);
+                        if (ret) {
+                                dev_err(&spi->dev,
+                                        "unable to use DMA, fallback to PIO\n");
+                                atmel_spi_next_xfer_pio(master, xfer);
+                        } else {
+                                as->current_remaining_bytes -= len;
                         }
+                } else {
+                        atmel_spi_next_xfer_pio(master, xfer);
                 }
 
-                if (xfer->bits_per_word > 8) {
-                        if (xfer->len % 2) {
-                                dev_dbg(&spi->dev, "buffer len should be 16 bits aligned\n");
-                                return -EINVAL;
-                        }
+                ret = wait_for_completion_timeout(&as->xfer_completion,
+                                                        SPI_DMA_TIMEOUT);
+                if (WARN_ON(ret == 0)) {
+                        dev_err(&spi->dev,
+                                "spi trasfer timeout, err %d\n", ret);
+                        as->done_status = -EIO;
+                } else {
+                        ret = 0;
                 }
 
-                /*
-                 * DMA map early, for performance (empties dcache ASAP) and
-                 * better fault reporting.
-                 */
-                if ((!msg->is_dma_mapped) && (atmel_spi_use_dma(as, xfer)
-                        || as->use_pdc)) {
-                        if (atmel_spi_dma_map_xfer(as, xfer) < 0)
-                                return -ENOMEM;
+                if (as->done_status)
+                        break;
+        }
+
+        if (as->done_status) {
+                if (as->use_pdc) {
+                        dev_warn(master->dev.parent,
+                                "overrun (%u/%u remaining)\n",
+                                spi_readl(as, TCR), spi_readl(as, RCR));
+
+                        /*
+                         * Clean up DMA registers and make sure the data
+                         * registers are empty.
+                         */
+                        spi_writel(as, RNCR, 0);
+                        spi_writel(as, TNCR, 0);
+                        spi_writel(as, RCR, 0);
+                        spi_writel(as, TCR, 0);
+                        for (timeout = 1000; timeout; timeout--)
+                                if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
+                                        break;
+                        if (!timeout)
+                                dev_warn(master->dev.parent,
+                                         "timeout waiting for TXEMPTY");
+                        while (spi_readl(as, SR) & SPI_BIT(RDRF))
+                                spi_readl(as, RDR);
+
+                        /* Clear any overrun happening while cleaning up */
+                        spi_readl(as, SR);
+
+                } else if (atmel_spi_use_dma(as, xfer)) {
+                        atmel_spi_stop_dma(as);
+                }
+
+                if (!msg->is_dma_mapped
+                        && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
+                        atmel_spi_dma_unmap_xfer(master, xfer);
+
+                return 0;
+
+        } else {
+                /* only update length if no error */
+                msg->actual_length += xfer->len;
+        }
+
+        if (!msg->is_dma_mapped
+                && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
+                atmel_spi_dma_unmap_xfer(master, xfer);
+
+        if (xfer->delay_usecs)
+                udelay(xfer->delay_usecs);
+
+        if (xfer->cs_change) {
+                if (list_is_last(&xfer->transfer_list,
+                                 &msg->transfers)) {
+                        as->keep_cs = true;
+                } else {
+                        as->cs_active = !as->cs_active;
+                        if (as->cs_active)
+                                cs_activate(as, msg->spi);
+                        else
+                                cs_deactivate(as, msg->spi);
                 }
         }
 
-#ifdef VERBOSE
+        return 0;
+}
+
+static int atmel_spi_transfer_one_message(struct spi_master *master,
+                                                struct spi_message *msg)
+{
+        struct atmel_spi *as;
+        struct spi_transfer *xfer;
+        struct spi_device *spi = msg->spi;
+        int ret = 0;
+
+        as = spi_master_get_devdata(master);
+
+        dev_dbg(&spi->dev, "new message %p submitted for %s\n",
+                                        msg, dev_name(&spi->dev));
+
+        if (unlikely(list_empty(&msg->transfers)))
+                return -EINVAL;
+
+        atmel_spi_lock(as);
+        cs_activate(as, spi);
+
+        as->cs_active = true;
+        as->keep_cs = false;
+
+        msg->status = 0;
+        msg->actual_length = 0;
+
+        list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+                ret = atmel_spi_one_transfer(master, msg, xfer);
+                if (ret)
+                        goto msg_done;
+        }
+
+        if (as->use_pdc)
+                atmel_spi_disable_pdc_transfer(as);
+
         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
-                dev_dbg(controller,
+                dev_dbg(&spi->dev,
                         "  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
                         xfer, xfer->len,
                         xfer->tx_buf, xfer->tx_dma,
                         xfer->rx_buf, xfer->rx_dma);
         }
-#endif
 
-        msg->status = -EINPROGRESS;
-        msg->actual_length = 0;
+msg_done:
+        if (!as->keep_cs)
+                cs_deactivate(as, msg->spi);
 
-        atmel_spi_lock(as);
-        list_add_tail(&msg->queue, &as->queue);
-        if (!as->current_transfer)
-                atmel_spi_next_message(spi->master);
         atmel_spi_unlock(as);
 
-        return 0;
+        msg->status = as->done_status;
+        spi_finalize_current_message(spi->master);
+
+        return ret;
 }
 
 static void atmel_spi_cleanup(struct spi_device *spi)
 {
-        struct atmel_spi        *as = spi_master_get_devdata(spi->master);
         struct atmel_spi_device *asd = spi->controller_state;
         unsigned                gpio = (unsigned) spi->controller_data;
 
         if (!asd)
                 return;
 
-        atmel_spi_lock(as);
-        if (as->stay == spi) {
-                as->stay = NULL;
-                cs_deactivate(as, spi);
-        }
-        atmel_spi_unlock(as);
-
         spi->controller_state = NULL;
         gpio_free(gpio);
         kfree(asd);
@@ -1545,7 +1328,7 @@ static int atmel_spi_probe(struct platform_device *pdev)
         master->bus_num = pdev->id;
         master->num_chipselect = master->dev.of_node ? 0 : 4;
         master->setup = atmel_spi_setup;
-        master->transfer = atmel_spi_transfer;
+        master->transfer_one_message = atmel_spi_transfer_one_message;
         master->cleanup = atmel_spi_cleanup;
         platform_set_drvdata(pdev, master);
 
@@ -1561,7 +1344,6 @@ static int atmel_spi_probe(struct platform_device *pdev)
                 goto out_free;
 
         spin_lock_init(&as->lock);
-        INIT_LIST_HEAD(&as->queue);
 
         as->pdev = pdev;
         as->regs = devm_ioremap_resource(&pdev->dev, regs);
@@ -1573,6 +1355,8 @@ static int atmel_spi_probe(struct platform_device *pdev)
         as->irq = irq;
         as->clk = clk;
 
+        init_completion(&as->xfer_completion);
+
         atmel_get_caps(as);
 
         as->use_dma = false;
@@ -1591,9 +1375,6 @@ static int atmel_spi_probe(struct platform_device *pdev)
                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
                                         0, dev_name(&pdev->dev), master);
         } else {
-                tasklet_init(&as->tasklet, atmel_spi_tasklet_func,
-                                        (unsigned long)master);
-
                 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
                                         0, dev_name(&pdev->dev), master);
         }
@@ -1637,8 +1418,6 @@ out_free_dma:
 out_free_irq:
 out_unmap_regs:
 out_free_buffer:
-        if (!as->use_pdc)
-                tasklet_kill(&as->tasklet);
         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
                         as->buffer_dma);
 out_free:
@@ -1650,12 +1429,9 @@ static int atmel_spi_remove(struct platform_device *pdev)
 {
         struct spi_master       *master = platform_get_drvdata(pdev);
         struct atmel_spi        *as = spi_master_get_devdata(master);
-        struct spi_message      *msg;
-        struct spi_transfer     *xfer;
 
         /* reset the hardware and block queue progress */
         spin_lock_irq(&as->lock);
-        as->stopping = 1;
         if (as->use_dma) {
                 atmel_spi_stop_dma(as);
                 atmel_spi_release_dma(as);
@@ -1666,20 +1442,6 @@ static int atmel_spi_remove(struct platform_device *pdev)
         spi_readl(as, SR);
         spin_unlock_irq(&as->lock);
 
-        /* Terminate remaining queued transfers */
-        list_for_each_entry(msg, &as->queue, queue) {
-                list_for_each_entry(xfer, &msg->transfers, transfer_list) {
-                        if (!msg->is_dma_mapped
-                                && (atmel_spi_use_dma(as, xfer)
-                                        || as->use_pdc))
-                                atmel_spi_dma_unmap_xfer(master, xfer);
-                }
-                msg->status = -ESHUTDOWN;
-                msg->complete(msg->context);
-        }
-
-        if (!as->use_pdc)
-                tasklet_kill(&as->tasklet);
         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
                         as->buffer_dma);