spi: atmel: Refactor spi-atmel to use SPI framework queue
authorWenyou Yang <wenyou.yang@atmel.com>
Thu, 9 Jan 2014 05:19:15 +0000 (13:19 +0800)
committerMark Brown <broonie@linaro.org>
Thu, 9 Jan 2014 17:41:23 +0000 (17:41 +0000)
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>
drivers/spi/spi-atmel.c

index b96f9a89cdc6a0872958926d7b5a7a3e47eceb9c..b0842f75101647616ada3a3db4f545a57b519be0 100644 (file)
  */
 #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
@@ -843,83 +791,10 @@ 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
@@ -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);