spi/bitbang: Factor out message transfer from message pump loop

In order to make it easier to convert to transfer_one_message() lift the
code that does the actual message transfer out of the work function that
implements the message pump. This should have no functional impact, it's
just a simple code motion patch.

Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 104 insertions, 95 deletions

diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index 495ce0a51d2f..8b8487c9694e 100644
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -255,117 +255,126 @@ static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t)
  * Drivers can provide word-at-a-time i/o primitives, or provide
  * transfer-at-a-time ones to leverage dma or fifo hardware.
  */
-static void bitbang_work(struct work_struct *work)
+static int spi_bitbang_transfer_one(struct spi_device *spi,
+                                    struct spi_message *m)
 {
-        struct spi_bitbang      *bitbang =
-                container_of(work, struct spi_bitbang, work);
-        unsigned long           flags;
-        struct spi_message      *m, *_m;
+        struct spi_bitbang      *bitbang;
+        unsigned                nsecs;
+        struct spi_transfer     *t = NULL;
+        unsigned                tmp;
+        unsigned                cs_change;
+        int                     status;
+        int                     do_setup = -1;
 
-        spin_lock_irqsave(&bitbang->lock, flags);
-        bitbang->busy = 1;
-        list_for_each_entry_safe(m, _m, &bitbang->queue, queue) {
-                struct spi_device       *spi;
-                unsigned                nsecs;
-                struct spi_transfer     *t = NULL;
-                unsigned                tmp;
-                unsigned                cs_change;
-                int                     status;
-                int                     do_setup = -1;
+        bitbang = spi_master_get_devdata(spi->master);
 
-                list_del(&m->queue);
-                spin_unlock_irqrestore(&bitbang->lock, flags);
+        /* FIXME this is made-up ... the correct value is known to
+         * word-at-a-time bitbang code, and presumably chipselect()
+         * should enforce these requirements too?
+         */
+        nsecs = 100;
 
-                /* FIXME this is made-up ... the correct value is known to
-                 * word-at-a-time bitbang code, and presumably chipselect()
-                 * should enforce these requirements too?
-                 */
-                nsecs = 100;
+        tmp = 0;
+        cs_change = 1;
+        status = 0;
 
-                spi = m->spi;
-                tmp = 0;
-                cs_change = 1;
-                status = 0;
+        list_for_each_entry (t, &m->transfers, transfer_list) {
 
-                list_for_each_entry (t, &m->transfers, transfer_list) {
-
-                        /* override speed or wordsize? */
-                        if (t->speed_hz || t->bits_per_word)
-                                do_setup = 1;
-
-                        /* init (-1) or override (1) transfer params */
-                        if (do_setup != 0) {
-                                status = bitbang->setup_transfer(spi, t);
-                                if (status < 0)
-                                        break;
-                                if (do_setup == -1)
-                                        do_setup = 0;
-                        }
-
-                        /* set up default clock polarity, and activate chip;
-                         * this implicitly updates clock and spi modes as
-                         * previously recorded for this device via setup().
-                         * (and also deselects any other chip that might be
-                         * selected ...)
-                         */
-                        if (cs_change) {
-                                bitbang->chipselect(spi, BITBANG_CS_ACTIVE);
-                                ndelay(nsecs);
-                        }
-                        cs_change = t->cs_change;
-                        if (!t->tx_buf && !t->rx_buf && t->len) {
-                                status = -EINVAL;
-                                break;
-                        }
+                /* override speed or wordsize? */
+                if (t->speed_hz || t->bits_per_word)
+                        do_setup = 1;
 
-                        /* transfer data.  the lower level code handles any
-                         * new dma mappings it needs. our caller always gave
-                         * us dma-safe buffers.
-                         */
-                        if (t->len) {
-                                /* REVISIT dma API still needs a designated
-                                 * DMA_ADDR_INVALID; ~0 might be better.
-                                 */
-                                if (!m->is_dma_mapped)
-                                        t->rx_dma = t->tx_dma = 0;
-                                status = bitbang->txrx_bufs(spi, t);
-                        }
-                        if (status > 0)
-                                m->actual_length += status;
-                        if (status != t->len) {
-                                /* always report some kind of error */
-                                if (status >= 0)
-                                        status = -EREMOTEIO;
+                /* init (-1) or override (1) transfer params */
+                if (do_setup != 0) {
+                        status = bitbang->setup_transfer(spi, t);
+                        if (status < 0)
                                 break;
-                        }
-                        status = 0;
-
-                        /* protocol tweaks before next transfer */
-                        if (t->delay_usecs)
-                                udelay(t->delay_usecs);
-
-                        if (cs_change && !list_is_last(&t->transfer_list, &m->transfers)) {
-                                /* sometimes a short mid-message deselect of the chip
-                                 * may be needed to terminate a mode or command
-                                 */
-                                ndelay(nsecs);
-                                bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
-                                ndelay(nsecs);
-                        }
+                        if (do_setup == -1)
+                                do_setup = 0;
                 }
 
-                m->status = status;
-                m->complete(m->context);
+                /* set up default clock polarity, and activate chip;
+                 * this implicitly updates clock and spi modes as
+                 * previously recorded for this device via setup().
+                 * (and also deselects any other chip that might be
+                 * selected ...)
+                 */
+                if (cs_change) {
+                        bitbang->chipselect(spi, BITBANG_CS_ACTIVE);
+                        ndelay(nsecs);
+                }
+                cs_change = t->cs_change;
+                if (!t->tx_buf && !t->rx_buf && t->len) {
+                        status = -EINVAL;
+                        break;
+                }
 
-                /* normally deactivate chipselect ... unless no error and
-                 * cs_change has hinted that the next message will probably
-                 * be for this chip too.
+                /* transfer data.  the lower level code handles any
+                 * new dma mappings it needs. our caller always gave
+                 * us dma-safe buffers.
                  */
-                if (!(status == 0 && cs_change)) {
+                if (t->len) {
+                        /* REVISIT dma API still needs a designated
+                         * DMA_ADDR_INVALID; ~0 might be better.
+                         */
+                        if (!m->is_dma_mapped)
+                                t->rx_dma = t->tx_dma = 0;
+                        status = bitbang->txrx_bufs(spi, t);
+                }
+                if (status > 0)
+                        m->actual_length += status;
+                if (status != t->len) {
+                        /* always report some kind of error */
+                        if (status >= 0)
+                                status = -EREMOTEIO;
+                        break;
+                }
+                status = 0;
+
+                /* protocol tweaks before next transfer */
+                if (t->delay_usecs)
+                        udelay(t->delay_usecs);
+
+                if (cs_change && !list_is_last(&t->transfer_list, &m->transfers)) {
+                        /* sometimes a short mid-message deselect of the chip
+                         * may be needed to terminate a mode or command
+                         */
                         ndelay(nsecs);
                         bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
                         ndelay(nsecs);
                 }
+        }
+
+        m->status = status;
+        m->complete(m->context);
+
+        /* normally deactivate chipselect ... unless no error and
+         * cs_change has hinted that the next message will probably
+         * be for this chip too.
+         */
+        if (!(status == 0 && cs_change)) {
+                ndelay(nsecs);
+                bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
+                ndelay(nsecs);
+        }
+
+        return status;
+}
+
+static void bitbang_work(struct work_struct *work)
+{
+        struct spi_bitbang      *bitbang =
+                container_of(work, struct spi_bitbang, work);
+        unsigned long           flags;
+        struct spi_message      *m, *_m;
+
+        spin_lock_irqsave(&bitbang->lock, flags);
+        bitbang->busy = 1;
+        list_for_each_entry_safe(m, _m, &bitbang->queue, queue) {
+                list_del(&m->queue);
+                spin_unlock_irqrestore(&bitbang->lock, flags);
+
+                spi_bitbang_transfer_one(m->spi, m);
 
                 spin_lock_irqsave(&bitbang->lock, flags);
         }