spi: davinci: let DMA operation be specified on per-device basis

Let DMA operation be specified on a per-device basis instead
of selecting it once during probe.

A side effect of this is the need to combine the PIO and DMA buffer
txrx_bufs routine. This is good since they anyway share some common
functionality.

Signed-off-by: Brian Niebuhr <bniebuhr@efjohnson.com>
Tested-By: Michael Williamson <michael.williamson@criticallink.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

2 files changed, 156 insertions, 187 deletions

diff --git a/arch/arm/mach-davinci/include/mach/spi.h b/arch/arm/mach-davinci/include/mach/spi.h
index f7586a03678c..b3ab7d04943a 100644
--- a/arch/arm/mach-davinci/include/mach/spi.h
+++ b/arch/arm/mach-davinci/include/mach/spi.h
@@ -41,6 +41,7 @@ struct davinci_spi_config {
         u8      parity_enable;
 #define SPI_IO_TYPE_INTR        0
 #define SPI_IO_TYPE_POLL        1
+#define SPI_IO_TYPE_DMA         2
         u8      io_type;
         u8      timer_disable;
         u8      c2tdelay;
diff --git a/drivers/spi/davinci_spi.c b/drivers/spi/davinci_spi.c
index 6094e3a07853..5fe298099a1a 100644
--- a/drivers/spi/davinci_spi.c
+++ b/drivers/spi/davinci_spi.c
@@ -500,6 +500,25 @@ out:
         return errors;
 }
 
+static void davinci_spi_dma_callback(unsigned lch, u16 status, void *data)
+{
+        struct davinci_spi *davinci_spi = data;
+        struct davinci_spi_dma *davinci_spi_dma = &davinci_spi->dma_channels;
+
+        edma_stop(lch);
+
+        if (status == DMA_COMPLETE) {
+                if (lch == davinci_spi_dma->dma_rx_channel)
+                        davinci_spi->rcount = 0;
+                if (lch == davinci_spi_dma->dma_tx_channel)
+                        davinci_spi->wcount = 0;
+        }
+
+        if ((!davinci_spi->wcount && !davinci_spi->rcount) ||
+            (status != DMA_COMPLETE))
+                complete(&davinci_spi->done);
+}
+
 /**
  * davinci_spi_bufs - functions which will handle transfer data
  * @spi: spi device on which data transfer to be done
@@ -509,25 +528,30 @@ out:
  * of SPI controller and then wait until the completion will be marked
  * by the IRQ Handler.
  */
-static int davinci_spi_bufs_pio(struct spi_device *spi, struct spi_transfer *t)
+static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
 {
         struct davinci_spi *davinci_spi;
-        int ret;
+        int data_type, ret;
         u32 tx_data, data1_reg_val;
         u32 errors = 0;
         struct davinci_spi_config *spicfg;
         struct davinci_spi_platform_data *pdata;
+        unsigned uninitialized_var(rx_buf_count);
+        struct device *sdev;
 
         davinci_spi = spi_master_get_devdata(spi->master);
         pdata = davinci_spi->pdata;
         spicfg = (struct davinci_spi_config *)spi->controller_data;
         if (!spicfg)
                 spicfg = &davinci_spi_default_cfg;
+        sdev = davinci_spi->bitbang.master->dev.parent;
+
+        /* convert len to words based on bits_per_word */
+        data_type = davinci_spi->bytes_per_word[spi->chip_select];
 
         davinci_spi->tx = t->tx_buf;
         davinci_spi->rx = t->rx_buf;
-        davinci_spi->wcount = t->len /
-                                davinci_spi->bytes_per_word[spi->chip_select];
+        davinci_spi->wcount = t->len / data_type;
         davinci_spi->rcount = davinci_spi->wcount;
 
         data1_reg_val = ioread32(davinci_spi->base + SPIDAT1);
@@ -535,20 +559,117 @@ static int davinci_spi_bufs_pio(struct spi_device *spi, struct spi_transfer *t)
         /* Enable SPI */
         set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
 
-        if (spicfg->io_type == SPI_IO_TYPE_INTR) {
+        INIT_COMPLETION(davinci_spi->done);
+
+        if (spicfg->io_type == SPI_IO_TYPE_INTR)
                 set_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKINT);
-                INIT_COMPLETION(davinci_spi->done);
-        }
 
-        /* start the transfer */
-        davinci_spi->wcount--;
-        tx_data = davinci_spi->get_tx(davinci_spi);
-        data1_reg_val &= 0xFFFF0000;
-        data1_reg_val |= tx_data & 0xFFFF;
-        iowrite32(data1_reg_val, davinci_spi->base + SPIDAT1);
+        if (spicfg->io_type != SPI_IO_TYPE_DMA) {
+                /* start the transfer */
+                davinci_spi->wcount--;
+                tx_data = davinci_spi->get_tx(davinci_spi);
+                data1_reg_val &= 0xFFFF0000;
+                data1_reg_val |= tx_data & 0xFFFF;
+                iowrite32(data1_reg_val, davinci_spi->base + SPIDAT1);
+        } else {
+                struct davinci_spi_dma *davinci_spi_dma;
+                unsigned long tx_reg, rx_reg;
+                struct edmacc_param param;
+                void *rx_buf;
+
+                davinci_spi_dma = &davinci_spi->dma_channels;
+
+                tx_reg = (unsigned long)davinci_spi->pbase + SPIDAT1;
+                rx_reg = (unsigned long)davinci_spi->pbase + SPIBUF;
+
+                /*
+                 * Transmit DMA setup
+                 *
+                 * If there is transmit data, map the transmit buffer, set it
+                 * as the source of data and set the source B index to data
+                 * size. If there is no transmit data, set the transmit register
+                 * as the source of data, and set the source B index to zero.
+                 *
+                 * The destination is always the transmit register itself. And
+                 * the destination never increments.
+                 */
+
+                if (t->tx_buf) {
+                        t->tx_dma = dma_map_single(&spi->dev, (void *)t->tx_buf,
+                                        davinci_spi->wcount, DMA_TO_DEVICE);
+                        if (dma_mapping_error(&spi->dev, t->tx_dma)) {
+                                dev_dbg(sdev, "Unable to DMA map %d bytes"
+                                                "TX buffer\n",
+                                                davinci_spi->wcount);
+                                return -ENOMEM;
+                        }
+                }
+
+                param.opt = TCINTEN | EDMA_TCC(davinci_spi_dma->dma_tx_channel);
+                param.src = t->tx_buf ? t->tx_dma : tx_reg;
+                param.a_b_cnt = davinci_spi->wcount << 16 | data_type;
+                param.dst = tx_reg;
+                param.src_dst_bidx = t->tx_buf ? data_type : 0;
+                param.link_bcntrld = 0xffff;
+                param.src_dst_cidx = 0;
+                param.ccnt = 1;
+                edma_write_slot(davinci_spi_dma->dma_tx_channel, &param);
+                edma_link(davinci_spi_dma->dma_tx_channel,
+                                davinci_spi_dma->dummy_param_slot);
+
+                /*
+                 * Receive DMA setup
+                 *
+                 * If there is receive buffer, use it to receive data. If there
+                 * is none provided, use a temporary receive buffer. Set the
+                 * destination B index to 0 so effectively only one byte is used
+                 * in the temporary buffer (address does not increment).
+                 *
+                 * The source of receive data is the receive data register. The
+                 * source address never increments.
+                 */
+
+                if (t->rx_buf) {
+                        rx_buf = t->rx_buf;
+                        rx_buf_count = davinci_spi->rcount;
+                } else {
+                        rx_buf = davinci_spi->rx_tmp_buf;
+                        rx_buf_count = sizeof(davinci_spi->rx_tmp_buf);
+                }
+
+                t->rx_dma = dma_map_single(&spi->dev, rx_buf, rx_buf_count,
+                                                        DMA_FROM_DEVICE);
+                if (dma_mapping_error(&spi->dev, t->rx_dma)) {
+                        dev_dbg(sdev, "Couldn't DMA map a %d bytes RX buffer\n",
+                                                                rx_buf_count);
+                        if (t->tx_buf)
+                                dma_unmap_single(NULL, t->tx_dma,
+                                                davinci_spi->wcount,
+                                                DMA_TO_DEVICE);
+                        return -ENOMEM;
+                }
+
+                param.opt = TCINTEN | EDMA_TCC(davinci_spi_dma->dma_rx_channel);
+                param.src = rx_reg;
+                param.a_b_cnt = davinci_spi->rcount << 16 | data_type;
+                param.dst = t->rx_dma;
+                param.src_dst_bidx = (t->rx_buf ? data_type : 0) << 16;
+                param.link_bcntrld = 0xffff;
+                param.src_dst_cidx = 0;
+                param.ccnt = 1;
+                edma_write_slot(davinci_spi_dma->dma_rx_channel, &param);
+
+                if (pdata->cshold_bug)
+                        iowrite16(data1_reg_val >> 16,
+                                        davinci_spi->base + SPIDAT1 + 2);
+
+                edma_start(davinci_spi_dma->dma_rx_channel);
+                edma_start(davinci_spi_dma->dma_tx_channel);
+                set_io_bits(davinci_spi->base + SPIINT, SPIINT_DMA_REQ_EN);
+        }
 
         /* Wait for the transfer to complete */
-        if (spicfg->io_type == SPI_IO_TYPE_INTR) {
+        if (spicfg->io_type != SPI_IO_TYPE_POLL) {
                 wait_for_completion_interruptible(&(davinci_spi->done));
         } else {
                 while (davinci_spi->rcount > 0 || davinci_spi->wcount > 0) {
@@ -560,6 +681,17 @@ static int davinci_spi_bufs_pio(struct spi_device *spi, struct spi_transfer *t)
         }
 
         clear_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKALL);
+        if (spicfg->io_type == SPI_IO_TYPE_DMA) {
+
+                if (t->tx_buf)
+                        dma_unmap_single(NULL, t->tx_dma, davinci_spi->wcount,
+                                                                DMA_TO_DEVICE);
+
+                dma_unmap_single(NULL, t->rx_dma, rx_buf_count,
+                                                        DMA_FROM_DEVICE);
+
+                clear_io_bits(davinci_spi->base + SPIINT, SPIINT_DMA_REQ_EN);
+        }
 
         /*
          * Check for bit error, desync error,parity error,timeout error and
@@ -572,6 +704,11 @@ static int davinci_spi_bufs_pio(struct spi_device *spi, struct spi_transfer *t)
                 return ret;
         }
 
+        if (davinci_spi->rcount != 0 || davinci_spi->wcount != 0) {
+                dev_err(sdev, "SPI data transfer error\n");
+                return -EIO;
+        }
+
         return t->len;
 }
 
@@ -601,174 +738,6 @@ static irqreturn_t davinci_spi_irq(s32 irq, void *context_data)
         return IRQ_HANDLED;
 }
 
-static void davinci_spi_dma_callback(unsigned lch, u16 status, void *data)
-{
-        struct davinci_spi *davinci_spi = data;
-        struct davinci_spi_dma *davinci_spi_dma = &davinci_spi->dma_channels;
-
-        edma_stop(lch);
-
-        if (status == DMA_COMPLETE) {
-                if (lch == davinci_spi_dma->dma_rx_channel)
-                        davinci_spi->rcount = 0;
-                if (lch == davinci_spi_dma->dma_tx_channel)
-                        davinci_spi->wcount = 0;
-        }
-
-        if ((!davinci_spi->wcount && !davinci_spi->rcount) ||
-            (status != DMA_COMPLETE))
-                complete(&davinci_spi->done);
-}
-
-static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t)
-{
-        struct davinci_spi *davinci_spi;
-        int int_status = 0;
-        unsigned rx_buf_count;
-        struct davinci_spi_dma *davinci_spi_dma;
-        int data_type, ret;
-        unsigned long tx_reg, rx_reg;
-        struct davinci_spi_platform_data *pdata;
-        void *rx_buf;
-        struct device *sdev;
-        struct edmacc_param param;
-
-        davinci_spi = spi_master_get_devdata(spi->master);
-        pdata = davinci_spi->pdata;
-        sdev = davinci_spi->bitbang.master->dev.parent;
-
-        davinci_spi_dma = &davinci_spi->dma_channels;
-
-        /* convert len to words based on bits_per_word */
-        data_type = davinci_spi->bytes_per_word[spi->chip_select];
-
-        tx_reg = (unsigned long)davinci_spi->pbase + SPIDAT1;
-        rx_reg = (unsigned long)davinci_spi->pbase + SPIBUF;
-
-        davinci_spi->tx = t->tx_buf;
-        davinci_spi->rx = t->rx_buf;
-        davinci_spi->wcount = t->len / data_type;
-        davinci_spi->rcount = davinci_spi->wcount;
-
-        INIT_COMPLETION(davinci_spi->done);
-
-        /* disable all interrupts for dma transfers */
-        clear_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKALL);
-        /* Enable SPI */
-        set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
-
-        /*
-         * Transmit DMA setup
-         *
-         * If there is transmit data, map the transmit buffer, set it as the
-         * source of data and set the source B index to data size.
-         * If there is no transmit data, set the transmit register as the
-         * source of data, and set the source B index to zero.
-         *
-         * The destination is always the transmit register itself. And the
-         * destination never increments.
-         */
-
-        if (t->tx_buf) {
-                t->tx_dma = dma_map_single(&spi->dev, (void *)t->tx_buf,
-                                        davinci_spi->wcount, DMA_TO_DEVICE);
-                if (dma_mapping_error(&spi->dev, t->tx_dma)) {
-                        dev_dbg(sdev, "Unable to DMA map %d bytes TX buffer\n",
-                                                        davinci_spi->wcount);
-                        return -ENOMEM;
-                }
-        }
-
-        param.opt = TCINTEN | EDMA_TCC(davinci_spi_dma->dma_tx_channel);
-        param.src = t->tx_buf ? t->tx_dma : tx_reg;
-        param.a_b_cnt = davinci_spi->wcount << 16 | data_type;
-        param.dst = tx_reg;
-        param.src_dst_bidx = t->tx_buf ? data_type : 0;
-        param.link_bcntrld = 0xffff;
-        param.src_dst_cidx = 0;
-        param.ccnt = 1;
-        edma_write_slot(davinci_spi_dma->dma_tx_channel, &param);
-        edma_link(davinci_spi_dma->dma_tx_channel,
-                        davinci_spi_dma->dummy_param_slot);
-
-        /*
-         * Receive DMA setup
-         *
-         * If there is receive buffer, use it to receive data. If there
-         * is none provided, use a temporary receive buffer. Set the
-         * destination B index to 0 so effectively only one byte is used
-         * in the temporary buffer (address does not increment).
-         *
-         * The source of receive data is the receive data register. The
-         * source address never increments.
-         */
-
-        if (t->rx_buf) {
-                rx_buf = t->rx_buf;
-                rx_buf_count = davinci_spi->rcount;
-        } else {
-                rx_buf = davinci_spi->rx_tmp_buf;
-                rx_buf_count = sizeof(davinci_spi->rx_tmp_buf);
-        }
-
-        t->rx_dma = dma_map_single(&spi->dev, rx_buf, rx_buf_count,
-                                                        DMA_FROM_DEVICE);
-        if (dma_mapping_error(&spi->dev, t->rx_dma)) {
-                dev_dbg(sdev, "Couldn't DMA map a %d bytes RX buffer\n",
-                                                                rx_buf_count);
-                if (t->tx_buf)
-                        dma_unmap_single(NULL, t->tx_dma, davinci_spi->wcount,
-                                                                DMA_TO_DEVICE);
-                return -ENOMEM;
-        }
-
-        param.opt = TCINTEN | EDMA_TCC(davinci_spi_dma->dma_rx_channel);
-        param.src = rx_reg;
-        param.a_b_cnt = davinci_spi->rcount << 16 | data_type;
-        param.dst = t->rx_dma;
-        param.src_dst_bidx = (t->rx_buf ? data_type : 0) << 16;
-        param.link_bcntrld = 0xffff;
-        param.src_dst_cidx = 0;
-        param.ccnt = 1;
-        edma_write_slot(davinci_spi_dma->dma_rx_channel, &param);
-
-        if (pdata->cshold_bug) {
-                u16 spidat1 = ioread16(davinci_spi->base + SPIDAT1 + 2);
-                iowrite16(spidat1, davinci_spi->base + SPIDAT1 + 2);
-        }
-
-        edma_start(davinci_spi_dma->dma_rx_channel);
-        edma_start(davinci_spi_dma->dma_tx_channel);
-        set_io_bits(davinci_spi->base + SPIINT, SPIINT_DMA_REQ_EN);
-
-        wait_for_completion_interruptible(&davinci_spi->done);
-
-        if (t->tx_buf)
-                dma_unmap_single(NULL, t->tx_dma, davinci_spi->wcount,
-                                                                DMA_TO_DEVICE);
-
-        dma_unmap_single(NULL, t->rx_dma, rx_buf_count, DMA_FROM_DEVICE);
-
-        clear_io_bits(davinci_spi->base + SPIINT, SPIINT_DMA_REQ_EN);
-
-        /*
-         * Check for bit error, desync error,parity error,timeout error and
-         * receive overflow errors
-         */
-        int_status = ioread32(davinci_spi->base + SPIFLG);
-
-        ret = davinci_spi_check_error(davinci_spi, int_status);
-        if (ret != 0)
-                return ret;
-
-        if (davinci_spi->rcount != 0 || davinci_spi->wcount != 0) {
-                dev_err(sdev, "SPI data transfer error\n");
-                return -EIO;
-        }
-
-        return t->len;
-}
-
 static int davinci_spi_request_dma(struct davinci_spi *davinci_spi)
 {
         int r;
@@ -918,7 +887,7 @@ static int davinci_spi_probe(struct platform_device *pdev)
         if (r)
                 dma_eventq = r->start;
 
-        davinci_spi->bitbang.txrx_bufs = davinci_spi_bufs_pio;
+        davinci_spi->bitbang.txrx_bufs = davinci_spi_bufs;
         if (dma_rx_chan != SPI_NO_RESOURCE &&
             dma_tx_chan != SPI_NO_RESOURCE &&
             dma_eventq != SPI_NO_RESOURCE) {
@@ -930,10 +899,9 @@ static int davinci_spi_probe(struct platform_device *pdev)
                 if (ret)
                         goto free_clk;
 
-                davinci_spi->bitbang.txrx_bufs = davinci_spi_bufs_dma;
-                dev_info(&pdev->dev, "DaVinci SPI driver in EDMA mode\n"
-                                "Using RX channel = %d , TX channel = %d and "
-                                "event queue = %d", dma_rx_chan, dma_tx_chan,
+                dev_info(&pdev->dev, "DMA: supported\n");
+                dev_info(&pdev->dev, "DMA: RX channel: %d, TX channel: %d, "
+                                "event queue: %d\n", dma_rx_chan, dma_tx_chan,
                                 dma_eventq);
         }