spi: imx: add support for all SPI word width for DMA

DMA transfer for SPI was limited to up to 8 bits word size until now.
Sync in SPI burst size and DMA bus width is necessary to correctly
support 16 and 32 BPW.

Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 567a2426e314cbf37946f4992b165aa881cc5b3e..15b23f0b83e8c5cc326175db4a2a4695782af54c 100644 (file)
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -89,11 +89,15 @@ struct spi_imx_data {
 
        struct completion xfer_done;
        void __iomem *base;
+       unsigned long base_phys;
+
        struct clk *clk_per;
        struct clk *clk_ipg;
        unsigned long spi_clk;
        unsigned int spi_bus_clk;
 
+       unsigned int bytes_per_word;
+
        unsigned int count;
        void (*tx)(struct spi_imx_data *);
        void (*rx)(struct spi_imx_data *);
@@ -199,15 +203,35 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin,
        return 7;
 }
 
+static int spi_imx_bytes_per_word(const int bpw)
+{
+       return DIV_ROUND_UP(bpw, BITS_PER_BYTE);
+}
+
 static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
                         struct spi_transfer *transfer)
 {
        struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
+       unsigned int bpw = transfer->bits_per_word;
+
+       if (!master->dma_rx)
+               return false;
+
+       if (!bpw)
+               bpw = spi->bits_per_word;
+
+       bpw = spi_imx_bytes_per_word(bpw);
+
+       if (bpw != 1 && bpw != 2 && bpw != 4)
+               return false;
+
+       if (transfer->len < spi_imx->wml * bpw)
+               return false;
+
+       if (transfer->len % (spi_imx->wml * bpw))
+               return false;
 
-       if (master->dma_rx && transfer->len >= spi_imx->wml &&
-           (transfer->len % spi_imx->wml) == 0)
-               return true;
-       return false;
+       return true;
 }
 
 #define MX51_ECSPI_CTRL                0x08
@@ -775,11 +799,63 @@ static irqreturn_t spi_imx_isr(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
+static int spi_imx_dma_configure(struct spi_master *master,
+                                int bytes_per_word)
+{
+       int ret;
+       enum dma_slave_buswidth buswidth;
+       struct dma_slave_config rx = {}, tx = {};
+       struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
+
+       if (bytes_per_word == spi_imx->bytes_per_word)
+               /* Same as last time */
+               return 0;
+
+       switch (bytes_per_word) {
+       case 4:
+               buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
+               break;
+       case 2:
+               buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
+               break;
+       case 1:
+               buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       tx.direction = DMA_MEM_TO_DEV;
+       tx.dst_addr = spi_imx->base_phys + MXC_CSPITXDATA;
+       tx.dst_addr_width = buswidth;
+       tx.dst_maxburst = spi_imx->wml;
+       ret = dmaengine_slave_config(master->dma_tx, &tx);
+       if (ret) {
+               dev_err(spi_imx->dev, "TX dma configuration failed with %d\n", ret);
+               return ret;
+       }
+
+       rx.direction = DMA_DEV_TO_MEM;
+       rx.src_addr = spi_imx->base_phys + MXC_CSPIRXDATA;
+       rx.src_addr_width = buswidth;
+       rx.src_maxburst = spi_imx->wml;
+       ret = dmaengine_slave_config(master->dma_rx, &rx);
+       if (ret) {
+               dev_err(spi_imx->dev, "RX dma configuration failed with %d\n", ret);
+               return ret;
+       }
+
+       spi_imx->bytes_per_word = bytes_per_word;
+
+       return 0;
+}
+
 static int spi_imx_setupxfer(struct spi_device *spi,
                                 struct spi_transfer *t)
 {
        struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
        struct spi_imx_config config;
+       int ret;
 
        config.bpw = t ? t->bits_per_word : spi->bits_per_word;
        config.speed_hz  = t ? t->speed_hz : spi->max_speed_hz;
@@ -808,6 +884,13 @@ static int spi_imx_setupxfer(struct spi_device *spi,
        else
                spi_imx->usedma = 0;
 
+       if (spi_imx->usedma) {
+               ret = spi_imx_dma_configure(spi->master,
+                                           spi_imx_bytes_per_word(config.bpw));
+               if (ret)
+                       return ret;
+       }
+
        spi_imx->devtype_data->config(spi_imx, &config);
 
        return 0;
@@ -829,10 +912,8 @@ static void spi_imx_sdma_exit(struct spi_imx_data *spi_imx)
 }
 
 static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
-                            struct spi_master *master,
-                            const struct resource *res)
+                            struct spi_master *master)
 {
-       struct dma_slave_config slave_config = {};
        int ret;
 
        /* use pio mode for i.mx6dl chip TKT238285 */
@@ -850,16 +931,6 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
                goto err;
        }
 
-       slave_config.direction = DMA_MEM_TO_DEV;
-       slave_config.dst_addr = res->start + MXC_CSPITXDATA;
-       slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
-       slave_config.dst_maxburst = spi_imx->wml;
-       ret = dmaengine_slave_config(master->dma_tx, &slave_config);
-       if (ret) {
-               dev_err(dev, "error in TX dma configuration.\n");
-               goto err;
-       }
-
        /* Prepare for RX : */
        master->dma_rx = dma_request_slave_channel_reason(dev, "rx");
        if (IS_ERR(master->dma_rx)) {
@@ -869,15 +940,7 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
                goto err;
        }
 
-       slave_config.direction = DMA_DEV_TO_MEM;
-       slave_config.src_addr = res->start + MXC_CSPIRXDATA;
-       slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
-       slave_config.src_maxburst = spi_imx->wml;
-       ret = dmaengine_slave_config(master->dma_rx, &slave_config);
-       if (ret) {
-               dev_err(dev, "error in RX dma configuration.\n");
-               goto err;
-       }
+       spi_imx_dma_configure(master, 1);
 
        init_completion(&spi_imx->dma_rx_completion);
        init_completion(&spi_imx->dma_tx_completion);
@@ -1164,6 +1227,7 @@ static int spi_imx_probe(struct platform_device *pdev)
                ret = PTR_ERR(spi_imx->base);
                goto out_master_put;
        }
+       spi_imx->base_phys = res->start;
 
        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
@@ -1204,7 +1268,7 @@ static int spi_imx_probe(struct platform_device *pdev)
         * other chips.
         */
        if (is_imx51_ecspi(spi_imx)) {
-               ret = spi_imx_sdma_init(&pdev->dev, spi_imx, master, res);
+               ret = spi_imx_sdma_init(&pdev->dev, spi_imx, master);
                if (ret == -EPROBE_DEFER)
                        goto out_clk_put;