spi: rspi: Extract rspi_request_dma_chan()

Setup of the receive and transmit DMA channels is very similar, so let's
consolidate.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 55 insertions, 34 deletions

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 94a99ec7d989..0a7a2d618f0f 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -942,52 +942,73 @@ static irqreturn_t rspi_irq_tx(int irq, void *_sr)
         return 0;
 }
 
-static int rspi_request_dma(struct rspi_data *rspi,
-                                      struct platform_device *pdev)
+static struct dma_chan *rspi_request_dma_chan(struct device *dev,
+                                              enum dma_transfer_direction dir,
+                                              unsigned int id,
+                                              dma_addr_t port_addr)
 {
-        const struct rspi_plat_data *rspi_pd = dev_get_platdata(&pdev->dev);
-        struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         dma_cap_mask_t mask;
+        struct dma_chan *chan;
         struct dma_slave_config cfg;
         int ret;
 
+        dma_cap_zero(mask);
+        dma_cap_set(DMA_SLAVE, mask);
+
+        chan = dma_request_channel(mask, shdma_chan_filter,
+                                   (void *)(unsigned long)id);
+        if (!chan) {
+                dev_warn(dev, "dma_request_channel failed\n");
+                return NULL;
+        }
+
+        memset(&cfg, 0, sizeof(cfg));
+        cfg.slave_id = id;
+        cfg.direction = dir;
+        if (dir == DMA_MEM_TO_DEV)
+                cfg.dst_addr = port_addr;
+        else
+                cfg.src_addr = port_addr;
+
+        ret = dmaengine_slave_config(chan, &cfg);
+        if (ret) {
+                dev_warn(dev, "dmaengine_slave_config failed %d\n", ret);
+                dma_release_channel(chan);
+                return NULL;
+        }
+
+        return chan;
+}
+
+static int rspi_request_dma(struct rspi_data *rspi,
+                            struct platform_device *pdev)
+{
+        const struct rspi_plat_data *rspi_pd = dev_get_platdata(&pdev->dev);
+        struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
         if (!res || !rspi_pd)
                 return 0;       /* The driver assumes no error. */
 
         /* If the module receives data by DMAC, it also needs TX DMAC */
         if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) {
-                dma_cap_zero(mask);
-                dma_cap_set(DMA_SLAVE, mask);
-                rspi->chan_rx = dma_request_channel(mask, shdma_chan_filter,
-                                                    (void *)rspi_pd->dma_rx_id);
-                if (rspi->chan_rx) {
-                        cfg.slave_id = rspi_pd->dma_rx_id;
-                        cfg.direction = DMA_DEV_TO_MEM;
-                        cfg.dst_addr = 0;
-                        cfg.src_addr = res->start + RSPI_SPDR;
-                        ret = dmaengine_slave_config(rspi->chan_rx, &cfg);
-                        if (!ret)
-                                dev_info(&pdev->dev, "Use DMA when rx.\n");
-                        else
-                                return ret;
-                }
+                rspi->chan_rx = rspi_request_dma_chan(&pdev->dev,
+                                                      DMA_DEV_TO_MEM,
+                                                      rspi_pd->dma_rx_id,
+                                                      res->start + RSPI_SPDR);
+                if (!rspi->chan_rx)
+                        return -ENODEV;
+
+                dev_info(&pdev->dev, "Use DMA when rx.\n");
         }
         if (rspi_pd->dma_tx_id) {
-                dma_cap_zero(mask);
-                dma_cap_set(DMA_SLAVE, mask);
-                rspi->chan_tx = dma_request_channel(mask, shdma_chan_filter,
-                                                    (void *)rspi_pd->dma_tx_id);
-                if (rspi->chan_tx) {
-                        cfg.slave_id = rspi_pd->dma_tx_id;
-                        cfg.direction = DMA_MEM_TO_DEV;
-                        cfg.dst_addr = res->start + RSPI_SPDR;
-                        cfg.src_addr = 0;
-                        ret = dmaengine_slave_config(rspi->chan_tx, &cfg);
-                        if (!ret)
-                                dev_info(&pdev->dev, "Use DMA when tx\n");
-                        else
-                                return ret;
-                }
+                rspi->chan_tx = rspi_request_dma_chan(&pdev->dev,
+                                                      DMA_MEM_TO_DEV,
+                                                      rspi_pd->dma_tx_id,
+                                                      res->start + RSPI_SPDR);
+                if (!rspi->chan_tx)
+                        return -ENODEV;
+
+                dev_info(&pdev->dev, "Use DMA when tx\n");
         }
 
         return 0;