From: Marek Vasut Date: Fri, 3 Aug 2012 15:26:13 +0000 (+0200) Subject: spi/mxs: Add DMA support into SPI driver X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=474afc042fb9db8f88b68243f78a38cb764692fc;p=linux-beck.git spi/mxs: Add DMA support into SPI driver Signed-off-by: Marek Vasut Acked-by: Chris Ball Acked-by: Shawn Guo Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c index 0f28afb80310..130a43688352 100644 --- a/drivers/spi/spi-mxs.c +++ b/drivers/spi/spi-mxs.c @@ -55,8 +55,12 @@ #define SSP_TIMEOUT 1000 /* 1000 ms */ +#define SG_NUM 4 +#define SG_MAXLEN 0xff00 + struct mxs_spi { struct mxs_ssp ssp; + struct completion c; }; static int mxs_spi_setup_transfer(struct spi_device *dev, @@ -194,6 +198,115 @@ static int mxs_ssp_wait(struct mxs_spi *spi, int offset, int mask, bool set) return 0; } +static void mxs_ssp_dma_irq_callback(void *param) +{ + struct mxs_spi *spi = param; + complete(&spi->c); +} + +static irqreturn_t mxs_ssp_irq_handler(int irq, void *dev_id) +{ + struct mxs_ssp *ssp = dev_id; + dev_err(ssp->dev, "%s[%i] CTRL1=%08x STATUS=%08x\n", + __func__, __LINE__, + readl(ssp->base + HW_SSP_CTRL1(ssp)), + readl(ssp->base + HW_SSP_STATUS(ssp))); + return IRQ_HANDLED; +} + +static int mxs_spi_txrx_dma(struct mxs_spi *spi, int cs, + unsigned char *buf, int len, + int *first, int *last, int write) +{ + struct mxs_ssp *ssp = &spi->ssp; + struct dma_async_tx_descriptor *desc; + struct scatterlist sg[SG_NUM]; + int sg_count; + uint32_t pio = BM_SSP_CTRL0_DATA_XFER | mxs_spi_cs_to_reg(cs); + int ret; + + if (len > SG_NUM * SG_MAXLEN) { + dev_err(ssp->dev, "Data chunk too big for DMA\n"); + return -EINVAL; + } + + init_completion(&spi->c); + + if (*first) + pio |= BM_SSP_CTRL0_LOCK_CS; + if (*last) + pio |= BM_SSP_CTRL0_IGNORE_CRC; + if (!write) + pio |= BM_SSP_CTRL0_READ; + + if (ssp->devid == IMX23_SSP) + pio |= len; + else + writel(len, ssp->base + HW_SSP_XFER_SIZE); + + /* Queue the PIO register write transfer. */ + desc = dmaengine_prep_slave_sg(ssp->dmach, + (struct scatterlist *)&pio, + 1, DMA_TRANS_NONE, 0); + if (!desc) { + dev_err(ssp->dev, + "Failed to get PIO reg. write descriptor.\n"); + return -EINVAL; + } + + /* Queue the DMA data transfer. */ + sg_init_table(sg, (len / SG_MAXLEN) + 1); + sg_count = 0; + while (len) { + sg_set_buf(&sg[sg_count++], buf, min(len, SG_MAXLEN)); + len -= min(len, SG_MAXLEN); + buf += min(len, SG_MAXLEN); + } + dma_map_sg(ssp->dev, sg, sg_count, + write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); + + desc = dmaengine_prep_slave_sg(ssp->dmach, sg, sg_count, + write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + + if (!desc) { + dev_err(ssp->dev, + "Failed to get DMA data write descriptor.\n"); + ret = -EINVAL; + goto err; + } + + /* + * The last descriptor must have this callback, + * to finish the DMA transaction. + */ + desc->callback = mxs_ssp_dma_irq_callback; + desc->callback_param = spi; + + /* Start the transfer. */ + dmaengine_submit(desc); + dma_async_issue_pending(ssp->dmach); + + ret = wait_for_completion_timeout(&spi->c, + msecs_to_jiffies(SSP_TIMEOUT)); + + if (!ret) { + dev_err(ssp->dev, "DMA transfer timeout\n"); + ret = -ETIMEDOUT; + goto err; + } + + ret = 0; + +err: + for (--sg_count; sg_count >= 0; sg_count--) { + dma_unmap_sg(ssp->dev, &sg[sg_count], 1, + write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); + } + + return ret; +} + static int mxs_spi_txrx_pio(struct mxs_spi *spi, int cs, unsigned char *buf, int len, int *first, int *last, int write) @@ -281,19 +394,49 @@ static int mxs_spi_transfer_one(struct spi_master *master, first = 1; if (&t->transfer_list == m->transfers.prev) last = 1; - if (t->rx_buf && t->tx_buf) { + if ((t->rx_buf && t->tx_buf) || (t->rx_dma && t->tx_dma)) { dev_err(ssp->dev, "Cannot send and receive simultaneously\n"); status = -EINVAL; break; } - if (t->tx_buf) - status = mxs_spi_txrx_pio(spi, cs, (void *)t->tx_buf, - t->len, &first, &last, 1); - if (t->rx_buf) - status = mxs_spi_txrx_pio(spi, cs, t->rx_buf, - t->len, &first, &last, 0); + /* + * Small blocks can be transfered via PIO. + * Measured by empiric means: + * + * dd if=/dev/mtdblock0 of=/dev/null bs=1024k count=1 + * + * DMA only: 2.164808 seconds, 473.0KB/s + * Combined: 1.676276 seconds, 610.9KB/s + */ + if (t->len <= 256) { + writel(BM_SSP_CTRL1_DMA_ENABLE, + ssp->base + HW_SSP_CTRL1(ssp) + + STMP_OFFSET_REG_CLR); + + if (t->tx_buf) + status = mxs_spi_txrx_pio(spi, cs, + (void *)t->tx_buf, + t->len, &first, &last, 1); + if (t->rx_buf) + status = mxs_spi_txrx_pio(spi, cs, + t->rx_buf, t->len, + &first, &last, 0); + } else { + writel(BM_SSP_CTRL1_DMA_ENABLE, + ssp->base + HW_SSP_CTRL1(ssp) + + STMP_OFFSET_REG_SET); + + if (t->tx_buf) + status = mxs_spi_txrx_dma(spi, cs, + (void *)t->tx_buf, t->len, + &first, &last, 1); + if (t->rx_buf) + status = mxs_spi_txrx_dma(spi, cs, + t->rx_buf, t->len, + &first, &last, 0); + } m->actual_length += t->len; if (status) @@ -308,6 +451,21 @@ static int mxs_spi_transfer_one(struct spi_master *master, return status; } +static bool mxs_ssp_dma_filter(struct dma_chan *chan, void *param) +{ + struct mxs_ssp *ssp = param; + + if (!mxs_dma_is_apbh(chan)) + return false; + + if (chan->chan_id != ssp->dma_channel) + return false; + + chan->private = &ssp->dma_data; + + return true; +} + static const struct of_device_id mxs_spi_dt_ids[] = { { .compatible = "fsl,imx23-spi", .data = (void *) IMX23_SSP, }, { .compatible = "fsl,imx28-spi", .data = (void *) IMX28_SSP, }, @@ -323,15 +481,18 @@ static int __devinit mxs_spi_probe(struct platform_device *pdev) struct spi_master *master; struct mxs_spi *spi; struct mxs_ssp *ssp; - struct resource *iores; + struct resource *iores, *dmares; struct pinctrl *pinctrl; struct clk *clk; void __iomem *base; - int devid; - int ret = 0; + int devid, dma_channel; + int ret = 0, irq_err, irq_dma; + dma_cap_mask_t mask; iores = platform_get_resource(pdev, IORESOURCE_MEM, 0); - if (!iores) + irq_err = platform_get_irq(pdev, 0); + irq_dma = platform_get_irq(pdev, 1); + if (!iores || irq_err < 0 || irq_dma < 0) return -EINVAL; base = devm_request_and_ioremap(&pdev->dev, iores); @@ -346,10 +507,26 @@ static int __devinit mxs_spi_probe(struct platform_device *pdev) if (IS_ERR(clk)) return PTR_ERR(clk); - if (np) + if (np) { devid = (enum mxs_ssp_id) of_id->data; - else + /* + * TODO: This is a temporary solution and should be changed + * to use generic DMA binding later when the helpers get in. + */ + ret = of_property_read_u32(np, "fsl,ssp-dma-channel", + &dma_channel); + if (ret) { + dev_err(&pdev->dev, + "Failed to get DMA channel\n"); + return -EINVAL; + } + } else { + dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0); + if (!dmares) + return -EINVAL; devid = pdev->id_entry->driver_data; + dma_channel = dmares->start; + } master = spi_alloc_master(&pdev->dev, sizeof(*spi)); if (!master) @@ -368,8 +545,28 @@ static int __devinit mxs_spi_probe(struct platform_device *pdev) ssp->clk = clk; ssp->base = base; ssp->devid = devid; + ssp->dma_channel = dma_channel; + + ret = devm_request_irq(&pdev->dev, irq_err, mxs_ssp_irq_handler, 0, + DRIVER_NAME, ssp); + if (ret) + goto out_master_free; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + ssp->dma_data.chan_irq = irq_dma; + ssp->dmach = dma_request_channel(mask, mxs_ssp_dma_filter, ssp); + if (!ssp->dmach) { + dev_err(ssp->dev, "Failed to request DMA\n"); + goto out_master_free; + } + /* + * Crank up the clock to 120MHz, this will be further divided onto a + * proper speed. + */ clk_prepare_enable(ssp->clk); + clk_set_rate(ssp->clk, 120 * 1000 * 1000); ssp->clk_rate = clk_get_rate(ssp->clk) / 1000; stmp_reset_block(ssp->base); @@ -379,14 +576,16 @@ static int __devinit mxs_spi_probe(struct platform_device *pdev) ret = spi_register_master(master); if (ret) { dev_err(&pdev->dev, "Cannot register SPI master, %d\n", ret); - goto out_master_free; + goto out_free_dma; } return 0; -out_master_free: +out_free_dma: platform_set_drvdata(pdev, NULL); + dma_release_channel(ssp->dmach); clk_disable_unprepare(ssp->clk); +out_master_free: spi_master_put(master); return ret; } @@ -405,6 +604,8 @@ static int __devexit mxs_spi_remove(struct platform_device *pdev) platform_set_drvdata(pdev, NULL); + dma_release_channel(ssp->dmach); + clk_disable_unprepare(ssp->clk); spi_master_put(master);