On Thu, Sep 11, 2014 at 09:18:44AM +0800, Robin Gong wrote: > Enable DMA support on i.mx6. The read speed can increase from 600KB/s > to 1.2MB/s on i.mx6q. You can disable or enable dma function in dts. > If not set "dma-names" in dts, spi will use PIO mode. This patch only > validate on i.mx6, not i.mx5, but encourage ones to apply this patch > on i.mx5 since they share the same IP.
Adding Maerk (who I had to add to earlier versions of this patch). > > Note: > Sometime, there is a weid data in rxfifo after one full tx/rx > transfer finish by DMA on i.mx6dl, so we disable dma functhion on > i.mx6dl. > > Signed-off-by: Frank Li <frank...@freescale.com> > Signed-off-by: Robin Gong <b38...@freescale.com> > > --- > Change from v5: > 1. Update binding doc fsl-imx-cspi.txt. > 2. remove usedma flag set from can_dma interface. > > Change from v4: > 1. Enrich comments. > 2. Remove the rxfifo workaround. The issue only exist on i.mx6dl, so disable > dma function in dts. > > Change from v3: > 1. Use spi core framwork to handle dump tx/rx buf > 2. Add one workaround for weird data in rxfifo when one full transfer done. > > Change from v2: > http://thread.gmane.org/gmane.linux.ports.arm.kernel/291722/focus=294363 > 1. Dma setup only for imx51-ecspi > 2. Use one small dummy buffer(1 bd size) to templiy store data > for meanless rx/tx, instead of malloc the actual transfer size. > 3. Split spi_mx_sdma_transfer to smaller and easily to read. > 4. Fix some code indent. > --- > .../devicetree/bindings/spi/fsl-imx-cspi.txt | 5 + > drivers/spi/spi-imx.c | 286 > ++++++++++++++++++++- > 2 files changed, 285 insertions(+), 6 deletions(-) > > diff --git a/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt > b/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt > index 4256a6d..aad527b 100644 > --- a/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt > +++ b/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt > @@ -7,6 +7,9 @@ Required properties: > - interrupts : Should contain CSPI/eCSPI interrupt > - fsl,spi-num-chipselects : Contains the number of the chipselect > - cs-gpios : Specifies the gpio pins to be used for chipselects. > +- dmas: DMA specifiers for tx and rx dma. See the DMA client binding, > + Documentation/devicetree/bindings/dma/dma.txt > +- dma-names: DMA request names should include "tx" and "rx" if present. > > Example: > > @@ -19,4 +22,6 @@ ecspi@70010000 { > fsl,spi-num-chipselects = <2>; > cs-gpios = <&gpio3 24 0>, /* GPIO3_24 */ > <&gpio3 25 0>; /* GPIO3_25 */ > + dmas = <&sdma 3 7 1>, <&sdma 4 7 2>; > + dma-names = "rx", "tx"; > }; > diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c > index 5daff20..3637847 100644 > --- a/drivers/spi/spi-imx.c > +++ b/drivers/spi/spi-imx.c > @@ -21,6 +21,8 @@ > #include <linux/clk.h> > #include <linux/completion.h> > #include <linux/delay.h> > +#include <linux/dmaengine.h> > +#include <linux/dma-mapping.h> > #include <linux/err.h> > #include <linux/gpio.h> > #include <linux/interrupt.h> > @@ -37,6 +39,7 @@ > #include <linux/of_device.h> > #include <linux/of_gpio.h> > > +#include <linux/platform_data/dma-imx.h> > #include <linux/platform_data/spi-imx.h> > > #define DRIVER_NAME "spi_imx" > @@ -51,6 +54,9 @@ > #define MXC_INT_RR (1 << 0) /* Receive data ready interrupt */ > #define MXC_INT_TE (1 << 1) /* Transmit FIFO empty interrupt */ > > +/* The maximum bytes that a sdma BD can transfer.*/ > +#define MAX_SDMA_BD_BYTES (1 << 15) > +#define IMX_DMA_TIMEOUT (msecs_to_jiffies(3000)) > struct spi_imx_config { > unsigned int speed_hz; > unsigned int bpw; > @@ -95,6 +101,16 @@ struct spi_imx_data { > const void *tx_buf; > unsigned int txfifo; /* number of words pushed in tx FIFO */ > > + /* DMA */ > + unsigned int dma_is_inited; > + unsigned int dma_finished; > + bool usedma; > + u32 rx_wml; > + u32 tx_wml; > + u32 rxt_wml; > + struct completion dma_rx_completion; > + struct completion dma_tx_completion; > + > const struct spi_imx_devtype_data *devtype_data; > int chipselect[0]; > }; > @@ -181,9 +197,21 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin, > return 7; > } > > +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); > + > + if (spi_imx->dma_is_inited && (transfer->len > spi_imx->rx_wml) > + && (transfer->len > spi_imx->tx_wml)) > + return true; > + return false; > +} > + > #define MX51_ECSPI_CTRL 0x08 > #define MX51_ECSPI_CTRL_ENABLE (1 << 0) > #define MX51_ECSPI_CTRL_XCH (1 << 2) > +#define MX51_ECSPI_CTRL_SMC (1 << 3) > #define MX51_ECSPI_CTRL_MODE_MASK (0xf << 4) > #define MX51_ECSPI_CTRL_POSTDIV_OFFSET 8 > #define MX51_ECSPI_CTRL_PREDIV_OFFSET 12 > @@ -201,6 +229,18 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin, > #define MX51_ECSPI_INT_TEEN (1 << 0) > #define MX51_ECSPI_INT_RREN (1 << 3) > > +#define MX51_ECSPI_DMA 0x14 > +#define MX51_ECSPI_DMA_TX_WML_OFFSET 0 > +#define MX51_ECSPI_DMA_TX_WML_MASK 0x3F > +#define MX51_ECSPI_DMA_RX_WML_OFFSET 16 > +#define MX51_ECSPI_DMA_RX_WML_MASK (0x3F << 16) > +#define MX51_ECSPI_DMA_RXT_WML_OFFSET 24 > +#define MX51_ECSPI_DMA_RXT_WML_MASK (0x3F << 24) > + > +#define MX51_ECSPI_DMA_TEDEN_OFFSET 7 > +#define MX51_ECSPI_DMA_RXDEN_OFFSET 23 > +#define MX51_ECSPI_DMA_RXTDEN_OFFSET 31 > + > #define MX51_ECSPI_STAT 0x18 > #define MX51_ECSPI_STAT_RR (1 << 3) > > @@ -257,17 +297,22 @@ static void __maybe_unused mx51_ecspi_intctrl(struct > spi_imx_data *spi_imx, int > > static void __maybe_unused mx51_ecspi_trigger(struct spi_imx_data *spi_imx) > { > - u32 reg; > - > - reg = readl(spi_imx->base + MX51_ECSPI_CTRL); > - reg |= MX51_ECSPI_CTRL_XCH; > + u32 reg = readl(spi_imx->base + MX51_ECSPI_CTRL); > + > + if (!spi_imx->usedma) > + reg |= MX51_ECSPI_CTRL_XCH; > + else if (!spi_imx->dma_finished) > + reg |= MX51_ECSPI_CTRL_SMC; > + else > + reg &= ~MX51_ECSPI_CTRL_SMC; > writel(reg, spi_imx->base + MX51_ECSPI_CTRL); > } > > static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx, > struct spi_imx_config *config) > { > - u32 ctrl = MX51_ECSPI_CTRL_ENABLE, cfg = 0; > + u32 ctrl = MX51_ECSPI_CTRL_ENABLE, cfg = 0, dma = 0; > + u32 tx_wml_cfg, rx_wml_cfg, rxt_wml_cfg; > u32 clk = config->speed_hz, delay; > > /* > @@ -319,6 +364,30 @@ static int __maybe_unused mx51_ecspi_config(struct > spi_imx_data *spi_imx, > else /* SCLK is _very_ slow */ > usleep_range(delay, delay + 10); > > + /* > + * Configure the DMA register: setup the watermark > + * and enable DMA request. > + */ > + if (spi_imx->dma_is_inited) { > + dma = readl(spi_imx->base + MX51_ECSPI_DMA); > + > + spi_imx->tx_wml = spi_imx_get_fifosize(spi_imx) / 2; > + spi_imx->rx_wml = spi_imx_get_fifosize(spi_imx) / 2; > + spi_imx->rxt_wml = spi_imx_get_fifosize(spi_imx) / 2; > + rx_wml_cfg = spi_imx->rx_wml << MX51_ECSPI_DMA_RX_WML_OFFSET; > + tx_wml_cfg = spi_imx->tx_wml << MX51_ECSPI_DMA_TX_WML_OFFSET; > + rxt_wml_cfg = spi_imx->rxt_wml << MX51_ECSPI_DMA_RXT_WML_OFFSET; > + dma = (dma & ~MX51_ECSPI_DMA_TX_WML_MASK > + & ~MX51_ECSPI_DMA_RX_WML_MASK > + & ~MX51_ECSPI_DMA_RXT_WML_MASK) > + | rx_wml_cfg | tx_wml_cfg | rxt_wml_cfg > + |(1 << MX51_ECSPI_DMA_TEDEN_OFFSET) > + |(1 << MX51_ECSPI_DMA_RXDEN_OFFSET) > + |(1 << MX51_ECSPI_DMA_RXTDEN_OFFSET); > + > + writel(dma, spi_imx->base + MX51_ECSPI_DMA); > + } > + > return 0; > } > > @@ -730,7 +799,186 @@ static int spi_imx_setupxfer(struct spi_device *spi, > return 0; > } > > -static int spi_imx_transfer(struct spi_device *spi, > +static void spi_imx_sdma_exit(struct spi_imx_data *spi_imx) > +{ > + struct spi_master *master = spi_imx->bitbang.master; > + > + if (master->dma_rx) { > + dma_release_channel(master->dma_rx); > + master->dma_rx = NULL; > + } > + > + if (master->dma_tx) { > + dma_release_channel(master->dma_tx); > + master->dma_tx = NULL; > + } > + > + spi_imx->dma_is_inited = 0; > +} > + > +static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data > *spi_imx, > + struct spi_master *master, > + const struct resource *res) > +{ > + struct dma_slave_config slave_config = {}; > + int ret; > + > + /* Prepare for TX DMA: */ > + master->dma_tx = dma_request_slave_channel(dev, "tx"); > + if (!master->dma_tx) { > + dev_err(dev, "cannot get the TX DMA channel!\n"); > + ret = -EINVAL; > + 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_get_fifosize(spi_imx) / 2; > + 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(dev, "rx"); > + if (!master->dma_rx) { > + dev_dbg(dev, "cannot get the DMA channel.\n"); > + ret = -EINVAL; > + 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_get_fifosize(spi_imx) / 2; > + ret = dmaengine_slave_config(master->dma_rx, &slave_config); > + if (ret) { > + dev_err(dev, "error in RX dma configuration.\n"); > + goto err; > + } > + > + init_completion(&spi_imx->dma_rx_completion); > + init_completion(&spi_imx->dma_tx_completion); > + master->can_dma = spi_imx_can_dma; > + master->max_dma_len = MAX_SDMA_BD_BYTES; > + spi_imx->bitbang.master->flags = SPI_MASTER_MUST_RX | > + SPI_MASTER_MUST_TX; > + spi_imx->dma_is_inited = 1; > + > + return 0; > +err: > + spi_imx_sdma_exit(spi_imx); > + return ret; > +} > + > +static void spi_imx_dma_rx_callback(void *cookie) > +{ > + struct spi_imx_data *spi_imx = (struct spi_imx_data *)cookie; > + > + complete(&spi_imx->dma_rx_completion); > +} > + > +static void spi_imx_dma_tx_callback(void *cookie) > +{ > + struct spi_imx_data *spi_imx = (struct spi_imx_data *)cookie; > + > + complete(&spi_imx->dma_tx_completion); > +} > + > +static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx, > + struct spi_transfer *transfer) > +{ > + struct dma_async_tx_descriptor *desc_tx = NULL, *desc_rx = NULL; > + int ret; > + u32 dma; > + int left; > + struct spi_master *master = spi_imx->bitbang.master; > + struct sg_table *tx = &transfer->tx_sg, *rx = &transfer->rx_sg; > + > + if (tx) { > + desc_tx = dmaengine_prep_slave_sg(master->dma_tx, > + tx->sgl, tx->nents, DMA_TO_DEVICE, > + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); > + if (!desc_tx) > + goto no_dma; > + > + desc_tx->callback = spi_imx_dma_tx_callback; > + desc_tx->callback_param = (void *)spi_imx; > + dmaengine_submit(desc_tx); > + } > + > + if (rx) { > + desc_rx = dmaengine_prep_slave_sg(master->dma_rx, > + rx->sgl, rx->nents, DMA_FROM_DEVICE, > + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); > + if (!desc_rx) > + goto no_dma; > + > + desc_rx->callback = spi_imx_dma_rx_callback; > + desc_rx->callback_param = (void *)spi_imx; > + dmaengine_submit(desc_rx); > + } > + > + reinit_completion(&spi_imx->dma_rx_completion); > + reinit_completion(&spi_imx->dma_tx_completion); > + > + /* Trigger the cspi module. */ > + spi_imx->dma_finished = 0; > + > + dma = readl(spi_imx->base + MX51_ECSPI_DMA); > + dma = dma & (~MX51_ECSPI_DMA_RXT_WML_MASK); > + /* Change RX_DMA_LENGTH trigger dma fetch tail data */ > + left = transfer->len % spi_imx->rxt_wml; > + if (left) > + writel(dma | (left << MX51_ECSPI_DMA_RXT_WML_OFFSET), > + spi_imx->base + MX51_ECSPI_DMA); > + spi_imx->devtype_data->trigger(spi_imx); > + > + dma_async_issue_pending(master->dma_tx); > + dma_async_issue_pending(master->dma_rx); > + /* Wait SDMA to finish the data transfer.*/ > + ret = wait_for_completion_timeout(&spi_imx->dma_tx_completion, > + IMX_DMA_TIMEOUT); > + if (!ret) { > + pr_warn("%s %s: I/O Error in DMA TX\n", > + dev_driver_string(&master->dev), > + dev_name(&master->dev)); > + dmaengine_terminate_all(master->dma_tx); > + } else { > + ret = wait_for_completion_timeout(&spi_imx->dma_rx_completion, > + IMX_DMA_TIMEOUT); > + if (!ret) { > + pr_warn("%s %s: I/O Error in DMA RX\n", > + dev_driver_string(&master->dev), > + dev_name(&master->dev)); > + spi_imx->devtype_data->reset(spi_imx); > + dmaengine_terminate_all(master->dma_rx); > + } > + writel(dma | > + spi_imx->rxt_wml << MX51_ECSPI_DMA_RXT_WML_OFFSET, > + spi_imx->base + MX51_ECSPI_DMA); > + } > + > + spi_imx->dma_finished = 1; > + spi_imx->devtype_data->trigger(spi_imx); > + > + if (!ret) > + ret = -ETIMEDOUT; > + else if (ret > 0) > + ret = transfer->len; > + > + return ret; > + > +no_dma: > + pr_warn_once("%s %s: DMA not available, falling back to PIO\n", > + dev_driver_string(&master->dev), > + dev_name(&master->dev)); > + return -EAGAIN; > +} > + > +static int spi_imx_pio_transfer(struct spi_device *spi, > struct spi_transfer *transfer) > { > struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master); > @@ -751,6 +999,24 @@ static int spi_imx_transfer(struct spi_device *spi, > return transfer->len; > } > > +static int spi_imx_transfer(struct spi_device *spi, > + struct spi_transfer *transfer) > +{ > + int ret; > + struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master); > + > + if (spi_imx->bitbang.master->can_dma && > + spi_imx_can_dma(spi_imx->bitbang.master, spi, transfer)) { > + spi_imx->usedma = true; > + ret = spi_imx_dma_transfer(spi_imx, transfer); > + if (ret != -EAGAIN) > + return ret; > + } > + spi_imx->usedma = false; > + > + return spi_imx_pio_transfer(spi, transfer); > +} > + > static int spi_imx_setup(struct spi_device *spi) > { > struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master); > @@ -911,6 +1177,13 @@ static int spi_imx_probe(struct platform_device *pdev) > goto out_put_per; > > spi_imx->spi_clk = clk_get_rate(spi_imx->clk_per); > + /* > + * Only validated on i.mx6 now, can remove the constrain if validated on > + * other chips. > + */ > + if (spi_imx->devtype_data == &imx51_ecspi_devtype_data > + && spi_imx_sdma_init(&pdev->dev, spi_imx, master, res)) > + dev_err(&pdev->dev, "dma setup error,use pio instead\n"); > > spi_imx->devtype_data->reset(spi_imx); > > @@ -949,6 +1222,7 @@ static int spi_imx_remove(struct platform_device *pdev) > writel(0, spi_imx->base + MXC_CSPICTRL); > clk_unprepare(spi_imx->clk_ipg); > clk_unprepare(spi_imx->clk_per); > + spi_imx_sdma_exit(spi_imx); > spi_master_put(master); > > return 0; > -- > 1.9.1 > >
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