[PATCH V1] spi: imx: add dma support for ecspi
From: Robin Gong
Date: Wed Feb 12 2014 - 04:57:34 EST
Add basical dma support for ecspi. Validate on i.MX6qsabresd board.
Signed-off-by: Robin Gong <b38343@xxxxxxxxxxxxx>
---
drivers/spi/spi-imx.c | 221 ++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 211 insertions(+), 10 deletions(-)
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index a5474ef..6a80658 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/dma-mapping.h>
+#include <linux/dmaengine.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/init.h>
@@ -42,6 +44,9 @@
#define DRIVER_NAME "spi_imx"
+#define DMA_SG_MAXLEN 0xffff /* align with imx-sdma.c */
+#define ECSPI_TIMEOUT 1000
+
#define MXC_CSPIRXDATA 0x00
#define MXC_CSPITXDATA 0x04
#define MXC_CSPICTRL 0x08
@@ -76,13 +81,14 @@ struct spi_imx_devtype_data {
void (*trigger)(struct spi_imx_data *);
int (*rx_available)(struct spi_imx_data *);
void (*reset)(struct spi_imx_data *);
+ void (*dmactrl)(struct spi_imx_data *, int);
enum spi_imx_devtype devtype;
};
struct spi_imx_data {
struct spi_bitbang bitbang;
- struct completion xfer_done;
+ struct completion rx_done; /* PIO mode use rx_done both rx/tx */
void __iomem *base;
int irq;
struct clk *clk_per;
@@ -96,6 +102,16 @@ struct spi_imx_data {
const void *tx_buf;
unsigned int txfifo; /* number of words pushed in tx FIFO */
+ /* DMA used */
+ struct dma_chan *rx_dmach; /* rx dma channel */
+ struct dma_chan *tx_dmach; /* tx dma channel */
+ dma_addr_t src_start;
+ dma_addr_t dst_start;
+ dma_addr_t rxfifo_phy;
+ dma_addr_t txfifo_phy;
+ struct completion tx_done;
+ void *dummy_buf; /* send or receive dummy data in DMA mode */
+
const struct spi_imx_devtype_data *devtype_data;
int chipselect[0];
};
@@ -185,6 +201,7 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin,
#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
@@ -202,6 +219,17 @@ 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_TXTHR_OFFSET (0)
+#define MX51_ECSPI_DMA_TXTHR_MASK (0x3f << MX51_ECSPI_DMA_TXTHR_OFFSET)
+#define MX51_ECSPI_DMA_TXDEN (1 << 7)
+#define MX51_ECSPI_DMA_RXTHR_OFFSET (16)
+#define MX51_ECSPI_DMA_RXTHR_MASK (0x3f << MX51_ECSPI_DMA_RXTHR_OFFSET)
+#define MX51_ECSPI_DMA_RXDEN (1 << 23)
+#define MX51_ECSPI_DMA_RXDMALEN_OFFSET (24)
+#define MX51_ECSPI_DMA_RXDMALEN_MASK (0x3f << MX51_ECSPI_DMA_RXDMALEN_OFFSET)
+#define MX51_ECSPI_DMA_RXTDEN (1 << 31)
+
#define MX51_ECSPI_STAT 0x18
#define MX51_ECSPI_STAT_RR (1 << 3)
@@ -288,6 +316,10 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
ctrl |= (config->bpw - 1) << MX51_ECSPI_CTRL_BL_OFFSET;
+ /* set smc bit for dma */
+ if (spi_imx->rx_dmach)
+ ctrl |= MX51_ECSPI_CTRL_SMC;
+
cfg |= MX51_ECSPI_CONFIG_SBBCTRL(config->cs);
if (config->mode & SPI_CPHA)
@@ -303,6 +335,26 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
+ /* set rx/tx fifo threshold in DMA mode */
+ if (spi_imx->rx_dmach) {
+ cfg = readl(spi_imx->base + MX51_ECSPI_DMA);
+ cfg &= ~(MX51_ECSPI_DMA_TXTHR_MASK | MX51_ECSPI_DMA_RXTHR_MASK
+ | MX51_ECSPI_DMA_RXDMALEN_MASK);
+ /* set rx/tx fifo threshold */
+ cfg |= (spi_imx_get_fifosize(spi_imx) / 2) <<
+ MX51_ECSPI_DMA_TXTHR_OFFSET;
+ cfg |= (spi_imx_get_fifosize(spi_imx) / 2) <<
+ MX51_ECSPI_DMA_RXTHR_OFFSET;
+ /*
+ * set RX_DMA_LENTH to 1 to prvent missing the last bytes which
+ * is less than rx threshold based on current design.
+ */
+ cfg |= 1 << MX51_ECSPI_DMA_RXDMALEN_OFFSET;
+ cfg |= MX51_ECSPI_DMA_RXTDEN;
+
+ writel(cfg, spi_imx->base + MX51_ECSPI_DMA);
+ }
+
/*
* Wait until the changes in the configuration register CONFIGREG
* propagate into the hardware. It takes exactly one tick of the
@@ -335,6 +387,17 @@ static void __maybe_unused mx51_ecspi_reset(struct spi_imx_data *spi_imx)
readl(spi_imx->base + MXC_CSPIRXDATA);
}
+static void __maybe_unused mx51_ecspi_dmactrl(struct spi_imx_data *spi_imx, int enable)
+{
+ u32 value = readl(spi_imx->base + MX51_ECSPI_DMA);
+
+ if (enable)
+ value |= MX51_ECSPI_DMA_TXDEN | MX51_ECSPI_DMA_RXDEN;
+ else
+ value &= ~(MX51_ECSPI_DMA_TXDEN | MX51_ECSPI_DMA_RXDEN);
+ writel(value, spi_imx->base + MX51_ECSPI_DMA);
+}
+
#define MX31_INTREG_TEEN (1 << 0)
#define MX31_INTREG_RREN (1 << 3)
@@ -606,6 +669,7 @@ static struct spi_imx_devtype_data imx51_ecspi_devtype_data = {
.trigger = mx51_ecspi_trigger,
.rx_available = mx51_ecspi_rx_available,
.reset = mx51_ecspi_reset,
+ .dmactrl = mx51_ecspi_dmactrl,
.devtype = IMX51_ECSPI,
};
@@ -693,7 +757,7 @@ static irqreturn_t spi_imx_isr(int irq, void *dev_id)
}
spi_imx->devtype_data->intctrl(spi_imx, 0);
- complete(&spi_imx->xfer_done);
+ complete(&spi_imx->rx_done);
return IRQ_HANDLED;
}
@@ -703,6 +767,8 @@ static int spi_imx_setupxfer(struct spi_device *spi,
{
struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
struct spi_imx_config config;
+ struct dma_slave_config slave_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;
@@ -728,9 +794,116 @@ static int spi_imx_setupxfer(struct spi_device *spi,
spi_imx->devtype_data->config(spi_imx, &config);
+ /* DMA channel config */
+ if (spi_imx->rx_dmach) {
+ slave_config.direction = DMA_DEV_TO_MEM;
+ slave_config.src_addr = spi_imx->rxfifo_phy;
+ slave_config.src_addr_width = config.bpw / 8;
+ slave_config.src_maxburst = spi_imx_get_fifosize(spi_imx) / 2;
+ ret = dmaengine_slave_config(spi_imx->rx_dmach, &slave_config);
+ if (ret) {
+ dev_err(&spi->dev, "error in RX dma configuration.\n");
+ return ret;
+ }
+ }
+ if (spi_imx->tx_dmach) {
+ slave_config.direction = DMA_MEM_TO_DEV;
+ slave_config.dst_addr = spi_imx->txfifo_phy;
+ slave_config.dst_addr_width = config.bpw / 8;
+ slave_config.dst_maxburst = spi_imx_get_fifosize(spi_imx) / 2;
+ ret = dmaengine_slave_config(spi_imx->tx_dmach, &slave_config);
+ if (ret) {
+ dev_err(&spi->dev, "error in TX dma configuration.\n");
+ return ret;
+ }
+ }
+
return 0;
}
+static int spi_imx_transfer_pio(struct spi_device *spi,
+ struct spi_transfer *transfer)
+{
+ struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
+
+ init_completion(&spi_imx->rx_done);
+
+ spi_imx_push(spi_imx);
+
+ spi_imx->devtype_data->intctrl(spi_imx, MXC_INT_TE);
+
+ wait_for_completion(&spi_imx->rx_done);
+
+ return transfer->len;
+}
+
+static void spi_imx_dma_done_callback(void *data)
+{
+ struct completion *dma_complete = data;
+
+ complete(dma_complete);
+}
+
+static int spi_imx_transfer_dma(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct dma_async_tx_descriptor *rx_desc, *tx_desc;
+ struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
+ int ret;
+
+ spi_imx->tx_buf = t->tx_buf ? t->tx_buf : spi_imx->dummy_buf;
+ spi_imx->rx_buf = t->rx_buf ? t->rx_buf : spi_imx->dummy_buf;
+
+ init_completion(&spi_imx->rx_done);
+ init_completion(&spi_imx->tx_done);
+
+ spi_imx->dst_start = dma_map_single(&spi->dev, spi_imx->rx_buf, t->len,
+ DMA_FROM_DEVICE);
+ rx_desc = dmaengine_prep_slave_single(spi_imx->rx_dmach,
+ spi_imx->dst_start, t->len, DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ rx_desc->callback = spi_imx_dma_done_callback;
+ rx_desc->callback_param = &spi_imx->rx_done;
+
+ spi_imx->src_start = dma_map_single(&spi->dev, (void *)spi_imx->tx_buf,
+ t->len, DMA_TO_DEVICE);
+ tx_desc = dmaengine_prep_slave_single(spi_imx->tx_dmach,
+ spi_imx->src_start, t->len, DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ tx_desc->callback = spi_imx_dma_done_callback;
+ tx_desc->callback_param = &spi_imx->tx_done;
+
+ dmaengine_submit(tx_desc);
+ dmaengine_submit(rx_desc);
+ dma_async_issue_pending(spi_imx->tx_dmach);
+ dma_async_issue_pending(spi_imx->rx_dmach);
+
+ /* enable rx/tx DMA transfer */
+ spi_imx->devtype_data->dmactrl(spi_imx, 1);
+
+ /* only wait tx event */
+ ret = wait_for_completion_timeout(&spi_imx->tx_done,
+ msecs_to_jiffies(ECSPI_TIMEOUT));
+ if (!ret) {
+ dev_err(&spi->dev, "DMA transfer timeout\n");
+ ret = -ETIMEDOUT;
+ dmaengine_terminate_all(spi_imx->tx_dmach);
+ dmaengine_terminate_all(spi_imx->rx_dmach);
+ goto unmap_rxtx;
+ }
+
+ ret = t->len;
+
+unmap_rxtx:
+ dma_unmap_single(&spi->dev, spi_imx->src_start, t->len, DMA_TO_DEVICE);
+ dma_unmap_single(&spi->dev, spi_imx->dst_start, t->len, DMA_FROM_DEVICE);
+
+ /* disable rx/tx DMA transfer */
+ spi_imx->devtype_data->dmactrl(spi_imx, 0);
+
+ return ret;
+}
+
static int spi_imx_transfer(struct spi_device *spi,
struct spi_transfer *transfer)
{
@@ -741,13 +914,10 @@ static int spi_imx_transfer(struct spi_device *spi,
spi_imx->count = transfer->len;
spi_imx->txfifo = 0;
- init_completion(&spi_imx->xfer_done);
-
- spi_imx_push(spi_imx);
-
- spi_imx->devtype_data->intctrl(spi_imx, MXC_INT_TE);
-
- wait_for_completion(&spi_imx->xfer_done);
+ if (spi_imx->rx_dmach && transfer->len < DMA_SG_MAXLEN)
+ transfer->len = spi_imx_transfer_dma(spi, transfer);
+ else
+ transfer->len = spi_imx_transfer_pio(spi, transfer);
return transfer->len;
}
@@ -866,7 +1036,7 @@ static int spi_imx_probe(struct platform_device *pdev)
spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
- init_completion(&spi_imx->xfer_done);
+ init_completion(&spi_imx->rx_done);
spi_imx->devtype_data = of_id ? of_id->data :
(struct spi_imx_devtype_data *) pdev->id_entry->driver_data;
@@ -891,6 +1061,37 @@ static int spi_imx_probe(struct platform_device *pdev)
goto out_master_put;
}
+ spi_imx->rx_dmach = dma_request_slave_channel(&pdev->dev, "rx");
+ spi_imx->tx_dmach = dma_request_slave_channel(&pdev->dev, "tx");
+
+ /*
+ * work in PIO mode if NOT set dma channel in dts or requeset dma
+ * channel failed. Only validated in i.MX6(MX51) now.
+ */
+ if (spi_imx->rx_dmach && spi_imx->tx_dmach) {
+ dev_info(&pdev->dev, "requested DMA channel rx:%d,tx:%d\n",
+ spi_imx->rx_dmach->chan_id, spi_imx->tx_dmach->chan_id);
+
+ spi_imx->rxfifo_phy = res->start + MXC_CSPIRXDATA;
+ spi_imx->txfifo_phy = res->start + MXC_CSPITXDATA;
+ /* malloc one max SG buf(64KB) to read/write rx/tx FIFO */
+ spi_imx->dummy_buf = kmalloc(DMA_SG_MAXLEN, GFP_KERNEL);
+ if (!spi_imx->dummy_buf) {
+ ret = -ENOMEM;
+ dma_release_channel(spi_imx->rx_dmach);
+ dma_release_channel(spi_imx->tx_dmach);
+ goto out_master_put;
+ }
+ } else if (spi_imx->rx_dmach) {
+ /* rx dma requested but tx failed, force to both PIO mode */
+ dma_release_channel(spi_imx->rx_dmach);
+ spi_imx->rx_dmach = NULL;
+ } else if (spi_imx->tx_dmach) {
+ /* tx dma requested but rx failed, force to both PIO mode */
+ dma_release_channel(spi_imx->tx_dmach);
+ spi_imx->tx_dmach = NULL;
+ }
+
spi_imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
if (IS_ERR(spi_imx->clk_ipg)) {
ret = PTR_ERR(spi_imx->clk_ipg);
--
1.7.5.4
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