[PATCH 08/12] spi: imx: add support for all SPI word width for DMA
Sascha Hauer
s.hauer at pengutronix.de
Thu Feb 18 23:43:08 PST 2016
From: Anton Bondarenko <anton.bondarenko.sama at gmail.com>
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 at gmail.com>
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
drivers/spi/spi-imx.c | 118 ++++++++++++++++++++++++++++++++++++++------------
1 file changed, 91 insertions(+), 27 deletions(-)
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 57b7af8..6a0e004 100644
--- 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);
@@ -1162,6 +1225,7 @@ 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) {
@@ -1202,7 +1266,7 @@ 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;
--
2.7.0
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