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Subject[PATCH v2 3/8] spi: imx: add support for all SPI word width for DMA transfer
Date
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 other BPW supported by HW.

Signed-off-by: Anton Bondarenko <anton_bondarenko@mentor.com>
---
drivers/spi/spi-imx.c | 121 ++++++++++++++++++++++++++++++++++++--------------
1 file changed, 87 insertions(+), 34 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 6c98eda..d9b730d 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -91,11 +91,15 @@ 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 bpw_w;
+
unsigned int count;
void (*tx)(struct spi_imx_data *);
void (*rx)(struct spi_imx_data *);
@@ -201,9 +205,13 @@ 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_w = transfer->bits_per_word;

- if (spi_imx->dma_is_inited &&
- (transfer->len > spi_imx->wml * sizeof(u32)))
+ if (!bpw_w)
+ bpw_w = spi->bits_per_word;
+
+ bpw_w = DIV_ROUND_UP(bpw_w, 8);
+ if (spi_imx->dma_is_inited && (transfer->len > spi_imx->wml * bpw_w))
return true;
return false;
}
@@ -761,11 +769,62 @@ static irqreturn_t spi_imx_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}

+static int spi_imx_sdma_configure(struct spi_master *master)
+{
+ int ret;
+ enum dma_slave_buswidth dsb_default = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ struct dma_slave_config slave_config = {};
+ struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
+
+ switch (spi_imx->bpw_w) {
+ case 4:
+ dsb_default = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ break;
+ case 2:
+ dsb_default = DMA_SLAVE_BUSWIDTH_2_BYTES;
+ break;
+ case 1:
+ dsb_default = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ break;
+ default:
+ pr_err("Not supported word size %d\n", spi_imx->bpw_w);
+ ret = -EINVAL;
+ goto err;
+ }
+
+ slave_config.direction = DMA_MEM_TO_DEV;
+ slave_config.dst_addr = spi_imx->base_phys + MXC_CSPITXDATA;
+ slave_config.dst_addr_width = dsb_default;
+ slave_config.dst_maxburst = spi_imx_get_fifosize(spi_imx)
+ - spi_imx->wml;
+ ret = dmaengine_slave_config(master->dma_tx, &slave_config);
+ if (ret) {
+ pr_err("error in TX dma configuration.\n");
+ goto err;
+ }
+
+ memset(&slave_config, 0, sizeof(slave_config));
+
+ slave_config.direction = DMA_DEV_TO_MEM;
+ slave_config.src_addr = spi_imx->base_phys + MXC_CSPIRXDATA;
+ slave_config.src_addr_width = dsb_default;
+ slave_config.src_maxburst = spi_imx_get_fifosize(spi_imx)
+ - spi_imx->wml;
+ ret = dmaengine_slave_config(master->dma_rx, &slave_config);
+ if (ret)
+ pr_err("error in RX dma configuration.\n");
+
+err:
+ return ret;
+}
+
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;
+ unsigned int bpw_w_new;
+ int ret = 0;

config.bpw = t ? t->bits_per_word : spi->bits_per_word;
config.speed_hz = t ? t->speed_hz : spi->max_speed_hz;
@@ -789,9 +848,18 @@ static int spi_imx_setupxfer(struct spi_device *spi,
spi_imx->tx = spi_imx_buf_tx_u32;
}

- spi_imx->devtype_data->config(spi_imx, &config);
+ bpw_w_new = DIV_ROUND_UP(config.bpw, 8);
+ if (spi_imx->dma_is_inited && spi_imx->bpw_w != bpw_w_new) {
+ spi_imx->bpw_w = bpw_w_new;
+ ret = spi_imx_sdma_configure(spi->master);
+ if (ret != 0)
+ pr_err("Can't configure SDMA, error %d\n", ret);
+ }

- return 0;
+ if (!ret)
+ ret = spi_imx->devtype_data->config(spi_imx, &config);
+
+ return ret;
}

static void spi_imx_sdma_exit(struct spi_imx_data *spi_imx)
@@ -812,10 +880,8 @@ 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 */
@@ -832,17 +898,6 @@ 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_get_fifosize(spi_imx)
- - 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(dev, "rx");
if (!master->dma_rx) {
@@ -851,23 +906,19 @@ 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_get_fifosize(spi_imx)
- - 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;
- }
-
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->bpw_w = 1;
+ ret = spi_imx_sdma_configure(master);
+ if (ret) {
+ dev_info(dev, "cannot get setup DMA.\n");
+ goto err;
+ }
+
spi_imx->dma_is_inited = 1;

return 0;
@@ -924,7 +975,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
int ret;
unsigned long timeout;
unsigned long transfer_timeout;
- const int left = transfer->len % spi_imx->wml;
+ const int left = transfer->len % (spi_imx->wml * spi_imx->bpw_w);
struct spi_master *master = spi_imx->bitbang.master;
struct sg_table *tx = &transfer->tx_sg, *rx = &transfer->rx_sg;

@@ -989,7 +1040,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
dmaengine_terminate_all(master->dma_rx);
} else {
transfer_timeout = spi_imx_calculate_timeout(spi_imx,
- spi_imx->wml * 2);
+ spi_imx->bpw_w * spi_imx->wml * 2);
timeout = wait_for_completion_timeout(
&spi_imx->dma_rx_completion, transfer_timeout);
if (!timeout) {
@@ -1007,7 +1058,8 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
DMA_FROM_DEVICE);

spi_imx->rx_buf = pio_buffer;
- spi_imx->txfifo = left;
+ spi_imx->txfifo = DIV_ROUND_UP(left, spi_imx->bpw_w);
+
reinit_completion(&spi_imx->xfer_done);

spi_imx->devtype_data->intctrl(spi_imx, MXC_INT_TCEN);
@@ -1207,6 +1259,7 @@ 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) {
@@ -1246,8 +1299,8 @@ static int spi_imx_probe(struct platform_device *pdev)
* 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))
+ if (spi_imx->devtype_data == &imx51_ecspi_devtype_data &&
+ spi_imx_sdma_init(&pdev->dev, spi_imx, master))
dev_err(&pdev->dev, "dma setup error,use pio instead\n");

spi_imx->devtype_data->reset(spi_imx);
--
2.5.2


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