[PATCH v2] spi: spi-fsl-dspi: Add DMA support for Vybrid
Sanchayan Maity
maitysanchayan at gmail.com
Tue Oct 4 03:58:33 PDT 2016
Add DMA support for Vybrid.
Signed-off-by: Sanchayan Maity <maitysanchayan at gmail.com>
---
Changes since v1:
- Change in the dspi_dma_xfer function. Use more apt DSPI_FIFO_SIZE
instead of sizeof(u32)
- Do not set RSER on every iteration of loop
Tested on Toradex Colibri Vybrid VF61 module with spi based MCP CAN 251x
and spidev using RX/TX loopback and based on shawn's for-next branch
currently at 4.8-rc1.
Regards,
Sanchayan.
---
drivers/spi/spi-fsl-dspi.c | 291 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 291 insertions(+)
diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 9e9dadb..0f81075 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -15,6 +15,8 @@
#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
@@ -40,6 +42,7 @@
#define TRAN_STATE_WORD_ODD_NUM 0x04
#define DSPI_FIFO_SIZE 4
+#define DSPI_DMA_BUFSIZE (DSPI_FIFO_SIZE * 1024)
#define SPI_MCR 0x00
#define SPI_MCR_MASTER (1 << 31)
@@ -71,6 +74,11 @@
#define SPI_SR_EOQF 0x10000000
#define SPI_SR_TCFQF 0x80000000
+#define SPI_RSER_TFFFE BIT(25)
+#define SPI_RSER_TFFFD BIT(24)
+#define SPI_RSER_RFDFE BIT(17)
+#define SPI_RSER_RFDFD BIT(16)
+
#define SPI_RSER 0x30
#define SPI_RSER_EOQFE 0x10000000
#define SPI_RSER_TCFQE 0x80000000
@@ -108,6 +116,8 @@
#define SPI_TCR_TCNT_MAX 0x10000
+#define DMA_COMPLETION_TIMEOUT msecs_to_jiffies(3000)
+
struct chip_data {
u32 mcr_val;
u32 ctar_val;
@@ -117,6 +127,7 @@ struct chip_data {
enum dspi_trans_mode {
DSPI_EOQ_MODE = 0,
DSPI_TCFQ_MODE,
+ DSPI_DMA_MODE,
};
struct fsl_dspi_devtype_data {
@@ -139,6 +150,22 @@ static const struct fsl_dspi_devtype_data ls2085a_data = {
.max_clock_factor = 8,
};
+struct fsl_dspi_dma {
+ u32 curr_xfer_len;
+
+ u32 *tx_dma_buf;
+ struct dma_chan *chan_tx;
+ dma_addr_t tx_dma_phys;
+ struct completion cmd_tx_complete;
+ struct dma_async_tx_descriptor *tx_desc;
+
+ u32 *rx_dma_buf;
+ struct dma_chan *chan_rx;
+ dma_addr_t rx_dma_phys;
+ struct completion cmd_rx_complete;
+ struct dma_async_tx_descriptor *rx_desc;
+};
+
struct fsl_dspi {
struct spi_master *master;
struct platform_device *pdev;
@@ -165,6 +192,7 @@ struct fsl_dspi {
u32 waitflags;
u32 spi_tcnt;
+ struct fsl_dspi_dma *dma;
};
static inline int is_double_byte_mode(struct fsl_dspi *dspi)
@@ -368,6 +396,259 @@ static void dspi_tcfq_read(struct fsl_dspi *dspi)
dspi_data_from_popr(dspi, rx_word);
}
+static void dspi_tx_dma_callback(void *arg)
+{
+ struct fsl_dspi *dspi = arg;
+ struct fsl_dspi_dma *dma = dspi->dma;
+
+ complete(&dma->cmd_tx_complete);
+}
+
+static void dspi_rx_dma_callback(void *arg)
+{
+ struct fsl_dspi *dspi = arg;
+ struct fsl_dspi_dma *dma = dspi->dma;
+ int rx_word;
+ int i, len;
+ u16 d;
+
+ rx_word = is_double_byte_mode(dspi);
+
+ len = rx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len;
+
+ if (!(dspi->dataflags & TRAN_STATE_RX_VOID)) {
+ for (i = 0; i < len; i++) {
+ d = dspi->dma->rx_dma_buf[i];
+ rx_word ? (*(u16 *)dspi->rx = d) :
+ (*(u8 *)dspi->rx = d);
+ dspi->rx += rx_word + 1;
+ }
+ }
+
+ complete(&dma->cmd_rx_complete);
+}
+
+static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
+{
+ struct fsl_dspi_dma *dma = dspi->dma;
+ struct device *dev = &dspi->pdev->dev;
+ int time_left;
+ int tx_word;
+ int i, len;
+ u16 val;
+
+ tx_word = is_double_byte_mode(dspi);
+
+ len = tx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len;
+
+ for (i = 0; i < len - 1; i++) {
+ val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
+ dspi->dma->tx_dma_buf[i] =
+ SPI_PUSHR_TXDATA(val) | SPI_PUSHR_PCS(dspi->cs) |
+ SPI_PUSHR_CTAS(0) | SPI_PUSHR_CONT;
+ dspi->tx += tx_word + 1;
+ }
+
+ val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
+ dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
+ SPI_PUSHR_PCS(dspi->cs) |
+ SPI_PUSHR_CTAS(0);
+ dspi->tx += tx_word + 1;
+
+ dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
+ dma->tx_dma_phys,
+ DSPI_DMA_BUFSIZE, DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!dma->tx_desc) {
+ dev_err(dev, "Not able to get desc for DMA xfer\n");
+ return -EIO;
+ }
+
+ dma->tx_desc->callback = dspi_tx_dma_callback;
+ dma->tx_desc->callback_param = dspi;
+ if (dma_submit_error(dmaengine_submit(dma->tx_desc))) {
+ dev_err(dev, "DMA submit failed\n");
+ return -EINVAL;
+ }
+
+ dma->rx_desc = dmaengine_prep_slave_single(dma->chan_rx,
+ dma->rx_dma_phys,
+ DSPI_DMA_BUFSIZE, DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!dma->rx_desc) {
+ dev_err(dev, "Not able to get desc for DMA xfer\n");
+ return -EIO;
+ }
+
+ dma->rx_desc->callback = dspi_rx_dma_callback;
+ dma->rx_desc->callback_param = dspi;
+ if (dma_submit_error(dmaengine_submit(dma->rx_desc))) {
+ dev_err(dev, "DMA submit failed\n");
+ return -EINVAL;
+ }
+
+ reinit_completion(&dspi->dma->cmd_rx_complete);
+ reinit_completion(&dspi->dma->cmd_tx_complete);
+
+ dma_async_issue_pending(dma->chan_rx);
+ dma_async_issue_pending(dma->chan_tx);
+
+ time_left = wait_for_completion_timeout(&dspi->dma->cmd_tx_complete,
+ DMA_COMPLETION_TIMEOUT);
+ if (time_left == 0) {
+ dev_err(dev, "DMA tx timeout\n");
+ dmaengine_terminate_all(dma->chan_tx);
+ dmaengine_terminate_all(dma->chan_rx);
+ return -ETIMEDOUT;
+ }
+
+ time_left = wait_for_completion_timeout(&dspi->dma->cmd_rx_complete,
+ DMA_COMPLETION_TIMEOUT);
+ if (time_left == 0) {
+ dev_err(dev, "DMA rx timeout\n");
+ dmaengine_terminate_all(dma->chan_tx);
+ dmaengine_terminate_all(dma->chan_rx);
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+static int dspi_dma_xfer(struct fsl_dspi *dspi)
+{
+ struct fsl_dspi_dma *dma = dspi->dma;
+ struct device *dev = &dspi->pdev->dev;
+ int curr_remaining_bytes;
+ int ret = 0;
+
+ curr_remaining_bytes = dspi->len;
+ while (curr_remaining_bytes) {
+ /* Check if current transfer fits the DMA buffer */
+ dma->curr_xfer_len = curr_remaining_bytes;
+ if (curr_remaining_bytes > DSPI_DMA_BUFSIZE / DSPI_FIFO_SIZE)
+ dma->curr_xfer_len = DSPI_DMA_BUFSIZE / DSPI_FIFO_SIZE;
+
+ ret = dspi_next_xfer_dma_submit(dspi);
+ if (ret) {
+ dev_err(dev, "DMA transfer failed\n");
+ goto exit;
+
+ } else {
+ curr_remaining_bytes -= dma->curr_xfer_len;
+ if (curr_remaining_bytes < 0)
+ curr_remaining_bytes = 0;
+ dspi->len = curr_remaining_bytes;
+ }
+ }
+
+exit:
+ return ret;
+}
+
+static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr)
+{
+ struct fsl_dspi_dma *dma;
+ struct dma_slave_config cfg;
+ struct device *dev = &dspi->pdev->dev;
+ int ret;
+
+ dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL);
+ if (!dma)
+ return -ENOMEM;
+
+ dma->chan_rx = dma_request_slave_channel(dev, "rx");
+ if (!dma->chan_rx) {
+ dev_err(dev, "rx dma channel not available\n");
+ ret = -ENODEV;
+ return ret;
+ }
+
+ dma->chan_tx = dma_request_slave_channel(dev, "tx");
+ if (!dma->chan_tx) {
+ dev_err(dev, "tx dma channel not available\n");
+ ret = -ENODEV;
+ goto err_tx_channel;
+ }
+
+ dma->tx_dma_buf = dma_alloc_coherent(dev, DSPI_DMA_BUFSIZE,
+ &dma->tx_dma_phys, GFP_KERNEL);
+ if (!dma->tx_dma_buf) {
+ ret = -ENOMEM;
+ goto err_tx_dma_buf;
+ }
+
+ dma->rx_dma_buf = dma_alloc_coherent(dev, DSPI_DMA_BUFSIZE,
+ &dma->rx_dma_phys, GFP_KERNEL);
+ if (!dma->rx_dma_buf) {
+ ret = -ENOMEM;
+ goto err_rx_dma_buf;
+ }
+
+ cfg.src_addr = phy_addr + SPI_POPR;
+ cfg.dst_addr = phy_addr + SPI_PUSHR;
+ cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ cfg.src_maxburst = 1;
+ cfg.dst_maxburst = 1;
+
+ cfg.direction = DMA_DEV_TO_MEM;
+ ret = dmaengine_slave_config(dma->chan_rx, &cfg);
+ if (ret) {
+ dev_err(dev, "can't configure rx dma channel\n");
+ ret = -EINVAL;
+ goto err_slave_config;
+ }
+
+ cfg.direction = DMA_MEM_TO_DEV;
+ ret = dmaengine_slave_config(dma->chan_tx, &cfg);
+ if (ret) {
+ dev_err(dev, "can't configure tx dma channel\n");
+ ret = -EINVAL;
+ goto err_slave_config;
+ }
+
+ dspi->dma = dma;
+ dspi->devtype_data->trans_mode = DSPI_DMA_MODE;
+ init_completion(&dma->cmd_tx_complete);
+ init_completion(&dma->cmd_rx_complete);
+
+ return 0;
+
+err_slave_config:
+ devm_kfree(dev, dma->rx_dma_buf);
+err_rx_dma_buf:
+ devm_kfree(dev, dma->tx_dma_buf);
+err_tx_dma_buf:
+ dma_release_channel(dma->chan_tx);
+err_tx_channel:
+ dma_release_channel(dma->chan_rx);
+
+ devm_kfree(dev, dma);
+ dspi->dma = NULL;
+
+ return ret;
+}
+
+static void dspi_release_dma(struct fsl_dspi *dspi)
+{
+ struct fsl_dspi_dma *dma = dspi->dma;
+ struct device *dev = &dspi->pdev->dev;
+
+ if (dma) {
+ if (dma->chan_tx) {
+ dma_unmap_single(dev, dma->tx_dma_phys,
+ DSPI_DMA_BUFSIZE, DMA_TO_DEVICE);
+ dma_release_channel(dma->chan_tx);
+ }
+
+ if (dma->chan_rx) {
+ dma_unmap_single(dev, dma->rx_dma_phys,
+ DSPI_DMA_BUFSIZE, DMA_FROM_DEVICE);
+ dma_release_channel(dma->chan_rx);
+ }
+ }
+}
+
static int dspi_transfer_one_message(struct spi_master *master,
struct spi_message *message)
{
@@ -424,6 +705,12 @@ static int dspi_transfer_one_message(struct spi_master *master,
regmap_write(dspi->regmap, SPI_RSER, SPI_RSER_TCFQE);
dspi_tcfq_write(dspi);
break;
+ case DSPI_DMA_MODE:
+ regmap_write(dspi->regmap, SPI_RSER,
+ SPI_RSER_TFFFE | SPI_RSER_TFFFD |
+ SPI_RSER_RFDFE | SPI_RSER_RFDFD);
+ status = dspi_dma_xfer(dspi);
+ goto out;
default:
dev_err(&dspi->pdev->dev, "unsupported trans_mode %u\n",
trans_mode);
@@ -730,6 +1017,9 @@ static int dspi_probe(struct platform_device *pdev)
}
clk_prepare_enable(dspi->clk);
+ if (dspi_request_dma(dspi, res->start))
+ dev_warn(&pdev->dev, "can't get dma channels\n");
+
master->max_speed_hz =
clk_get_rate(dspi->clk) / dspi->devtype_data->max_clock_factor;
@@ -758,6 +1048,7 @@ static int dspi_remove(struct platform_device *pdev)
struct fsl_dspi *dspi = spi_master_get_devdata(master);
/* Disconnect from the SPI framework */
+ dspi_release_dma(dspi);
clk_disable_unprepare(dspi->clk);
spi_unregister_master(dspi->master);
spi_master_put(dspi->master);
--
2.10.0
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