Interrupt based pio mode is supported to reduce CPU load.
If transfer size is larger than 32 byte, it is processed using interrupt.
Signed-off-by: Jaewon Kim <jaewon02.kim@xxxxxxxxxxx>
---
drivers/spi/spi-s3c64xx.c | 82 ++++++++++++++++++++++++++++++++-------
1 file changed, 67 insertions(+), 15 deletions(-)
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index cf3060b2639b..ce1afb9a4ed4 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -58,6 +58,8 @@
#define S3C64XX_SPI_MODE_BUS_TSZ_HALFWORD (1<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_WORD (2<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_MASK (3<<17)
+#define S3C64XX_SPI_MODE_RX_RDY_LVL GENMASK(16, 11)
+#define S3C64XX_SPI_MODE_RX_RDY_LVL_SHIFT 11
#define S3C64XX_SPI_MODE_SELF_LOOPBACK (1<<3)
#define S3C64XX_SPI_MODE_RXDMA_ON (1<<2)
#define S3C64XX_SPI_MODE_TXDMA_ON (1<<1)
@@ -114,6 +116,8 @@
#define S3C64XX_SPI_TRAILCNT S3C64XX_SPI_MAX_TRAILCNT
+#define S3C64XX_SPI_POLLING_SIZE 32
+
#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
#define is_polling(x) (x->cntrlr_info->polling)
@@ -552,10 +556,11 @@ static int s3c64xx_wait_for_dma(struct s3c64xx_spi_driver_data *sdd,
}
static int s3c64xx_wait_for_pio(struct s3c64xx_spi_driver_data *sdd,
- struct spi_transfer *xfer)
+ struct spi_transfer *xfer, int use_irq)
{
void __iomem *regs = sdd->regs;
unsigned long val;
+ unsigned long time;
u32 status;
int loops;
u32 cpy_len;
@@ -563,17 +568,24 @@ static int s3c64xx_wait_for_pio(struct s3c64xx_spi_driver_data *sdd,
int ms;
u32 tx_time;
- /* sleep during signal transfer time */
- status = readl(regs + S3C64XX_SPI_STATUS);
- if (RX_FIFO_LVL(status, sdd) < xfer->len) {
- tx_time = (xfer->len * 8 * 1000 * 1000) / sdd->cur_speed;
- usleep_range(tx_time / 2, tx_time);
- }
-
/* millisecs to xfer 'len' bytes @ 'cur_speed' */
ms = xfer->len * 8 * 1000 / sdd->cur_speed;
ms += 10; /* some tolerance */
+ if (use_irq) {
+ val = msecs_to_jiffies(ms);
+ time = wait_for_completion_timeout(&sdd->xfer_completion, val);
+ if (!time)
+ return -EIO;
+ } else {
+ /* sleep during signal transfer time */
+ status = readl(regs + S3C64XX_SPI_STATUS);
+ if (RX_FIFO_LVL(status, sdd) < xfer->len) {
+ tx_time = (xfer->len * 8 * 1000 * 1000) / sdd->cur_speed;
+ usleep_range(tx_time / 2, tx_time);
+ }
+ }
+
val = msecs_to_loops(ms);
do {
cpu_relax();
@@ -737,10 +749,13 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
void *rx_buf = NULL;
int target_len = 0, origin_len = 0;
int use_dma = 0;
+ int use_irq = 0;
int status;
u32 speed;
u8 bpw;
unsigned long flags;
+ u32 rdy_lv;
+ u32 val;
reinit_completion(&sdd->xfer_completion);
@@ -761,17 +776,46 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
sdd->rx_dma.ch && sdd->tx_dma.ch) {
use_dma = 1;
- } else if (xfer->len > fifo_len) {
+ } else if (xfer->len >= fifo_len) {
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
origin_len = xfer->len;
-
target_len = xfer->len;
- if (xfer->len > fifo_len)
- xfer->len = fifo_len;
+ xfer->len = fifo_len - 1;
}
do {
+ /* transfer size is greater than 32, change to IRQ mode */
+ if (xfer->len > S3C64XX_SPI_POLLING_SIZE)
+ use_irq = 1;
+
+ if (use_irq) {
+ reinit_completion(&sdd->xfer_completion);
+
+ rdy_lv = xfer->len;
+ /* Setup RDY_FIFO trigger Level
+ * RDY_LVL =
+ * fifo_lvl up to 64 byte -> N bytes
+ * 128 byte -> RDY_LVL * 2 bytes
+ * 256 byte -> RDY_LVL * 4 bytes
+ */
+ if (fifo_len == 128)
+ rdy_lv /= 2;
+ else if (fifo_len == 256)
+ rdy_lv /= 4;
+
+ val = readl(sdd->regs + S3C64XX_SPI_MODE_CFG);
+ val &= ~S3C64XX_SPI_MODE_RX_RDY_LVL;
+ val |= (rdy_lv << S3C64XX_SPI_MODE_RX_RDY_LVL_SHIFT);
+ writel(val, sdd->regs + S3C64XX_SPI_MODE_CFG);
+
+ /* Enable FIFO_RDY_EN IRQ */
+ val = readl(sdd->regs + S3C64XX_SPI_INT_EN);
+ writel((val | S3C64XX_SPI_INT_RX_FIFORDY_EN),
+ sdd->regs + S3C64XX_SPI_INT_EN);
+
+ }
+
spin_lock_irqsave(&sdd->lock, flags);
/* Pending only which is to be done */
@@ -793,7 +837,7 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
if (use_dma)
status = s3c64xx_wait_for_dma(sdd, xfer);
else
- status = s3c64xx_wait_for_pio(sdd, xfer);
+ status = s3c64xx_wait_for_pio(sdd, xfer, use_irq);
if (status) {
dev_err(&spi->dev,
@@ -832,8 +876,8 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
if (xfer->rx_buf)
xfer->rx_buf += xfer->len;
- if (target_len > fifo_len)
- xfer->len = fifo_len;
+ if (target_len >= fifo_len)
+ xfer->len = fifo_len - 1;
else
xfer->len = target_len;
}
@@ -1003,6 +1047,14 @@ static irqreturn_t s3c64xx_spi_irq(int irq, void *data)
dev_err(&spi->dev, "TX underrun\n");
}
+ if (val & S3C64XX_SPI_ST_RX_FIFORDY) {
+ complete(&sdd->xfer_completion);
+ /* No pending clear irq, turn-off INT_EN_RX_FIFO_RDY */
+ val = readl(sdd->regs + S3C64XX_SPI_INT_EN);
+ writel((val & ~S3C64XX_SPI_INT_RX_FIFORDY_EN),
+ sdd->regs + S3C64XX_SPI_INT_EN);
+ }
+
/* Clear the pending irq by setting and then clearing it */
writel(clr, sdd->regs + S3C64XX_SPI_PENDING_CLR);
writel(0, sdd->regs + S3C64XX_SPI_PENDING_CLR);
--
2.17.1
