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spi: spi-s3c64xx: Allow higher transfer lengths in polling IO mode 

Some variants of the SPI controller have no DMA support, in such case
SPI transfers longer than the FIFO length are not currently properly
handled by the driver. Fix it by doing multiple transfers in the
s3c64xx_spi_transfer_one() function if the SPI transfer length exceeds
the FIFO size.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Andi Shyti <andi@etezian.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Sylwester Nawrocki 2018-04-17 16:29:54 +02:00 committed by Mark Brown
parent f6364e66c6
commit 0af7af7da6
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 64 additions and 31 deletions
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95
drivers/spi/spi-s3c64xx.c
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@ -635,11 +635,14 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
{
struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);
const unsigned int fifo_len = (FIFO_LVL_MASK(sdd) >> 1) + 1;
const void *tx_buf = NULL;
void *rx_buf = NULL;
int target_len = 0, origin_len = 0;
int use_dma = 0;
int status;
u32 speed;
u8 bpw;
unsigned long flags;
int use_dma;
reinit_completion(&sdd->xfer_completion);
@ -654,47 +657,77 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
s3c64xx_spi_config(sdd);
}
/* Polling method for xfers not bigger than FIFO capacity */
use_dma = 0;
if (!is_polling(sdd) && (xfer->len > fifo_len) &&
sdd->rx_dma.ch && sdd->tx_dma.ch)
sdd->rx_dma.ch && sdd->tx_dma.ch) {
use_dma = 1;
spin_lock_irqsave(&sdd->lock, flags);
} else if (is_polling(sdd) && xfer->len > fifo_len) {
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
origin_len = xfer->len;
/* Pending only which is to be done */
sdd->state &= ~RXBUSY;
sdd->state &= ~TXBUSY;
target_len = xfer->len;
if (xfer->len > fifo_len)
xfer->len = fifo_len;
}
s3c64xx_enable_datapath(sdd, xfer, use_dma);
do {
spin_lock_irqsave(&sdd->lock, flags);
/* Start the signals */
s3c64xx_spi_set_cs(spi, true);
/* Pending only which is to be done */
sdd->state &= ~RXBUSY;
sdd->state &= ~TXBUSY;
spin_unlock_irqrestore(&sdd->lock, flags);
s3c64xx_enable_datapath(sdd, xfer, use_dma);
if (use_dma)
status = s3c64xx_wait_for_dma(sdd, xfer);
else
status = s3c64xx_wait_for_pio(sdd, xfer);
/* Start the signals */
s3c64xx_spi_set_cs(spi, true);
if (status) {
dev_err(&spi->dev, "I/O Error: rx-%d tx-%d res:rx-%c tx-%c len-%d\n",
xfer->rx_buf ? 1 : 0, xfer->tx_buf ? 1 : 0,
(sdd->state & RXBUSY) ? 'f' : 'p',
(sdd->state & TXBUSY) ? 'f' : 'p',
xfer->len);
spin_unlock_irqrestore(&sdd->lock, flags);
if (use_dma) {
if (xfer->tx_buf != NULL
&& (sdd->state & TXBUSY))
dmaengine_terminate_all(sdd->tx_dma.ch);
if (xfer->rx_buf != NULL
&& (sdd->state & RXBUSY))
dmaengine_terminate_all(sdd->rx_dma.ch);
if (use_dma)
status = s3c64xx_wait_for_dma(sdd, xfer);
else
status = s3c64xx_wait_for_pio(sdd, xfer);
if (status) {
dev_err(&spi->dev,
"I/O Error: rx-%d tx-%d res:rx-%c tx-%c len-%d\n",
xfer->rx_buf ? 1 : 0, xfer->tx_buf ? 1 : 0,
(sdd->state & RXBUSY) ? 'f' : 'p',
(sdd->state & TXBUSY) ? 'f' : 'p',
xfer->len);
if (use_dma) {
if (xfer->tx_buf && (sdd->state & TXBUSY))
dmaengine_terminate_all(sdd->tx_dma.ch);
if (xfer->rx_buf && (sdd->state & RXBUSY))
dmaengine_terminate_all(sdd->rx_dma.ch);
}
} else {
s3c64xx_flush_fifo(sdd);
}
} else {
s3c64xx_flush_fifo(sdd);
if (target_len > 0) {
target_len -= xfer->len;
if (xfer->tx_buf)
xfer->tx_buf += xfer->len;
if (xfer->rx_buf)
xfer->rx_buf += xfer->len;
if (target_len > fifo_len)
xfer->len = fifo_len;
else
xfer->len = target_len;
}
} while (target_len > 0);
if (origin_len) {
/* Restore original xfer buffers and length */
xfer->tx_buf = tx_buf;
xfer->rx_buf = rx_buf;
xfer->len = origin_len;
}
return status;