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spi/bcm63xx: reject transfers unable to transfer

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The hardware does not support keeping CS asserted after sending one
FIFO buffer worth of data, so reject transfers requiring CS being kept
asserted, either between transers or for a certain time after it,
or exceeding the FIFO size.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Jonas Gorski 2013-02-03 15:15:12 +01:00 committed by Grant Likely
parent 2cd94c8a1b
commit c0fde3ba0e
1 changed files with 43 additions and 50 deletions
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93
drivers/spi/spi-bcm63xx.c
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@ -49,16 +49,10 @@ struct bcm63xx_spi {
unsigned int msg_type_shift;
unsigned int msg_ctl_width;
/* Data buffers */
const unsigned char *tx_ptr;
unsigned char *rx_ptr;
/* data iomem */
u8 __iomem *tx_io;
const u8 __iomem *rx_io;
int remaining_bytes;
struct clk *clk;
struct platform_device *pdev;
};
@ -175,24 +169,13 @@ static int bcm63xx_spi_setup(struct spi_device *spi)
return 0;
}
/* Fill the TX FIFO with as many bytes as possible */
static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs)
{
u8 size;
/* Fill the Tx FIFO with as many bytes as possible */
size = bs->remaining_bytes < bs->fifo_size ? bs->remaining_bytes :
bs->fifo_size;
memcpy_toio(bs->tx_io, bs->tx_ptr, size);
bs->remaining_bytes -= size;
}
static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi,
struct spi_transfer *t)
static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
u16 msg_ctl;
u16 cmd;
u8 rx_tail;
unsigned int timeout = 0;
/* Disable the CMD_DONE interrupt */
bcm_spi_writeb(bs, 0, SPI_INT_MASK);
@ -200,14 +183,8 @@ static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi,
dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
t->tx_buf, t->rx_buf, t->len);
/* Transmitter is inhibited */
bs->tx_ptr = t->tx_buf;
bs->rx_ptr = t->rx_buf;
if (t->tx_buf) {
bs->remaining_bytes = t->len;
bcm63xx_spi_fill_tx_fifo(bs);
}
if (t->tx_buf)
memcpy_toio(bs->tx_io, t->tx_buf, t->len);
init_completion(&bs->done);
@ -239,7 +216,18 @@ static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi,
/* Enable the CMD_DONE interrupt */
bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK);
return t->len - bs->remaining_bytes;
timeout = wait_for_completion_timeout(&bs->done, HZ);
if (!timeout)
return -ETIMEDOUT;
/* read out all data */
rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
/* Read out all the data */
if (rx_tail)
memcpy_fromio(t->rx_ptr, bs->rx_io, rx_tail);
return 0;
}
static int bcm63xx_spi_prepare_transfer(struct spi_master *master)
@ -267,36 +255,41 @@ static int bcm63xx_spi_transfer_one(struct spi_master *master,
struct spi_transfer *t;
struct spi_device *spi = m->spi;
int status = 0;
unsigned int timeout = 0;
list_for_each_entry(t, &m->transfers, transfer_list) {
unsigned int len = t->len;
u8 rx_tail;
status = bcm63xx_spi_check_transfer(spi, t);
if (status < 0)
goto exit;
/* we can only transfer one fifo worth of data */
if (t->len > bs->fifo_size) {
dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n",
t->len, bs->fifo_size);
status = -EINVAL;
goto exit;
}
/* CS will be deasserted directly after transfer */
if (t->delay_usecs) {
dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
status = -EINVAL;
goto exit;
}
if (!t->cs_change &&
!list_is_last(&t->transfer_list, &m->transfers)) {
dev_err(&spi->dev, "unable to keep CS asserted between transfers\n");
status = -EINVAL;
goto exit;
}
/* configure adapter for a new transfer */
bcm63xx_spi_setup_transfer(spi, t);
while (len) {
/* send the data */
len -= bcm63xx_txrx_bufs(spi, t);
timeout = wait_for_completion_timeout(&bs->done, HZ);
if (!timeout) {
status = -ETIMEDOUT;
goto exit;
}
/* read out all data */
rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
/* Read out all the data */
if (rx_tail)
memcpy_fromio(bs->rx_ptr, bs->rx_io, rx_tail);
}
/* send the data */
status = bcm63xx_txrx_bufs(spi, t);
if (status)
goto exit;
m->actual_length += t->len;
}