spi/bcm63xx: reject transfers unable to transfer
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>
diff --git a/drivers/spi/spi-bcm63xx.c b/drivers/spi/spi-bcm63xx.c
index f44ab55..27667c1 100644
--- a/drivers/spi/spi-bcm63xx.c
+++ b/drivers/spi/spi-bcm63xx.c
@@ -49,16 +49,10 @@
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 @@
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 @@
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 @@
/* 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 @@
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;
}