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path: root/drivers/spi/spi-bcm63xx.c
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Diffstat (limited to 'drivers/spi/spi-bcm63xx.c')
-rw-r--r--drivers/spi/spi-bcm63xx.c179
1 files changed, 125 insertions, 54 deletions
diff --git a/drivers/spi/spi-bcm63xx.c b/drivers/spi/spi-bcm63xx.c
index f44ab550853..9578af782a7 100644
--- a/drivers/spi/spi-bcm63xx.c
+++ b/drivers/spi/spi-bcm63xx.c
@@ -37,6 +37,8 @@
#define PFX KBUILD_MODNAME
+#define BCM63XX_SPI_MAX_PREPEND 15
+
struct bcm63xx_spi {
struct completion done;
@@ -49,16 +51,10 @@ 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 +171,17 @@ 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 *first,
+ unsigned int num_transfers)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
u16 msg_ctl;
u16 cmd;
+ u8 rx_tail;
+ unsigned int i, timeout = 0, prepend_len = 0, len = 0;
+ struct spi_transfer *t = first;
+ bool do_rx = false;
+ bool do_tx = false;
/* Disable the CMD_DONE interrupt */
bcm_spi_writeb(bs, 0, SPI_INT_MASK);
@@ -200,25 +189,45 @@ 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 (num_transfers > 1 && t->tx_buf && t->len <= BCM63XX_SPI_MAX_PREPEND)
+ prepend_len = t->len;
- if (t->tx_buf) {
- bs->remaining_bytes = t->len;
- bcm63xx_spi_fill_tx_fifo(bs);
+ /* prepare the buffer */
+ for (i = 0; i < num_transfers; i++) {
+ if (t->tx_buf) {
+ do_tx = true;
+ memcpy_toio(bs->tx_io + len, t->tx_buf, t->len);
+
+ /* don't prepend more than one tx */
+ if (t != first)
+ prepend_len = 0;
+ }
+
+ if (t->rx_buf) {
+ do_rx = true;
+ /* prepend is half-duplex write only */
+ if (t == first)
+ prepend_len = 0;
+ }
+
+ len += t->len;
+
+ t = list_entry(t->transfer_list.next, struct spi_transfer,
+ transfer_list);
}
+ len -= prepend_len;
+
init_completion(&bs->done);
/* Fill in the Message control register */
- msg_ctl = (t->len << SPI_BYTE_CNT_SHIFT);
+ msg_ctl = (len << SPI_BYTE_CNT_SHIFT);
- if (t->rx_buf && t->tx_buf)
+ if (do_rx && do_tx && prepend_len == 0)
msg_ctl |= (SPI_FD_RW << bs->msg_type_shift);
- else if (t->rx_buf)
+ else if (do_rx)
msg_ctl |= (SPI_HD_R << bs->msg_type_shift);
- else if (t->tx_buf)
+ else if (do_tx)
msg_ctl |= (SPI_HD_W << bs->msg_type_shift);
switch (bs->msg_ctl_width) {
@@ -232,14 +241,41 @@ static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi,
/* Issue the transfer */
cmd = SPI_CMD_START_IMMEDIATE;
- cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
+ cmd |= (prepend_len << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
cmd |= (spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
bcm_spi_writew(bs, cmd, SPI_CMD);
/* 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);
+
+ if (do_rx && rx_tail != len)
+ return -EIO;
+
+ if (!rx_tail)
+ return 0;
+
+ len = 0;
+ t = first;
+ /* Read out all the data */
+ for (i = 0; i < num_transfers; i++) {
+ if (t->rx_buf)
+ memcpy_fromio(t->rx_buf, bs->rx_io + len, t->len);
+
+ if (t != first || prepend_len == 0)
+ len += t->len;
+
+ t = list_entry(t->transfer_list.next, struct spi_transfer,
+ transfer_list);
+ }
+
+ return 0;
}
static int bcm63xx_spi_prepare_transfer(struct spi_master *master)
@@ -264,41 +300,76 @@ static int bcm63xx_spi_transfer_one(struct spi_master *master,
struct spi_message *m)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
- struct spi_transfer *t;
+ struct spi_transfer *t, *first = NULL;
struct spi_device *spi = m->spi;
int status = 0;
- unsigned int timeout = 0;
-
+ unsigned int n_transfers = 0, total_len = 0;
+ bool can_use_prepend = false;
+
+ /*
+ * This SPI controller does not support keeping CS active after a
+ * transfer.
+ * Work around this by merging as many transfers we can into one big
+ * full-duplex transfers.
+ */
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;
- /* configure adapter for a new transfer */
- bcm63xx_spi_setup_transfer(spi, t);
+ if (!first)
+ first = t;
+
+ n_transfers++;
+ total_len += t->len;
+
+ if (n_transfers == 2 && !first->rx_buf && !t->tx_buf &&
+ first->len <= BCM63XX_SPI_MAX_PREPEND)
+ can_use_prepend = true;
+ else if (can_use_prepend && t->tx_buf)
+ can_use_prepend = false;
+
+ /* we can only transfer one fifo worth of data */
+ if ((can_use_prepend &&
+ total_len > (bs->fifo_size + BCM63XX_SPI_MAX_PREPEND)) ||
+ (!can_use_prepend && total_len > bs->fifo_size)) {
+ dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n",
+ total_len, bs->fifo_size);
+ status = -EINVAL;
+ goto exit;
+ }
+
+ /* all combined transfers have to have the same speed */
+ if (t->speed_hz != first->speed_hz) {
+ dev_err(&spi->dev, "unable to change speed between transfers\n");
+ status = -EINVAL;
+ goto exit;
+ }
- while (len) {
- /* send the data */
- len -= bcm63xx_txrx_bufs(spi, t);
+ /* 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)) {
+ /* configure adapter for a new transfer */
+ bcm63xx_spi_setup_transfer(spi, first);
- timeout = wait_for_completion_timeout(&bs->done, HZ);
- if (!timeout) {
- status = -ETIMEDOUT;
+ /* send the data */
+ status = bcm63xx_txrx_bufs(spi, first, n_transfers);
+ if (status)
goto exit;
- }
- /* read out all data */
- rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
+ m->actual_length += total_len;
- /* Read out all the data */
- if (rx_tail)
- memcpy_fromio(bs->rx_ptr, bs->rx_io, rx_tail);
+ first = NULL;
+ n_transfers = 0;
+ total_len = 0;
+ can_use_prepend = false;
}
-
- m->actual_length += t->len;
}
exit:
m->status = status;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-18 11:53:27 +0000