162 lines
4.3 KiB
Diff
162 lines
4.3 KiB
Diff
From 243970ea035623f70431a80ece802f572cd446be Mon Sep 17 00:00:00 2001
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From: Jonas Gorski <jogo@openwrt.org>
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Date: Sun, 9 Dec 2012 00:10:00 +0100
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Subject: [PATCH V2 1/2] spi/bcm63xx: reject transfers unable to transfer
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The hardware does not support keeping CS asserted after sending one
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FIFO buffer worth of data, so reject transfers requiring CS being kept
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asserted, either between transers or for a certain time after it,
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or exceeding the FIFO size.
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Signed-off-by: Jonas Gorski <jogo@openwrt.org>
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---
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drivers/spi/spi-bcm63xx.c | 91 +++++++++++++++++++++------------------------
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1 file changed, 42 insertions(+), 49 deletions(-)
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--- a/drivers/spi/spi-bcm63xx.c
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+++ b/drivers/spi/spi-bcm63xx.c
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@@ -49,16 +49,10 @@ struct bcm63xx_spi {
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unsigned int msg_type_shift;
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unsigned int msg_ctl_width;
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- /* Data buffers */
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- const unsigned char *tx_ptr;
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- unsigned char *rx_ptr;
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-
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/* data iomem */
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u8 __iomem *tx_io;
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const u8 __iomem *rx_io;
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- int remaining_bytes;
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-
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struct clk *clk;
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struct platform_device *pdev;
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};
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@@ -175,24 +169,13 @@ static int bcm63xx_spi_setup(struct spi_
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return 0;
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}
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-/* Fill the TX FIFO with as many bytes as possible */
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-static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs)
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-{
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- u8 size;
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-
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- /* Fill the Tx FIFO with as many bytes as possible */
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- size = bs->remaining_bytes < bs->fifo_size ? bs->remaining_bytes :
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- bs->fifo_size;
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- memcpy_toio(bs->tx_io, bs->tx_ptr, size);
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- bs->remaining_bytes -= size;
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-}
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-
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-static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi,
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- struct spi_transfer *t)
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+static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
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{
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struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
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u16 msg_ctl;
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u16 cmd;
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+ u8 rx_tail;
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+ unsigned int timeout = 0;
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/* Disable the CMD_DONE interrupt */
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bcm_spi_writeb(bs, 0, SPI_INT_MASK);
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@@ -200,14 +183,8 @@ static unsigned int bcm63xx_txrx_bufs(st
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dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
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t->tx_buf, t->rx_buf, t->len);
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- /* Transmitter is inhibited */
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- bs->tx_ptr = t->tx_buf;
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- bs->rx_ptr = t->rx_buf;
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-
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- if (t->tx_buf) {
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- bs->remaining_bytes = t->len;
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- bcm63xx_spi_fill_tx_fifo(bs);
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- }
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+ if (t->tx_buf)
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+ memcpy_toio(bs->tx_io, t->tx_buf, t->len);
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init_completion(&bs->done);
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@@ -239,7 +216,18 @@ static unsigned int bcm63xx_txrx_bufs(st
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/* Enable the CMD_DONE interrupt */
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bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK);
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- return t->len - bs->remaining_bytes;
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+ timeout = wait_for_completion_timeout(&bs->done, HZ);
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+ if (!timeout)
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+ return -ETIMEDOUT;
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+
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+ /* read out all data */
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+ rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
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+
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+ /* Read out all the data */
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+ if (rx_tail)
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+ memcpy_fromio(t->rx_ptr, bs->rx_io, rx_tail);
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+
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+ return 0;
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}
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static int bcm63xx_spi_prepare_transfer(struct spi_master *master)
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@@ -267,36 +255,41 @@ static int bcm63xx_spi_transfer_one(stru
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struct spi_transfer *t;
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struct spi_device *spi = m->spi;
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int status = 0;
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- unsigned int timeout = 0;
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list_for_each_entry(t, &m->transfers, transfer_list) {
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- unsigned int len = t->len;
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- u8 rx_tail;
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-
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status = bcm63xx_spi_check_transfer(spi, t);
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if (status < 0)
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goto exit;
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+ /* we can only transfer one fifo worth of data */
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+ if (t->len > bs->fifo_size) {
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+ dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n",
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+ t->len, bs->fifo_size);
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+ status = -EINVAL;
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+ goto exit;
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+ }
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+
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+ /* CS will be deasserted directly after transfer */
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+ if (t->delay_usecs) {
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+ dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
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+ status = -EINVAL;
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+ goto exit;
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+ }
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+
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+ if (!t->cs_change &&
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+ !list_is_last(&t->transfer_list, &m->transfers)) {
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+ dev_err(&spi->dev, "unable to keep CS asserted between transfers\n");
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+ status = -EINVAL;
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+ goto exit;
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+ }
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+
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/* configure adapter for a new transfer */
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bcm63xx_spi_setup_transfer(spi, t);
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- while (len) {
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- /* send the data */
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- len -= bcm63xx_txrx_bufs(spi, t);
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-
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- timeout = wait_for_completion_timeout(&bs->done, HZ);
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- if (!timeout) {
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- status = -ETIMEDOUT;
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- goto exit;
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- }
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-
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- /* read out all data */
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- rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
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-
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- /* Read out all the data */
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- if (rx_tail)
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- memcpy_fromio(bs->rx_ptr, bs->rx_io, rx_tail);
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- }
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+ /* send the data */
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+ status = bcm63xx_txrx_bufs(spi, t);
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+ if (status)
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+ goto exit;
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m->actual_length += t->len;
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}
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