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-rw-r--r--target/linux/brcm63xx/patches-3.8/002-spi-bcm63xx-fix-multi-transfer-messages.patch240
1 files changed, 240 insertions, 0 deletions
diff --git a/target/linux/brcm63xx/patches-3.8/002-spi-bcm63xx-fix-multi-transfer-messages.patch b/target/linux/brcm63xx/patches-3.8/002-spi-bcm63xx-fix-multi-transfer-messages.patch
new file mode 100644
index 000000000..85b8524de
--- /dev/null
+++ b/target/linux/brcm63xx/patches-3.8/002-spi-bcm63xx-fix-multi-transfer-messages.patch
@@ -0,0 +1,240 @@
+From 725e81d507b1098cd275d4e3333c77c4b750fa79 Mon Sep 17 00:00:00 2001
+From: Jonas Gorski <jogo@openwrt.org>
+Date: Sun, 9 Dec 2012 01:53:05 +0100
+Subject: [PATCH V2 2/2] spi/bcm63xx: work around inability to keep CS up
+
+This SPI controller does not support keeping CS asserted after sending
+a transfer.
+Since messages expected on this SPI controller are rather short, we can
+work around it for normal use cases by sending all transfers at once in
+a big full duplex stream.
+
+This means that we cannot change the speed between transfers if they
+require CS to be kept asserted, but these would have been rejected
+before anyway because of the inability of keeping CS asserted.
+
+Signed-off-by: Jonas Gorski <jogo@openwrt.org>
+---
+V1 -> V2:
+ * split out rejection logic into separate patch
+ * fixed return type of bcm63xx_txrx_bufs()
+ * slightly reworked bcm63xx_txrx_bufs, obsoleting one local variable
+
+ drivers/spi/spi-bcm63xx.c | 134 +++++++++++++++++++++++++++++++++++----------
+ 1 file changed, 106 insertions(+), 28 deletions(-)
+
+--- 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;
+
+@@ -169,13 +171,17 @@ static int bcm63xx_spi_setup(struct spi_
+ return 0;
+ }
+
+-static 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 timeout = 0;
++ 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);
+@@ -183,19 +189,45 @@ static int bcm63xx_txrx_bufs(struct spi_
+ dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
+ t->tx_buf, t->rx_buf, t->len);
+
+- if (t->tx_buf)
+- memcpy_toio(bs->tx_io, t->tx_buf, t->len);
++ if (num_transfers > 1 && t->tx_buf && t->len <= BCM63XX_SPI_MAX_PREPEND)
++ prepend_len = t->len;
++
++ /* 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) {
+@@ -209,7 +241,7 @@ static int bcm63xx_txrx_bufs(struct 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);
+
+@@ -223,9 +255,25 @@ static int bcm63xx_txrx_bufs(struct spi_
+ /* 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 */
+- if (rx_tail)
+- memcpy_fromio(t->rx_ptr, bs->rx_io, rx_tail);
++ 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;
+ }
+@@ -252,46 +300,76 @@ static int bcm63xx_spi_transfer_one(stru
+ 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 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) {
+ status = bcm63xx_spi_check_transfer(spi, t);
+ if (status < 0)
+ goto exit;
+
++ 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 (t->len > bs->fifo_size) {
++ 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",
+- t->len, bs->fifo_size);
++ total_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");
++ /* 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;
+ }
+
+- if (!t->cs_change &&
+- !list_is_last(&t->transfer_list, &m->transfers)) {
+- dev_err(&spi->dev, "unable to keep CS asserted between transfers\n");
++ /* 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;
+ }
+
+- /* configure adapter for a new transfer */
+- bcm63xx_spi_setup_transfer(spi, t);
+-
+- /* send the data */
+- status = bcm63xx_txrx_bufs(spi, t);
+- if (status)
+- goto exit;
+-
+- m->actual_length += t->len;
++ if (t->cs_change ||
++ list_is_last(&t->transfer_list, &m->transfers)) {
++ /* configure adapter for a new transfer */
++ bcm63xx_spi_setup_transfer(spi, first);
++
++ /* send the data */
++ status = bcm63xx_txrx_bufs(spi, first, n_transfers);
++ if (status)
++ goto exit;
++
++ m->actual_length += total_len;
++
++ first = NULL;
++ n_transfers = 0;
++ total_len = 0;
++ can_use_prepend = false;
++ }
+ }
+ exit:
+ m->status = status;
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