The patch titled
mpc52xx_psc_spi: fix block transfer
has been added to the -mm tree. Its filename is
mpc52xx_psc_spi-fix-block-transfer.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
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Subject: mpc52xx_psc_spi: fix block transfer
From: Luotao Fu <l.fu@xxxxxxxxxxxxxx>
The block transfer routine in the mpc52xx psc spi driver misinterpret the
datasheet. According to the processor datasheet the chipselect is held as
long as the EOF is not written. Theoretically block of any sizes can be
transferred in this way. The old routine however writes an EOF after
every word, which has the size of size_of_word. This makes the transfer
slow. Also fixed some duplicate code.
Signed-off-by: Luotao Fu <l.fu@xxxxxxxxxxxxxx>
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/spi/mpc52xx_psc_spi.c | 22 +++++++---------------
1 file changed, 7 insertions(+), 15 deletions(-)
diff -puN drivers/spi/mpc52xx_psc_spi.c~mpc52xx_psc_spi-fix-block-transfer drivers/spi/mpc52xx_psc_spi.c
--- a/drivers/spi/mpc52xx_psc_spi.c~mpc52xx_psc_spi-fix-block-transfer
+++ a/drivers/spi/mpc52xx_psc_spi.c
@@ -148,7 +148,6 @@ static int mpc52xx_psc_spi_transfer_rxtx
unsigned rfalarm;
unsigned send_at_once = MPC52xx_PSC_BUFSIZE;
unsigned recv_at_once;
- unsigned bpw = mps->bits_per_word / 8;
if (!t->tx_buf && !t->rx_buf && t->len)
return -EINVAL;
@@ -164,22 +163,15 @@ static int mpc52xx_psc_spi_transfer_rxtx
}
dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once);
- if (tx_buf) {
- for (; send_at_once; sb++, send_at_once--) {
- /* set EOF flag */
- if (mps->bits_per_word
- && (sb + 1) % bpw == 0)
- out_8(&psc->ircr2, 0x01);
+ for (; send_at_once; sb++, send_at_once--) {
+ /* set EOF flag before the last word is sent */
+ if (send_at_once == 1)
+ out_8(&psc->ircr2, 0x01);
+
+ if (tx_buf)
out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);
- }
- } else {
- for (; send_at_once; sb++, send_at_once--) {
- /* set EOF flag */
- if (mps->bits_per_word
- && ((sb + 1) % bpw) == 0)
- out_8(&psc->ircr2, 0x01);
+ else
out_8(&psc->mpc52xx_psc_buffer_8, 0);
- }
}
_
Patches currently in -mm which might be from l.fu@xxxxxxxxxxxxxx are
mpc52xx_psc_spi-fix-block-transfer.patch
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