Patchwork [U-Boot,1/2] SPI: mxc_spi: fix swapping bug and add missing swapping in unaligned rx case

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Submitter Anatolij Gustschin
Date Jan. 16, 2011, 6:17 p.m.
Message ID <1295201837-26836-1-git-send-email-agust@denx.de>
Download mbox | patch
Permalink /patch/79094/
State Accepted
Delegated to: Stefano Babic
Headers show

Comments

Anatolij Gustschin - Jan. 16, 2011, 6:17 p.m.
We need to shift only one time in each cycle in the swapping loop
for unaligned tx case. Currently two byte shift operations are
performed in each loop cycle causing zero gaps in the transmited
data, so not all data scheduled for transmition is actually
transmited.

The proper swapping in unaligned rx case is missing, so add it
as we need to put the received data into the rx buffer in the
correct byte order.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
---
 drivers/spi/mxc_spi.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
Stefano Babic - Jan. 18, 2011, 11:20 a.m.
On 01/16/2011 07:17 PM, Anatolij Gustschin wrote:
> We need to shift only one time in each cycle in the swapping loop
> for unaligned tx case. Currently two byte shift operations are
> performed in each loop cycle causing zero gaps in the transmited
> data, so not all data scheduled for transmition is actually
> transmited.

Tested on a mx35pdk.

Tested-by: Stefano Babic <sbabic@denx.de>

Best regards,
Stefano Babic

Patch

diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
index d558137..9ed2891 100644
--- a/drivers/spi/mxc_spi.c
+++ b/drivers/spi/mxc_spi.c
@@ -304,7 +304,7 @@  int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen,
 			/* Buffer is not 32-bit aligned */
 			if ((unsigned long)dout & 0x03) {
 				data = 0;
-				for (i = 0; i < 4; i++, data <<= 8) {
+				for (i = 0; i < 4; i++) {
 					data = (data << 8) | (*dout++ & 0xFF);
 				}
 			} else {
@@ -337,11 +337,11 @@  int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen,
 	if (bitlen % 32) {
 		data = reg_read(mxcs->base + MXC_CSPIRXDATA);
 		cnt = (bitlen % 32) / 8;
+		data = cpu_to_be32(data) >> ((sizeof(data) - cnt) * 8);
 		debug("SPI Rx unaligned: 0x%x\n", data);
 		if (din) {
-			for (i = 0; i < cnt; i++, data >>= 8) {
-				*din++ = data & 0xFF;
-			}
+			memcpy(din, &data, cnt);
+			din += cnt;
 		}
 		nbytes -= cnt;
 	}