drivers/net/wireless/ti/wl*/spi.c: Simplify CRC computation

These devices require commands stored in buffers in an odd order,
different from that in which the CRC is computed.

Rather than make two copies of the commands in two different orders,
form the commands in logical (CRC) order, append the CRC, then byte-swap
in place to the desired order.

The old code worked fine, I'm just scratching an "ugh, that's ugly"
itch.

Signed-off-by: George Spelvin <linux@horizon.com>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 21 insertions, 22 deletions

diff --git a/drivers/net/wireless/ti/wl1251/spi.c b/drivers/net/wireless/ti/wl1251/spi.c
index e94b57cd5a2..a0aa8fa7239 100644
--- a/drivers/net/wireless/ti/wl1251/spi.c
+++ b/drivers/net/wireless/ti/wl1251/spi.c
@@ -23,6 +23,7 @@
 #include <linux/irq.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/swab.h>
 #include <linux/crc7.h>
 #include <linux/spi/spi.h>
 #include <linux/wl12xx.h>
@@ -83,46 +84,44 @@ static void wl1251_spi_reset(struct wl1251 *wl)
 
 static void wl1251_spi_wake(struct wl1251 *wl)
 {
-	u8 crc[WSPI_INIT_CMD_CRC_LEN], *cmd;
 	struct spi_transfer t;
 	struct spi_message m;
+	u8 *cmd = kzalloc(WSPI_INIT_CMD_LEN, GFP_KERNEL);
 
-	cmd = kzalloc(WSPI_INIT_CMD_LEN, GFP_KERNEL);
 	if (!cmd) {
 		wl1251_error("could not allocate cmd for spi init");
 		return;
 	}
 
-	memset(crc, 0, sizeof(crc));
 	memset(&t, 0, sizeof(t));
 	spi_message_init(&m);
 
 	/* Set WSPI_INIT_COMMAND
 	 * the data is being send from the MSB to LSB
 	 */
-	cmd[2] = 0xff;
-	cmd[3] = 0xff;
-	cmd[1] = WSPI_INIT_CMD_START | WSPI_INIT_CMD_TX;
-	cmd[0] = 0;
-	cmd[7] = 0;
-	cmd[6] |= HW_ACCESS_WSPI_INIT_CMD_MASK << 3;
-	cmd[6] |= HW_ACCESS_WSPI_FIXED_BUSY_LEN & WSPI_INIT_CMD_FIXEDBUSY_LEN;
+	cmd[0] = 0xff;
+	cmd[1] = 0xff;
+	cmd[2] = WSPI_INIT_CMD_START | WSPI_INIT_CMD_TX;
+	cmd[3] = 0;
+	cmd[4] = 0;
+	cmd[5] = HW_ACCESS_WSPI_INIT_CMD_MASK << 3;
+	cmd[5] |= HW_ACCESS_WSPI_FIXED_BUSY_LEN & WSPI_INIT_CMD_FIXEDBUSY_LEN;
+
+	cmd[6] = WSPI_INIT_CMD_IOD | WSPI_INIT_CMD_IP | WSPI_INIT_CMD_CS
+		| WSPI_INIT_CMD_WSPI | WSPI_INIT_CMD_WS;
 
 	if (HW_ACCESS_WSPI_FIXED_BUSY_LEN == 0)
-		cmd[5] |=  WSPI_INIT_CMD_DIS_FIXEDBUSY;
+		cmd[6] |= WSPI_INIT_CMD_DIS_FIXEDBUSY;
 	else
-		cmd[5] |= WSPI_INIT_CMD_EN_FIXEDBUSY;
-
-	cmd[5] |= WSPI_INIT_CMD_IOD | WSPI_INIT_CMD_IP | WSPI_INIT_CMD_CS
-		| WSPI_INIT_CMD_WSPI | WSPI_INIT_CMD_WS;
-
-	crc[0] = cmd[1];
-	crc[1] = cmd[0];
-	crc[2] = cmd[7];
-	crc[3] = cmd[6];
-	crc[4] = cmd[5];
+		cmd[6] |= WSPI_INIT_CMD_EN_FIXEDBUSY;
 
-	cmd[4] = crc7_be(0, crc, WSPI_INIT_CMD_CRC_LEN) | WSPI_INIT_CMD_END;
+	cmd[7] = crc7_be(0, cmd+2, WSPI_INIT_CMD_CRC_LEN) | WSPI_INIT_CMD_END;
+	/*
+	 * The above is the logical order; it must actually be stored
+	 * in the buffer byte-swapped.
+	 */
+	__swab32s((u32 *)cmd);
+	__swab32s((u32 *)cmd+1);
 
 	t.tx_buf = cmd;
 	t.len = WSPI_INIT_CMD_LEN;