Marc Schink has uploaded this change for review.

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helpers: Add reverse_byte() and reverse_bytes()

Change-Id: I9d2e1e2856c835d22eed3b3a34bc0379773dd831
Signed-off-by: Marc Schink <flashrom-dev@marcschink.de>
---
M ch341a_spi.c
M flash.h
M helpers.c
3 files changed, 21 insertions(+), 11 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/86/28086/1

diff --git a/ch341a_spi.c b/ch341a_spi.c
index f88b624..44f20f2 100644
--- a/ch341a_spi.c
+++ b/ch341a_spi.c
@@ -274,15 +274,6 @@
 	return ret;
 }
 
-/* ch341 requires LSB first, swap the bit order before send and after receive */
-static uint8_t swap_byte(uint8_t x)
-{
-	x = ((x >> 1) & 0x55) | ((x << 1) & 0xaa);
-	x = ((x >> 2) & 0x33) | ((x << 2) & 0xcc);
-	x = ((x >> 4) & 0x0f) | ((x << 4) & 0xf0);
-	return x;
-}
-
 /* The assumed map between UIO command bits, pins on CH341A chip and pins on SPI chip:
  * UIO	CH341A	SPI	CH341A SPI name
  * 0	D0/15	CS/1	(CS0)
@@ -372,7 +363,7 @@
 		*ptr++ = CH341A_CMD_SPI_STREAM;
 		unsigned int i;
 		for (i = 0; i < write_now; ++i)
-			*ptr++ = swap_byte(*writearr++);
+			*ptr++ = reverse_byte(*writearr++);
 		if (read_now) {
 			memset(ptr, 0xFF, read_now);
 			read_left -= read_now;
@@ -387,7 +378,7 @@
 
 	unsigned int i;
 	for (i = 0; i < readcnt; i++) {
-		*readarr++ = swap_byte(rbuf[writecnt + i]);
+		*readarr++ = reverse_byte(rbuf[writecnt + i]);
 	}
 
 	return 0;
diff --git a/flash.h b/flash.h
index fca3775..01ff5cd 100644
--- a/flash.h
+++ b/flash.h
@@ -295,6 +295,8 @@
 int min(int a, int b);
 char *strcat_realloc(char *dest, const char *src);
 void tolower_string(char *str);
+uint8_t reverse_byte(uint8_t x);
+void reverse_bytes(uint8_t *dst, const uint8_t *src, size_t length);
 #ifdef __MINGW32__
 char* strtok_r(char *str, const char *delim, char **nextp);
 #endif
diff --git a/helpers.c b/helpers.c
index 2fcda65..a714908 100644
--- a/helpers.c
+++ b/helpers.c
@@ -66,6 +66,23 @@
 		*str = (char)tolower((unsigned char)*str);
 }
 
+uint8_t reverse_byte(uint8_t x)
+{
+	x = ((x >> 1) & 0x55) | ((x << 1) & 0xaa);
+	x = ((x >> 2) & 0x33) | ((x << 2) & 0xcc);
+	x = ((x >> 4) & 0x0f) | ((x << 4) & 0xf0);
+
+	return x;
+}
+
+void reverse_bytes(uint8_t *dst, const uint8_t *src, size_t length)
+{
+	size_t i;
+
+	for (i = 0; i < length; i++)
+		dst[i] = reverse_byte(src[i]);
+}
+
 /* FIXME: Find a better solution for MinGW. Maybe wrap strtok_s (C11) if it becomes available */
 #ifdef __MINGW32__
 char* strtok_r(char *str, const char *delim, char **nextp)

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