Change in flashrom[staging]: helpers: Add swap_byte() and swap_bytes()

[Marc Schink (Code Review)]

Marc Schink has uploaded a new change for review. ( https://review.coreboot.org/19993 )

Change subject: helpers: Add swap_byte() and swap_bytes()
......................................................................

helpers: Add swap_byte() and swap_bytes()

Change-Id: I9d2e1e2856c835d22eed3b3a34bc0379773dd831
Signed-off-by: Marc Schink 
---
M ch341a_spi.c
M flash.h
M helpers.c
3 files changed, 19 insertions(+), 9 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/93/19993/1

diff --git a/ch341a_spi.c b/ch341a_spi.c
index 6eb2804..1ffa437 100644
--- a/ch341a_spi.c
+++ b/ch341a_spi.c
@@ -278,15 +278,6 @@
    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)
diff --git a/flash.h b/flash.h
index da049d1..2b539a8 100644
--- a/flash.h
+++ b/flash.h
@@ -257,6 +257,8 @@
 int min(int a, int b);
 char *strcat_realloc(char *dest, const char *src);
 void tolower_string(char *str);
+uint8_t swap_byte(uint8_t x);
+void swap_bytes(uint8_t *buffer, 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 f6eae46..69c14ed 100644
--- a/helpers.c
+++ b/helpers.c
@@ -70,6 +70,23 @@
    	*str = (char)tolower((unsigned char)*str);
 }

+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;
+}
+
+void swap_bytes(uint8_t *buffer, size_t length)
+{
+	size_t i;
+
+	for (i = 0; i < length; i++)
+		buffer[i] = swap_byte(buffer[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)