drivers/spi/flashconsole: Fix shadowing local variable

Commit c9b13594eb removed the g_ prefix from
global variables, leaving the local "offset" variable shadowing the
global one. This commit partially reverts this by renaming one of the
occations and converting the flushing logic to work on the
global object.

Change-Id: I246ebdcfd3b973e6a4aa3c15fc5f32497dcf8398
Signed-off-by: Johanna Schander <coreboot@mimoja.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38171
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/drivers/spi/flashconsole.c

@@ -32,7 +32,7 @@ void flashconsole_init(void)
 {
 	uint8_t buffer[READ_BUFFER_SIZE];
 	size_t size;
-	size_t offset = 0;
+	size_t initial_offset = 0;
 	size_t len = READ_BUFFER_SIZE;
 	size_t i;
 
@@ -52,30 +52,30 @@ void flashconsole_init(void)
 	 * the sector is already erased, so we would need to read
 	 * anyways to check if it's all 0xff).
 	 */
-	for (i = 0; i < len && offset < size;) {
+	for (i = 0; i < len && initial_offset < size;) {
 		// Fill the buffer on first iteration
 		if (i == 0) {
 			len = MIN(READ_BUFFER_SIZE, size - offset);
-			if (rdev_readat(&rdev, buffer, offset, len) != len)
+			if (rdev_readat(&rdev, buffer, initial_offset, len) != len)
 				return;
 		}
 		if (buffer[i] == 0xff) {
-			offset += i;
+			initial_offset += i;
 			break;
 		}
 		// If we're done, repeat the process for the next sector
 		if (++i == READ_BUFFER_SIZE) {
-			offset += len;
+			initial_offset += len;
 			i = 0;
 		}
 	}
 	// Make sure there is still space left on the console
-	if (offset >= size) {
+	if (initial_offset >= size) {
 		printk(BIOS_INFO, "No space left on 'console' region in SPI flash\n");
 		return;
 	}
 
-	offset = offset;
+	offset = initial_offset;
 	rdev_ptr = &rdev;
 }
 
@@ -96,7 +96,6 @@ void flashconsole_tx_byte(unsigned char c)
 
 void flashconsole_tx_flush(void)
 {
-	size_t offset = offset;
 	size_t len = line_offset;
 	size_t region_size;
 	static int busy;
@@ -122,7 +121,7 @@ void flashconsole_tx_flush(void)
 	if (offset + len >= region_size)
 		return;
 
-	offset = offset + len;
+	offset += len;
 	line_offset = 0;
 
 	busy = 0;