Enable sector erase function for selected ST M50 chips

Affected chips: M50FLW040A, M50FLW040B, M50FLW080A, M50FLW080B.

Corresponding to flashrom svn r1738.
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

flashchips.c

@@ -11022,7 +11022,7 @@ const struct flashchip flashchips[] = {
 					{4 * 1024, 16}, /* sector */
 					{4 * 1024, 16}, /* sector */
 				},
-				.block_erase = NULL,
+				.block_erase = erase_sector_stm50,
 			}, {
 				.eraseblocks = { {64 * 1024, 8}, },
 				.block_erase = erase_block_82802ab,
@@ -11055,7 +11055,7 @@ const struct flashchip flashchips[] = {
 					{64 * 1024, 5}, /* block */
 					{4 * 1024, 16}, /* sector */
 				},
-				.block_erase = NULL,
+				.block_erase = erase_sector_stm50,
 			}, {
 				.eraseblocks = { {64 * 1024, 8}, },
 				.block_erase = erase_block_82802ab,
@@ -11088,7 +11088,7 @@ const struct flashchip flashchips[] = {
 					{4 * 1024, 16}, /* sector */
 					{4 * 1024, 16}, /* sector */
 				},
-				.block_erase = NULL,
+				.block_erase = erase_sector_stm50,
 			}, {
 				.eraseblocks = { {64 * 1024, 16}, },
 				.block_erase = erase_block_82802ab,
@@ -11121,7 +11121,7 @@ const struct flashchip flashchips[] = {
 					{64 * 1024, 13}, /* block */
 					{4 * 1024, 16}, /* sector */
 				},
-				.block_erase = NULL,
+				.block_erase = erase_sector_stm50,
 			}, {
 				.eraseblocks = { {64 * 1024, 16}, },
 				.block_erase = erase_block_82802ab,

stm50.c

@@ -84,10 +84,9 @@ int unlock_stm50_uniform(struct flashctx *flash)
 	return 0;
 }
 
-/* This function is unused. */
-int erase_sector_stm50(struct flashctx *flash, unsigned int sector, unsigned int sectorsize)
+static int stm50_erase_sector(struct flashctx *flash, unsigned int addr)
 {
-	chipaddr bios = flash->virtual_memory + sector;
+	chipaddr bios = flash->virtual_memory + addr;
 
 	// clear status register
 	chip_writeb(flash, 0x50, bios);
@@ -96,8 +95,21 @@ int erase_sector_stm50(struct flashctx *flash, unsigned int sector, unsigned int
 	chip_writeb(flash, 0xd0, bios);
 	programmer_delay(10);
 
-	wait_82802ab(flash);
+	uint8_t status = wait_82802ab(flash);
+	print_status_82802ab(status);
 
-	/* FIXME: Check the status register for errors. */
-	return 0;
+	return status == 0x80;
+}
+
+/* Some ST M50* chips do support erasing of sectors. This function will derive the erase function to use from
+ * the length of the of the block. For calls that apparently do not address a sector (but a block) we just call
+ * the block erase function instead. FIXME: This duplicates the behavior of the remaining erasers for blocks and
+ * might be fixed when flashrom supports multiple functions per eraser or erasers that do erase parts of the
+ * chip only. */
+int erase_sector_stm50(struct flashctx *flash, unsigned int addr, unsigned int len)
+{
+	if (len == 4096)
+		return stm50_erase_sector(flash, addr);
+	else
+		return erase_block_82802ab(flash, addr, len);
 }