sf: turn probe switch into a lookup table

This allows for arbitrarily long manufacturer ids following the JEDEC
standard of 0x7f continuation bytes.  It also makes adding new entries
easier as it's just one element in an array.  The downside is that it
increases code size a bit, but we're talking ~50 bytes.

Signed-off-by: Reinhard Meyer <u-boot@emk-elektronik.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

drivers/mtd/spi/spi_flash.c

@@ -2,6 +2,8 @@
  * SPI flash interface
  *
  * Copyright (C) 2008 Atmel Corporation
+ * Copyright (C) 2010 Reinhard Meyer, EMK Elektronik
+ *
  * Licensed under the GPL-2 or later.
  */
 
@@ -96,13 +98,68 @@ int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd,
 	return ret;
 }
 
+/*
+ * The following table holds all device probe functions
+ *
+ * shift:  number of continuation bytes before the ID
+ * idcode: the expected IDCODE or 0xff for non JEDEC devices
+ * probe:  the function to call
+ *
+ * Non JEDEC devices should be ordered in the table such that
+ * the probe functions with best detection algorithms come first.
+ *
+ * Several matching entries are permitted, they will be tried
+ * in sequence until a probe function returns non NULL.
+ *
+ * IDCODE_CONT_LEN may be redefined if a device needs to declare a
+ * larger "shift" value.  IDCODE_PART_LEN generally shouldn't be
+ * changed.  This is the max number of bytes probe functions may
+ * examine when looking up part-specific identification info.
+ *
+ * Probe functions will be given the idcode buffer starting at their
+ * manu id byte (the "idcode" in the table below).  In other words,
+ * all of the continuation bytes will be skipped (the "shift" below).
+ */
+#define IDCODE_CONT_LEN 0
+#define IDCODE_PART_LEN 5
+static const struct {
+	const u8 shift;
+	const u8 idcode;
+	struct spi_flash *(*probe) (struct spi_slave *spi, u8 *idcode);
+} flashes[] = {
+	/* Keep it sorted by define name */
+#ifdef CONFIG_SPI_FLASH_ATMEL
+	{ 0, 0x1f, spi_flash_probe_atmel, },
+#endif
+#ifdef CONFIG_SPI_FLASH_MACRONIX
+	{ 0, 0xc2, spi_flash_probe_macronix, },
+#endif
+#ifdef CONFIG_SPI_FLASH_SPANSION
+	{ 0, 0x01, spi_flash_probe_spansion, },
+#endif
+#ifdef CONFIG_SPI_FLASH_SST
+	{ 0, 0xbf, spi_flash_probe_sst, },
+#endif
+#ifdef CONFIG_SPI_FLASH_STMICRO
+	{ 0, 0x20, spi_flash_probe_stmicro, },
+#endif
+#ifdef CONFIG_SPI_FLASH_WINBOND
+	{ 0, 0xef, spi_flash_probe_winbond, },
+#endif
+	/* Keep it sorted by best detection */
+#ifdef CONFIG_SPI_FLASH_STMICRO
+	{ 0, 0xff, spi_flash_probe_stmicro, },
+#endif
+};
+#define IDCODE_LEN (IDCODE_CONT_LEN + IDCODE_PART_LEN)
+
 struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
 		unsigned int max_hz, unsigned int spi_mode)
 {
 	struct spi_slave *spi;
-	struct spi_flash *flash;
-	int ret;
-	u8 idcode[5];
+	struct spi_flash *flash = NULL;
+	int ret, i, shift;
+	u8 idcode[IDCODE_LEN], *idp;
 
 	spi = spi_setup_slave(bus, cs, max_hz, spi_mode);
 	if (!spi) {
@@ -117,53 +174,34 @@ struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
 	}
 
 	/* Read the ID codes */
-	ret = spi_flash_cmd(spi, CMD_READ_ID, &idcode, sizeof(idcode));
+	ret = spi_flash_cmd(spi, CMD_READ_ID, idcode, sizeof(idcode));
 	if (ret)
 		goto err_read_id;
 
-	debug("SF: Got idcode %02x %02x %02x %02x %02x\n", idcode[0],
-			idcode[1], idcode[2], idcode[3], idcode[4]);
-
-	switch (idcode[0]) {
-#ifdef CONFIG_SPI_FLASH_SPANSION
-	case 0x01:
-		flash = spi_flash_probe_spansion(spi, idcode);
-		break;
+#ifdef DEBUG
+	printf("SF: Got idcodes\n");
+	print_buffer(0, idcode, 1, sizeof(idcode), 0);
 #endif
-#ifdef CONFIG_SPI_FLASH_ATMEL
-	case 0x1F:
-		flash = spi_flash_probe_atmel(spi, idcode);
-		break;
-#endif
-#ifdef CONFIG_SPI_FLASH_MACRONIX
-	case 0xc2:
-		flash = spi_flash_probe_macronix(spi, idcode);
-		break;
-#endif
-#ifdef CONFIG_SPI_FLASH_WINBOND
-	case 0xef:
-		flash = spi_flash_probe_winbond(spi, idcode);
-		break;
-#endif
-#ifdef CONFIG_SPI_FLASH_STMICRO
-	case 0x20:
-	case 0xff: /* Let the stmicro func handle non-JEDEC ids */
-		flash = spi_flash_probe_stmicro(spi, idcode);
-		break;
-#endif
-#ifdef CONFIG_SPI_FLASH_SST
-	case 0xBF:
-		flash = spi_flash_probe_sst(spi, idcode);
-		break;
-#endif
-	default:
-		printf("SF: Unsupported manufacturer %02X\n", idcode[0]);
-		flash = NULL;
-		break;
-	}
 
-	if (!flash)
+	/* count the number of continuation bytes */
+	for (shift = 0, idp = idcode;
+	     shift < IDCODE_CONT_LEN && *idp == 0x7f;
+	     ++shift, ++idp)
+		continue;
+
+	/* search the table for matches in shift and id */
+	for (i = 0; i < ARRAY_SIZE(flashes); ++i)
+		if (flashes[i].shift == shift && flashes[i].idcode == *idp) {
+			/* we have a match, call probe */
+			flash = flashes[i].probe(spi, idp);
+			if (flash)
+				break;
+		}
+
+	if (!flash) {
+		printf("SF: Unsupported manufacturer %02x\n", *idp);
 		goto err_manufacturer_probe;
+	}
 
 	spi_release_bus(spi);