[U-Boot] [PATCH v3] MTD/SPI: introduce table driven probing

[Reinhard Meyer]

for JEDEC devices without and with extension bytes
for non JEDEC devices
Signed-off-by: Reinhard Meyer <u-boot at emk-elektronik.de>
---
 drivers/mtd/spi/spi_flash.c |  139 +++++++++++++++++++++++++++++--------------
 1 files changed, 94 insertions(+), 45 deletions(-)

diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
index ea875dc..099eb4a 100644
--- a/drivers/mtd/spi/spi_flash.c
+++ b/drivers/mtd/spi/spi_flash.c
@@ -1,8 +1,26 @@
 /*
- * SPI flash interface
+ * (C) Copyright 2010
+ * Reinhard Meyer, EMK Elektronik, reinhard.meyer at emk-elektronik.de
  *
  * Copyright (C) 2008 Atmel Corporation
- * Licensed under the GPL-2 or later.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
  */
 
 #include <common.h>
@@ -96,13 +114,59 @@ 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
+ *
+ * IDBUF_LEN may be redefined if a device detection requires
+ * more then 5 bytes read.
+ */
+#define IDBUF_LEN 5
+const struct {
+	const u8 shift;
+	const u8 idcode;
+	struct spi_flash *(*probe) (struct spi_slave *spi, u8 *idcode);
+} flashes[] = {
+#ifdef CONFIG_SPI_FLASH_SPANSION
+	{ 0, 0x01, spi_flash_probe_spansion, },
+#endif
+#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_WINBOND
+	{ 0, 0xef, spi_flash_probe_winbond, },
+#endif
+#ifdef CONFIG_SPI_FLASH_STMICRO
+	{ 0, 0x20, spi_flash_probe_stmicro, },
+	{ 0, 0xff, spi_flash_probe_stmicro, },
+#endif
+#ifdef CONFIG_SPI_FLASH_SST
+	{ 0, 0xBF, spi_flash_probe_sst, },
+#endif
+};
+
 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;
+	struct spi_flash *flash = NULL;
 	int ret;
-	u8 idcode[5];
+	int shift;
+	int i;
+	u8 idbuf[IDBUF_LEN];
+	u8 *idp;
 
 	spi = spi_setup_slave(bus, cs, max_hz, spi_mode);
 	if (!spi) {
@@ -117,53 +181,38 @@ 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, &idbuf, sizeof(idbuf));
 	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;
-#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;
+#ifdef DEBUG
+	printf("SF: Got idcodes\n");
+	print_buffer(0, idbuf, 1, sizeof(idbuf), 0);
 #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, but
+	 * leave at least 3 bytes to the end of the buffer untouched
+	 */
+	for (shift = 0, idp = idbuf;
+		shift < (sizeof(idbuf) - 3) && *idp == 0x7f;
+			shift++, idp++)
+		;
+
+	/* 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);
 
-- 
1.5.6.5