MIPS: BCM63XX: Add flash type detection

On BCM6358 and BCM6368 the attached flash type is exposed through a
bootstrapping register. Use it for auto detecting the flash type on
those and default to parallel flash for earlier SoCs.

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Maxime Bizon <mbizon@freebox.fr>
Cc: Florian Fainelli <florian@openwrt.org>
Cc: Kevin Cernekee <cernekee@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/3954/
Reviewed-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/bcm63xx/dev-flash.c

@@ -7,6 +7,7 @@
  *
  * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
  * Copyright (C) 2008 Florian Fainelli <florian@openwrt.org>
+ * Copyright (C) 2012 Jonas Gorski <jonas.gorski@gmail.com>
  */
 
 #include <linux/init.h>
@@ -54,16 +55,63 @@ static struct platform_device mtd_dev = {
 	},
 };
 
+static int __init bcm63xx_detect_flash_type(void)
+{
+	u32 val;
+
+	switch (bcm63xx_get_cpu_id()) {
+	case BCM6338_CPU_ID:
+	case BCM6345_CPU_ID:
+	case BCM6348_CPU_ID:
+		/* no way to auto detect so assume parallel */
+		return BCM63XX_FLASH_TYPE_PARALLEL;
+	case BCM6358_CPU_ID:
+		val = bcm_gpio_readl(GPIO_STRAPBUS_REG);
+		if (val & STRAPBUS_6358_BOOT_SEL_PARALLEL)
+			return BCM63XX_FLASH_TYPE_PARALLEL;
+		else
+			return BCM63XX_FLASH_TYPE_SERIAL;
+	case BCM6368_CPU_ID:
+		val = bcm_gpio_readl(GPIO_STRAPBUS_REG);
+		switch (val & STRAPBUS_6368_BOOT_SEL_MASK) {
+		case STRAPBUS_6368_BOOT_SEL_NAND:
+			return BCM63XX_FLASH_TYPE_NAND;
+		case STRAPBUS_6368_BOOT_SEL_SERIAL:
+			return BCM63XX_FLASH_TYPE_SERIAL;
+		case STRAPBUS_6368_BOOT_SEL_PARALLEL:
+			return BCM63XX_FLASH_TYPE_PARALLEL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
 int __init bcm63xx_flash_register(void)
 {
+	int flash_type;
 	u32 val;
 
-	/* read base address of boot chip select (0) */
-	val = bcm_mpi_readl(MPI_CSBASE_REG(0));
-	val &= MPI_CSBASE_BASE_MASK;
+	flash_type = bcm63xx_detect_flash_type();
 
-	mtd_resources[0].start = val;
-	mtd_resources[0].end = 0x1FFFFFFF;
+	switch (flash_type) {
+	case BCM63XX_FLASH_TYPE_PARALLEL:
+		/* read base address of boot chip select (0) */
+		val = bcm_mpi_readl(MPI_CSBASE_REG(0));
+		val &= MPI_CSBASE_BASE_MASK;
 
-	return platform_device_register(&mtd_dev);
+		mtd_resources[0].start = val;
+		mtd_resources[0].end = 0x1FFFFFFF;
+
+		return platform_device_register(&mtd_dev);
+	case BCM63XX_FLASH_TYPE_SERIAL:
+		pr_warn("unsupported serial flash detected\n");
+		return -ENODEV;
+	case BCM63XX_FLASH_TYPE_NAND:
+		pr_warn("unsupported NAND flash detected\n");
+		return -ENODEV;
+	default:
+		pr_err("flash detection failed for BCM%x: %d\n",
+		       bcm63xx_get_cpu_id(), flash_type);
+		return -ENODEV;
+	}
 }

arch/mips/include/asm/mach-bcm63xx/bcm63xx_dev_flash.h

@@ -1,6 +1,12 @@
 #ifndef __BCM63XX_FLASH_H
 #define __BCM63XX_FLASH_H
 
+enum {
+	BCM63XX_FLASH_TYPE_PARALLEL,
+	BCM63XX_FLASH_TYPE_SERIAL,
+	BCM63XX_FLASH_TYPE_NAND,
+};
+
 int __init bcm63xx_flash_register(void);
 
 #endif /* __BCM63XX_FLASH_H */

arch/mips/include/asm/mach-bcm63xx/bcm63xx_regs.h

@@ -507,6 +507,15 @@
 #define GPIO_BASEMODE_6368_MASK		0x7
 /* those bits must be kept as read in gpio basemode register*/
 
+#define GPIO_STRAPBUS_REG		0x40
+#define STRAPBUS_6358_BOOT_SEL_PARALLEL	(1 << 1)
+#define STRAPBUS_6358_BOOT_SEL_SERIAL	(0 << 1)
+#define STRAPBUS_6368_BOOT_SEL_MASK	0x3
+#define STRAPBUS_6368_BOOT_SEL_NAND	0
+#define STRAPBUS_6368_BOOT_SEL_SERIAL	1
+#define STRAPBUS_6368_BOOT_SEL_PARALLEL	3
+
+
 /*************************************************************************
  * _REG relative to RSET_ENET
  *************************************************************************/