integrator: make flash writeable on boot

This reconfigures the EBI (External Bus Interface) on the
integrator so that chip select 1, handling the flash memory, is
set to writeable. Without this it is not possible for U-Boot to
access flash memory and it crashes on startup since CFI won't
work properly.

Since this is the first time we use the EBI, we create a header
file for its registers.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

board/armltd/integrator/arm-ebi.h

@@ -0,0 +1,62 @@
+/*
+ * (C) Copyright 2011
+ * Linaro
+ * Linus Walleij <linus.walleij@linaro.org>
+ * Register definitions for the External Bus Interface (EBI)
+ * found in the ARM Integrator AP and CP reference designs
+ *
+ * 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
+ */
+
+#ifndef __ARM_EBI_H
+#define __ARM_EBI_H
+
+#define EBI_BASE		0x12000000
+
+#define EBI_CSR0_REG		0x00 /* CS0 = Boot ROM */
+#define EBI_CSR1_REG		0x04 /* CS1 = Flash */
+#define EBI_CSR2_REG		0x08 /* CS2 = SSRAM */
+#define EBI_CSR3_REG		0x0C /* CS3 = Expansion memory */
+/*
+ * The four upper bits are the waitstates for each chip select
+ * 0x00 = 2 cycles, 0x10 = 3 cycles, ... 0xe0 = 16 cycles, 0xf0 = 16 cycles
+ */
+#define EBI_CSR_WAIT_MASK	0xF0
+/* Whether memory is synchronous or asynchronous */
+#define EBI_CSR_SYNC_MASK	0xF7
+#define EBI_CSR_ASYNC		0x00
+#define EBI_CSR_SYNC		0x08
+/* Whether memory is write enabled or not */
+#define EBI_CSR_WREN_MASK	0xFB
+#define EBI_CSR_WREN_DISABLE	0x00
+#define EBI_CSR_WREN_ENABLE	0x04
+/* Memory bit width for each chip select */
+#define EBI_CSR_MEMSIZE_MASK	0xFC
+#define EBI_CSR_MEMSIZE_8BIT	0x00
+#define EBI_CSR_MEMSIZE_16BIT	0x01
+#define EBI_CSR_MEMSIZE_32BIT	0x02
+
+/*
+ * The lock register need to be written with 0xa05f before anything in the
+ * EBI can be changed.
+ */
+#define EBI_LOCK_REG		0x20
+#define EBI_UNLOCK_MAGIC	0xA05F
+
+#endif

board/armltd/integrator/integrator.c

@@ -36,6 +36,7 @@
 #include <common.h>
 #include <netdev.h>
 #include <asm/io.h>
+#include "arm-ebi.h"
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -56,6 +57,8 @@ void show_boot_progress(int progress)
 
 int board_init (void)
 {
+	u32 val;
+
 	/* arch number of Integrator Board */
 #ifdef CONFIG_ARCH_CINTEGRATOR
 	gd->bd->bi_arch_number = MACH_TYPE_CINTEGRATOR;
@@ -73,6 +76,18 @@ extern void cm_remap(void);
 	cm_remap();	/* remaps writeable memory to 0x00000000 */
 #endif
 
+	/*
+	 * The system comes up with the flash memory non-writable and
+	 * configuration locked. If we want U-Boot to be used for flash
+	 * access we cannot have the flash memory locked.
+	 */
+	writel(EBI_UNLOCK_MAGIC, EBI_BASE + EBI_LOCK_REG);
+	val = readl(EBI_BASE + EBI_CSR1_REG);
+	val &= EBI_CSR_WREN_MASK;
+	val |= EBI_CSR_WREN_ENABLE;
+	writel(val, EBI_BASE + EBI_CSR1_REG);
+	writel(0, EBI_BASE + EBI_LOCK_REG);
+
 	icache_enable ();
 
 	return 0;