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-rw-r--r--arch/arm/mach-at91/at91sam9_alt_reset.S48
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/at91sam9_alt_reset.S b/arch/arm/mach-at91/at91sam9_alt_reset.S
new file mode 100644
index 000000000000..e0256deb91fb
--- /dev/null
+++ b/arch/arm/mach-at91/at91sam9_alt_reset.S
@@ -0,0 +1,48 @@
+/*
+ * reset AT91SAM9G20 as per errata
+ *
+ * (C) BitBox Ltd 2010
+ *
+ * unless the SDRAM is cleanly shutdown before we hit the
+ * reset register it can be left driving the data bus and
+ * killing the chance of a subsequent boot from NAND
+ *
+ * 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.
+ */
+
+#include <linux/linkage.h>
+#include <asm/system.h>
+#include <mach/hardware.h>
+#include <mach/at91sam9_sdramc.h>
+#include <mach/at91_rstc.h>
+
+ .arm
+
+ .globl at91sam9_alt_reset
+
+at91sam9_alt_reset: mrc p15, 0, r0, c1, c0, 0
+ orr r0, r0, #CR_I
+ mcr p15, 0, r0, c1, c0, 0 @ enable I-cache
+
+ ldr r0, .at91_va_base_sdramc @ preload constants
+ ldr r1, .at91_va_base_rstc_cr
+
+ mov r2, #1
+ mov r3, #AT91_SDRAMC_LPCB_POWER_DOWN
+ ldr r4, =AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST
+
+ .balign 32 @ align to cache line
+
+ str r2, [r0, #AT91_SDRAMC_TR] @ disable SDRAM access
+ str r3, [r0, #AT91_SDRAMC_LPR] @ power down SDRAM
+ str r4, [r1] @ reset processor
+
+ b .
+
+.at91_va_base_sdramc:
+ .word AT91_VA_BASE_SYS + AT91_SDRAMC0
+.at91_va_base_rstc_cr:
+ .word AT91_VA_BASE_SYS + AT91_RSTC_CR