* [PATCH] ARM: i.MX25: fixup broken DryIce GPR
@ 2016-02-03 10:49 Steffen Trumtrar
2016-02-04 7:45 ` Sascha Hauer
0 siblings, 1 reply; 2+ messages in thread
From: Steffen Trumtrar @ 2016-02-03 10:49 UTC (permalink / raw)
To: barebox; +Cc: Steffen Trumtrar
Fixup the DryIce Non-Non-Volatile-Memory GPR register.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
arch/arm/mach-imx/imx25.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/arch/arm/mach-imx/imx25.c b/arch/arm/mach-imx/imx25.c
index 8761d636820f..3cfeebbe9348 100644
--- a/arch/arm/mach-imx/imx25.c
+++ b/arch/arm/mach-imx/imx25.c
@@ -20,6 +20,9 @@
#include <mach/generic.h>
#include <linux/sizes.h>
+#define MX25_BOOTROM_HAB_MAGIC 0x3c95cac6
+#define MX25_DRYICE_GPR 0x3c
+
void imx25_setup_weimcs(size_t cs, unsigned upper, unsigned lower,
unsigned additional)
{
@@ -55,9 +58,32 @@ u64 imx_uid(void)
int imx25_init(void)
{
+ int val;
+
imx25_boot_save_loc((void *)MX25_CCM_BASE_ADDR);
add_generic_device("imx25-esdctl", 0, NULL, MX25_ESDCTL_BASE_ADDR, 0x1000, IORESOURCE_MEM, NULL);
+ /*
+ * When the i.MX25 is used with internal boot, the boot ROM always
+ * performs some HAB actions. These will copy the value from DryIce
+ * GPR (0x53ffc03c) to a location in SRAM (0x78001734) and then overwrites
+ * the GPR with 0x3c95cac6.
+ * After the HAB routine is done, the boot ROM should copy the previously
+ * saved value from SRAM back to the GPR. The last step is not done.
+ * The boot ROM is officially broken in this regard.
+ * This renders the Non-volatile memory to a Non-Non-volatile memory.
+ * To still be able to use the GPR for its intended purpose, copy the
+ * saved SRAM value back manually.
+ */
+ val = readl(MX25_IRAM_BASE_ADDR + 0x1734);
+
+ /*
+ * When there is a different value in SRAM than the magic value
+ * it must be a value saved to the GPR.
+ */
+ if (val != MX25_BOOTROM_HAB_MAGIC)
+ writel(val, MX25_DRYICE_BASE_ADDR + MX25_DRYICE_GPR);
+
return 0;
}
--
2.7.0.rc3
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