Blackfin arch: Workaround reboot bug, issue SSYNC at the start of bfin_reset

reboot failes on BF533
http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=3500

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

2 files changed, 98 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/reboot.c b/arch/blackfin/kernel/reboot.c
new file mode 100644
index 000000000000..356078ec462b
--- /dev/null
+++ b/arch/blackfin/kernel/reboot.c
@@ -0,0 +1,78 @@
+/*
+ * arch/blackfin/kernel/reboot.c - handle shutdown/reboot
+ *
+ * Copyright 2004-2007 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/interrupt.h>
+#include <asm/bfin-global.h>
+#include <asm/reboot.h>
+#include <asm/system.h>
+
+#if defined(BF537_FAMILY) || defined(BF533_FAMILY)
+#define SYSCR_VAL       0x0
+#elif defined(BF561_FAMILY)
+#define SYSCR_VAL       0x20
+#elif defined(BF548_FAMILY)
+#define SYSCR_VAL       0x10
+#endif
+
+/* A system soft reset makes external memory unusable
+ * so force this function into L1.
+ */
+__attribute__((l1_text))
+void bfin_reset(void)
+{
+        /* force BMODE and disable Core B (as needed) */
+        bfin_write_SYSCR(SYSCR_VAL);
+
+        /* we use asm ssync here because it's save and we save some L1 */
+        asm("ssync;");
+
+        while (1) {
+                /* initiate system soft reset with magic 0x7 */
+                bfin_write_SWRST(0x7);
+                asm("ssync;");
+                /* clear system soft reset */
+                bfin_write_SWRST(0);
+                asm("ssync;");
+                /* issue core reset */
+                asm("raise 1");
+        }
+}
+
+__attribute__((weak))
+void native_machine_restart(char *cmd)
+{
+}
+
+void machine_restart(char *cmd)
+{
+        native_machine_restart(cmd);
+        local_irq_disable();
+        bfin_reset();
+}
+
+__attribute__((weak))
+void native_machine_halt(void)
+{
+        idle_with_irq_disabled();
+}
+
+void machine_halt(void)
+{
+        native_machine_halt();
+}
+
+__attribute__((weak))
+void native_machine_power_off(void)
+{
+        idle_with_irq_disabled();
+}
+
+void machine_power_off(void)
+{
+        native_machine_power_off();
+}
diff --git a/include/asm-blackfin/reboot.h b/include/asm-blackfin/reboot.h
new file mode 100644
index 000000000000..6d448b5f5985
--- /dev/null
+++ b/include/asm-blackfin/reboot.h
@@ -0,0 +1,20 @@
+/*
+ * include/asm-blackfin/reboot.h - shutdown/reboot header
+ *
+ * Copyright 2004-2007 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#ifndef __ASM_REBOOT_H__
+#define __ASM_REBOOT_H__
+
+/* optional board specific hooks */
+extern void native_machine_restart(char *cmd);
+extern void native_machine_halt(void);
+extern void native_machine_power_off(void);
+
+/* common reboot workarounds */
+extern void bfin_gpio_reset_spi0_ssel1(void);
+
+#endif