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-rw-r--r--cpu/blackfin/reset.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/cpu/blackfin/reset.c b/cpu/blackfin/reset.c
new file mode 100644
index 0000000..d1e34b3
--- /dev/null
+++ b/cpu/blackfin/reset.c
@@ -0,0 +1,96 @@
+/*
+ * reset.c - logic for resetting the cpu
+ *
+ * Copyright (c) 2005-2008 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <common.h>
+#include <command.h>
+#include <asm/blackfin.h>
+#include "cpu.h"
+
+/* A system soft reset makes external memory unusable so force
+ * this function into L1. We use the compiler ssync here rather
+ * than SSYNC() because it's safe (no interrupts and such) and
+ * we save some L1. We do not need to force sanity in the SYSCR
+ * register as the BMODE selection bit is cleared by the soft
+ * reset while the Core B bit (on dual core parts) is cleared by
+ * the core reset.
+ */
+__attribute__ ((__l1_text__, __noreturn__))
+void bfin_reset(void)
+{
+ /* Wait for completion of "system" events such as cache line
+ * line fills so that we avoid infinite stalls later on as
+ * much as possible. This code is in L1, so it won't trigger
+ * any such event after this point in time.
+ */
+ __builtin_bfin_ssync();
+
+ while (1) {
+ /* Initiate System software reset. */
+ bfin_write_SWRST(0x7);
+
+ /* Due to the way reset is handled in the hardware, we need
+ * to delay for 7 SCLKS. The only reliable way to do this is
+ * to calculate the CCLK/SCLK ratio and multiply 7. For now,
+ * we'll assume worse case which is a 1:15 ratio.
+ */
+ asm(
+ "LSETUP (1f, 1f) LC0 = %0\n"
+ "1: nop;"
+ :
+ : "a" (15 * 7)
+ : "LC0", "LB0", "LT0"
+ );
+
+ /* Clear System software reset */
+ bfin_write_SWRST(0);
+
+ /* Wait for the SWRST write to complete. Cannot rely on SSYNC
+ * though as the System state is all reset now.
+ */
+ asm(
+ "LSETUP (1f, 1f) LC1 = %0\n"
+ "1: nop;"
+ :
+ : "a" (15 * 1)
+ : "LC1", "LB1", "LT1"
+ );
+
+ /* Issue core reset */
+ asm("raise 1");
+ }
+}
+
+/* We need to trampoline ourselves up into L1 since our linker
+ * does not have relaxtion support and will only generate a
+ * PC relative call with a 25 bit immediate. This is not enough
+ * to get us from the top of SDRAM into L1.
+ */
+__attribute__ ((__noreturn__))
+static inline void bfin_reset_trampoline(void)
+{
+ if (board_reset)
+ board_reset();
+ while (1)
+ asm("jump (%0);" : : "a" (bfin_reset));
+}
+
+__attribute__ ((__noreturn__))
+void bfin_reset_or_hang(void)
+{
+#ifdef CONFIG_PANIC_HANG
+ hang();
+#else
+ bfin_reset_trampoline();
+#endif
+}
+
+int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+ bfin_reset_trampoline();
+ return 0;
+}