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;
+}