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-rw-r--r--arch/blackfin/kernel/reboot.c69
1 files changed, 40 insertions, 29 deletions
diff --git a/arch/blackfin/kernel/reboot.c b/arch/blackfin/kernel/reboot.c
index 483f93dfc1b..367e2dc0988 100644
--- a/arch/blackfin/kernel/reboot.c
+++ b/arch/blackfin/kernel/reboot.c
@@ -11,45 +11,56 @@
#include <asm/reboot.h>
#include <asm/system.h>
-#if defined(BF537_FAMILY) || defined(BF533_FAMILY) || defined(BF527_FAMILY)
-#define SYSCR_VAL 0x0
-#elif defined(BF561_FAMILY)
-#define SYSCR_VAL 0x20
-#elif defined(BF548_FAMILY)
-#define SYSCR_VAL 0x10
-#endif
-
-/*
- * Delay min 5 SCLK cycles using worst case CCLK/SCLK ratio (15)
- */
-#define SWRST_DELAY (5 * 15)
-
-/* A system soft reset makes external memory unusable
- * so force this function into L1.
+/* 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))
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;");
+ /* 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 soft reset with magic 0x7 */
+ /* Initiate System software reset. */
bfin_write_SWRST(0x7);
- /* Wait for System reset to actually reset, needs to be 5 SCLKs, */
- /* Assume CCLK / SCLK ratio is worst case (15), and use 5*15 */
-
- asm("LSETUP(.Lfoo,.Lfoo) LC0 = %0\n .Lfoo: NOP;\n"
- : : "a" (SWRST_DELAY) : "LC0", "LT0", "LB0");
+ /* 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 soft reset */
+ /* Clear System software reset */
bfin_write_SWRST(0);
- asm("ssync;");
- /* issue core reset */
+
+ /* 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");
}
}