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-rw-r--r--target/linux/ar71xx/patches-2.6.26/902-mips_clocksource_init_war.patch56
1 files changed, 38 insertions, 18 deletions
diff --git a/target/linux/ar71xx/patches-2.6.26/902-mips_clocksource_init_war.patch b/target/linux/ar71xx/patches-2.6.26/902-mips_clocksource_init_war.patch
index 7c5125f933..bdf0d0fb69 100644
--- a/target/linux/ar71xx/patches-2.6.26/902-mips_clocksource_init_war.patch
+++ b/target/linux/ar71xx/patches-2.6.26/902-mips_clocksource_init_war.patch
@@ -1,45 +1,65 @@
---- a/include/asm-mips/hazards.h
-+++ b/include/asm-mips/hazards.h
-@@ -64,7 +64,7 @@
- _ehb
- )
- ASMMACRO(back_to_back_c0_hazard,
-- _ehb
-+ _ssnop; _ssnop; _ssnop; _ehb
- )
- /*
- * gcc has a tradition of misscompiling the previous construct using the
--- a/arch/mips/kernel/cevt-r4k.c
+++ b/arch/mips/kernel/cevt-r4k.c
-@@ -187,7 +187,7 @@
+@@ -13,6 +13,22 @@
+ #include <asm/smtc_ipi.h>
+ #include <asm/time.h>
+
++/*
++ * Compare interrupt can be routed and latched outside the core,
++ * so a single execution hazard barrier may not be enough to give
++ * it time to clear as seen in the Cause register. 4 time the
++ * pipeline depth seems reasonably conservative, and empirically
++ * works better in configurations with high CPU/bus clock ratios.
++ */
++
++#define compare_change_hazard() \
++ do { \
++ irq_disable_hazard(); \
++ irq_disable_hazard(); \
++ irq_disable_hazard(); \
++ irq_disable_hazard(); \
++ } while (0)
++
+ static int mips_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+ {
+@@ -28,6 +44,7 @@
+ cnt = read_c0_count();
+ cnt += delta;
+ write_c0_compare(cnt);
++ compare_change_hazard();
+ res = ((int)(read_c0_count() - cnt) > 0) ? -ETIME : 0;
+ #ifdef CONFIG_MIPS_MT_SMTC
+ evpe(vpflags);
+@@ -187,7 +204,7 @@
*/
if (c0_compare_int_pending()) {
write_c0_compare(read_c0_count());
- irq_disable_hazard();
-+ back_to_back_c0_hazard();
++ compare_change_hazard();
if (c0_compare_int_pending())
return 0;
}
-@@ -196,7 +196,7 @@
+@@ -196,7 +213,7 @@
cnt = read_c0_count();
cnt += delta;
write_c0_compare(cnt);
- irq_disable_hazard();
-+ back_to_back_c0_hazard();
++ compare_change_hazard();
if ((int)(read_c0_count() - cnt) < 0)
break;
/* increase delta if the timer was already expired */
-@@ -205,11 +205,12 @@
+@@ -205,11 +222,12 @@
while ((int)(read_c0_count() - cnt) <= 0)
; /* Wait for expiry */
-+ back_to_back_c0_hazard();
++ compare_change_hazard();
if (!c0_compare_int_pending())
return 0;
write_c0_compare(read_c0_count());
- irq_disable_hazard();
-+ back_to_back_c0_hazard();
++ compare_change_hazard();
if (c0_compare_int_pending())
return 0;