Prior to release 6 of the MIPS architecture it has been implementation
dependent whether masked interrupts cause a wait instruction to return,
so the kernel has effectively had to maintain a whitelist of cores upon
which it is safe to use the r4k_wait_irqoff cpu_wait implementation.
With MIPSr6 this is no longer implementation dependent and
r4k_wait_irqoff can always be used.
Remove the existing I6400 case which will no longer ever be hit, and was
incorrect anyway since I6400 & r6 in general doesn't have the WII bit.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---
arch/mips/kernel/idle.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c
index ab1478d..3e2b0b6 100644
--- a/arch/mips/kernel/idle.c
+++ b/arch/mips/kernel/idle.c
@@ -134,6 +134,16 @@ void __init check_wait(void)
return;
}
+ /*
+ * MIPSr6 specifies that masked interrupts should unblock an executing
+ * wait instruction, and thus that it is safe for us to use
+ * r4k_wait_irqoff. Yippee!
+ */
+ if (cpu_has_mips_r6) {
+ cpu_wait = r4k_wait_irqoff;
+ return;
+ }
+
switch (current_cpu_type()) {
case CPU_R3081:
case CPU_R3081E:
@@ -196,7 +206,6 @@ void __init check_wait(void)
case CPU_INTERAPTIV:
case CPU_M5150:
case CPU_QEMU_GENERIC:
- case CPU_I6400:
cpu_wait = r4k_wait;
if (read_c0_config7() & MIPS_CONF7_WII)
cpu_wait = r4k_wait_irqoff;
--
2.5.3
