MIPS: Always use r4k_wait_irqoff for MIPSr6

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@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11210/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c
index ab1478d5a4db1b247caa94527925da0d005adf10..3e2b0b6c3b08a03d2aa56025c1427befd376a48a 100644 (file)
--- 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;