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authorManuel Lauss <manuel.lauss@gmail.com>2013-06-08 19:15:41 +0000
committerRalf Baechle <ralf@linux-mips.org>2013-06-10 17:59:46 +0200
commite63a24ddc79cc801766646fb643451ad366a1121 (patch)
treecf2b75c0fae6e1ff1e036ae890a890ba8f4fb07e
parent317ddd256b9c24b0d78fa8018f80f1e495481a10 (diff)
downloadlinux-linaro-stable-e63a24ddc79cc801766646fb643451ad366a1121.tar.gz
MIPS: Alchemy: fix wait function
Only an interrupt can wake the core from 'wait', enable interrupts locally before executing 'wait'. [ralf@linux-mips.org: This leave the race between an interrupt that's setting TIF_NEED_RESCHEd and entering the WAIT status. but at least it's going to bring Alchemy back from the dead, so I'm going to apply this patch.] Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com> Cc: Linux-MIPS <linux-mips@linux-mips.org> Cc: Maciej W. Rozycki <macro@linux-mips.org> Patchwork: https://patchwork.linux-mips.org/patch/5408/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--arch/mips/kernel/idle.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c
index 3b09b888afa9..0c655deeea4a 100644
--- a/arch/mips/kernel/idle.c
+++ b/arch/mips/kernel/idle.c
@@ -93,26 +93,27 @@ static void rm7k_wait_irqoff(void)
}
/*
- * The Au1xxx wait is available only if using 32khz counter or
- * external timer source, but specifically not CP0 Counter.
- * alchemy/common/time.c may override cpu_wait!
+ * Au1 'wait' is only useful when the 32kHz counter is used as timer,
+ * since coreclock (and the cp0 counter) stops upon executing it. Only an
+ * interrupt can wake it, so they must be enabled before entering idle modes.
*/
static void au1k_wait(void)
{
+ unsigned long c0status = read_c0_status() | 1; /* irqs on */
+
__asm__(
" .set mips3 \n"
" cache 0x14, 0(%0) \n"
" cache 0x14, 32(%0) \n"
" sync \n"
- " nop \n"
+ " mtc0 %1, $12 \n" /* wr c0status */
" wait \n"
" nop \n"
" nop \n"
" nop \n"
" nop \n"
" .set mips0 \n"
- : : "r" (au1k_wait));
- local_irq_enable();
+ : : "r" (au1k_wait), "r" (c0status));
}
static int __initdata nowait;