MIPS: Consolidate idle loop / WAIT instruction support in a single file.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c
new file mode 100644
index 0000000..1e9d938
--- /dev/null
+++ b/arch/mips/kernel/idle.c
@@ -0,0 +1,232 @@
+/*
+ * MIPS idle loop and WAIT instruction support.
+ *
+ * Copyright (C) xxxx the Anonymous
+ * Copyright (C) 1994 - 2006 Ralf Baechle
+ * Copyright (C) 2003, 2004 Maciej W. Rozycki
+ * Copyright (C) 2001, 2004, 2011, 2012 MIPS Technologies, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/irqflags.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <asm/cpu.h>
+#include <asm/cpu-info.h>
+#include <asm/mipsregs.h>
+
+/*
+ * Not all of the MIPS CPUs have the "wait" instruction available. Moreover,
+ * the implementation of the "wait" feature differs between CPU families. This
+ * points to the function that implements CPU specific wait.
+ * The wait instruction stops the pipeline and reduces the power consumption of
+ * the CPU very much.
+ */
+void (*cpu_wait)(void);
+EXPORT_SYMBOL(cpu_wait);
+
+static void r3081_wait(void)
+{
+ unsigned long cfg = read_c0_conf();
+ write_c0_conf(cfg | R30XX_CONF_HALT);
+}
+
+static void r39xx_wait(void)
+{
+ local_irq_disable();
+ if (!need_resched())
+ write_c0_conf(read_c0_conf() | TX39_CONF_HALT);
+ local_irq_enable();
+}
+
+extern void r4k_wait(void);
+
+/*
+ * This variant is preferable as it allows testing need_resched and going to
+ * sleep depending on the outcome atomically. Unfortunately the "It is
+ * implementation-dependent whether the pipeline restarts when a non-enabled
+ * interrupt is requested" restriction in the MIPS32/MIPS64 architecture makes
+ * using this version a gamble.
+ */
+void r4k_wait_irqoff(void)
+{
+ local_irq_disable();
+ if (!need_resched())
+ __asm__(" .set push \n"
+ " .set mips3 \n"
+ " wait \n"
+ " .set pop \n");
+ local_irq_enable();
+ __asm__(" .globl __pastwait \n"
+ "__pastwait: \n");
+}
+
+/*
+ * The RM7000 variant has to handle erratum 38. The workaround is to not
+ * have any pending stores when the WAIT instruction is executed.
+ */
+static void rm7k_wait_irqoff(void)
+{
+ local_irq_disable();
+ if (!need_resched())
+ __asm__(
+ " .set push \n"
+ " .set mips3 \n"
+ " .set noat \n"
+ " mfc0 $1, $12 \n"
+ " sync \n"
+ " mtc0 $1, $12 # stalls until W stage \n"
+ " wait \n"
+ " mtc0 $1, $12 # stalls until W stage \n"
+ " .set pop \n");
+ local_irq_enable();
+}
+
+/*
+ * 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!
+ */
+static void au1k_wait(void)
+{
+ __asm__(" .set mips3 \n"
+ " cache 0x14, 0(%0) \n"
+ " cache 0x14, 32(%0) \n"
+ " sync \n"
+ " nop \n"
+ " wait \n"
+ " nop \n"
+ " nop \n"
+ " nop \n"
+ " nop \n"
+ " .set mips0 \n"
+ : : "r" (au1k_wait));
+}
+
+static int __initdata nowait;
+
+static int __init wait_disable(char *s)
+{
+ nowait = 1;
+
+ return 1;
+}
+
+__setup("nowait", wait_disable);
+
+void __init check_wait(void)
+{
+ struct cpuinfo_mips *c = ¤t_cpu_data;
+
+ if (nowait) {
+ printk("Wait instruction disabled.\n");
+ return;
+ }
+
+ switch (c->cputype) {
+ case CPU_R3081:
+ case CPU_R3081E:
+ cpu_wait = r3081_wait;
+ break;
+ case CPU_TX3927:
+ cpu_wait = r39xx_wait;
+ break;
+ case CPU_R4200:
+/* case CPU_R4300: */
+ case CPU_R4600:
+ case CPU_R4640:
+ case CPU_R4650:
+ case CPU_R4700:
+ case CPU_R5000:
+ case CPU_R5500:
+ case CPU_NEVADA:
+ case CPU_4KC:
+ case CPU_4KEC:
+ case CPU_4KSC:
+ case CPU_5KC:
+ case CPU_25KF:
+ case CPU_PR4450:
+ case CPU_BMIPS3300:
+ case CPU_BMIPS4350:
+ case CPU_BMIPS4380:
+ case CPU_BMIPS5000:
+ case CPU_CAVIUM_OCTEON:
+ case CPU_CAVIUM_OCTEON_PLUS:
+ case CPU_CAVIUM_OCTEON2:
+ case CPU_JZRISC:
+ case CPU_LOONGSON1:
+ case CPU_XLR:
+ case CPU_XLP:
+ cpu_wait = r4k_wait;
+ break;
+
+ case CPU_RM7000:
+ cpu_wait = rm7k_wait_irqoff;
+ break;
+
+ case CPU_M14KC:
+ case CPU_M14KEC:
+ case CPU_24K:
+ case CPU_34K:
+ case CPU_1004K:
+ cpu_wait = r4k_wait;
+ if (read_c0_config7() & MIPS_CONF7_WII)
+ cpu_wait = r4k_wait_irqoff;
+ break;
+
+ case CPU_74K:
+ cpu_wait = r4k_wait;
+ if ((c->processor_id & 0xff) >= PRID_REV_ENCODE_332(2, 1, 0))
+ cpu_wait = r4k_wait_irqoff;
+ break;
+
+ case CPU_TX49XX:
+ cpu_wait = r4k_wait_irqoff;
+ break;
+ case CPU_ALCHEMY:
+ cpu_wait = au1k_wait;
+ break;
+ case CPU_20KC:
+ /*
+ * WAIT on Rev1.0 has E1, E2, E3 and E16.
+ * WAIT on Rev2.0 and Rev3.0 has E16.
+ * Rev3.1 WAIT is nop, why bother
+ */
+ if ((c->processor_id & 0xff) <= 0x64)
+ break;
+
+ /*
+ * Another rev is incremeting c0_count at a reduced clock
+ * rate while in WAIT mode. So we basically have the choice
+ * between using the cp0 timer as clocksource or avoiding
+ * the WAIT instruction. Until more details are known,
+ * disable the use of WAIT for 20Kc entirely.
+ cpu_wait = r4k_wait;
+ */
+ break;
+ case CPU_RM9000:
+ if ((c->processor_id & 0x00ff) >= 0x40)
+ cpu_wait = r4k_wait;
+ break;
+ default:
+ break;
+ }
+}
+
+void arch_cpu_idle(void)
+{
+#ifdef CONFIG_MIPS_MT_SMTC
+ extern void smtc_idle_loop_hook(void);
+
+ smtc_idle_loop_hook();
+#endif
+ if (cpu_wait)
+ (*cpu_wait)();
+ else
+ local_irq_enable();
+}