patch-2.4.19 linux-2.4.19/arch/ppc64/kernel/idle.c

• Lines: 135
• Date: Fri Aug 2 17:39:43 2002
• Orig file: linux-2.4.18/arch/ppc64/kernel/idle.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.18/arch/ppc64/kernel/idle.c linux-2.4.19/arch/ppc64/kernel/idle.c
@@ -0,0 +1,134 @@
+/*
+ * Idle daemon for PowerPC.  Idle daemon will handle any action
+ * that needs to be taken when the system becomes idle.
+ *
+ * Written by Cort Dougan (cort@cs.nmt.edu)
+ *
+ * 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/config.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+
+#include <asm/pgtable.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/mmu.h>
+#include <asm/cache.h>
+
+#include <asm/time.h>
+#include <asm/iSeries/LparData.h>
+#include <asm/iSeries/HvCall.h>
+#include <asm/iSeries/ItLpQueue.h>
+
+unsigned long maxYieldTime = 0;
+unsigned long minYieldTime = 0xffffffffffffffffUL;
+
+#ifdef CONFIG_PPC_ISERIES
+static void yield_shared_processor(void)
+{
+	struct paca_struct *lpaca = get_paca();
+	unsigned long tb;
+	unsigned long yieldTime;
+
+	HvCall_setEnabledInterrupts( HvCall_MaskIPI |
+				     HvCall_MaskLpEvent |
+				     HvCall_MaskLpProd |
+				     HvCall_MaskTimeout );
+
+	tb = get_tb();
+	/* Compute future tb value when yield should expire */
+	HvCall_yieldProcessor( HvCall_YieldTimed, tb+tb_ticks_per_jiffy );
+
+	yieldTime = get_tb() - tb;
+	if ( yieldTime > maxYieldTime )
+		maxYieldTime = yieldTime;
+
+	if ( yieldTime < minYieldTime )
+		minYieldTime = yieldTime;
+	
+	/* The decrementer stops during the yield.  Force a fake decrementer
+	 * here and let the timer_interrupt code sort out the actual time.
+	 */
+	lpaca->xLpPaca.xIntDword.xFields.xDecrInt = 1;
+	process_iSeries_events();
+}
+#endif /* CONFIG_PPC_ISERIES */
+
+int idled(void)
+{
+	struct paca_struct *lpaca;
+	long oldval;
+#ifdef CONFIG_PPC_ISERIES
+	unsigned long CTRL;
+#endif
+
+	/* endless loop with no priority at all */
+	current->nice = 20;
+	current->counter = -100;
+#ifdef CONFIG_PPC_ISERIES
+	/* ensure iSeries run light will be out when idle */
+	current->thread.flags &= ~PPC_FLAG_RUN_LIGHT;
+	CTRL = mfspr(CTRLF);
+	CTRL &= ~RUNLATCH;
+	mtspr(CTRLT, CTRL);
+#endif
+	init_idle();	
+
+	lpaca = get_paca();
+
+	for (;;) {
+#ifdef CONFIG_PPC_ISERIES
+		if ( lpaca->xLpPaca.xSharedProc ) {
+			if ( ItLpQueue_isLpIntPending( lpaca->lpQueuePtr ) )
+				process_iSeries_events();
+			if ( !current->need_resched )
+				yield_shared_processor();
+		}
+		else 
+#endif
+		{
+			/* Avoid an IPI by setting need_resched */
+			oldval = xchg(&current->need_resched, -1);
+			if (!oldval) {
+				while(current->need_resched == -1) {
+#ifdef CONFIG_PPC_ISERIES
+					HMT_medium();
+					if ( ItLpQueue_isLpIntPending( lpaca->lpQueuePtr ) )
+						process_iSeries_events();
+#endif
+					HMT_low();
+				}
+			}
+		}
+		HMT_medium();
+		if (current->need_resched) {
+			schedule();
+			check_pgt_cache();
+		}
+	}
+	return 0;
+}
+
+/*
+ * SMP entry into the idle task - calls the same thing as the
+ * non-smp versions. -- Cort
+ */
+int cpu_idle(void)
+{
+	idled();
+	return 0; 
+}