[PATCH] cell: enable pause(0) in cpu_idle

This patch enables support for pause(0) power management state
for the Cell Broadband Processor, which is import for power efficient
operation. The pervasive infrastructure will in the future enable
us to introduce more functionality specific to the Cell's
pervasive unit.

From: Maximino Aguilar <maguilar@us.ibm.com>
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/cputable.c

@@ -273,7 +273,7 @@ struct cpu_spec	cpu_specs[] = {
 		.oprofile_model		= &op_model_power4,
 #endif
 	},
-	{	/* BE DD1.x */
+	{	/* Cell Broadband Engine */
 		.pvr_mask		= 0xffff0000,
 		.pvr_value		= 0x00700000,
 		.cpu_name		= "Cell Broadband Engine",

arch/powerpc/kernel/traps.c

@@ -230,8 +230,10 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
 void system_reset_exception(struct pt_regs *regs)
 {
 	/* See if any machine dependent calls */
-	if (ppc_md.system_reset_exception)
-		ppc_md.system_reset_exception(regs);
+	if (ppc_md.system_reset_exception) {
+		if (ppc_md.system_reset_exception(regs))
+			return;
+	}
 
 	die("System Reset", regs, SIGABRT);
 

arch/powerpc/platforms/cell/Makefile

@@ -1,4 +1,6 @@
 obj-y			+= interrupt.o iommu.o setup.o spider-pic.o
+obj-y			+= pervasive.o
+
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_SPU_FS)	+= spufs/ spu_base.o
 builtin-spufs-$(CONFIG_SPU_FS)	+= spu_syscalls.o

arch/powerpc/platforms/cell/pervasive.c

@@ -0,0 +1,229 @@
+/*
+ * CBE Pervasive Monitor and Debug
+ *
+ * (C) Copyright IBM Corporation 2005
+ *
+ * Authors: Maximino Aguilar (maguilar@us.ibm.com)
+ *          Michael N. Day (mnday@us.ibm.com)
+ *
+ * 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, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#undef DEBUG
+
+#include <linux/config.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/percpu.h>
+#include <linux/types.h>
+#include <linux/kallsyms.h>
+
+#include <asm/io.h>
+#include <asm/machdep.h>
+#include <asm/prom.h>
+#include <asm/pgtable.h>
+#include <asm/reg.h>
+
+#include "pervasive.h"
+
+static DEFINE_SPINLOCK(cbe_pervasive_lock);
+struct cbe_pervasive {
+	struct pmd_regs __iomem *regs;
+	unsigned int thread;
+};
+
+/* can't use per_cpu from setup_arch */
+static struct cbe_pervasive cbe_pervasive[NR_CPUS];
+
+static void __init cbe_enable_pause_zero(void)
+{
+	unsigned long thread_switch_control;
+	unsigned long temp_register;
+	struct cbe_pervasive *p;
+	int thread;
+
+	spin_lock_irq(&cbe_pervasive_lock);
+	p = &cbe_pervasive[smp_processor_id()];
+
+	if (!cbe_pervasive->regs)
+		goto out;
+
+	pr_debug("Power Management: CPU %d\n", smp_processor_id());
+
+	 /* Enable Pause(0) control bit */
+	temp_register = in_be64(&p->regs->pm_control);
+
+	out_be64(&p->regs->pm_control,
+		 temp_register|PMD_PAUSE_ZERO_CONTROL);
+
+	/* Enable DEC and EE interrupt request */
+	thread_switch_control  = mfspr(SPRN_TSC_CELL);
+	thread_switch_control |= TSC_CELL_EE_ENABLE | TSC_CELL_EE_BOOST;
+
+	switch ((mfspr(SPRN_CTRLF) & CTRL_CT)) {
+	case CTRL_CT0:
+		thread_switch_control |= TSC_CELL_DEC_ENABLE_0;
+		thread = 0;
+		break;
+	case CTRL_CT1:
+		thread_switch_control |= TSC_CELL_DEC_ENABLE_1;
+		thread = 1;
+		break;
+	default:
+		printk(KERN_WARNING "%s: unknown configuration\n",
+			__FUNCTION__);
+		thread = -1;
+		break;
+	}
+
+	if (p->thread != thread)
+		printk(KERN_WARNING "%s: device tree inconsistant, "
+				     "cpu %i: %d/%d\n", __FUNCTION__,
+				     smp_processor_id(),
+				     p->thread, thread);
+
+	mtspr(SPRN_TSC_CELL, thread_switch_control);
+
+out:
+	spin_unlock_irq(&cbe_pervasive_lock);
+}
+
+static void cbe_idle(void)
+{
+	unsigned long ctrl;
+
+	cbe_enable_pause_zero();
+
+	while (1) {
+		if (!need_resched()) {
+			local_irq_disable();
+			while (!need_resched()) {
+				/* go into low thread priority */
+				HMT_low();
+
+				/*
+				 * atomically disable thread execution
+				 * and runlatch.
+				 * External and Decrementer exceptions
+				 * are still handled when the thread
+				 * is disabled but now enter in
+				 * cbe_system_reset_exception()
+				 */
+				ctrl = mfspr(SPRN_CTRLF);
+				ctrl &= ~(CTRL_RUNLATCH | CTRL_TE);
+				mtspr(SPRN_CTRLT, ctrl);
+			}
+			/* restore thread prio */
+			HMT_medium();
+			local_irq_enable();
+		}
+
+		/*
+		 * turn runlatch on again before scheduling the
+		 * process we just woke up
+		 */
+		ppc64_runlatch_on();
+
+		preempt_enable_no_resched();
+		schedule();
+		preempt_disable();
+	}
+}
+
+int cbe_system_reset_exception(struct pt_regs *regs)
+{
+	switch (regs->msr & SRR1_WAKEMASK) {
+	case SRR1_WAKEEE:
+		do_IRQ(regs);
+		break;
+	case SRR1_WAKEDEC:
+		timer_interrupt(regs);
+		break;
+	case SRR1_WAKEMT:
+		/* no action required */
+		break;
+	default:
+		/* do system reset */
+		return 0;
+	}
+	/* everything handled */
+	return 1;
+}
+
+static int __init cbe_find_pmd_mmio(int cpu, struct cbe_pervasive *p)
+{
+	struct device_node *node;
+	unsigned int *int_servers;
+	char *addr;
+	unsigned long real_address;
+	unsigned int size;
+
+	struct pmd_regs __iomem *pmd_mmio_area;
+	int hardid, thread;
+	int proplen;
+
+	pmd_mmio_area = NULL;
+	hardid = get_hard_smp_processor_id(cpu);
+	for (node = NULL; (node = of_find_node_by_type(node, "cpu"));) {
+		int_servers = (void *) get_property(node,
+				"ibm,ppc-interrupt-server#s", &proplen);
+		if (!int_servers) {
+			printk(KERN_WARNING "%s misses "
+				"ibm,ppc-interrupt-server#s property",
+				node->full_name);
+			continue;
+		}
+		for (thread = 0; thread < proplen / sizeof (int); thread++) {
+			if (hardid == int_servers[thread]) {
+				addr = get_property(node, "pervasive", NULL);
+				goto found;
+			}
+		}
+	}
+
+	printk(KERN_WARNING "%s: CPU %d not found\n", __FUNCTION__, cpu);
+	return -EINVAL;
+
+found:
+	real_address = *(unsigned long*) addr;
+	addr += sizeof (unsigned long);
+	size = *(unsigned int*) addr;
+
+	pr_debug("pervasive area for CPU %d at %lx, size %x\n",
+			cpu, real_address, size);
+	p->regs = __ioremap(real_address, size, _PAGE_NO_CACHE);
+	p->thread = thread;
+	return 0;
+}
+
+void __init cell_pervasive_init(void)
+{
+	struct cbe_pervasive *p;
+	int cpu;
+	int ret;
+
+	if (!cpu_has_feature(CPU_FTR_PAUSE_ZERO))
+		return;
+
+	for_each_cpu(cpu) {
+		p = &cbe_pervasive[cpu];
+		ret = cbe_find_pmd_mmio(cpu, p);
+		if (ret)
+			return;
+	}
+
+	ppc_md.idle_loop = cbe_idle;
+	ppc_md.system_reset_exception = cbe_system_reset_exception;
+}

arch/powerpc/platforms/cell/pervasive.h

@@ -0,0 +1,62 @@
+/*
+ * Cell Pervasive Monitor and Debug interface and HW structures
+ *
+ * (C) Copyright IBM Corporation 2005
+ *
+ * Authors: Maximino Aguilar (maguilar@us.ibm.com)
+ *          David J. Erb (djerb@us.ibm.com)
+ *
+ * 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, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#ifndef PERVASIVE_H
+#define PERVASIVE_H
+
+struct pmd_regs {
+	u8 pad_0x0000_0x0800[0x0800 - 0x0000];			/* 0x0000 */
+
+	/* Thermal Sensor Registers */
+	u64  ts_ctsr1;						/* 0x0800 */
+	u64  ts_ctsr2;						/* 0x0808 */
+	u64  ts_mtsr1;						/* 0x0810 */
+	u64  ts_mtsr2;						/* 0x0818 */
+	u64  ts_itr1;						/* 0x0820 */
+	u64  ts_itr2;						/* 0x0828 */
+	u64  ts_gitr;						/* 0x0830 */
+	u64  ts_isr;						/* 0x0838 */
+	u64  ts_imr;						/* 0x0840 */
+	u64  tm_cr1;						/* 0x0848 */
+	u64  tm_cr2;						/* 0x0850 */
+	u64  tm_simr;						/* 0x0858 */
+	u64  tm_tpr;						/* 0x0860 */
+	u64  tm_str1;						/* 0x0868 */
+	u64  tm_str2;						/* 0x0870 */
+	u64  tm_tsr;						/* 0x0878 */
+
+	/* Power Management */
+	u64  pm_control;					/* 0x0880 */
+#define PMD_PAUSE_ZERO_CONTROL		0x10000
+	u64  pm_status;						/* 0x0888 */
+
+	/* Time Base Register */
+	u64  tbr;						/* 0x0890 */
+
+	u8   pad_0x0898_0x1000 [0x1000 - 0x0898];		/* 0x0898 */
+};
+
+void __init cell_pervasive_init(void);
+
+#endif

arch/powerpc/platforms/cell/setup.c

@@ -49,6 +49,7 @@
 
 #include "interrupt.h"
 #include "iommu.h"
+#include "pervasive.h"
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
@@ -165,6 +166,7 @@ static void __init cell_setup_arch(void)
 	init_pci_config_tokens();
 	find_and_init_phbs();
 	spider_init_IRQ();
+	cell_pervasive_init();
 #ifdef CONFIG_DUMMY_CONSOLE
 	conswitchp = &dummy_con;
 #endif

arch/powerpc/platforms/pseries/ras.c

@@ -51,6 +51,8 @@
 #include <asm/udbg.h>
 #include <asm/firmware.h>
 
+#include "ras.h"
+
 static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX];
 static DEFINE_SPINLOCK(ras_log_buf_lock);
 
@@ -278,7 +280,7 @@ static void fwnmi_release_errinfo(void)
 		printk("FWNMI: nmi-interlock failed: %d\n", ret);
 }
 
-void pSeries_system_reset_exception(struct pt_regs *regs)
+int pSeries_system_reset_exception(struct pt_regs *regs)
 {
 	if (fwnmi_active) {
 		struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
@@ -287,6 +289,7 @@ void pSeries_system_reset_exception(struct pt_regs *regs)
 		}
 		fwnmi_release_errinfo();
 	}
+	return 0; /* need to perform reset */
 }
 
 /*

arch/powerpc/platforms/pseries/ras.h

@@ -0,0 +1,9 @@
+#ifndef _PSERIES_RAS_H
+#define _PSERIES_RAS_H
+
+struct pt_regs;
+
+extern int pSeries_system_reset_exception(struct pt_regs *regs);
+extern int pSeries_machine_check_exception(struct pt_regs *regs);
+
+#endif /* _PSERIES_RAS_H */

arch/powerpc/platforms/pseries/setup.c

@@ -69,6 +69,7 @@
 #include <asm/smp.h>
 
 #include "plpar_wrappers.h"
+#include "ras.h"
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
@@ -80,9 +81,6 @@ extern void find_udbg_vterm(void);
 
 int fwnmi_active;  /* TRUE if an FWNMI handler is present */
 
-extern void pSeries_system_reset_exception(struct pt_regs *regs);
-extern int pSeries_machine_check_exception(struct pt_regs *regs);
-
 static void pseries_shared_idle(void);
 static void pseries_dedicated_idle(void);