PPC32: Add support for CPU frequency scaling on some PowerMacs

arch/ppc/Kconfig

@@ -666,6 +666,52 @@ config MATH_EMULATION
 	  here.  Saying Y here will not hurt performance (on any machine) but
 	  will increase the size of the kernel.
 
+config CPU_FREQ
+	bool "CPU Frequency scaling"
+	help
+	  Clock scaling allows you to change the clock speed of CPUs on the
+	  fly. This is a nice method to save battery power on notebooks,
+	  because the lower the clock speed, the less power the CPU consumes.
+
+	  For more information, take a look at linux/Documentation/cpufreq or
+	  at <http://www.brodo.de/cpufreq/>
+
+	  If in doubt, say N.
+
+config CPU_FREQ_PROC_INTF
+	bool "/proc/cpufreq interface (DEPRECATED)"
+	depends on CPU_FREQ && PROC_FS
+	help
+	  This enables the /proc/cpufreq interface for controlling
+	  CPUFreq. Please note that it is recommended to use the sysfs
+	  interface instead (which is built automatically). 
+	  
+	  For details, take a look at linux/Documentation/cpufreq. 
+	  
+	  If in doubt, say N.
+
+config CPU_FREQ_24_API
+	bool "/proc/sys/cpu/ interface (2.4. / OLD)"
+	depends on CPU_FREQ
+	help
+	  This enables the /proc/sys/cpu/ sysctl interface for controlling
+	  CPUFreq, as known from the 2.4.-kernel patches for CPUFreq. 2.5
+	  uses a sysfs interface instead. Please note that some drivers do 
+	  not work well with the 2.4. /proc/sys/cpu sysctl interface,
+	  so if in doubt, say N here.
+
+	  For details, take a look at linux/Documentation/cpufreq. 
+
+	  If in doubt, say N.
+
+config CPU_FREQ_PMAC
+	bool "Support for Apple PowerBooks"
+	depends on CPU_FREQ && ADB_PMU
+	help
+	  This adds support for frequency switching on Apple PowerBooks,
+	  this currently includes some models of iBook & Titanium
+	  PowerBook.
+
 endmenu
 
 menu "General setup"

arch/ppc/platforms/Makefile

@@ -24,6 +24,9 @@ ifeq ($(CONFIG_ALL_PPC),y)
 obj-$(CONFIG_NVRAM)		+= pmac_nvram.o
 endif
 obj-$(CONFIG_PMAC_BACKLIGHT)	+= pmac_backlight.o
+ifeq ($(CONFIG_ALL_PPC),y)
+obj-$(CONFIG_CPU_FREQ_PMAC)	+= pmac_cpufreq.o
+endif
 obj-$(CONFIG_PPC_RTAS)		+= error_log.o proc_rtas.o
 obj-$(CONFIG_PREP_RESIDUAL)	+= residual.o
 obj-$(CONFIG_ADIR)		+= adir_setup.o adir_pic.o adir_pci.o

arch/ppc/platforms/pmac_cpufreq.c

+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/adb.h>
+#include <linux/pmu.h>
+#include <linux/slab.h>
+#include <linux/cpufreq.h>
+#include <linux/init.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+#include <asm/irq.h>
+#include <asm/hardirq.h>
+#include <asm/pmac_feature.h>
+#include <asm/mmu_context.h>
+#include <asm/sections.h>
+#include <asm/cputable.h>
+#include <asm/time.h>
+
+#undef DEBUG_FREQ
+
+extern void low_choose_750fx_pll(int pll);
+extern void low_sleep_handler(void);
+extern void openpic_sleep_save_intrs(void);
+extern void openpic_sleep_restore_intrs(void);
+extern void enable_kernel_altivec(void);
+extern void enable_kernel_fp(void);
+
+static unsigned int low_freq;
+static unsigned int hi_freq;
+static unsigned int cur_freq;
+static int cpufreq_uses_pmu;
+
+#define PMAC_CPU_LOW_SPEED	1
+#define PMAC_CPU_HIGH_SPEED	0
+
+static inline void
+wakeup_decrementer(void)
+{
+	set_dec(tb_ticks_per_jiffy);
+	/* No currently-supported powerbook has a 601,
+	 * so use get_tbl, not native
+	 */
+	last_jiffy_stamp(0) = tb_last_stamp = get_tbl();
+}
+
+#ifdef DEBUG_FREQ
+static inline void
+debug_calc_bogomips(void)
+{
+	/* This will cause a recalc of bogomips and display the
+	 * result. We backup/restore the value to avoid affecting the
+	 * core cpufreq framework's own calculation.
+	 */
+	extern void calibrate_delay(void);
+
+	unsigned long save_lpj = loops_per_jiffy;
+	calibrate_delay();
+	loops_per_jiffy = save_lpj;
+}
+#endif
+
+/* Switch CPU speed under 750FX CPU control
+ */
+static int __pmac
+cpu_750fx_cpu_speed(int low_speed)
+{
+#ifdef DEBUG_FREQ
+	printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));	
+#endif
+	low_choose_750fx_pll(low_speed);
+#ifdef DEBUG_FREQ
+	printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));	
+	debug_calc_bogomips();
+#endif
+
+	return 0;
+}
+
+/* Switch CPU speed under PMU control
+ */
+static int __pmac
+pmu_set_cpu_speed(unsigned int low_speed)
+{
+	struct adb_request req;
+	unsigned long save_l2cr;
+	unsigned long save_l3cr;
+	
+#ifdef DEBUG_FREQ
+	printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));	
+#endif
+	/* Disable all interrupt sources on openpic */
+	openpic_sleep_save_intrs();
+
+	/* Make sure the PMU is idle */
+	pmu_suspend();
+
+	/* Make sure the decrementer won't interrupt us */
+	asm volatile("mtdec %0" : : "r" (0x7fffffff));
+	/* Make sure any pending DEC interrupt occuring while we did
+	 * the above didn't re-enable the DEC */
+	mb();
+	asm volatile("mtdec %0" : : "r" (0x7fffffff));
+
+	/* We can now disable MSR_EE */
+	local_irq_disable();
+
+	/* Giveup the FPU & vec */
+	enable_kernel_fp();
+
+#ifdef CONFIG_ALTIVEC
+	if (cur_cpu_spec[0]->cpu_features & CPU_FTR_ALTIVEC)
+		enable_kernel_altivec();
+#endif /* CONFIG_ALTIVEC */
+
+	/* Save & disable L2 and L3 caches */
+	save_l3cr = _get_L3CR();	/* (returns -1 if not available) */
+	save_l2cr = _get_L2CR();	/* (returns -1 if not available) */
+	if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
+		_set_L3CR(save_l3cr & 0x7fffffff);
+	if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
+		_set_L2CR(save_l2cr & 0x7fffffff);
+
+	/* Send the new speed command. My assumption is that this command
+	 * will cause PLL_CFG[0..3] to be changed next time CPU goes to sleep
+	 */
+	pmu_request(&req, NULL, 6, PMU_CPU_SPEED, 'W', 'O', 'O', 'F', low_speed);
+	while (!req.complete)
+		pmu_poll();
+	
+	pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,1);
+
+	low_sleep_handler();
+	
+	pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,0);
+
+	/* Restore L2 cache */
+	if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
+ 		_set_L2CR(save_l2cr);
+	/* Restore L3 cache */
+	if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
+ 		_set_L3CR(save_l3cr);
+
+	/* Restore userland MMU context */
+	set_context(current->active_mm->context, current->active_mm->pgd);
+
+#ifdef DEBUG_FREQ
+	printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));	
+#endif
+
+	/* Restore decrementer */
+	wakeup_decrementer();
+
+	/* Restore interrupts */
+	openpic_sleep_restore_intrs();
+
+	pmu_resume();
+
+	/* Let interrupts flow again ... */
+	local_irq_enable();
+
+#ifdef DEBUG_FREQ
+	debug_calc_bogomips();
+#endif
+
+	return 0;
+}
+
+static int __pmac
+do_set_cpu_speed(int speed_mode)
+{
+	struct cpufreq_freqs    freqs;
+	int rc;
+	
+	freqs.old = cur_freq;
+	freqs.new = (speed_mode == PMAC_CPU_HIGH_SPEED) ? hi_freq : low_freq;
+	freqs.cpu = CPUFREQ_ALL_CPUS;
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+	if (cpufreq_uses_pmu)
+		rc = pmu_set_cpu_speed(speed_mode);
+	else
+		rc = cpu_750fx_cpu_speed(speed_mode);
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+	cur_freq = (speed_mode == PMAC_CPU_HIGH_SPEED) ? hi_freq : low_freq;
+
+	return rc;
+}
+
+static int __pmac
+pmac_cpufreq_verify(struct cpufreq_policy *policy)
+{
+	if (!policy)
+		return -EINVAL;
+		
+	policy->cpu = 0; /* UP only */
+
+	cpufreq_verify_within_limits(policy, low_freq, hi_freq);
+
+	if ((policy->min > low_freq) && 
+	    (policy->max < hi_freq))
+		policy->max = hi_freq;
+
+	return 0;
+}
+
+static int __pmac
+pmac_cpufreq_setpolicy(struct cpufreq_policy *policy)
+{
+	int rc;
+	
+	if (!policy)
+		return -EINVAL;
+	if (policy->min > low_freq)
+		rc = do_set_cpu_speed(PMAC_CPU_HIGH_SPEED);
+	else if (policy->max < hi_freq)
+		rc = do_set_cpu_speed(PMAC_CPU_LOW_SPEED);
+	else if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
+		rc = do_set_cpu_speed(PMAC_CPU_LOW_SPEED);
+	else
+		rc = do_set_cpu_speed(PMAC_CPU_HIGH_SPEED);
+
+	return rc;
+}
+
+unsigned int __pmac
+pmac_get_one_cpufreq(int i)
+{
+	/* Supports only one CPU for now */
+	return (i == 0) ? cur_freq : 0;
+}
+
+
+/* Currently, we support the following machines:
+ * 
+ *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
+ *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
+ *  - iBook2 500 (PMU based, 400Mhz & 500Mhz)
+ *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
+ */
+static int __init
+pmac_cpufreq_setup(void)
+{	
+	struct device_node	*cpunode;
+	struct cpufreq_driver   *driver;
+	u32			*value;
+	int			has_freq_ctl = 0;
+	int			rc;
+	
+	memset(&driver, 0, sizeof(driver));
+
+	/* Assume only one CPU */
+	cpunode = find_type_devices("cpu");
+	if (!cpunode)
+		goto out;
+
+	/* Get current cpu clock freq */
+	value = (u32 *)get_property(cpunode, "clock-frequency", NULL);
+	if (!value)
+		goto out;
+	cur_freq = (*value) / 1000;
+
+	/* Check for tibook 800Mhz or 1Ghz */
+	if (machine_is_compatible("PowerBook3,4") || machine_is_compatible("PowerBook3,5")) {
+		value = (u32 *)get_property(cpunode, "min-clock-frequency", NULL);
+		if (!value)
+			goto out;
+		low_freq = (*value) / 1000;
+
+		value = (u32 *)get_property(cpunode, "max-clock-frequency", NULL);
+		if (!value)
+			goto out;
+		hi_freq = (*value) / 1000;			
+		has_freq_ctl = 1;
+		cpufreq_uses_pmu = 1;
+	}
+	/* Else check for iBook2 500 */
+	else if (machine_is_compatible("PowerBook4,1")) {
+		/* We only know about 500Mhz model */
+		if (cur_freq < 450000 || cur_freq > 550000)
+			goto out;
+		hi_freq = cur_freq;
+		low_freq = 400000;
+		has_freq_ctl = 1;
+		cpufreq_uses_pmu = 1;
+	}
+	/* Else check for TiPb 500 */
+	else if (machine_is_compatible("PowerBook3,2")) {
+		/* We only know about 500Mhz model */
+		if (cur_freq < 450000 || cur_freq > 550000)
+			goto out;
+		hi_freq = cur_freq;
+		low_freq = 300000;
+		has_freq_ctl = 1;
+		cpufreq_uses_pmu = 1;
+	}
+	/* Else check for 750FX */
+	else if (PVR_VER(mfspr(PVR)) == 0x7000) {
+		if (get_property(cpunode, "dynamic-power-step", NULL) == NULL)
+			goto out;	
+		hi_freq = cur_freq;
+		value = (u32 *)get_property(cpunode, "reduced-clock-frequency", NULL);
+		if (!value)
+			goto out;
+		low_freq = (*value) / 1000;
+		cpufreq_uses_pmu = 0;
+		has_freq_ctl = 1;
+	}
+out:
+	if (!has_freq_ctl)
+		return -ENODEV;
+	
+	/* initialization of main "cpufreq" code*/
+	driver = kmalloc(sizeof(struct cpufreq_driver) + 
+			 NR_CPUS * sizeof(struct cpufreq_policy), GFP_KERNEL);
+	if (!driver)
+		return -ENOMEM;
+
+	driver->policy = (struct cpufreq_policy *) (driver + 1);
+
+#ifdef CONFIG_CPU_FREQ_24_API
+	driver->cpu_cur_freq[0]	= cur_freq;
+#endif
+
+	driver->verify		= &pmac_cpufreq_verify;
+	driver->setpolicy	= &pmac_cpufreq_setpolicy;
+	driver->init		= NULL;
+	driver->exit		= NULL;
+	strncpy(driver->name, "powermac", CPUFREQ_NAME_LEN);
+
+	driver->policy[0].cpu				= 0;
+	driver->policy[0].cpuinfo.transition_latency	= CPUFREQ_ETERNAL;
+	driver->policy[0].cpuinfo.min_freq		= low_freq;
+	driver->policy[0].min				= low_freq;
+	driver->policy[0].max				= cur_freq;
+	driver->policy[0].cpuinfo.max_freq		= cur_freq;
+	driver->policy[0].policy			= (cur_freq == low_freq) ? 
+	    	CPUFREQ_POLICY_POWERSAVE : CPUFREQ_POLICY_PERFORMANCE;
+
+	rc = cpufreq_register_driver(driver);
+	if (rc)
+		kfree(driver);
+	return rc;
+}
+
+__initcall(pmac_cpufreq_setup);
+

arch/ppc/platforms/pmac_setup.c

@@ -225,6 +225,20 @@ pmac_show_cpuinfo(struct seq_file *m)
 	return 0;
 }
 
+int __openfirmware
+pmac_show_percpuinfo(struct seq_file *m, int i)
+{
+#ifdef CONFIG_CPU_FREQ_PMAC
+	extern unsigned int pmac_get_one_cpufreq(int i);
+	unsigned int freq = pmac_get_one_cpufreq(i);
+	if (freq != 0) {
+		seq_printf(m, "clock\t\t: %dMHz\n", freq/1000);
+		return 0;
+	}
+#endif /* CONFIG_CPU_FREQ_PMAC */
+	return of_show_percpuinfo(m, i);
+}
+
 static volatile u32 *sysctrl_regs;
 
 void __init
@@ -604,7 +618,7 @@ pmac_init(unsigned long r3, unsigned long r4, unsigned long r5,
 
 	ppc_md.setup_arch     = pmac_setup_arch;
 	ppc_md.show_cpuinfo   = pmac_show_cpuinfo;
-	ppc_md.show_percpuinfo = of_show_percpuinfo;
+	ppc_md.show_percpuinfo = pmac_show_percpuinfo;
 	ppc_md.irq_cannonicalize = NULL;
 	ppc_md.init_IRQ       = pmac_pic_init;
 	ppc_md.get_irq        = pmac_get_irq; /* Changed later on ... */