1 files changed, 274 insertions, 0 deletions
diff --git a/arch/sparc/kernel/us3_cpufreq.c b/arch/sparc/kernel/us3_cpufreq.c
new file mode 100644
index 000000000000..365b6464e2ce
--- /dev/null
+++ b/arch/sparc/kernel/us3_cpufreq.c
@@ -0,0 +1,274 @@
+/* us3_cpufreq.c: UltraSPARC-III cpu frequency support
+ *
+ * Copyright (C) 2003 David S. Miller (davem@redhat.com)
+ *
+ * Many thanks to Dominik Brodowski for fixing up the cpufreq
+ * infrastructure in order to make this driver easier to implement.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/cpufreq.h>
+#include <linux/threads.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+
+#include <asm/head.h>
+#include <asm/timer.h>
+
+static struct cpufreq_driver *cpufreq_us3_driver;
+
+struct us3_freq_percpu_info {
+	struct cpufreq_frequency_table table[4];
+};
+
+/* Indexed by cpu number. */
+static struct us3_freq_percpu_info *us3_freq_table;
+
+/* UltraSPARC-III has three dividers: 1, 2, and 32.  These are controlled
+ * in the Safari config register.
+ */
+#define SAFARI_CFG_DIV_1	0x0000000000000000UL
+#define SAFARI_CFG_DIV_2	0x0000000040000000UL
+#define SAFARI_CFG_DIV_32	0x0000000080000000UL
+#define SAFARI_CFG_DIV_MASK	0x00000000C0000000UL
+
+static unsigned long read_safari_cfg(void)
+{
+	unsigned long ret;
+
+	__asm__ __volatile__("ldxa	[%%g0] %1, %0"
+			     : "=&r" (ret)
+			     : "i" (ASI_SAFARI_CONFIG));
+	return ret;
+}
+
+static void write_safari_cfg(unsigned long val)
+{
+	__asm__ __volatile__("stxa	%0, [%%g0] %1\n\t"
+			     "membar	#Sync"
+			     : /* no outputs */
+			     : "r" (val), "i" (ASI_SAFARI_CONFIG)
+			     : "memory");
+}
+
+static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg)
+{
+	unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
+	unsigned long ret;
+
+	switch (safari_cfg & SAFARI_CFG_DIV_MASK) {
+	case SAFARI_CFG_DIV_1:
+		ret = clock_tick / 1;
+		break;
+	case SAFARI_CFG_DIV_2:
+		ret = clock_tick / 2;
+		break;
+	case SAFARI_CFG_DIV_32:
+		ret = clock_tick / 32;
+		break;
+	default:
+		BUG();
+	};
+
+	return ret;
+}
+
+static unsigned int us3_freq_get(unsigned int cpu)
+{
+	cpumask_t cpus_allowed;
+	unsigned long reg;
+	unsigned int ret;
+
+	if (!cpu_online(cpu))
+		return 0;
+
+	cpus_allowed = current->cpus_allowed;
+	set_cpus_allowed(current, cpumask_of_cpu(cpu));
+
+	reg = read_safari_cfg();
+	ret = get_current_freq(cpu, reg);
+
+	set_cpus_allowed(current, cpus_allowed);
+
+	return ret;
+}
+
+static void us3_set_cpu_divider_index(unsigned int cpu, unsigned int index)
+{
+	unsigned long new_bits, new_freq, reg;
+	cpumask_t cpus_allowed;
+	struct cpufreq_freqs freqs;
+
+	if (!cpu_online(cpu))
+		return;
+
+	cpus_allowed = current->cpus_allowed;
+	set_cpus_allowed(current, cpumask_of_cpu(cpu));
+
+	new_freq = sparc64_get_clock_tick(cpu) / 1000;
+	switch (index) {
+	case 0:
+		new_bits = SAFARI_CFG_DIV_1;
+		new_freq /= 1;
+		break;
+	case 1:
+		new_bits = SAFARI_CFG_DIV_2;
+		new_freq /= 2;
+		break;
+	case 2:
+		new_bits = SAFARI_CFG_DIV_32;
+		new_freq /= 32;
+		break;
+
+	default:
+		BUG();
+	};
+
+	reg = read_safari_cfg();
+
+	freqs.old = get_current_freq(cpu, reg);
+	freqs.new = new_freq;
+	freqs.cpu = cpu;
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	reg &= ~SAFARI_CFG_DIV_MASK;
+	reg |= new_bits;
+	write_safari_cfg(reg);
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+	set_cpus_allowed(current, cpus_allowed);
+}
+
+static int us3_freq_target(struct cpufreq_policy *policy,
+			  unsigned int target_freq,
+			  unsigned int relation)
+{
+	unsigned int new_index = 0;
+
+	if (cpufreq_frequency_table_target(policy,
+					   &us3_freq_table[policy->cpu].table[0],
+					   target_freq,
+					   relation,
+					   &new_index))
+		return -EINVAL;
+
+	us3_set_cpu_divider_index(policy->cpu, new_index);
+
+	return 0;
+}
+
+static int us3_freq_verify(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy,
+					      &us3_freq_table[policy->cpu].table[0]);
+}
+
+static int __init us3_freq_cpu_init(struct cpufreq_policy *policy)
+{
+	unsigned int cpu = policy->cpu;
+	unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
+	struct cpufreq_frequency_table *table =
+		&us3_freq_table[cpu].table[0];
+
+	table[0].index = 0;
+	table[0].frequency = clock_tick / 1;
+	table[1].index = 1;
+	table[1].frequency = clock_tick / 2;
+	table[2].index = 2;
+	table[2].frequency = clock_tick / 32;
+	table[3].index = 0;
+	table[3].frequency = CPUFREQ_TABLE_END;
+
+	policy->cpuinfo.transition_latency = 0;
+	policy->cur = clock_tick;
+
+	return cpufreq_frequency_table_cpuinfo(policy, table);
+}
+
+static int us3_freq_cpu_exit(struct cpufreq_policy *policy)
+{
+	if (cpufreq_us3_driver)
+		us3_set_cpu_divider_index(policy->cpu, 0);
+
+	return 0;
+}
+
+static int __init us3_freq_init(void)
+{
+	unsigned long manuf, impl, ver;
+	int ret;
+
+	if (tlb_type != cheetah && tlb_type != cheetah_plus)
+		return -ENODEV;
+
+	__asm__("rdpr %%ver, %0" : "=r" (ver));
+	manuf = ((ver >> 48) & 0xffff);
+	impl  = ((ver >> 32) & 0xffff);
+
+	if (manuf == CHEETAH_MANUF &&
+	    (impl == CHEETAH_IMPL ||
+	     impl == CHEETAH_PLUS_IMPL ||
+	     impl == JAGUAR_IMPL ||
+	     impl == PANTHER_IMPL)) {
+		struct cpufreq_driver *driver;
+
+		ret = -ENOMEM;
+		driver = kzalloc(sizeof(struct cpufreq_driver), GFP_KERNEL);
+		if (!driver)
+			goto err_out;
+
+		us3_freq_table = kzalloc(
+			(NR_CPUS * sizeof(struct us3_freq_percpu_info)),
+			GFP_KERNEL);
+		if (!us3_freq_table)
+			goto err_out;
+
+		driver->init = us3_freq_cpu_init;
+		driver->verify = us3_freq_verify;
+		driver->target = us3_freq_target;
+		driver->get = us3_freq_get;
+		driver->exit = us3_freq_cpu_exit;
+		driver->owner = THIS_MODULE,
+		strcpy(driver->name, "UltraSPARC-III");
+
+		cpufreq_us3_driver = driver;
+		ret = cpufreq_register_driver(driver);
+		if (ret)
+			goto err_out;
+
+		return 0;
+
+err_out:
+		if (driver) {
+			kfree(driver);
+			cpufreq_us3_driver = NULL;
+		}
+		kfree(us3_freq_table);
+		us3_freq_table = NULL;
+		return ret;
+	}
+
+	return -ENODEV;
+}
+
+static void __exit us3_freq_exit(void)
+{
+	if (cpufreq_us3_driver) {
+		cpufreq_unregister_driver(cpufreq_us3_driver);
+		kfree(cpufreq_us3_driver);
+		cpufreq_us3_driver = NULL;
+		kfree(us3_freq_table);
+		us3_freq_table = NULL;
+	}
+}
+
+MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
+MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");
+MODULE_LICENSE("GPL");
+
+module_init(us3_freq_init);
+module_exit(us3_freq_exit);