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path: root/drivers/cpufreq/sparc-us3-cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/sparc-us3-cpufreq.c')
-rw-r--r--drivers/cpufreq/sparc-us3-cpufreq.c269
1 files changed, 269 insertions, 0 deletions
diff --git a/drivers/cpufreq/sparc-us3-cpufreq.c b/drivers/cpufreq/sparc-us3-cpufreq.c
new file mode 100644
index 00000000000..c71ee142347
--- /dev/null
+++ b/drivers/cpufreq/sparc-us3-cpufreq.c
@@ -0,0 +1,269 @@
+/* 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;
+
+ cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
+ set_cpus_allowed_ptr(current, cpumask_of(cpu));
+
+ reg = read_safari_cfg();
+ ret = get_current_freq(cpu, reg);
+
+ set_cpus_allowed_ptr(current, &cpus_allowed);
+
+ return ret;
+}
+
+static void us3_set_cpu_divider_index(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ unsigned int cpu = policy->cpu;
+ unsigned long new_bits, new_freq, reg;
+ cpumask_t cpus_allowed;
+ struct cpufreq_freqs freqs;
+
+ cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
+ set_cpus_allowed_ptr(current, cpumask_of(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;
+ cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
+
+ reg &= ~SAFARI_CFG_DIV_MASK;
+ reg |= new_bits;
+ write_safari_cfg(reg);
+
+ cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
+
+ set_cpus_allowed_ptr(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, 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, 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);
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