1 files changed, 255 insertions, 0 deletions

diff --git a/arch/sparc64/kernel/us3_cpufreq.c b/arch/sparc64/kernel/us3_cpufreq.c
new file mode 100644
index 000000000000..18fe54b8aa55
--- /dev/null
+++ b/arch/sparc64/kernel/us3_cpufreq.c
@@ -0,0 +1,255 @@
+/* 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);
+        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 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);
+        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);
+        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->governor = CPUFREQ_DEFAULT_GOVERNOR;
+        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;
+
+        __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)) {
+                struct cpufreq_driver *driver;
+
+                ret = -ENOMEM;
+                driver = kmalloc(sizeof(struct cpufreq_driver), GFP_KERNEL);
+                if (!driver)
+                        goto err_out;
+                memset(driver, 0, sizeof(*driver));
+
+                us3_freq_table = kmalloc(
+                        (NR_CPUS * sizeof(struct us3_freq_percpu_info)),
+                        GFP_KERNEL);
+                if (!us3_freq_table)
+                        goto err_out;
+
+                memset(us3_freq_table, 0,
+                       (NR_CPUS * sizeof(struct us3_freq_percpu_info)));
+
+                driver->verify = us3_freq_verify;
+                driver->target = us3_freq_target;
+                driver->init = us3_freq_cpu_init;
+                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;
+                }
+                if (us3_freq_table) {
+                        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);