1 files changed, 248 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/cell/cbe_cpufreq.c b/arch/powerpc/platforms/cell/cbe_cpufreq.c
new file mode 100644
index 00000000000..a3850fd1e94
--- /dev/null
+++ b/arch/powerpc/platforms/cell/cbe_cpufreq.c
@@ -0,0 +1,248 @@
+/*
+ * cpufreq driver for the cell processor
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
+ *
+ * Author: Christian Krafft <krafft@de.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.
+ */
+
+#include <linux/cpufreq.h>
+#include <linux/timer.h>
+
+#include <asm/hw_irq.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/prom.h>
+#include <asm/time.h>
+
+#include "cbe_regs.h"
+
+static DEFINE_MUTEX(cbe_switch_mutex);
+
+
+/* the CBE supports an 8 step frequency scaling */
+static struct cpufreq_frequency_table cbe_freqs[] = {
+        {1,     0},
+        {2,     0},
+        {3,     0},
+        {4,     0},
+        {5,     0},
+        {6,     0},
+        {8,     0},
+        {10,    0},
+        {0,     CPUFREQ_TABLE_END},
+};
+
+/* to write to MIC register */
+static u64 MIC_Slow_Fast_Timer_table[] = {
+        [0 ... 7] = 0x007fc00000000000ull,
+};
+
+/* more values for the MIC */
+static u64 MIC_Slow_Next_Timer_table[] = {
+        0x0000240000000000ull,
+        0x0000268000000000ull,
+        0x000029C000000000ull,
+        0x00002D0000000000ull,
+        0x0000300000000000ull,
+        0x0000334000000000ull,
+        0x000039C000000000ull,
+        0x00003FC000000000ull,
+};
+
+/*
+ * hardware specific functions
+ */
+
+static int get_pmode(int cpu)
+{
+        int ret;
+        struct cbe_pmd_regs __iomem *pmd_regs;
+
+        pmd_regs = cbe_get_cpu_pmd_regs(cpu);
+        ret = in_be64(&pmd_regs->pmsr) & 0x07;
+
+        return ret;
+}
+
+static int set_pmode(int cpu, unsigned int pmode)
+{
+        struct cbe_pmd_regs __iomem *pmd_regs;
+        struct cbe_mic_tm_regs __iomem *mic_tm_regs;
+        u64 flags;
+        u64 value;
+
+        local_irq_save(flags);
+
+        mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
+        pmd_regs = cbe_get_cpu_pmd_regs(cpu);
+
+        pr_debug("pm register is mapped at %p\n", &pmd_regs->pmcr);
+        pr_debug("mic register is mapped at %p\n", &mic_tm_regs->slow_fast_timer_0);
+
+        out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
+        out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
+
+        out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
+        out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
+
+        value = in_be64(&pmd_regs->pmcr);
+        /* set bits to zero */
+        value &= 0xFFFFFFFFFFFFFFF8ull;
+        /* set bits to next pmode */
+        value |= pmode;
+
+        out_be64(&pmd_regs->pmcr, value);
+
+        /* wait until new pmode appears in status register */
+        value = in_be64(&pmd_regs->pmsr) & 0x07;
+        while(value != pmode) {
+                cpu_relax();
+                value = in_be64(&pmd_regs->pmsr) & 0x07;
+        }
+
+        local_irq_restore(flags);
+
+        return 0;
+}
+
+/*
+ * cpufreq functions
+ */
+
+static int cbe_cpufreq_cpu_init (struct cpufreq_policy *policy)
+{
+        u32 *max_freq;
+        int i, cur_pmode;
+        struct device_node *cpu;
+
+        cpu = of_get_cpu_node(policy->cpu, NULL);
+
+        if(!cpu)
+                return -ENODEV;
+
+        pr_debug("init cpufreq on CPU %d\n", policy->cpu);
+
+        max_freq = (u32*) get_property(cpu, "clock-frequency", NULL);
+
+        if(!max_freq)
+                return -EINVAL;
+
+        // we need the freq in kHz
+        *max_freq /= 1000;
+
+        pr_debug("max clock-frequency is at %u kHz\n", *max_freq);
+        pr_debug("initializing frequency table\n");
+
+        // initialize frequency table
+        for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
+                cbe_freqs[i].frequency = *max_freq / cbe_freqs[i].index;
+                pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
+        }
+
+        policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+        /* if DEBUG is enabled set_pmode() measures the correct latency of a transition */
+        policy->cpuinfo.transition_latency = 25000;
+
+        cur_pmode = get_pmode(policy->cpu);
+        pr_debug("current pmode is at %d\n",cur_pmode);
+
+        policy->cur = cbe_freqs[cur_pmode].frequency;
+
+#ifdef CONFIG_SMP
+        policy->cpus = cpu_sibling_map[policy->cpu];
+#endif
+
+        cpufreq_frequency_table_get_attr (cbe_freqs, policy->cpu);
+
+        /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */
+        return cpufreq_frequency_table_cpuinfo (policy, cbe_freqs);
+}
+
+static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+        cpufreq_frequency_table_put_attr(policy->cpu);
+        return 0;
+}
+
+static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
+{
+        return cpufreq_frequency_table_verify(policy, cbe_freqs);
+}
+
+
+static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int target_freq,
+                            unsigned int relation)
+{
+        int rc;
+        struct cpufreq_freqs freqs;
+        int cbe_pmode_new;
+
+        cpufreq_frequency_table_target(policy,
+                                       cbe_freqs,
+                                       target_freq,
+                                       relation,
+                                       &cbe_pmode_new);
+
+        freqs.old = policy->cur;
+        freqs.new = cbe_freqs[cbe_pmode_new].frequency;
+        freqs.cpu = policy->cpu;
+
+        mutex_lock (&cbe_switch_mutex);
+        cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+        pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
+                 policy->cpu,
+                 cbe_freqs[cbe_pmode_new].frequency,
+                 cbe_freqs[cbe_pmode_new].index);
+
+        rc = set_pmode(policy->cpu, cbe_pmode_new);
+        cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+        mutex_unlock(&cbe_switch_mutex);
+
+        return rc;
+}
+
+static struct cpufreq_driver cbe_cpufreq_driver = {
+        .verify         = cbe_cpufreq_verify,
+        .target         = cbe_cpufreq_target,
+        .init           = cbe_cpufreq_cpu_init,
+        .exit           = cbe_cpufreq_cpu_exit,
+        .name           = "cbe-cpufreq",
+        .owner          = THIS_MODULE,
+        .flags          = CPUFREQ_CONST_LOOPS,
+};
+
+/*
+ * module init and destoy
+ */
+
+static int __init cbe_cpufreq_init(void)
+{
+        return cpufreq_register_driver(&cbe_cpufreq_driver);
+}
+
+static void __exit cbe_cpufreq_exit(void)
+{
+        cpufreq_unregister_driver(&cbe_cpufreq_driver);
+}
+
+module_init(cbe_cpufreq_init);
+module_exit(cbe_cpufreq_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");