1 files changed, 326 insertions, 0 deletions

diff --git a/arch/i386/kernel/cpu/cpufreq/longrun.c b/arch/i386/kernel/cpu/cpufreq/longrun.c
new file mode 100644
index 000000000000..e3868de4dc2e
--- /dev/null
+++ b/arch/i386/kernel/cpu/cpufreq/longrun.c
@@ -0,0 +1,326 @@
+/*
+ * (C) 2002 - 2003  Dominik Brodowski <linux@brodo.de>
+ *
+ *  Licensed under the terms of the GNU GPL License version 2.
+ *
+ *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/cpufreq.h>
+
+#include <asm/msr.h>
+#include <asm/processor.h>
+#include <asm/timex.h>
+
+#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "longrun", msg)
+
+static struct cpufreq_driver    longrun_driver;
+
+/**
+ * longrun_{low,high}_freq is needed for the conversion of cpufreq kHz
+ * values into per cent values. In TMTA microcode, the following is valid:
+ * performance_pctg = (current_freq - low_freq)/(high_freq - low_freq)
+ */
+static unsigned int longrun_low_freq, longrun_high_freq;
+
+
+/**
+ * longrun_get_policy - get the current LongRun policy
+ * @policy: struct cpufreq_policy where current policy is written into
+ *
+ * Reads the current LongRun policy by access to MSR_TMTA_LONGRUN_FLAGS
+ * and MSR_TMTA_LONGRUN_CTRL
+ */
+static void __init longrun_get_policy(struct cpufreq_policy *policy)
+{
+        u32 msr_lo, msr_hi;
+
+        rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
+        dprintk("longrun flags are %x - %x\n", msr_lo, msr_hi);
+        if (msr_lo & 0x01)
+                policy->policy = CPUFREQ_POLICY_PERFORMANCE;
+        else
+                policy->policy = CPUFREQ_POLICY_POWERSAVE;
+
+        rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
+        dprintk("longrun ctrl is %x - %x\n", msr_lo, msr_hi);
+        msr_lo &= 0x0000007F;
+        msr_hi &= 0x0000007F;
+
+        if ( longrun_high_freq <= longrun_low_freq ) {
+                /* Assume degenerate Longrun table */
+                policy->min = policy->max = longrun_high_freq;
+        } else {
+                policy->min = longrun_low_freq + msr_lo *
+                        ((longrun_high_freq - longrun_low_freq) / 100);
+                policy->max = longrun_low_freq + msr_hi *
+                        ((longrun_high_freq - longrun_low_freq) / 100);
+        }
+        policy->cpu = 0;
+}
+
+
+/**
+ * longrun_set_policy - sets a new CPUFreq policy
+ * @policy: new policy
+ *
+ * Sets a new CPUFreq policy on LongRun-capable processors. This function
+ * has to be called with cpufreq_driver locked.
+ */
+static int longrun_set_policy(struct cpufreq_policy *policy)
+{
+        u32 msr_lo, msr_hi;
+        u32 pctg_lo, pctg_hi;
+
+        if (!policy)
+                return -EINVAL;
+
+        if ( longrun_high_freq <= longrun_low_freq ) {
+                /* Assume degenerate Longrun table */
+                pctg_lo = pctg_hi = 100;
+        } else {
+                pctg_lo = (policy->min - longrun_low_freq) /
+                        ((longrun_high_freq - longrun_low_freq) / 100);
+                pctg_hi = (policy->max - longrun_low_freq) /
+                        ((longrun_high_freq - longrun_low_freq) / 100);
+        }
+
+        if (pctg_hi > 100)
+                pctg_hi = 100;
+        if (pctg_lo > pctg_hi)
+                pctg_lo = pctg_hi;
+
+        /* performance or economy mode */
+        rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
+        msr_lo &= 0xFFFFFFFE;
+        switch (policy->policy) {
+        case CPUFREQ_POLICY_PERFORMANCE:
+                msr_lo |= 0x00000001;
+                break;
+        case CPUFREQ_POLICY_POWERSAVE:
+                break;
+        }
+        wrmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
+
+        /* lower and upper boundary */
+        rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
+        msr_lo &= 0xFFFFFF80;
+        msr_hi &= 0xFFFFFF80;
+        msr_lo |= pctg_lo;
+        msr_hi |= pctg_hi;
+        wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
+
+        return 0;
+}
+
+
+/**
+ * longrun_verify_poliy - verifies a new CPUFreq policy
+ * @policy: the policy to verify
+ *
+ * Validates a new CPUFreq policy. This function has to be called with
+ * cpufreq_driver locked.
+ */
+static int longrun_verify_policy(struct cpufreq_policy *policy)
+{
+        if (!policy)
+                return -EINVAL;
+
+        policy->cpu = 0;
+        cpufreq_verify_within_limits(policy,
+                policy->cpuinfo.min_freq,
+                policy->cpuinfo.max_freq);
+
+        if ((policy->policy != CPUFREQ_POLICY_POWERSAVE) &&
+            (policy->policy != CPUFREQ_POLICY_PERFORMANCE))
+                return -EINVAL;
+
+        return 0;
+}
+
+static unsigned int longrun_get(unsigned int cpu)
+{
+        u32 eax, ebx, ecx, edx;
+
+        if (cpu)
+                return 0;
+
+        cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
+        dprintk("cpuid eax is %u\n", eax);
+
+        return (eax * 1000);
+}
+
+/**
+ * longrun_determine_freqs - determines the lowest and highest possible core frequency
+ * @low_freq: an int to put the lowest frequency into
+ * @high_freq: an int to put the highest frequency into
+ *
+ * Determines the lowest and highest possible core frequencies on this CPU.
+ * This is necessary to calculate the performance percentage according to
+ * TMTA rules:
+ * performance_pctg = (target_freq - low_freq)/(high_freq - low_freq)
+ */
+static unsigned int __init longrun_determine_freqs(unsigned int *low_freq,
+                                                   unsigned int *high_freq)
+{
+        u32 msr_lo, msr_hi;
+        u32 save_lo, save_hi;
+        u32 eax, ebx, ecx, edx;
+        u32 try_hi;
+        struct cpuinfo_x86 *c = cpu_data;
+
+        if (!low_freq || !high_freq)
+                return -EINVAL;
+
+        if (cpu_has(c, X86_FEATURE_LRTI)) {
+                /* if the LongRun Table Interface is present, the
+                 * detection is a bit easier:
+                 * For minimum frequency, read out the maximum
+                 * level (msr_hi), write that into "currently
+                 * selected level", and read out the frequency.
+                 * For maximum frequency, read out level zero.
+                 */
+                /* minimum */
+                rdmsr(MSR_TMTA_LRTI_READOUT, msr_lo, msr_hi);
+                wrmsr(MSR_TMTA_LRTI_READOUT, msr_hi, msr_hi);
+                rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi);
+                *low_freq = msr_lo * 1000; /* to kHz */
+
+                /* maximum */
+                wrmsr(MSR_TMTA_LRTI_READOUT, 0, msr_hi);
+                rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi);
+                *high_freq = msr_lo * 1000; /* to kHz */
+
+                dprintk("longrun table interface told %u - %u kHz\n", *low_freq, *high_freq);
+
+                if (*low_freq > *high_freq)
+                        *low_freq = *high_freq;
+                return 0;
+        }
+
+        /* set the upper border to the value determined during TSC init */
+        *high_freq = (cpu_khz / 1000);
+        *high_freq = *high_freq * 1000;
+        dprintk("high frequency is %u kHz\n", *high_freq);
+
+        /* get current borders */
+        rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
+        save_lo = msr_lo & 0x0000007F;
+        save_hi = msr_hi & 0x0000007F;
+
+        /* if current perf_pctg is larger than 90%, we need to decrease the
+         * upper limit to make the calculation more accurate.
+         */
+        cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
+        /* try decreasing in 10% steps, some processors react only
+         * on some barrier values */
+        for (try_hi = 80; try_hi > 0 && ecx > 90; try_hi -=10) {
+                /* set to 0 to try_hi perf_pctg */
+                msr_lo &= 0xFFFFFF80;
+                msr_hi &= 0xFFFFFF80;
+                msr_lo |= 0;
+                msr_hi |= try_hi;
+                wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
+
+                /* read out current core MHz and current perf_pctg */
+                cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
+
+                /* restore values */
+                wrmsr(MSR_TMTA_LONGRUN_CTRL, save_lo, save_hi);
+        }
+        dprintk("percentage is %u %%, freq is %u MHz\n", ecx, eax);
+
+        /* performance_pctg = (current_freq - low_freq)/(high_freq - low_freq)
+         * eqals
+         * low_freq * ( 1 - perf_pctg) = (cur_freq - high_freq * perf_pctg)
+         *
+         * high_freq * perf_pctg is stored tempoarily into "ebx".
+         */
+        ebx = (((cpu_khz / 1000) * ecx) / 100); /* to MHz */
+
+        if ((ecx > 95) || (ecx == 0) || (eax < ebx))
+                return -EIO;
+
+        edx = (eax - ebx) / (100 - ecx);
+        *low_freq = edx * 1000; /* back to kHz */
+
+        dprintk("low frequency is %u kHz\n", *low_freq);
+
+        if (*low_freq > *high_freq)
+                *low_freq = *high_freq;
+
+        return 0;
+}
+
+
+static int __init longrun_cpu_init(struct cpufreq_policy *policy)
+{
+        int result = 0;
+
+        /* capability check */
+        if (policy->cpu != 0)
+                return -ENODEV;
+
+        /* detect low and high frequency */
+        result = longrun_determine_freqs(&longrun_low_freq, &longrun_high_freq);
+        if (result)
+                return result;
+
+        /* cpuinfo and default policy values */
+        policy->cpuinfo.min_freq = longrun_low_freq;
+        policy->cpuinfo.max_freq = longrun_high_freq;
+        policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+        longrun_get_policy(policy);
+
+        return 0;
+}
+
+
+static struct cpufreq_driver longrun_driver = {
+        .flags          = CPUFREQ_CONST_LOOPS,
+        .verify         = longrun_verify_policy,
+        .setpolicy      = longrun_set_policy,
+        .get            = longrun_get,
+        .init           = longrun_cpu_init,
+        .name           = "longrun",
+        .owner          = THIS_MODULE,
+};
+
+
+/**
+ * longrun_init - initializes the Transmeta Crusoe LongRun CPUFreq driver
+ *
+ * Initializes the LongRun support.
+ */
+static int __init longrun_init(void)
+{
+        struct cpuinfo_x86 *c = cpu_data;
+
+        if (c->x86_vendor != X86_VENDOR_TRANSMETA ||
+            !cpu_has(c, X86_FEATURE_LONGRUN))
+                return -ENODEV;
+
+        return cpufreq_register_driver(&longrun_driver);
+}
+
+
+/**
+ * longrun_exit - unregisters LongRun support
+ */
+static void __exit longrun_exit(void)
+{
+        cpufreq_unregister_driver(&longrun_driver);
+}
+
+
+MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>");
+MODULE_DESCRIPTION ("LongRun driver for Transmeta Crusoe and Efficeon processors.");
+MODULE_LICENSE ("GPL");
+
+module_init(longrun_init);
+module_exit(longrun_exit);