[CPUFREQ] AMD Elan SC520 cpufreq driver.

From: Sean Young <sean@mess.org>
Signed-off-by: Dave Jones <davej@redhat.com>

diff --git a/arch/i386/kernel/cpu/cpufreq/Kconfig b/arch/i386/kernel/cpu/cpufreq/Kconfig
index f25ffd74235caa330985b4cbaa6d5ece01b78b67..0f1eb507233b701c6bb7b158104e0e5cfd9e4d85 100644 (file)
--- a/arch/i386/kernel/cpu/cpufreq/Kconfig
+++ b/arch/i386/kernel/cpu/cpufreq/Kconfig
@@ -23,7 +23,7 @@ config X86_ACPI_CPUFREQ
          If in doubt, say N.
 
 config ELAN_CPUFREQ
-       tristate "AMD Elan"
+       tristate "AMD Elan SC400 and SC410"
        select CPU_FREQ_TABLE
        depends on X86_ELAN
        ---help---
@@ -38,6 +38,18 @@ config ELAN_CPUFREQ
 
          If in doubt, say N.
 
+config SC520_CPUFREQ
+       tristate "AMD Elan SC520"
+       select CPU_FREQ_TABLE
+       depends on X86_ELAN
+       ---help---
+         This adds the CPUFreq driver for AMD Elan SC520 processor.
+
+         For details, take a look at <file:Documentation/cpu-freq/>.
+
+         If in doubt, say N.
+
+
 config X86_POWERNOW_K6
        tristate "AMD Mobile K6-2/K6-3 PowerNow!"
        select CPU_FREQ_TABLE

diff --git a/arch/i386/kernel/cpu/cpufreq/Makefile b/arch/i386/kernel/cpu/cpufreq/Makefile
index a922e97aeedd5ee7283441a72e613504ef566086..2e894f1c89103f69f51e9c7da8748060d3019790 100644 (file)
--- a/arch/i386/kernel/cpu/cpufreq/Makefile
+++ b/arch/i386/kernel/cpu/cpufreq/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_X86_POWERNOW_K7)           += powernow-k7.o
 obj-$(CONFIG_X86_POWERNOW_K8)          += powernow-k8.o
 obj-$(CONFIG_X86_LONGHAUL)             += longhaul.o
 obj-$(CONFIG_ELAN_CPUFREQ)             += elanfreq.o
+obj-$(CONFIG_SC520_CPUFREQ)            += sc520_freq.o
 obj-$(CONFIG_X86_LONGRUN)              += longrun.o  
 obj-$(CONFIG_X86_GX_SUSPMOD)           += gx-suspmod.o
 obj-$(CONFIG_X86_SPEEDSTEP_ICH)                += speedstep-ich.o

diff --git a/arch/i386/kernel/cpu/cpufreq/sc520_freq.c b/arch/i386/kernel/cpu/cpufreq/sc520_freq.c
new file mode 100644 (file)
index 0000000..ef457d5
--- /dev/null
+++ b/arch/i386/kernel/cpu/cpufreq/sc520_freq.c
@@ -0,0 +1,186 @@
+/*
+ *     sc520_freq.c: cpufreq driver for the AMD Elan sc520
+ *
+ *     Copyright (C) 2005 Sean Young <sean@mess.org>
+ *
+ *     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 of the License, or (at your option) any later version.
+ *
+ *     Based on elanfreq.c
+ *
+ *     2005-03-30: - initial revision
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <linux/delay.h>
+#include <linux/cpufreq.h>
+
+#include <asm/msr.h>
+#include <asm/timex.h>
+#include <asm/io.h>
+
+#define MMCR_BASE      0xfffef000      /* The default base address */
+#define OFFS_CPUCTL    0x2   /* CPU Control Register */
+
+static __u8 __iomem *cpuctl;
+
+#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "sc520_freq", msg)
+
+static struct cpufreq_frequency_table sc520_freq_table[] = {
+       {0x01,  100000},
+       {0x02,  133000},
+       {0,     CPUFREQ_TABLE_END},
+};
+
+static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu)
+{
+       u8 clockspeed_reg = *cpuctl;
+
+       switch (clockspeed_reg & 0x03) {
+       default:
+               printk(KERN_ERR "sc520_freq: error: cpuctl register has unexpected value %02x\n", clockspeed_reg);
+       case 0x01:
+               return 100000;
+       case 0x02:
+               return 133000;
+       }
+}
+
+static void sc520_freq_set_cpu_state (unsigned int state)
+{
+
+       struct cpufreq_freqs    freqs;
+       u8 clockspeed_reg;
+
+       freqs.old = sc520_freq_get_cpu_frequency(0);
+       freqs.new = sc520_freq_table[state].frequency;
+       freqs.cpu = 0; /* AMD Elan is UP */
+
+       cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+       dprintk("attempting to set frequency to %i kHz\n",
+                       sc520_freq_table[state].frequency);
+
+       local_irq_disable();
+
+       clockspeed_reg = *cpuctl & ~0x03;
+       *cpuctl = clockspeed_reg | sc520_freq_table[state].index;
+
+       local_irq_enable();
+
+       cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+};
+
+static int sc520_freq_verify (struct cpufreq_policy *policy)
+{
+       return cpufreq_frequency_table_verify(policy, &sc520_freq_table[0]);
+}
+
+static int sc520_freq_target (struct cpufreq_policy *policy,
+                           unsigned int target_freq,
+                           unsigned int relation)
+{
+       unsigned int newstate = 0;
+
+       if (cpufreq_frequency_table_target(policy, sc520_freq_table, target_freq, relation, &newstate))
+               return -EINVAL;
+
+       sc520_freq_set_cpu_state(newstate);
+
+       return 0;
+}
+
+
+/*
+ *     Module init and exit code
+ */
+
+static int sc520_freq_cpu_init(struct cpufreq_policy *policy)
+{
+       struct cpuinfo_x86 *c = cpu_data;
+       int result;
+
+       /* capability check */
+       if (c->x86_vendor != X86_VENDOR_AMD ||
+           c->x86 != 4 || c->x86_model != 9)
+               return -ENODEV;
+
+       /* cpuinfo and default policy values */
+       policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+       policy->cpuinfo.transition_latency = 1000000; /* 1ms */
+       policy->cur = sc520_freq_get_cpu_frequency(0);
+
+       result = cpufreq_frequency_table_cpuinfo(policy, sc520_freq_table);
+       if (result)
+               return (result);
+
+       cpufreq_frequency_table_get_attr(sc520_freq_table, policy->cpu);
+
+       return 0;
+}
+
+
+static int sc520_freq_cpu_exit(struct cpufreq_policy *policy)
+{
+       cpufreq_frequency_table_put_attr(policy->cpu);
+       return 0;
+}
+
+
+static struct freq_attr* sc520_freq_attr[] = {
+       &cpufreq_freq_attr_scaling_available_freqs,
+       NULL,
+};
+
+
+static struct cpufreq_driver sc520_freq_driver = {
+       .get    = sc520_freq_get_cpu_frequency,
+       .verify = sc520_freq_verify,
+       .target = sc520_freq_target,
+       .init   = sc520_freq_cpu_init,
+       .exit   = sc520_freq_cpu_exit,
+       .name   = "sc520_freq",
+       .owner  = THIS_MODULE,
+       .attr   = sc520_freq_attr,
+};
+
+
+static int __init sc520_freq_init(void)
+{
+       struct cpuinfo_x86 *c = cpu_data;
+
+       /* Test if we have the right hardware */
+       if(c->x86_vendor != X86_VENDOR_AMD ||
+                               c->x86 != 4 || c->x86_model != 9) {
+               dprintk("no Elan SC520 processor found!\n");
+               return -ENODEV;
+       }
+       cpuctl = ioremap((unsigned long)(MMCR_BASE + OFFS_CPUCTL), 1);
+       if(!cpuctl) {
+               printk(KERN_ERR "sc520_freq: error: failed to remap memory\n");
+               return -ENOMEM;
+       }
+
+       return cpufreq_register_driver(&sc520_freq_driver);
+}
+
+
+static void __exit sc520_freq_exit(void)
+{
+       cpufreq_unregister_driver(&sc520_freq_driver);
+       iounmap(cpuctl);
+}
+
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sean Young <sean@mess.org>");
+MODULE_DESCRIPTION("cpufreq driver for AMD's Elan sc520 CPU");
+
+module_init(sc520_freq_init);
+module_exit(sc520_freq_exit);
+