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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/cpufreq/speedstep-smi.c
Initial import
Diffstat (limited to 'drivers/cpufreq/speedstep-smi.c')
-rw-r--r--drivers/cpufreq/speedstep-smi.c396
1 files changed, 396 insertions, 0 deletions
diff --git a/drivers/cpufreq/speedstep-smi.c b/drivers/cpufreq/speedstep-smi.c
new file mode 100644
index 000000000..819229e82
--- /dev/null
+++ b/drivers/cpufreq/speedstep-smi.c
@@ -0,0 +1,396 @@
+/*
+ * Intel SpeedStep SMI driver.
+ *
+ * (C) 2003 Hiroshi Miura <miura@da-cha.org>
+ *
+ * Licensed under the terms of the GNU GPL License version 2.
+ *
+ */
+
+
+/*********************************************************************
+ * SPEEDSTEP - DEFINITIONS *
+ *********************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <asm/ist.h>
+#include <asm/cpu_device_id.h>
+
+#include "speedstep-lib.h"
+
+/* speedstep system management interface port/command.
+ *
+ * These parameters are got from IST-SMI BIOS call.
+ * If user gives it, these are used.
+ *
+ */
+static int smi_port;
+static int smi_cmd;
+static unsigned int smi_sig;
+
+/* info about the processor */
+static enum speedstep_processor speedstep_processor;
+
+/*
+ * There are only two frequency states for each processor. Values
+ * are in kHz for the time being.
+ */
+static struct cpufreq_frequency_table speedstep_freqs[] = {
+ {0, SPEEDSTEP_HIGH, 0},
+ {0, SPEEDSTEP_LOW, 0},
+ {0, 0, CPUFREQ_TABLE_END},
+};
+
+#define GET_SPEEDSTEP_OWNER 0
+#define GET_SPEEDSTEP_STATE 1
+#define SET_SPEEDSTEP_STATE 2
+#define GET_SPEEDSTEP_FREQS 4
+
+/* how often shall the SMI call be tried if it failed, e.g. because
+ * of DMA activity going on? */
+#define SMI_TRIES 5
+
+/**
+ * speedstep_smi_ownership
+ */
+static int speedstep_smi_ownership(void)
+{
+ u32 command, result, magic, dummy;
+ u32 function = GET_SPEEDSTEP_OWNER;
+ unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
+
+ command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
+ magic = virt_to_phys(magic_data);
+
+ pr_debug("trying to obtain ownership with command %x at port %x\n",
+ command, smi_port);
+
+ __asm__ __volatile__(
+ "push %%ebp\n"
+ "out %%al, (%%dx)\n"
+ "pop %%ebp\n"
+ : "=D" (result),
+ "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
+ "=S" (dummy)
+ : "a" (command), "b" (function), "c" (0), "d" (smi_port),
+ "D" (0), "S" (magic)
+ : "memory"
+ );
+
+ pr_debug("result is %x\n", result);
+
+ return result;
+}
+
+/**
+ * speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
+ * @low: the low frequency value is placed here
+ * @high: the high frequency value is placed here
+ *
+ * Only available on later SpeedStep-enabled systems, returns false results or
+ * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
+ * shows that the latter occurs if !(ist_info.event & 0xFFFF).
+ */
+static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high)
+{
+ u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
+ u32 state = 0;
+ u32 function = GET_SPEEDSTEP_FREQS;
+
+ if (!(ist_info.event & 0xFFFF)) {
+ pr_debug("bug #1422 -- can't read freqs from BIOS\n");
+ return -ENODEV;
+ }
+
+ command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
+
+ pr_debug("trying to determine frequencies with command %x at port %x\n",
+ command, smi_port);
+
+ __asm__ __volatile__(
+ "push %%ebp\n"
+ "out %%al, (%%dx)\n"
+ "pop %%ebp"
+ : "=a" (result),
+ "=b" (high_mhz),
+ "=c" (low_mhz),
+ "=d" (state), "=D" (edi), "=S" (dummy)
+ : "a" (command),
+ "b" (function),
+ "c" (state),
+ "d" (smi_port), "S" (0), "D" (0)
+ );
+
+ pr_debug("result %x, low_freq %u, high_freq %u\n",
+ result, low_mhz, high_mhz);
+
+ /* abort if results are obviously incorrect... */
+ if ((high_mhz + low_mhz) < 600)
+ return -EINVAL;
+
+ *high = high_mhz * 1000;
+ *low = low_mhz * 1000;
+
+ return result;
+}
+
+/**
+ * speedstep_set_state - set the SpeedStep state
+ * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
+ *
+ */
+static void speedstep_set_state(unsigned int state)
+{
+ unsigned int result = 0, command, new_state, dummy;
+ unsigned long flags;
+ unsigned int function = SET_SPEEDSTEP_STATE;
+ unsigned int retry = 0;
+
+ if (state > 0x1)
+ return;
+
+ /* Disable IRQs */
+ preempt_disable();
+ local_irq_save(flags);
+
+ command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
+
+ pr_debug("trying to set frequency to state %u "
+ "with command %x at port %x\n",
+ state, command, smi_port);
+
+ do {
+ if (retry) {
+ /*
+ * We need to enable interrupts, otherwise the blockage
+ * won't resolve.
+ *
+ * We disable preemption so that other processes don't
+ * run. If other processes were running, they could
+ * submit more DMA requests, making the blockage worse.
+ */
+ pr_debug("retry %u, previous result %u, waiting...\n",
+ retry, result);
+ local_irq_enable();
+ mdelay(retry * 50);
+ local_irq_disable();
+ }
+ retry++;
+ __asm__ __volatile__(
+ "push %%ebp\n"
+ "out %%al, (%%dx)\n"
+ "pop %%ebp"
+ : "=b" (new_state), "=D" (result),
+ "=c" (dummy), "=a" (dummy),
+ "=d" (dummy), "=S" (dummy)
+ : "a" (command), "b" (function), "c" (state),
+ "d" (smi_port), "S" (0), "D" (0)
+ );
+ } while ((new_state != state) && (retry <= SMI_TRIES));
+
+ /* enable IRQs */
+ local_irq_restore(flags);
+ preempt_enable();
+
+ if (new_state == state)
+ pr_debug("change to %u MHz succeeded after %u tries "
+ "with result %u\n",
+ (speedstep_freqs[new_state].frequency / 1000),
+ retry, result);
+ else
+ printk(KERN_ERR "cpufreq: change to state %u "
+ "failed with new_state %u and result %u\n",
+ state, new_state, result);
+
+ return;
+}
+
+
+/**
+ * speedstep_target - set a new CPUFreq policy
+ * @policy: new policy
+ * @index: index of new freq
+ *
+ * Sets a new CPUFreq policy/freq.
+ */
+static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
+{
+ speedstep_set_state(index);
+
+ return 0;
+}
+
+
+static int speedstep_cpu_init(struct cpufreq_policy *policy)
+{
+ int result;
+ unsigned int *low, *high;
+
+ /* capability check */
+ if (policy->cpu != 0)
+ return -ENODEV;
+
+ result = speedstep_smi_ownership();
+ if (result) {
+ pr_debug("fails in acquiring ownership of a SMI interface.\n");
+ return -EINVAL;
+ }
+
+ /* detect low and high frequency */
+ low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
+ high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
+
+ result = speedstep_smi_get_freqs(low, high);
+ if (result) {
+ /* fall back to speedstep_lib.c dection mechanism:
+ * try both states out */
+ pr_debug("could not detect low and high frequencies "
+ "by SMI call.\n");
+ result = speedstep_get_freqs(speedstep_processor,
+ low, high,
+ NULL,
+ &speedstep_set_state);
+
+ if (result) {
+ pr_debug("could not detect two different speeds"
+ " -- aborting.\n");
+ return result;
+ } else
+ pr_debug("workaround worked.\n");
+ }
+
+ policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+ return cpufreq_table_validate_and_show(policy, speedstep_freqs);
+}
+
+static unsigned int speedstep_get(unsigned int cpu)
+{
+ if (cpu)
+ return -ENODEV;
+ return speedstep_get_frequency(speedstep_processor);
+}
+
+
+static int speedstep_resume(struct cpufreq_policy *policy)
+{
+ int result = speedstep_smi_ownership();
+
+ if (result)
+ pr_debug("fails in re-acquiring ownership of a SMI interface.\n");
+
+ return result;
+}
+
+static struct cpufreq_driver speedstep_driver = {
+ .name = "speedstep-smi",
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = speedstep_target,
+ .init = speedstep_cpu_init,
+ .get = speedstep_get,
+ .resume = speedstep_resume,
+ .attr = cpufreq_generic_attr,
+};
+
+static const struct x86_cpu_id ss_smi_ids[] = {
+ { X86_VENDOR_INTEL, 6, 0xb, },
+ { X86_VENDOR_INTEL, 6, 0x8, },
+ { X86_VENDOR_INTEL, 15, 2 },
+ {}
+};
+#if 0
+/* Not auto loaded currently */
+MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
+#endif
+
+/**
+ * speedstep_init - initializes the SpeedStep CPUFreq driver
+ *
+ * Initializes the SpeedStep support. Returns -ENODEV on unsupported
+ * BIOS, -EINVAL on problems during initiatization, and zero on
+ * success.
+ */
+static int __init speedstep_init(void)
+{
+ if (!x86_match_cpu(ss_smi_ids))
+ return -ENODEV;
+
+ speedstep_processor = speedstep_detect_processor();
+
+ switch (speedstep_processor) {
+ case SPEEDSTEP_CPU_PIII_T:
+ case SPEEDSTEP_CPU_PIII_C:
+ case SPEEDSTEP_CPU_PIII_C_EARLY:
+ break;
+ default:
+ speedstep_processor = 0;
+ }
+
+ if (!speedstep_processor) {
+ pr_debug("No supported Intel CPU detected.\n");
+ return -ENODEV;
+ }
+
+ pr_debug("signature:0x%.8x, command:0x%.8x, "
+ "event:0x%.8x, perf_level:0x%.8x.\n",
+ ist_info.signature, ist_info.command,
+ ist_info.event, ist_info.perf_level);
+
+ /* Error if no IST-SMI BIOS or no PARM
+ sig= 'ISGE' aka 'Intel Speedstep Gate E' */
+ if ((ist_info.signature != 0x47534943) && (
+ (smi_port == 0) || (smi_cmd == 0)))
+ return -ENODEV;
+
+ if (smi_sig == 1)
+ smi_sig = 0x47534943;
+ else
+ smi_sig = ist_info.signature;
+
+ /* setup smi_port from MODLULE_PARM or BIOS */
+ if ((smi_port > 0xff) || (smi_port < 0))
+ return -EINVAL;
+ else if (smi_port == 0)
+ smi_port = ist_info.command & 0xff;
+
+ if ((smi_cmd > 0xff) || (smi_cmd < 0))
+ return -EINVAL;
+ else if (smi_cmd == 0)
+ smi_cmd = (ist_info.command >> 16) & 0xff;
+
+ return cpufreq_register_driver(&speedstep_driver);
+}
+
+
+/**
+ * speedstep_exit - unregisters SpeedStep support
+ *
+ * Unregisters SpeedStep support.
+ */
+static void __exit speedstep_exit(void)
+{
+ cpufreq_unregister_driver(&speedstep_driver);
+}
+
+module_param(smi_port, int, 0444);
+module_param(smi_cmd, int, 0444);
+module_param(smi_sig, uint, 0444);
+
+MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
+ "-- Intel's default setting is 0xb2");
+MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
+ "-- Intel's default setting is 0x82");
+MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
+ "SMI interface.");
+
+MODULE_AUTHOR("Hiroshi Miura");
+MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
+MODULE_LICENSE("GPL");
+
+module_init(speedstep_init);
+module_exit(speedstep_exit);