1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c
new file mode 100644
index 0000000000..f2076d72bf
--- /dev/null
+++ b/drivers/cpufreq/speedstep-ich.c
@@ -0,0 +1,386 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * (C) 2001  Dave Jones, Arjan van de ven.
+ * (C) 2002 - 2003  Dominik Brodowski <linux@brodo.de>
+ *
+ *  Based upon reverse engineered information, and on Intel documentation
+ *  for chipsets ICH2-M and ICH3-M.
+ *
+ *  Many thanks to Ducrot Bruno for finding and fixing the last
+ *  "missing link" for ICH2-M/ICH3-M support, and to Thomas Winkler
+ *  for extensive testing.
+ *
+ *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
+ */
+
+
+/*********************************************************************
+ *                        SPEEDSTEP - DEFINITIONS                    *
+ *********************************************************************/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/pci.h>
+#include <linux/sched.h>
+
+#include <asm/cpu_device_id.h>
+
+#include "speedstep-lib.h"
+
+
+/* speedstep_chipset:
+ *   It is necessary to know which chipset is used. As accesses to
+ * this device occur at various places in this module, we need a
+ * static struct pci_dev * pointing to that device.
+ */
+static struct pci_dev *speedstep_chipset_dev;
+
+
+/* speedstep_processor
+ */
+static enum speedstep_processor speedstep_processor;
+
+static u32 pmbase;
+
+/*
+ *   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},
+};
+
+
+/**
+ * speedstep_find_register - read the PMBASE address
+ *
+ * Returns: -ENODEV if no register could be found
+ */
+static int speedstep_find_register(void)
+{
+	if (!speedstep_chipset_dev)
+		return -ENODEV;
+
+	/* get PMBASE */
+	pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
+	if (!(pmbase & 0x01)) {
+		pr_err("could not find speedstep register\n");
+		return -ENODEV;
+	}
+
+	pmbase &= 0xFFFFFFFE;
+	if (!pmbase) {
+		pr_err("could not find speedstep register\n");
+		return -ENODEV;
+	}
+
+	pr_debug("pmbase is 0x%x\n", pmbase);
+	return 0;
+}
+
+/**
+ * speedstep_set_state - set the SpeedStep state
+ * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
+ *
+ *   Tries to change the SpeedStep state.  Can be called from
+ *   smp_call_function_single.
+ */
+static void speedstep_set_state(unsigned int state)
+{
+	u8 pm2_blk;
+	u8 value;
+	unsigned long flags;
+
+	if (state > 0x1)
+		return;
+
+	/* Disable IRQs */
+	local_irq_save(flags);
+
+	/* read state */
+	value = inb(pmbase + 0x50);
+
+	pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
+
+	/* write new state */
+	value &= 0xFE;
+	value |= state;
+
+	pr_debug("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
+
+	/* Disable bus master arbitration */
+	pm2_blk = inb(pmbase + 0x20);
+	pm2_blk |= 0x01;
+	outb(pm2_blk, (pmbase + 0x20));
+
+	/* Actual transition */
+	outb(value, (pmbase + 0x50));
+
+	/* Restore bus master arbitration */
+	pm2_blk &= 0xfe;
+	outb(pm2_blk, (pmbase + 0x20));
+
+	/* check if transition was successful */
+	value = inb(pmbase + 0x50);
+
+	/* Enable IRQs */
+	local_irq_restore(flags);
+
+	pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
+
+	if (state == (value & 0x1))
+		pr_debug("change to %u MHz succeeded\n",
+			speedstep_get_frequency(speedstep_processor) / 1000);
+	else
+		pr_err("change failed - I/O error\n");
+
+	return;
+}
+
+/* Wrapper for smp_call_function_single. */
+static void _speedstep_set_state(void *_state)
+{
+	speedstep_set_state(*(unsigned int *)_state);
+}
+
+/**
+ * speedstep_activate - activate SpeedStep control in the chipset
+ *
+ *   Tries to activate the SpeedStep status and control registers.
+ * Returns -EINVAL on an unsupported chipset, and zero on success.
+ */
+static int speedstep_activate(void)
+{
+	u16 value = 0;
+
+	if (!speedstep_chipset_dev)
+		return -EINVAL;
+
+	pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
+	if (!(value & 0x08)) {
+		value |= 0x08;
+		pr_debug("activating SpeedStep (TM) registers\n");
+		pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
+	}
+
+	return 0;
+}
+
+
+/**
+ * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
+ *
+ *   Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
+ * the LPC bridge / PM module which contains all power-management
+ * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
+ * chipset, or zero on failure.
+ */
+static unsigned int speedstep_detect_chipset(void)
+{
+	speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+			      PCI_DEVICE_ID_INTEL_82801DB_12,
+			      PCI_ANY_ID, PCI_ANY_ID,
+			      NULL);
+	if (speedstep_chipset_dev)
+		return 4; /* 4-M */
+
+	speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+			      PCI_DEVICE_ID_INTEL_82801CA_12,
+			      PCI_ANY_ID, PCI_ANY_ID,
+			      NULL);
+	if (speedstep_chipset_dev)
+		return 3; /* 3-M */
+
+
+	speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+			      PCI_DEVICE_ID_INTEL_82801BA_10,
+			      PCI_ANY_ID, PCI_ANY_ID,
+			      NULL);
+	if (speedstep_chipset_dev) {
+		/* speedstep.c causes lockups on Dell Inspirons 8000 and
+		 * 8100 which use a pretty old revision of the 82815
+		 * host bridge. Abort on these systems.
+		 */
+		struct pci_dev *hostbridge;
+
+		hostbridge  = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+			      PCI_DEVICE_ID_INTEL_82815_MC,
+			      PCI_ANY_ID, PCI_ANY_ID,
+			      NULL);
+
+		if (!hostbridge)
+			return 2; /* 2-M */
+
+		if (hostbridge->revision < 5) {
+			pr_debug("hostbridge does not support speedstep\n");
+			speedstep_chipset_dev = NULL;
+			pci_dev_put(hostbridge);
+			return 0;
+		}
+
+		pci_dev_put(hostbridge);
+		return 2; /* 2-M */
+	}
+
+	return 0;
+}
+
+static void get_freq_data(void *_speed)
+{
+	unsigned int *speed = _speed;
+
+	*speed = speedstep_get_frequency(speedstep_processor);
+}
+
+static unsigned int speedstep_get(unsigned int cpu)
+{
+	unsigned int speed;
+
+	/* You're supposed to ensure CPU is online. */
+	BUG_ON(smp_call_function_single(cpu, get_freq_data, &speed, 1));
+
+	pr_debug("detected %u kHz as current frequency\n", speed);
+	return speed;
+}
+
+/**
+ * speedstep_target - set a new CPUFreq policy
+ * @policy: new policy
+ * @index: index of target frequency
+ *
+ * Sets a new CPUFreq policy.
+ */
+static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	unsigned int policy_cpu;
+
+	policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
+
+	smp_call_function_single(policy_cpu, _speedstep_set_state, &index,
+				 true);
+
+	return 0;
+}
+
+
+struct get_freqs {
+	struct cpufreq_policy *policy;
+	int ret;
+};
+
+static void get_freqs_on_cpu(void *_get_freqs)
+{
+	struct get_freqs *get_freqs = _get_freqs;
+
+	get_freqs->ret =
+		speedstep_get_freqs(speedstep_processor,
+			    &speedstep_freqs[SPEEDSTEP_LOW].frequency,
+			    &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
+			    &get_freqs->policy->cpuinfo.transition_latency,
+			    &speedstep_set_state);
+}
+
+static int speedstep_cpu_init(struct cpufreq_policy *policy)
+{
+	unsigned int policy_cpu;
+	struct get_freqs gf;
+
+	/* only run on CPU to be set, or on its sibling */
+#ifdef CONFIG_SMP
+	cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));
+#endif
+	policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
+
+	/* detect low and high frequency and transition latency */
+	gf.policy = policy;
+	smp_call_function_single(policy_cpu, get_freqs_on_cpu, &gf, 1);
+	if (gf.ret)
+		return gf.ret;
+
+	policy->freq_table = speedstep_freqs;
+
+	return 0;
+}
+
+
+static struct cpufreq_driver speedstep_driver = {
+	.name	= "speedstep-ich",
+	.verify	= cpufreq_generic_frequency_table_verify,
+	.target_index = speedstep_target,
+	.init	= speedstep_cpu_init,
+	.get	= speedstep_get,
+	.attr	= cpufreq_generic_attr,
+};
+
+static const struct x86_cpu_id ss_smi_ids[] = {
+	X86_MATCH_VENDOR_FAM_MODEL(INTEL,  6, 0x8, 0),
+	X86_MATCH_VENDOR_FAM_MODEL(INTEL,  6, 0xb, 0),
+	X86_MATCH_VENDOR_FAM_MODEL(INTEL, 15, 0x2, 0),
+	{}
+};
+
+/**
+ * speedstep_init - initializes the SpeedStep CPUFreq driver
+ *
+ *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
+ * devices, -EINVAL on problems during initiatization, and zero on
+ * success.
+ */
+static int __init speedstep_init(void)
+{
+	if (!x86_match_cpu(ss_smi_ids))
+		return -ENODEV;
+
+	/* detect processor */
+	speedstep_processor = speedstep_detect_processor();
+	if (!speedstep_processor) {
+		pr_debug("Intel(R) SpeedStep(TM) capable processor "
+				"not found\n");
+		return -ENODEV;
+	}
+
+	/* detect chipset */
+	if (!speedstep_detect_chipset()) {
+		pr_debug("Intel(R) SpeedStep(TM) for this chipset not "
+				"(yet) available.\n");
+		return -ENODEV;
+	}
+
+	/* activate speedstep support */
+	if (speedstep_activate()) {
+		pci_dev_put(speedstep_chipset_dev);
+		return -EINVAL;
+	}
+
+	if (speedstep_find_register())
+		return -ENODEV;
+
+	return cpufreq_register_driver(&speedstep_driver);
+}
+
+
+/**
+ * speedstep_exit - unregisters SpeedStep support
+ *
+ *   Unregisters SpeedStep support.
+ */
+static void __exit speedstep_exit(void)
+{
+	pci_dev_put(speedstep_chipset_dev);
+	cpufreq_unregister_driver(&speedstep_driver);
+}
+
+
+MODULE_AUTHOR("Dave Jones, Dominik Brodowski <linux@brodo.de>");
+MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
+		"with ICH-M southbridges.");
+MODULE_LICENSE("GPL");
+
+module_init(speedstep_init);
+module_exit(speedstep_exit);