1 files changed, 311 insertions, 0 deletions
diff --git a/drivers/cpufreq/powernow-k6.c b/drivers/cpufreq/powernow-k6.c
new file mode 100644
index 0000000000..41eefef95d
--- /dev/null
+++ b/drivers/cpufreq/powernow-k6.c
@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  This file was based upon code in Powertweak Linux (http://powertweak.sf.net)
+ *  (C) 2000-2003  Dave Jones, Arjan van de Ven, Janne Pänkälä,
+ *                 Dominik Brodowski.
+ *
+ *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
+ */
+
+#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/ioport.h>
+#include <linux/timex.h>
+#include <linux/io.h>
+
+#include <asm/cpu_device_id.h>
+#include <asm/msr.h>
+
+#define POWERNOW_IOPORT 0xfff0          /* it doesn't matter where, as long
+					   as it is unused */
+
+static unsigned int                     busfreq;   /* FSB, in 10 kHz */
+static unsigned int                     max_multiplier;
+
+static unsigned int			param_busfreq = 0;
+static unsigned int			param_max_multiplier = 0;
+
+module_param_named(max_multiplier, param_max_multiplier, uint, S_IRUGO);
+MODULE_PARM_DESC(max_multiplier, "Maximum multiplier (allowed values: 20 30 35 40 45 50 55 60)");
+
+module_param_named(bus_frequency, param_busfreq, uint, S_IRUGO);
+MODULE_PARM_DESC(bus_frequency, "Bus frequency in kHz");
+
+/* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
+static struct cpufreq_frequency_table clock_ratio[] = {
+	{0, 60,  /* 110 -> 6.0x */ 0},
+	{0, 55,  /* 011 -> 5.5x */ 0},
+	{0, 50,  /* 001 -> 5.0x */ 0},
+	{0, 45,  /* 000 -> 4.5x */ 0},
+	{0, 40,  /* 010 -> 4.0x */ 0},
+	{0, 35,  /* 111 -> 3.5x */ 0},
+	{0, 30,  /* 101 -> 3.0x */ 0},
+	{0, 20,  /* 100 -> 2.0x */ 0},
+	{0, 0, CPUFREQ_TABLE_END}
+};
+
+static const u8 index_to_register[8] = { 6, 3, 1, 0, 2, 7, 5, 4 };
+static const u8 register_to_index[8] = { 3, 2, 4, 1, 7, 6, 0, 5 };
+
+static const struct {
+	unsigned freq;
+	unsigned mult;
+} usual_frequency_table[] = {
+	{ 350000, 35 },	// 100   * 3.5
+	{ 400000, 40 },	// 100   * 4
+	{ 450000, 45 }, // 100   * 4.5
+	{ 475000, 50 }, //  95   * 5
+	{ 500000, 50 }, // 100   * 5
+	{ 506250, 45 }, // 112.5 * 4.5
+	{ 533500, 55 }, //  97   * 5.5
+	{ 550000, 55 }, // 100   * 5.5
+	{ 562500, 50 }, // 112.5 * 5
+	{ 570000, 60 }, //  95   * 6
+	{ 600000, 60 }, // 100   * 6
+	{ 618750, 55 }, // 112.5 * 5.5
+	{ 660000, 55 }, // 120   * 5.5
+	{ 675000, 60 }, // 112.5 * 6
+	{ 720000, 60 }, // 120   * 6
+};
+
+#define FREQ_RANGE		3000
+
+/**
+ * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
+ *
+ * Returns the current setting of the frequency multiplier. Core clock
+ * speed is frequency of the Front-Side Bus multiplied with this value.
+ */
+static int powernow_k6_get_cpu_multiplier(void)
+{
+	unsigned long invalue = 0;
+	u32 msrval;
+
+	local_irq_disable();
+
+	msrval = POWERNOW_IOPORT + 0x1;
+	wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
+	invalue = inl(POWERNOW_IOPORT + 0x8);
+	msrval = POWERNOW_IOPORT + 0x0;
+	wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
+
+	local_irq_enable();
+
+	return clock_ratio[register_to_index[(invalue >> 5)&7]].driver_data;
+}
+
+static void powernow_k6_set_cpu_multiplier(unsigned int best_i)
+{
+	unsigned long outvalue, invalue;
+	unsigned long msrval;
+	unsigned long cr0;
+
+	/* we now need to transform best_i to the BVC format, see AMD#23446 */
+
+	/*
+	 * The processor doesn't respond to inquiry cycles while changing the
+	 * frequency, so we must disable cache.
+	 */
+	local_irq_disable();
+	cr0 = read_cr0();
+	write_cr0(cr0 | X86_CR0_CD);
+	wbinvd();
+
+	outvalue = (1<<12) | (1<<10) | (1<<9) | (index_to_register[best_i]<<5);
+
+	msrval = POWERNOW_IOPORT + 0x1;
+	wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
+	invalue = inl(POWERNOW_IOPORT + 0x8);
+	invalue = invalue & 0x1f;
+	outvalue = outvalue | invalue;
+	outl(outvalue, (POWERNOW_IOPORT + 0x8));
+	msrval = POWERNOW_IOPORT + 0x0;
+	wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
+
+	write_cr0(cr0);
+	local_irq_enable();
+}
+
+/**
+ * powernow_k6_target - set the PowerNow! multiplier
+ * @best_i: clock_ratio[best_i] is the target multiplier
+ *
+ *   Tries to change the PowerNow! multiplier
+ */
+static int powernow_k6_target(struct cpufreq_policy *policy,
+		unsigned int best_i)
+{
+
+	if (clock_ratio[best_i].driver_data > max_multiplier) {
+		pr_err("invalid target frequency\n");
+		return -EINVAL;
+	}
+
+	powernow_k6_set_cpu_multiplier(best_i);
+
+	return 0;
+}
+
+static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
+{
+	struct cpufreq_frequency_table *pos;
+	unsigned int i, f;
+	unsigned khz;
+
+	if (policy->cpu != 0)
+		return -ENODEV;
+
+	max_multiplier = 0;
+	khz = cpu_khz;
+	for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) {
+		if (khz >= usual_frequency_table[i].freq - FREQ_RANGE &&
+		    khz <= usual_frequency_table[i].freq + FREQ_RANGE) {
+			khz = usual_frequency_table[i].freq;
+			max_multiplier = usual_frequency_table[i].mult;
+			break;
+		}
+	}
+	if (param_max_multiplier) {
+		cpufreq_for_each_entry(pos, clock_ratio)
+			if (pos->driver_data == param_max_multiplier) {
+				max_multiplier = param_max_multiplier;
+				goto have_max_multiplier;
+			}
+		pr_err("invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");
+		return -EINVAL;
+	}
+
+	if (!max_multiplier) {
+		pr_warn("unknown frequency %u, cannot determine current multiplier\n",
+			khz);
+		pr_warn("use module parameters max_multiplier and bus_frequency\n");
+		return -EOPNOTSUPP;
+	}
+
+have_max_multiplier:
+	param_max_multiplier = max_multiplier;
+
+	if (param_busfreq) {
+		if (param_busfreq >= 50000 && param_busfreq <= 150000) {
+			busfreq = param_busfreq / 10;
+			goto have_busfreq;
+		}
+		pr_err("invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n");
+		return -EINVAL;
+	}
+
+	busfreq = khz / max_multiplier;
+have_busfreq:
+	param_busfreq = busfreq * 10;
+
+	/* table init */
+	cpufreq_for_each_entry(pos, clock_ratio) {
+		f = pos->driver_data;
+		if (f > max_multiplier)
+			pos->frequency = CPUFREQ_ENTRY_INVALID;
+		else
+			pos->frequency = busfreq * f;
+	}
+
+	/* cpuinfo and default policy values */
+	policy->cpuinfo.transition_latency = 500000;
+	policy->freq_table = clock_ratio;
+
+	return 0;
+}
+
+
+static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
+{
+	unsigned int i;
+
+	for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
+		if (clock_ratio[i].driver_data == max_multiplier) {
+			struct cpufreq_freqs freqs;
+
+			freqs.old = policy->cur;
+			freqs.new = clock_ratio[i].frequency;
+			freqs.flags = 0;
+
+			cpufreq_freq_transition_begin(policy, &freqs);
+			powernow_k6_target(policy, i);
+			cpufreq_freq_transition_end(policy, &freqs, 0);
+			break;
+		}
+	}
+	return 0;
+}
+
+static unsigned int powernow_k6_get(unsigned int cpu)
+{
+	unsigned int ret;
+	ret = (busfreq * powernow_k6_get_cpu_multiplier());
+	return ret;
+}
+
+static struct cpufreq_driver powernow_k6_driver = {
+	.verify		= cpufreq_generic_frequency_table_verify,
+	.target_index	= powernow_k6_target,
+	.init		= powernow_k6_cpu_init,
+	.exit		= powernow_k6_cpu_exit,
+	.get		= powernow_k6_get,
+	.name		= "powernow-k6",
+	.attr		= cpufreq_generic_attr,
+};
+
+static const struct x86_cpu_id powernow_k6_ids[] = {
+	X86_MATCH_VENDOR_FAM_MODEL(AMD, 5, 12, NULL),
+	X86_MATCH_VENDOR_FAM_MODEL(AMD, 5, 13, NULL),
+	{}
+};
+MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids);
+
+/**
+ * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
+ *
+ *   Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
+ * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
+ * on success.
+ */
+static int __init powernow_k6_init(void)
+{
+	if (!x86_match_cpu(powernow_k6_ids))
+		return -ENODEV;
+
+	if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
+		pr_info("PowerNow IOPORT region already used\n");
+		return -EIO;
+	}
+
+	if (cpufreq_register_driver(&powernow_k6_driver)) {
+		release_region(POWERNOW_IOPORT, 16);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+
+/**
+ * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
+ *
+ *   Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
+ */
+static void __exit powernow_k6_exit(void)
+{
+	cpufreq_unregister_driver(&powernow_k6_driver);
+	release_region(POWERNOW_IOPORT, 16);
+}
+
+
+MODULE_AUTHOR("Arjan van de Ven, Dave Jones, "
+		"Dominik Brodowski <linux@brodo.de>");
+MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
+MODULE_LICENSE("GPL");
+
+module_init(powernow_k6_init);
+module_exit(powernow_k6_exit);