x86: Add Intel speedstep and turbo mode code

Intel chips have a turbo mode where they can run faster for a short period
until they reach thermal limits. Add code to adjust and query this feature.

Signed-off-by: Simon Glass <sjg@chromium.org>

4 files changed, 219 insertions, 0 deletions

diff --git a/arch/x86/cpu/Makefile b/arch/x86/cpu/Makefile
index 818969f..3839262 100644
--- a/arch/x86/cpu/Makefile
+++ b/arch/x86/cpu/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_SYS_COREBOOT) += coreboot/
 obj-$(CONFIG_NORTHBRIDGE_INTEL_SANDYBRIDGE) += ivybridge/
 obj-$(CONFIG_NORTHBRIDGE_INTEL_IVYBRIDGE) += ivybridge/
 obj-$(CONFIG_PCI) += pci.o
+obj-y += turbo.o
diff --git a/arch/x86/cpu/turbo.c b/arch/x86/cpu/turbo.c
new file mode 100644
index 0000000..254d0de
--- /dev/null
+++ b/arch/x86/cpu/turbo.c
@@ -0,0 +1,98 @@
+/*
+ * From Coreboot file of the same name
+ *
+ * Copyright (C) 2011 The Chromium Authors.
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <asm/cpu.h>
+#include <asm/msr.h>
+#include <asm/processor.h>
+#include <asm/turbo.h>
+
+#if CONFIG_CPU_INTEL_TURBO_NOT_PACKAGE_SCOPED
+static inline int get_global_turbo_state(void)
+{
+	return TURBO_UNKNOWN;
+}
+
+static inline void set_global_turbo_state(int state)
+{
+}
+#else
+static int g_turbo_state = TURBO_UNKNOWN;
+
+static inline int get_global_turbo_state(void)
+{
+	return g_turbo_state;
+}
+
+static inline void set_global_turbo_state(int state)
+{
+	g_turbo_state = state;
+}
+#endif
+
+static const char *const turbo_state_desc[] = {
+	[TURBO_UNKNOWN]		= "unknown",
+	[TURBO_UNAVAILABLE]	= "unavailable",
+	[TURBO_DISABLED]	= "available but hidden",
+	[TURBO_ENABLED]		= "available and visible"
+};
+
+/*
+ * Determine the current state of Turbo and cache it for later.
+ * Turbo is a package level config so it does not need to be
+ * enabled on every core.
+ */
+int turbo_get_state(void)
+{
+	struct cpuid_result cpuid_regs;
+	int turbo_en, turbo_cap;
+	msr_t msr;
+	int turbo_state = get_global_turbo_state();
+
+	/* Return cached state if available */
+	if (turbo_state != TURBO_UNKNOWN)
+		return turbo_state;
+
+	cpuid_regs = cpuid(CPUID_LEAF_PM);
+	turbo_cap = !!(cpuid_regs.eax & PM_CAP_TURBO_MODE);
+
+	msr = msr_read(MSR_IA32_MISC_ENABLES);
+	turbo_en = !(msr.hi & H_MISC_DISABLE_TURBO);
+
+	if (!turbo_cap && turbo_en) {
+		/* Unavailable */
+		turbo_state = TURBO_UNAVAILABLE;
+	} else if (!turbo_cap && !turbo_en) {
+		/* Available but disabled */
+		turbo_state = TURBO_DISABLED;
+	} else if (turbo_cap && turbo_en) {
+		/* Available */
+		turbo_state = TURBO_ENABLED;
+	}
+
+	set_global_turbo_state(turbo_state);
+	debug("Turbo is %s\n", turbo_state_desc[turbo_state]);
+	return turbo_state;
+}
+
+void turbo_enable(void)
+{
+	msr_t msr;
+
+	/* Only possible if turbo is available but hidden */
+	if (turbo_get_state() == TURBO_DISABLED) {
+		/* Clear Turbo Disable bit in Misc Enables */
+		msr = msr_read(MSR_IA32_MISC_ENABLES);
+		msr.hi &= ~H_MISC_DISABLE_TURBO;
+		msr_write(MSR_IA32_MISC_ENABLES, msr);
+
+		/* Update cached turbo state */
+		set_global_turbo_state(TURBO_ENABLED);
+		debug("Turbo has been enabled\n");
+	}
+}
diff --git a/arch/x86/include/asm/speedstep.h b/arch/x86/include/asm/speedstep.h
new file mode 100644
index 0000000..b938b86
--- /dev/null
+++ b/arch/x86/include/asm/speedstep.h
@@ -0,0 +1,89 @@
+/*
+ * From Coreboot file of same name
+ *
+ * Copyright (C) 2007-2009 coresystems GmbH
+ *               2012 secunet Security Networks AG
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#ifndef _ASM_SPEEDSTEP_H
+#define _ASM_SPEEDSTEP_H
+
+/* Magic value used to locate speedstep configuration in the device tree */
+#define SPEEDSTEP_APIC_MAGIC 0xACAC
+
+/* MWAIT coordination I/O base address. This must match
+ * the \_PR_.CPU0 PM base address.
+ */
+#define PMB0_BASE 0x510
+
+/* PMB1: I/O port that triggers SMI once cores are in the same state.
+ * See CSM Trigger, at PMG_CST_CONFIG_CONTROL[6:4]
+ */
+#define PMB1_BASE 0x800
+
+struct sst_state {
+	uint8_t dynfsb:1; /* whether this is SLFM */
+	uint8_t nonint:1; /* add .5 to ratio */
+	uint8_t ratio:6;
+	uint8_t vid;
+	uint8_t is_turbo;
+	uint8_t is_slfm;
+	uint32_t power;
+};
+#define SPEEDSTEP_RATIO_SHIFT		8
+#define SPEEDSTEP_RATIO_DYNFSB_SHIFT	(7 + SPEEDSTEP_RATIO_SHIFT)
+#define SPEEDSTEP_RATIO_DYNFSB		(1 << SPEEDSTEP_RATIO_DYNFSB_SHIFT)
+#define SPEEDSTEP_RATIO_NONINT_SHIFT	(6 + SPEEDSTEP_RATIO_SHIFT)
+#define SPEEDSTEP_RATIO_NONINT		(1 << SPEEDSTEP_RATIO_NONINT_SHIFT)
+#define SPEEDSTEP_RATIO_VALUE_MASK	(0x1f << SPEEDSTEP_RATIO_SHIFT)
+#define SPEEDSTEP_VID_MASK		0x3f
+#define SPEEDSTEP_STATE_FROM_MSR(val, mask) ((struct sst_state){	\
+		0, /* dynfsb won't be read. */				\
+		((val & mask) & SPEEDSTEP_RATIO_NONINT) ? 1 : 0,	\
+		(((val & mask) & SPEEDSTEP_RATIO_VALUE_MASK)		\
+					>> SPEEDSTEP_RATIO_SHIFT),	\
+		(val & mask) & SPEEDSTEP_VID_MASK,			\
+		0, /* not turbo by default */				\
+		0, /* not slfm by default */				\
+		0  /* power is hardcoded in software. */		\
+	})
+#define SPEEDSTEP_ENCODE_STATE(state)	(				\
+	((uint16_t)(state).dynfsb << SPEEDSTEP_RATIO_DYNFSB_SHIFT) |	\
+	((uint16_t)(state).nonint << SPEEDSTEP_RATIO_NONINT_SHIFT) |	\
+	((uint16_t)(state).ratio << SPEEDSTEP_RATIO_SHIFT) |		\
+	((uint16_t)(state).vid & SPEEDSTEP_VID_MASK))
+#define SPEEDSTEP_DOUBLE_RATIO(state)	(				\
+	((uint8_t)(state).ratio * 2) + (state).nonint)
+
+struct sst_params {
+	struct sst_state slfm;
+	struct sst_state min;
+	struct sst_state max;
+	struct sst_state turbo;
+};
+
+/* Looking at core2's spec, the highest normal bus ratio for an eist enabled
+   processor is 14, the lowest is always 6. This makes 5 states with the
+   minimal step width of 2. With turbo mode and super LFM we have at most 7. */
+#define SPEEDSTEP_MAX_NORMAL_STATES	5
+#define SPEEDSTEP_MAX_STATES		(SPEEDSTEP_MAX_NORMAL_STATES + 2)
+struct sst_table {
+	/* Table of p-states for EMTTM and ACPI by decreasing performance. */
+	struct sst_state states[SPEEDSTEP_MAX_STATES];
+	int num_states;
+};
+
+void speedstep_gen_pstates(struct sst_table *);
+
+#define SPEEDSTEP_MAX_POWER_YONAH	31000
+#define SPEEDSTEP_MIN_POWER_YONAH	13100
+#define SPEEDSTEP_MAX_POWER_MEROM	35000
+#define SPEEDSTEP_MIN_POWER_MEROM	25000
+#define SPEEDSTEP_SLFM_POWER_MEROM	12000
+#define SPEEDSTEP_MAX_POWER_PENRYN	35000
+#define SPEEDSTEP_MIN_POWER_PENRYN	15000
+#define SPEEDSTEP_SLFM_POWER_PENRYN	12000
+
+#endif
diff --git a/arch/x86/include/asm/turbo.h b/arch/x86/include/asm/turbo.h
new file mode 100644
index 0000000..bb0d4b4
--- /dev/null
+++ b/arch/x86/include/asm/turbo.h
@@ -0,0 +1,31 @@
+/*
+ * From coreboot file of the same name
+ *
+ * Copyright (C) 2011 The ChromiumOS Authors. All rights reserved.
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#ifndef _ASM_TURBO_H
+#define _ASM_TURBO_H
+
+#define CPUID_LEAF_PM		6
+#define PM_CAP_TURBO_MODE	(1 << 1)
+
+#define MSR_IA32_MISC_ENABLES	0x1a0
+#define H_MISC_DISABLE_TURBO	(1 << 6)
+
+enum {
+	TURBO_UNKNOWN,
+	TURBO_UNAVAILABLE,
+	TURBO_DISABLED,
+	TURBO_ENABLED,
+};
+
+/* Return current turbo state */
+int turbo_get_state(void);
+
+/* Enable turbo */
+void turbo_enable(void);
+
+#endif