x86: Add a CPU driver for baytrail

This driver supports multi-core init and sets up the CPU frequencies
correctly.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

2 files changed, 206 insertions, 0 deletions

diff --git a/arch/x86/cpu/baytrail/Makefile b/arch/x86/cpu/baytrail/Makefile
index 8914e8b..c78b644 100644
--- a/arch/x86/cpu/baytrail/Makefile
+++ b/arch/x86/cpu/baytrail/Makefile
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
+obj-y += cpu.o
 obj-y += early_uart.o
 obj-y += fsp_configs.o
 obj-y += pci.o
diff --git a/arch/x86/cpu/baytrail/cpu.c b/arch/x86/cpu/baytrail/cpu.c
new file mode 100644
index 0000000..1d48206
--- /dev/null
+++ b/arch/x86/cpu/baytrail/cpu.c
@@ -0,0 +1,205 @@
+/*
+ * Copyright (C) 2015 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ * Based on code from coreboot
+ */
+
+#include <common.h>
+#include <cpu.h>
+#include <dm.h>
+#include <asm/cpu.h>
+#include <asm/lapic.h>
+#include <asm/mp.h>
+#include <asm/msr.h>
+#include <asm/turbo.h>
+
+#ifdef CONFIG_SMP
+static int enable_smis(struct udevice *cpu, void *unused)
+{
+	return 0;
+}
+
+static struct mp_flight_record mp_steps[] = {
+	MP_FR_BLOCK_APS(mp_init_cpu, NULL, mp_init_cpu, NULL),
+	/* Wait for APs to finish initialization before proceeding. */
+	MP_FR_BLOCK_APS(NULL, NULL, enable_smis, NULL),
+};
+
+static int detect_num_cpus(void)
+{
+	int ecx = 0;
+
+	/*
+	 * Use the algorithm described in Intel 64 and IA-32 Architectures
+	 * Software Developer's Manual Volume 3 (3A, 3B & 3C): System
+	 * Programming Guide, Jan-2015. Section 8.9.2: Hierarchical Mapping
+	 * of CPUID Extended Topology Leaf.
+	 */
+	while (1) {
+		struct cpuid_result leaf_b;
+
+		leaf_b = cpuid_ext(0xb, ecx);
+
+		/*
+		 * Bay Trail doesn't have hyperthreading so just determine the
+		 * number of cores by from level type (ecx[15:8] == * 2)
+		 */
+		if ((leaf_b.ecx & 0xff00) == 0x0200)
+			return leaf_b.ebx & 0xffff;
+		ecx++;
+	}
+}
+
+static int baytrail_init_cpus(void)
+{
+	struct mp_params mp_params;
+
+	lapic_setup();
+
+	mp_params.num_cpus = detect_num_cpus();
+	mp_params.parallel_microcode_load = 0,
+	mp_params.flight_plan = &mp_steps[0];
+	mp_params.num_records = ARRAY_SIZE(mp_steps);
+	mp_params.microcode_pointer = 0;
+
+	if (mp_init(&mp_params)) {
+		printf("Warning: MP init failure\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+#endif
+
+int x86_init_cpus(void)
+{
+#ifdef CONFIG_SMP
+	debug("Init additional CPUs\n");
+	baytrail_init_cpus();
+#endif
+
+	return 0;
+}
+
+static void set_max_freq(void)
+{
+	msr_t perf_ctl;
+	msr_t msr;
+
+	/* Enable speed step */
+	msr = msr_read(MSR_IA32_MISC_ENABLES);
+	msr.lo |= (1 << 16);
+	msr_write(MSR_IA32_MISC_ENABLES, msr);
+
+	/*
+	 * Set guaranteed ratio [21:16] from IACORE_RATIOS to bits [15:8] of
+	 * the PERF_CTL
+	 */
+	msr = msr_read(MSR_IACORE_RATIOS);
+	perf_ctl.lo = (msr.lo & 0x3f0000) >> 8;
+
+	/*
+	 * Set guaranteed vid [21:16] from IACORE_VIDS to bits [7:0] of
+	 * the PERF_CTL
+	 */
+	msr = msr_read(MSR_IACORE_VIDS);
+	perf_ctl.lo |= (msr.lo & 0x7f0000) >> 16;
+	perf_ctl.hi = 0;
+
+	msr_write(MSR_IA32_PERF_CTL, perf_ctl);
+}
+
+static int cpu_x86_baytrail_probe(struct udevice *dev)
+{
+	debug("Init BayTrail core\n");
+
+	/*
+	 * On BayTrail the turbo disable bit is actually scoped at the
+	 * building-block level, not package. For non-BSP cores that are
+	 * within a building block, enable turbo. The cores within the BSP's
+	 * building block will just see it already enabled and move on.
+	 */
+	if (lapicid())
+		turbo_enable();
+
+	/* Dynamic L2 shrink enable and threshold */
+	msr_clrsetbits_64(MSR_PMG_CST_CONFIG_CONTROL, 0x3f000f, 0xe0008),
+
+	/* Disable C1E */
+	msr_clrsetbits_64(MSR_POWER_CTL, 2, 0);
+	msr_setbits_64(MSR_POWER_MISC, 0x44);
+
+	/* Set this core to max frequency ratio */
+	set_max_freq();
+
+	return 0;
+}
+
+static unsigned bus_freq(void)
+{
+	msr_t clk_info = msr_read(MSR_BSEL_CR_OVERCLOCK_CONTROL);
+	switch (clk_info.lo & 0x3) {
+	case 0:
+		return 83333333;
+	case 1:
+		return 100000000;
+	case 2:
+		return 133333333;
+	case 3:
+		return 116666666;
+	default:
+		return 0;
+	}
+}
+
+static unsigned long tsc_freq(void)
+{
+	msr_t platform_info;
+	ulong bclk = bus_freq();
+
+	if (!bclk)
+		return 0;
+
+	platform_info = msr_read(MSR_PLATFORM_INFO);
+
+	return bclk * ((platform_info.lo >> 8) & 0xff);
+}
+
+static int baytrail_get_info(struct udevice *dev, struct cpu_info *info)
+{
+	info->cpu_freq = tsc_freq();
+	info->features = 1 << CPU_FEAT_L1_CACHE | 1 << CPU_FEAT_MMU;
+
+	return 0;
+}
+
+static int cpu_x86_baytrail_bind(struct udevice *dev)
+{
+	struct cpu_platdata *plat = dev_get_parent_platdata(dev);
+
+	plat->cpu_id = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
+				      "intel,apic-id", -1);
+
+	return 0;
+}
+
+static const struct cpu_ops cpu_x86_baytrail_ops = {
+	.get_desc	= x86_cpu_get_desc,
+	.get_info	= baytrail_get_info,
+};
+
+static const struct udevice_id cpu_x86_baytrail_ids[] = {
+	{ .compatible = "intel,baytrail-cpu" },
+	{ }
+};
+
+U_BOOT_DRIVER(cpu_x86_baytrail_drv) = {
+	.name		= "cpu_x86_baytrail",
+	.id		= UCLASS_CPU,
+	.of_match	= cpu_x86_baytrail_ids,
+	.bind		= cpu_x86_baytrail_bind,
+	.probe		= cpu_x86_baytrail_probe,
+	.ops		= &cpu_x86_baytrail_ops,
+};