x86, intel-mid: Add Merrifield platform support

This code was partially based on Mark Brown's previous work.

Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Link: http://lkml.kernel.org/r/1387224459-25746-4-git-send-email-david.a.cohen@linux.intel.com
Signed-off-by: Fei Yang <fei.yang@intel.com>
Cc: Mark F. Brown <mark.f.brown@intel.com>
Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 103 insertions, 0 deletions

diff --git a/arch/x86/platform/intel-mid/mrfl.c b/arch/x86/platform/intel-mid/mrfl.c
new file mode 100644
index 000000000000..09d10159e7b7
--- /dev/null
+++ b/arch/x86/platform/intel-mid/mrfl.c
@@ -0,0 +1,103 @@
+/*
+ * mrfl.c: Intel Merrifield platform specific setup code
+ *
+ * (C) Copyright 2013 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/init.h>
+
+#include <asm/apic.h>
+#include <asm/intel-mid.h>
+
+#include "intel_mid_weak_decls.h"
+
+static unsigned long __init tangier_calibrate_tsc(void)
+{
+	unsigned long fast_calibrate;
+	u32 lo, hi, ratio, fsb, bus_freq;
+
+	/* *********************** */
+	/* Compute TSC:Ratio * FSB */
+	/* *********************** */
+
+	/* Compute Ratio */
+	rdmsr(MSR_PLATFORM_INFO, lo, hi);
+	pr_debug("IA32 PLATFORM_INFO is 0x%x : %x\n", hi, lo);
+
+	ratio = (lo >> 8) & 0xFF;
+	pr_debug("ratio is %d\n", ratio);
+	if (!ratio) {
+		pr_err("Read a zero ratio, force tsc ratio to 4 ...\n");
+		ratio = 4;
+	}
+
+	/* Compute FSB */
+	rdmsr(MSR_FSB_FREQ, lo, hi);
+	pr_debug("Actual FSB frequency detected by SOC 0x%x : %x\n",
+			hi, lo);
+
+	bus_freq = lo & 0x7;
+	pr_debug("bus_freq = 0x%x\n", bus_freq);
+
+	if (bus_freq == 0)
+		fsb = FSB_FREQ_100SKU;
+	else if (bus_freq == 1)
+		fsb = FSB_FREQ_100SKU;
+	else if (bus_freq == 2)
+		fsb = FSB_FREQ_133SKU;
+	else if (bus_freq == 3)
+		fsb = FSB_FREQ_167SKU;
+	else if (bus_freq == 4)
+		fsb = FSB_FREQ_83SKU;
+	else if (bus_freq == 5)
+		fsb = FSB_FREQ_400SKU;
+	else if (bus_freq == 6)
+		fsb = FSB_FREQ_267SKU;
+	else if (bus_freq == 7)
+		fsb = FSB_FREQ_333SKU;
+	else {
+		BUG();
+		pr_err("Invalid bus_freq! Setting to minimal value!\n");
+		fsb = FSB_FREQ_100SKU;
+	}
+
+	/* TSC = FSB Freq * Resolved HFM Ratio */
+	fast_calibrate = ratio * fsb;
+	pr_debug("calculate tangier tsc %lu KHz\n", fast_calibrate);
+
+	/* ************************************ */
+	/* Calculate Local APIC Timer Frequency */
+	/* ************************************ */
+	lapic_timer_frequency = (fsb * 1000) / HZ;
+
+	pr_debug("Setting lapic_timer_frequency = %d\n",
+			lapic_timer_frequency);
+
+	/* mark tsc clocksource as reliable */
+	set_cpu_cap(&boot_cpu_data, X86_FEATURE_TSC_RELIABLE);
+
+	if (fast_calibrate)
+		return fast_calibrate;
+
+	return 0;
+}
+
+static void __init tangier_arch_setup(void)
+{
+	x86_platform.calibrate_tsc = tangier_calibrate_tsc;
+}
+
+/* tangier arch ops */
+static struct intel_mid_ops tangier_ops = {
+	.arch_setup = tangier_arch_setup,
+};
+
+void * __cpuinit get_tangier_ops()
+{
+	return &tangier_ops;
+}