1/*
2 * mrfl.c: Intel Merrifield platform specific setup code
3 *
4 * (C) Copyright 2013 Intel Corporation
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; version 2
9 * of the License.
10 */
11
12#include <linux/init.h>
13
14#include <asm/apic.h>
15#include <asm/intel-mid.h>
16
17#include "intel_mid_weak_decls.h"
18
19static unsigned long __init tangier_calibrate_tsc(void)
20{
21	unsigned long fast_calibrate;
22	u32 lo, hi, ratio, fsb, bus_freq;
23
24	/* *********************** */
25	/* Compute TSC:Ratio * FSB */
26	/* *********************** */
27
28	/* Compute Ratio */
29	rdmsr(MSR_PLATFORM_INFO, lo, hi);
30	pr_debug("IA32 PLATFORM_INFO is 0x%x : %x\n", hi, lo);
31
32	ratio = (lo >> 8) & 0xFF;
33	pr_debug("ratio is %d\n", ratio);
34	if (!ratio) {
35		pr_err("Read a zero ratio, force tsc ratio to 4 ...\n");
36		ratio = 4;
37	}
38
39	/* Compute FSB */
40	rdmsr(MSR_FSB_FREQ, lo, hi);
41	pr_debug("Actual FSB frequency detected by SOC 0x%x : %x\n",
42			hi, lo);
43
44	bus_freq = lo & 0x7;
45	pr_debug("bus_freq = 0x%x\n", bus_freq);
46
47	if (bus_freq == 0)
48		fsb = FSB_FREQ_100SKU;
49	else if (bus_freq == 1)
50		fsb = FSB_FREQ_100SKU;
51	else if (bus_freq == 2)
52		fsb = FSB_FREQ_133SKU;
53	else if (bus_freq == 3)
54		fsb = FSB_FREQ_167SKU;
55	else if (bus_freq == 4)
56		fsb = FSB_FREQ_83SKU;
57	else if (bus_freq == 5)
58		fsb = FSB_FREQ_400SKU;
59	else if (bus_freq == 6)
60		fsb = FSB_FREQ_267SKU;
61	else if (bus_freq == 7)
62		fsb = FSB_FREQ_333SKU;
63	else {
64		BUG();
65		pr_err("Invalid bus_freq! Setting to minimal value!\n");
66		fsb = FSB_FREQ_100SKU;
67	}
68
69	/* TSC = FSB Freq * Resolved HFM Ratio */
70	fast_calibrate = ratio * fsb;
71	pr_debug("calculate tangier tsc %lu KHz\n", fast_calibrate);
72
73	/* ************************************ */
74	/* Calculate Local APIC Timer Frequency */
75	/* ************************************ */
76	lapic_timer_frequency = (fsb * 1000) / HZ;
77
78	pr_debug("Setting lapic_timer_frequency = %d\n",
79			lapic_timer_frequency);
80
81	/* mark tsc clocksource as reliable */
82	set_cpu_cap(&boot_cpu_data, X86_FEATURE_TSC_RELIABLE);
83
84	if (fast_calibrate)
85		return fast_calibrate;
86
87	return 0;
88}
89
90static void __init tangier_arch_setup(void)
91{
92	x86_platform.calibrate_tsc = tangier_calibrate_tsc;
93}
94
95/* tangier arch ops */
96static struct intel_mid_ops tangier_ops = {
97	.arch_setup = tangier_arch_setup,
98};
99
100void *get_tangier_ops(void)
101{
102	return &tangier_ops;
103}
104