diff options
author | Feng Tang <feng.tang@intel.com> | 2010-11-10 12:29:00 -0500 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2010-11-11 05:34:27 -0500 |
commit | 7309282c90d251cde77fe3b520a8276e25315c49 (patch) | |
tree | da33c8a838d0ee779c1b8a70e13002bf29cd4527 /arch/x86/platform/mrst/vrtc.c | |
parent | cfb505a7ebd4c84206b4cc7d9f966d864a2ac05a (diff) |
x86: mrst: Add vrtc driver which serves as a wall clock device
Moorestown platform doesn't have a m146818 RTC device like traditional
x86 PC, but a firmware emulated virtual RTC device(vrtc), which provides
some basic RTC functions like get/set time. vrtc serves as the only
wall clock device on Moorestown platform.
[ tglx: Changed the exports to _GPL ]
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
LKML-Reference: <20101110172837.3311.40483.stgit@localhost.localdomain>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/platform/mrst/vrtc.c')
-rw-r--r-- | arch/x86/platform/mrst/vrtc.c | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/arch/x86/platform/mrst/vrtc.c b/arch/x86/platform/mrst/vrtc.c new file mode 100644 index 00000000000..4944bd521d2 --- /dev/null +++ b/arch/x86/platform/mrst/vrtc.c | |||
@@ -0,0 +1,120 @@ | |||
1 | /* | ||
2 | * vrtc.c: Driver for virtual RTC device on Intel MID platform | ||
3 | * | ||
4 | * (C) Copyright 2009 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 | * Note: | ||
12 | * VRTC is emulated by system controller firmware, the real HW | ||
13 | * RTC is located in the PMIC device. SCU FW shadows PMIC RTC | ||
14 | * in a memory mapped IO space that is visible to the host IA | ||
15 | * processor. | ||
16 | * | ||
17 | * This driver is based on RTC CMOS driver. | ||
18 | */ | ||
19 | |||
20 | #include <linux/kernel.h> | ||
21 | #include <linux/init.h> | ||
22 | #include <linux/sfi.h> | ||
23 | |||
24 | #include <asm/mrst.h> | ||
25 | #include <asm/mrst-vrtc.h> | ||
26 | #include <asm/time.h> | ||
27 | #include <asm/fixmap.h> | ||
28 | |||
29 | static unsigned char __iomem *vrtc_virt_base; | ||
30 | |||
31 | unsigned char vrtc_cmos_read(unsigned char reg) | ||
32 | { | ||
33 | unsigned char retval; | ||
34 | |||
35 | /* vRTC's registers range from 0x0 to 0xD */ | ||
36 | if (reg > 0xd || !vrtc_virt_base) | ||
37 | return 0xff; | ||
38 | |||
39 | lock_cmos_prefix(reg); | ||
40 | retval = __raw_readb(vrtc_virt_base + (reg << 2)); | ||
41 | lock_cmos_suffix(reg); | ||
42 | return retval; | ||
43 | } | ||
44 | EXPORT_SYMBOL_GPL(vrtc_cmos_read); | ||
45 | |||
46 | void vrtc_cmos_write(unsigned char val, unsigned char reg) | ||
47 | { | ||
48 | if (reg > 0xd || !vrtc_virt_base) | ||
49 | return; | ||
50 | |||
51 | lock_cmos_prefix(reg); | ||
52 | __raw_writeb(val, vrtc_virt_base + (reg << 2)); | ||
53 | lock_cmos_suffix(reg); | ||
54 | } | ||
55 | EXPORT_SYMBOL_GPL(vrtc_cmos_write); | ||
56 | |||
57 | unsigned long vrtc_get_time(void) | ||
58 | { | ||
59 | u8 sec, min, hour, mday, mon; | ||
60 | u32 year; | ||
61 | |||
62 | while ((vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP)) | ||
63 | cpu_relax(); | ||
64 | |||
65 | sec = vrtc_cmos_read(RTC_SECONDS); | ||
66 | min = vrtc_cmos_read(RTC_MINUTES); | ||
67 | hour = vrtc_cmos_read(RTC_HOURS); | ||
68 | mday = vrtc_cmos_read(RTC_DAY_OF_MONTH); | ||
69 | mon = vrtc_cmos_read(RTC_MONTH); | ||
70 | year = vrtc_cmos_read(RTC_YEAR); | ||
71 | |||
72 | /* vRTC YEAR reg contains the offset to 1960 */ | ||
73 | year += 1960; | ||
74 | |||
75 | printk(KERN_INFO "vRTC: sec: %d min: %d hour: %d day: %d " | ||
76 | "mon: %d year: %d\n", sec, min, hour, mday, mon, year); | ||
77 | |||
78 | return mktime(year, mon, mday, hour, min, sec); | ||
79 | } | ||
80 | |||
81 | /* Only care about the minutes and seconds */ | ||
82 | int vrtc_set_mmss(unsigned long nowtime) | ||
83 | { | ||
84 | int real_sec, real_min; | ||
85 | int vrtc_min; | ||
86 | |||
87 | vrtc_min = vrtc_cmos_read(RTC_MINUTES); | ||
88 | |||
89 | real_sec = nowtime % 60; | ||
90 | real_min = nowtime / 60; | ||
91 | if (((abs(real_min - vrtc_min) + 15)/30) & 1) | ||
92 | real_min += 30; | ||
93 | real_min %= 60; | ||
94 | |||
95 | vrtc_cmos_write(real_sec, RTC_SECONDS); | ||
96 | vrtc_cmos_write(real_min, RTC_MINUTES); | ||
97 | return 0; | ||
98 | } | ||
99 | |||
100 | void __init mrst_rtc_init(void) | ||
101 | { | ||
102 | unsigned long rtc_paddr; | ||
103 | void __iomem *virt_base; | ||
104 | |||
105 | sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc); | ||
106 | if (!sfi_mrtc_num) | ||
107 | return; | ||
108 | |||
109 | rtc_paddr = sfi_mrtc_array[0].phys_addr; | ||
110 | |||
111 | /* vRTC's register address may not be page aligned */ | ||
112 | set_fixmap_nocache(FIX_LNW_VRTC, rtc_paddr); | ||
113 | |||
114 | virt_base = (void __iomem *)__fix_to_virt(FIX_LNW_VRTC); | ||
115 | virt_base += rtc_paddr & ~PAGE_MASK; | ||
116 | vrtc_virt_base = virt_base; | ||
117 | |||
118 | x86_platform.get_wallclock = vrtc_get_time; | ||
119 | x86_platform.set_wallclock = vrtc_set_mmss; | ||
120 | } | ||