2 * intel_mid_vrtc.c: Driver for virtual RTC device on Intel MID platform
4 * (C) Copyright 2009 Intel Corporation
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
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
17 * This driver is based on RTC CMOS driver.
20 #include <linux/kernel.h>
21 #include <linux/export.h>
22 #include <linux/init.h>
23 #include <linux/sfi.h>
24 #include <linux/platform_device.h>
26 #include <asm/intel-mid.h>
27 #include <asm/intel_mid_vrtc.h>
29 #include <asm/fixmap.h>
31 static unsigned char __iomem
*vrtc_virt_base
;
33 unsigned char vrtc_cmos_read(unsigned char reg
)
37 /* vRTC's registers range from 0x0 to 0xD */
38 if (reg
> 0xd || !vrtc_virt_base
)
41 lock_cmos_prefix(reg
);
42 retval
= __raw_readb(vrtc_virt_base
+ (reg
<< 2));
43 lock_cmos_suffix(reg
);
46 EXPORT_SYMBOL_GPL(vrtc_cmos_read
);
48 void vrtc_cmos_write(unsigned char val
, unsigned char reg
)
50 if (reg
> 0xd || !vrtc_virt_base
)
53 lock_cmos_prefix(reg
);
54 __raw_writeb(val
, vrtc_virt_base
+ (reg
<< 2));
55 lock_cmos_suffix(reg
);
57 EXPORT_SYMBOL_GPL(vrtc_cmos_write
);
59 void vrtc_get_time(struct timespec
*now
)
61 u8 sec
, min
, hour
, mday
, mon
;
65 spin_lock_irqsave(&rtc_lock
, flags
);
67 while ((vrtc_cmos_read(RTC_FREQ_SELECT
) & RTC_UIP
))
70 sec
= vrtc_cmos_read(RTC_SECONDS
);
71 min
= vrtc_cmos_read(RTC_MINUTES
);
72 hour
= vrtc_cmos_read(RTC_HOURS
);
73 mday
= vrtc_cmos_read(RTC_DAY_OF_MONTH
);
74 mon
= vrtc_cmos_read(RTC_MONTH
);
75 year
= vrtc_cmos_read(RTC_YEAR
);
77 spin_unlock_irqrestore(&rtc_lock
, flags
);
79 /* vRTC YEAR reg contains the offset to 1972 */
82 pr_info("vRTC: sec: %d min: %d hour: %d day: %d "
83 "mon: %d year: %d\n", sec
, min
, hour
, mday
, mon
, year
);
85 now
->tv_sec
= mktime(year
, mon
, mday
, hour
, min
, sec
);
89 int vrtc_set_mmss(const struct timespec
*now
)
96 rtc_time_to_tm(now
->tv_sec
, &tm
);
97 if (!rtc_valid_tm(&tm
) && tm
.tm_year
>= 72) {
99 * tm.year is the number of years since 1900, and the
100 * vrtc need the years since 1972.
102 year
= tm
.tm_year
- 72;
103 spin_lock_irqsave(&rtc_lock
, flags
);
104 vrtc_cmos_write(year
, RTC_YEAR
);
105 vrtc_cmos_write(tm
.tm_mon
, RTC_MONTH
);
106 vrtc_cmos_write(tm
.tm_mday
, RTC_DAY_OF_MONTH
);
107 vrtc_cmos_write(tm
.tm_hour
, RTC_HOURS
);
108 vrtc_cmos_write(tm
.tm_min
, RTC_MINUTES
);
109 vrtc_cmos_write(tm
.tm_sec
, RTC_SECONDS
);
110 spin_unlock_irqrestore(&rtc_lock
, flags
);
112 pr_err("%s: Invalid vRTC value: write of %lx to vRTC failed\n",
113 __FUNCTION__
, now
->tv_sec
);
119 void __init
intel_mid_rtc_init(void)
121 unsigned long vrtc_paddr
;
123 sfi_table_parse(SFI_SIG_MRTC
, NULL
, NULL
, sfi_parse_mrtc
);
125 vrtc_paddr
= sfi_mrtc_array
[0].phys_addr
;
126 if (!sfi_mrtc_num
|| !vrtc_paddr
)
129 vrtc_virt_base
= (void __iomem
*)set_fixmap_offset_nocache(FIX_LNW_VRTC
,
131 x86_platform
.get_wallclock
= vrtc_get_time
;
132 x86_platform
.set_wallclock
= vrtc_set_mmss
;
136 * The Moorestown platform has a memory mapped virtual RTC device that emulates
137 * the programming interface of the RTC.
140 static struct resource vrtc_resources
[] = {
142 .flags
= IORESOURCE_MEM
,
145 .flags
= IORESOURCE_IRQ
,
149 static struct platform_device vrtc_device
= {
152 .resource
= vrtc_resources
,
153 .num_resources
= ARRAY_SIZE(vrtc_resources
),
156 /* Register the RTC device if appropriate */
157 static int __init
intel_mid_device_create(void)
159 /* No Moorestown, no device */
160 if (!intel_mid_identify_cpu())
162 /* No timer, no device */
167 vrtc_resources
[0].start
= sfi_mrtc_array
[0].phys_addr
;
168 vrtc_resources
[0].end
= sfi_mrtc_array
[0].phys_addr
+
171 vrtc_resources
[1].start
= sfi_mrtc_array
[0].irq
;
172 vrtc_resources
[1].end
= sfi_mrtc_array
[0].irq
;
174 return platform_device_register(&vrtc_device
);
177 module_init(intel_mid_device_create
);