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/*
* vrtc.c: Driver for virtual RTC device on Intel MID platform
*
* (C) Copyright 2009 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.
*
* Note:
* VRTC is emulated by system controller firmware, the real HW
* RTC is located in the PMIC device. SCU FW shadows PMIC RTC
* in a memory mapped IO space that is visible to the host IA
* processor.
*
* This driver is based on RTC CMOS driver.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sfi.h>
#include <linux/platform_device.h>
#include <asm/mrst.h>
#include <asm/mrst-vrtc.h>
#include <asm/time.h>
#include <asm/fixmap.h>
static unsigned char __iomem *vrtc_virt_base;
unsigned char vrtc_cmos_read(unsigned char reg)
{
unsigned char retval;
/* vRTC's registers range from 0x0 to 0xD */
if (reg > 0xd || !vrtc_virt_base)
return 0xff;
lock_cmos_prefix(reg);
retval = __raw_readb(vrtc_virt_base + (reg << 2));
lock_cmos_suffix(reg);
return retval;
}
EXPORT_SYMBOL_GPL(vrtc_cmos_read);
void vrtc_cmos_write(unsigned char val, unsigned char reg)
{
if (reg > 0xd || !vrtc_virt_base)
return;
lock_cmos_prefix(reg);
__raw_writeb(val, vrtc_virt_base + (reg << 2));
lock_cmos_suffix(reg);
}
EXPORT_SYMBOL_GPL(vrtc_cmos_write);
unsigned long vrtc_get_time(void)
{
u8 sec, min, hour, mday, mon;
u32 year;
while ((vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP))
cpu_relax();
sec = vrtc_cmos_read(RTC_SECONDS);
min = vrtc_cmos_read(RTC_MINUTES);
hour = vrtc_cmos_read(RTC_HOURS);
mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
mon = vrtc_cmos_read(RTC_MONTH);
year = vrtc_cmos_read(RTC_YEAR);
/* vRTC YEAR reg contains the offset to 1960 */
year += 1960;
printk(KERN_INFO "vRTC: sec: %d min: %d hour: %d day: %d "
"mon: %d year: %d\n", sec, min, hour, mday, mon, year);
return mktime(year, mon, mday, hour, min, sec);
}
/* Only care about the minutes and seconds */
int vrtc_set_mmss(unsigned long nowtime)
{
int real_sec, real_min;
int vrtc_min;
vrtc_min = vrtc_cmos_read(RTC_MINUTES);
real_sec = nowtime % 60;
real_min = nowtime / 60;
if (((abs(real_min - vrtc_min) + 15)/30) & 1)
real_min += 30;
real_min %= 60;
vrtc_cmos_write(real_sec, RTC_SECONDS);
vrtc_cmos_write(real_min, RTC_MINUTES);
return 0;
}
void __init mrst_rtc_init(void)
{
unsigned long rtc_paddr;
void __iomem *virt_base;
sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc);
if (!sfi_mrtc_num)
return;
rtc_paddr = sfi_mrtc_array[0].phys_addr;
/* vRTC's register address may not be page aligned */
set_fixmap_nocache(FIX_LNW_VRTC, rtc_paddr);
virt_base = (void __iomem *)__fix_to_virt(FIX_LNW_VRTC);
virt_base += rtc_paddr & ~PAGE_MASK;
vrtc_virt_base = virt_base;
x86_platform.get_wallclock = vrtc_get_time;
x86_platform.set_wallclock = vrtc_set_mmss;
}
/*
* The Moorestown platform has a memory mapped virtual RTC device that emulates
* the programming interface of the RTC.
*/
static struct resource vrtc_resources[] = {
[0] = {
.flags = IORESOURCE_MEM,
},
[1] = {
.flags = IORESOURCE_IRQ,
}
};
static struct platform_device vrtc_device = {
.name = "rtc_mrst",
.id = -1,
.resource = vrtc_resources,
.num_resources = ARRAY_SIZE(vrtc_resources),
};
/* Register the RTC device if appropriate */
static int __init mrst_device_create(void)
{
/* No Moorestown, no device */
if (!mrst_identify_cpu())
return -ENODEV;
/* No timer, no device */
if (!sfi_mrtc_num)
return -ENODEV;
/* iomem resource */
vrtc_resources[0].start = sfi_mrtc_array[0].phys_addr;
vrtc_resources[0].end = sfi_mrtc_array[0].phys_addr +
MRST_VRTC_MAP_SZ;
/* irq resource */
vrtc_resources[1].start = sfi_mrtc_array[0].irq;
vrtc_resources[1].end = sfi_mrtc_array[0].irq;
return platform_device_register(&vrtc_device);
}
module_init(mrst_device_create);
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