diff options
Diffstat (limited to 'arch/x86/platform/mrst/vrtc.c')
| -rw-r--r-- | arch/x86/platform/mrst/vrtc.c | 165 |
1 files changed, 165 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..32cd7edd71a --- /dev/null +++ b/arch/x86/platform/mrst/vrtc.c @@ -0,0 +1,165 @@ +/* + * 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); |