diff options
Diffstat (limited to 'arch/x86/platform/intel-mid/intel_mid_vrtc.c')
| -rw-r--r-- | arch/x86/platform/intel-mid/intel_mid_vrtc.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/arch/x86/platform/intel-mid/intel_mid_vrtc.c b/arch/x86/platform/intel-mid/intel_mid_vrtc.c new file mode 100644 index 000000000..a52914aa3 --- /dev/null +++ b/arch/x86/platform/intel-mid/intel_mid_vrtc.c @@ -0,0 +1,177 @@ +/* + * intel_mid_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/export.h> +#include <linux/init.h> +#include <linux/sfi.h> +#include <linux/platform_device.h> +#include <linux/mc146818rtc.h> + +#include <asm/intel-mid.h> +#include <asm/intel_mid_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); + +void vrtc_get_time(struct timespec64 *now) +{ + u8 sec, min, hour, mday, mon; + unsigned long flags; + u32 year; + + spin_lock_irqsave(&rtc_lock, flags); + + 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); + + spin_unlock_irqrestore(&rtc_lock, flags); + + /* vRTC YEAR reg contains the offset to 1972 */ + year += 1972; + + pr_info("vRTC: sec: %d min: %d hour: %d day: %d " + "mon: %d year: %d\n", sec, min, hour, mday, mon, year); + + now->tv_sec = mktime64(year, mon, mday, hour, min, sec); + now->tv_nsec = 0; +} + +int vrtc_set_mmss(const struct timespec64 *now) +{ + unsigned long flags; + struct rtc_time tm; + int year; + int retval = 0; + + rtc_time64_to_tm(now->tv_sec, &tm); + if (!rtc_valid_tm(&tm) && tm.tm_year >= 72) { + /* + * tm.year is the number of years since 1900, and the + * vrtc need the years since 1972. + */ + year = tm.tm_year - 72; + spin_lock_irqsave(&rtc_lock, flags); + vrtc_cmos_write(year, RTC_YEAR); + vrtc_cmos_write(tm.tm_mon, RTC_MONTH); + vrtc_cmos_write(tm.tm_mday, RTC_DAY_OF_MONTH); + vrtc_cmos_write(tm.tm_hour, RTC_HOURS); + vrtc_cmos_write(tm.tm_min, RTC_MINUTES); + vrtc_cmos_write(tm.tm_sec, RTC_SECONDS); + spin_unlock_irqrestore(&rtc_lock, flags); + } else { + pr_err("%s: Invalid vRTC value: write of %llx to vRTC failed\n", + __func__, (s64)now->tv_sec); + retval = -EINVAL; + } + return retval; +} + +void __init intel_mid_rtc_init(void) +{ + unsigned long vrtc_paddr; + + sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc); + + vrtc_paddr = sfi_mrtc_array[0].phys_addr; + if (!sfi_mrtc_num || !vrtc_paddr) + return; + + vrtc_virt_base = (void __iomem *)set_fixmap_offset_nocache(FIX_LNW_VRTC, + vrtc_paddr); + 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 intel_mid_device_create(void) +{ + /* No Moorestown, no device */ + if (!intel_mid_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); +} +device_initcall(intel_mid_device_create); |