170 lines
4.0 KiB
C
170 lines
4.0 KiB
C
/*
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* vrtc.c: Driver for virtual RTC device on Intel MID platform
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*
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* (C) Copyright 2009 Intel Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*
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* Note:
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* VRTC is emulated by system controller firmware, the real HW
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* RTC is located in the PMIC device. SCU FW shadows PMIC RTC
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* in a memory mapped IO space that is visible to the host IA
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* processor.
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*
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* This driver is based on RTC CMOS driver.
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*/
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/init.h>
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#include <linux/sfi.h>
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#include <linux/platform_device.h>
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#include <asm/mrst.h>
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#include <asm/mrst-vrtc.h>
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#include <asm/time.h>
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#include <asm/fixmap.h>
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static unsigned char __iomem *vrtc_virt_base;
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unsigned char vrtc_cmos_read(unsigned char reg)
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{
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unsigned char retval;
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/* vRTC's registers range from 0x0 to 0xD */
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if (reg > 0xd || !vrtc_virt_base)
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return 0xff;
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lock_cmos_prefix(reg);
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retval = __raw_readb(vrtc_virt_base + (reg << 2));
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lock_cmos_suffix(reg);
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return retval;
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}
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EXPORT_SYMBOL_GPL(vrtc_cmos_read);
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void vrtc_cmos_write(unsigned char val, unsigned char reg)
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{
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if (reg > 0xd || !vrtc_virt_base)
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return;
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lock_cmos_prefix(reg);
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__raw_writeb(val, vrtc_virt_base + (reg << 2));
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lock_cmos_suffix(reg);
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}
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EXPORT_SYMBOL_GPL(vrtc_cmos_write);
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unsigned long vrtc_get_time(void)
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{
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u8 sec, min, hour, mday, mon;
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unsigned long flags;
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u32 year;
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spin_lock_irqsave(&rtc_lock, flags);
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while ((vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP))
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cpu_relax();
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sec = vrtc_cmos_read(RTC_SECONDS);
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min = vrtc_cmos_read(RTC_MINUTES);
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hour = vrtc_cmos_read(RTC_HOURS);
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mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
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mon = vrtc_cmos_read(RTC_MONTH);
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year = vrtc_cmos_read(RTC_YEAR);
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spin_unlock_irqrestore(&rtc_lock, flags);
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/* vRTC YEAR reg contains the offset to 1972 */
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year += 1972;
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printk(KERN_INFO "vRTC: sec: %d min: %d hour: %d day: %d "
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"mon: %d year: %d\n", sec, min, hour, mday, mon, year);
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return mktime(year, mon, mday, hour, min, sec);
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}
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/* Only care about the minutes and seconds */
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int vrtc_set_mmss(unsigned long nowtime)
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{
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int real_sec, real_min;
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unsigned long flags;
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int vrtc_min;
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spin_lock_irqsave(&rtc_lock, flags);
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vrtc_min = vrtc_cmos_read(RTC_MINUTES);
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real_sec = nowtime % 60;
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real_min = nowtime / 60;
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if (((abs(real_min - vrtc_min) + 15)/30) & 1)
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real_min += 30;
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real_min %= 60;
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vrtc_cmos_write(real_sec, RTC_SECONDS);
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vrtc_cmos_write(real_min, RTC_MINUTES);
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spin_unlock_irqrestore(&rtc_lock, flags);
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return 0;
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}
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void __init mrst_rtc_init(void)
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{
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unsigned long vrtc_paddr;
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sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc);
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vrtc_paddr = sfi_mrtc_array[0].phys_addr;
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if (!sfi_mrtc_num || !vrtc_paddr)
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return;
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vrtc_virt_base = (void __iomem *)set_fixmap_offset_nocache(FIX_LNW_VRTC,
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vrtc_paddr);
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x86_platform.get_wallclock = vrtc_get_time;
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x86_platform.set_wallclock = vrtc_set_mmss;
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}
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/*
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* The Moorestown platform has a memory mapped virtual RTC device that emulates
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* the programming interface of the RTC.
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*/
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static struct resource vrtc_resources[] = {
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[0] = {
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.flags = IORESOURCE_MEM,
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},
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[1] = {
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.flags = IORESOURCE_IRQ,
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}
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};
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static struct platform_device vrtc_device = {
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.name = "rtc_mrst",
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.id = -1,
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.resource = vrtc_resources,
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.num_resources = ARRAY_SIZE(vrtc_resources),
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};
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/* Register the RTC device if appropriate */
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static int __init mrst_device_create(void)
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{
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/* No Moorestown, no device */
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if (!mrst_identify_cpu())
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return -ENODEV;
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/* No timer, no device */
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if (!sfi_mrtc_num)
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return -ENODEV;
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/* iomem resource */
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vrtc_resources[0].start = sfi_mrtc_array[0].phys_addr;
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vrtc_resources[0].end = sfi_mrtc_array[0].phys_addr +
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MRST_VRTC_MAP_SZ;
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/* irq resource */
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vrtc_resources[1].start = sfi_mrtc_array[0].irq;
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vrtc_resources[1].end = sfi_mrtc_array[0].irq;
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return platform_device_register(&vrtc_device);
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}
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module_init(mrst_device_create);
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