Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * vrtc.c: Driver for virtual RTC device on Intel MID platform |
| 3 | * |
| 4 | * (C) Copyright 2009 Intel Corporation |
| 5 | * |
| 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 |
| 9 | * of the License. |
| 10 | * |
| 11 | * Note: |
| 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 |
| 15 | * processor. |
| 16 | * |
| 17 | * This driver is based on RTC CMOS driver. |
| 18 | */ |
| 19 | |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/init.h> |
| 22 | #include <linux/sfi.h> |
Feng Tang | 0146f26 | 2010-11-10 17:29:17 +0000 | [diff] [blame] | 23 | #include <linux/platform_device.h> |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 24 | |
| 25 | #include <asm/mrst.h> |
| 26 | #include <asm/mrst-vrtc.h> |
| 27 | #include <asm/time.h> |
| 28 | #include <asm/fixmap.h> |
| 29 | |
| 30 | static unsigned char __iomem *vrtc_virt_base; |
| 31 | |
| 32 | unsigned char vrtc_cmos_read(unsigned char reg) |
| 33 | { |
| 34 | unsigned char retval; |
| 35 | |
| 36 | /* vRTC's registers range from 0x0 to 0xD */ |
| 37 | if (reg > 0xd || !vrtc_virt_base) |
| 38 | return 0xff; |
| 39 | |
| 40 | lock_cmos_prefix(reg); |
| 41 | retval = __raw_readb(vrtc_virt_base + (reg << 2)); |
| 42 | lock_cmos_suffix(reg); |
| 43 | return retval; |
| 44 | } |
| 45 | EXPORT_SYMBOL_GPL(vrtc_cmos_read); |
| 46 | |
| 47 | void vrtc_cmos_write(unsigned char val, unsigned char reg) |
| 48 | { |
| 49 | if (reg > 0xd || !vrtc_virt_base) |
| 50 | return; |
| 51 | |
| 52 | lock_cmos_prefix(reg); |
| 53 | __raw_writeb(val, vrtc_virt_base + (reg << 2)); |
| 54 | lock_cmos_suffix(reg); |
| 55 | } |
| 56 | EXPORT_SYMBOL_GPL(vrtc_cmos_write); |
| 57 | |
| 58 | unsigned long vrtc_get_time(void) |
| 59 | { |
| 60 | u8 sec, min, hour, mday, mon; |
Matt Fleming | 47997d7 | 2011-09-21 16:08:03 +0200 | [diff] [blame^] | 61 | unsigned long flags; |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 62 | u32 year; |
| 63 | |
Matt Fleming | 47997d7 | 2011-09-21 16:08:03 +0200 | [diff] [blame^] | 64 | spin_lock_irqsave(&rtc_lock, flags); |
| 65 | |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 66 | while ((vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP)) |
| 67 | cpu_relax(); |
| 68 | |
| 69 | sec = vrtc_cmos_read(RTC_SECONDS); |
| 70 | min = vrtc_cmos_read(RTC_MINUTES); |
| 71 | hour = vrtc_cmos_read(RTC_HOURS); |
| 72 | mday = vrtc_cmos_read(RTC_DAY_OF_MONTH); |
| 73 | mon = vrtc_cmos_read(RTC_MONTH); |
| 74 | year = vrtc_cmos_read(RTC_YEAR); |
| 75 | |
Matt Fleming | 47997d7 | 2011-09-21 16:08:03 +0200 | [diff] [blame^] | 76 | spin_unlock_irqrestore(&rtc_lock, flags); |
| 77 | |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 78 | /* vRTC YEAR reg contains the offset to 1960 */ |
| 79 | year += 1960; |
| 80 | |
| 81 | printk(KERN_INFO "vRTC: sec: %d min: %d hour: %d day: %d " |
| 82 | "mon: %d year: %d\n", sec, min, hour, mday, mon, year); |
| 83 | |
| 84 | return mktime(year, mon, mday, hour, min, sec); |
| 85 | } |
| 86 | |
| 87 | /* Only care about the minutes and seconds */ |
| 88 | int vrtc_set_mmss(unsigned long nowtime) |
| 89 | { |
| 90 | int real_sec, real_min; |
Matt Fleming | 47997d7 | 2011-09-21 16:08:03 +0200 | [diff] [blame^] | 91 | unsigned long flags; |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 92 | int vrtc_min; |
| 93 | |
Matt Fleming | 47997d7 | 2011-09-21 16:08:03 +0200 | [diff] [blame^] | 94 | spin_lock_irqsave(&rtc_lock, flags); |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 95 | vrtc_min = vrtc_cmos_read(RTC_MINUTES); |
| 96 | |
| 97 | real_sec = nowtime % 60; |
| 98 | real_min = nowtime / 60; |
| 99 | if (((abs(real_min - vrtc_min) + 15)/30) & 1) |
| 100 | real_min += 30; |
| 101 | real_min %= 60; |
| 102 | |
| 103 | vrtc_cmos_write(real_sec, RTC_SECONDS); |
| 104 | vrtc_cmos_write(real_min, RTC_MINUTES); |
Matt Fleming | 47997d7 | 2011-09-21 16:08:03 +0200 | [diff] [blame^] | 105 | spin_unlock_irqrestore(&rtc_lock, flags); |
| 106 | |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 107 | return 0; |
| 108 | } |
| 109 | |
| 110 | void __init mrst_rtc_init(void) |
| 111 | { |
Feng Tang | 09552b2 | 2011-04-07 09:39:49 +0800 | [diff] [blame] | 112 | unsigned long vrtc_paddr; |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 113 | |
| 114 | sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc); |
Feng Tang | 09552b2 | 2011-04-07 09:39:49 +0800 | [diff] [blame] | 115 | |
| 116 | vrtc_paddr = sfi_mrtc_array[0].phys_addr; |
Feng Tang | 168202c | 2011-02-15 00:13:32 +0800 | [diff] [blame] | 117 | if (!sfi_mrtc_num || !vrtc_paddr) |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 118 | return; |
| 119 | |
Feng Tang | 168202c | 2011-02-15 00:13:32 +0800 | [diff] [blame] | 120 | vrtc_virt_base = (void __iomem *)set_fixmap_offset_nocache(FIX_LNW_VRTC, |
| 121 | vrtc_paddr); |
Feng Tang | 7309282 | 2010-11-10 17:29:00 +0000 | [diff] [blame] | 122 | x86_platform.get_wallclock = vrtc_get_time; |
| 123 | x86_platform.set_wallclock = vrtc_set_mmss; |
| 124 | } |
Feng Tang | 0146f26 | 2010-11-10 17:29:17 +0000 | [diff] [blame] | 125 | |
| 126 | /* |
| 127 | * The Moorestown platform has a memory mapped virtual RTC device that emulates |
| 128 | * the programming interface of the RTC. |
| 129 | */ |
| 130 | |
| 131 | static struct resource vrtc_resources[] = { |
| 132 | [0] = { |
| 133 | .flags = IORESOURCE_MEM, |
| 134 | }, |
| 135 | [1] = { |
| 136 | .flags = IORESOURCE_IRQ, |
| 137 | } |
| 138 | }; |
| 139 | |
| 140 | static struct platform_device vrtc_device = { |
| 141 | .name = "rtc_mrst", |
| 142 | .id = -1, |
| 143 | .resource = vrtc_resources, |
| 144 | .num_resources = ARRAY_SIZE(vrtc_resources), |
| 145 | }; |
| 146 | |
| 147 | /* Register the RTC device if appropriate */ |
| 148 | static int __init mrst_device_create(void) |
| 149 | { |
| 150 | /* No Moorestown, no device */ |
| 151 | if (!mrst_identify_cpu()) |
| 152 | return -ENODEV; |
| 153 | /* No timer, no device */ |
| 154 | if (!sfi_mrtc_num) |
| 155 | return -ENODEV; |
| 156 | |
| 157 | /* iomem resource */ |
| 158 | vrtc_resources[0].start = sfi_mrtc_array[0].phys_addr; |
| 159 | vrtc_resources[0].end = sfi_mrtc_array[0].phys_addr + |
| 160 | MRST_VRTC_MAP_SZ; |
| 161 | /* irq resource */ |
| 162 | vrtc_resources[1].start = sfi_mrtc_array[0].irq; |
| 163 | vrtc_resources[1].end = sfi_mrtc_array[0].irq; |
| 164 | |
Vasiliy Kulikov | 5ca9afd | 2010-11-18 21:16:45 +0300 | [diff] [blame] | 165 | return platform_device_register(&vrtc_device); |
Feng Tang | 0146f26 | 2010-11-10 17:29:17 +0000 | [diff] [blame] | 166 | } |
| 167 | |
| 168 | module_init(mrst_device_create); |