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0139085310
Previous changes effectively prevented PNP devices from being created for the CMOS RTC on x86 with ACPI. Although in principle a CMOS RTC PNP device may exist on an x86 system without ACPI (that is, an x86 system where there is no ACPI at all, not one booted with ACPI disabled), such systems were there in the field ~30 years ago and most likely they would not be able to run a contemporary Linux kernel. For the above reasons, drop the PNP device check from add_rtc_cmos(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> # x86 Link: https://patch.msgid.link/8660687.T7Z3S40VBb@rafael.j.wysocki
148 lines
3.3 KiB
C
148 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* RTC related functions
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*/
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#include <linux/acpi.h>
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#include <linux/platform_device.h>
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#include <linux/mc146818rtc.h>
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#include <linux/export.h>
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#include <asm/vsyscall.h>
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#include <asm/x86_init.h>
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#include <asm/time.h>
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#include <asm/setup.h>
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#ifdef CONFIG_X86_32
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/*
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* This is a special lock that is owned by the CPU and holds the index
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* register we are working with. It is required for NMI access to the
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* CMOS/RTC registers. See arch/x86/include/asm/mc146818rtc.h for details.
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*/
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volatile unsigned long cmos_lock;
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EXPORT_SYMBOL(cmos_lock);
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#endif /* CONFIG_X86_32 */
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DEFINE_SPINLOCK(rtc_lock);
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EXPORT_SYMBOL(rtc_lock);
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/*
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* In order to set the CMOS clock precisely, mach_set_cmos_time has to be
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* called 500 ms after the second nowtime has started, because when
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* nowtime is written into the registers of the CMOS clock, it will
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* jump to the next second precisely 500 ms later. Check the Motorola
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* MC146818A or Dallas DS12887 data sheet for details.
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*/
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int mach_set_cmos_time(const struct timespec64 *now)
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{
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unsigned long long nowtime = now->tv_sec;
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struct rtc_time tm;
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int retval = 0;
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rtc_time64_to_tm(nowtime, &tm);
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if (!rtc_valid_tm(&tm)) {
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retval = mc146818_set_time(&tm);
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if (retval)
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printk(KERN_ERR "%s: RTC write failed with error %d\n",
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__func__, retval);
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} else {
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printk(KERN_ERR
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"%s: Invalid RTC value: write of %llx to RTC failed\n",
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__func__, nowtime);
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retval = -EINVAL;
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}
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return retval;
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}
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void mach_get_cmos_time(struct timespec64 *now)
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{
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struct rtc_time tm;
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/*
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* If pm_trace abused the RTC as storage, set the timespec to 0,
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* which tells the caller that this RTC value is unusable.
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*/
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if (!pm_trace_rtc_valid()) {
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now->tv_sec = now->tv_nsec = 0;
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return;
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}
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if (mc146818_get_time(&tm, 1000)) {
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pr_err("Unable to read current time from RTC\n");
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now->tv_sec = now->tv_nsec = 0;
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return;
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}
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now->tv_sec = rtc_tm_to_time64(&tm);
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now->tv_nsec = 0;
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}
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/* Routines for accessing the CMOS RAM/RTC. */
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unsigned char rtc_cmos_read(unsigned char addr)
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{
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unsigned char val;
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lock_cmos_prefix(addr);
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outb(addr, RTC_PORT(0));
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val = inb(RTC_PORT(1));
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lock_cmos_suffix(addr);
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return val;
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}
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EXPORT_SYMBOL(rtc_cmos_read);
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void rtc_cmos_write(unsigned char val, unsigned char addr)
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{
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lock_cmos_prefix(addr);
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outb(addr, RTC_PORT(0));
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outb(val, RTC_PORT(1));
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lock_cmos_suffix(addr);
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}
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EXPORT_SYMBOL(rtc_cmos_write);
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int update_persistent_clock64(struct timespec64 now)
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{
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return x86_platform.set_wallclock(&now);
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}
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/* not static: needed by APM */
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void read_persistent_clock64(struct timespec64 *ts)
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{
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x86_platform.get_wallclock(ts);
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}
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static struct resource rtc_resources[] = {
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[0] = {
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.start = RTC_PORT(0),
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.end = RTC_PORT(1),
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.flags = IORESOURCE_IO,
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},
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[1] = {
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.start = RTC_IRQ,
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.end = RTC_IRQ,
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.flags = IORESOURCE_IRQ,
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}
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};
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static struct platform_device rtc_device = {
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.name = "rtc_cmos",
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.id = -1,
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.resource = rtc_resources,
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.num_resources = ARRAY_SIZE(rtc_resources),
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};
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static __init int add_rtc_cmos(void)
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{
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if (cmos_rtc_platform_device_present)
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return 0;
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if (!x86_platform.legacy.rtc)
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return -ENODEV;
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platform_device_register(&rtc_device);
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dev_info(&rtc_device.dev, "registered fallback platform RTC device\n");
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return 0;
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}
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device_initcall(add_rtc_cmos);
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