linux/arch/x86/platform/intel-mid/intel_mid_vrtc.c
Arnd Bergmann e27c49291a x86: Convert x86_platform_ops to timespec64
The x86 platform operations are fairly isolated, so it's easy to change
them from using timespec to timespec64. It has been checked that all the
users and callers are safe, and there is only one critical function that is
broken beyond 2106:

  pvclock_read_wallclock() uses a 32-bit number of seconds since the epoch
  to communicate the boot time between host and guest in a virtual
  environment. This will work until 2106, but fixing this is outside the
  scope of this change, Add a comment at least.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: jailhouse-dev@googlegroups.com
Cc: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Cc: y2038@lists.linaro.org
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: xen-devel@lists.xenproject.org
Cc: John Stultz <john.stultz@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Link: https://lkml.kernel.org/r/20180427201435.3194219-1-arnd@arndb.de
2018-05-19 14:03:14 +02:00

178 lines
4.4 KiB
C

/*
* 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);