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3ae8fd4157
Setting the century forward has been failing on AMD platforms.
There was a previous attempt at fixing this for family 0x17 as part of
commit 7ad295d519 ("rtc: Fix the AltCentury value on AMD/Hygon
platform") but this was later reverted due to some problems reported
that appeared to stem from an FW bug on a family 0x17 desktop system.
The same comments mentioned in the previous commit continue to apply
to the newer platforms as well.
```
MC146818 driver use function mc146818_set_time() to set register
RTC_FREQ_SELECT(RTC_REG_A)'s bit4-bit6 field which means divider stage
reset value on Intel platform to 0x7.
While AMD/Hygon RTC_REG_A(0Ah)'s bit4 is defined as DV0 [Reference]:
DV0 = 0 selects Bank 0, DV0 = 1 selects Bank 1. Bit5-bit6 is defined
as reserved.
DV0 is set to 1, it will select Bank 1, which will disable AltCentury
register(0x32) access. As UEFI pass acpi_gbl_FADT.century 0x32
(AltCentury), the CMOS write will be failed on code:
CMOS_WRITE(century, acpi_gbl_FADT.century).
Correct RTC_REG_A bank select bit(DV0) to 0 on AMD/Hygon CPUs, it will
enable AltCentury(0x32) register writing and finally setup century as
expected.
```
However in closer examination the change previously submitted was also
modifying bits 5 & 6 which are declared reserved in the AMD documentation.
So instead modify just the DV0 bank selection bit.
Being cognizant that there was a failure reported before, split the code
change out to a static function that can also be used for exclusions if
any regressions such as Mikhail's pop up again.
Cc: Jinke Fan <fanjinke@hygon.cn>
Cc: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Link: https://lore.kernel.org/all/CABXGCsMLob0DC25JS8wwAYydnDoHBSoMh2_YLPfqm3TTvDE-Zw@mail.gmail.com/
Link: https://www.amd.com/system/files/TechDocs/51192_Bolton_FCH_RRG.pdf
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220111225750.1699-1-mario.limonciello@amd.com
135 lines
4.7 KiB
C
135 lines
4.7 KiB
C
/* mc146818rtc.h - register definitions for the Real-Time-Clock / CMOS RAM
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* Copyright Torsten Duwe <duwe@informatik.uni-erlangen.de> 1993
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* derived from Data Sheet, Copyright Motorola 1984 (!).
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* It was written to be part of the Linux operating system.
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*/
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/* permission is hereby granted to copy, modify and redistribute this code
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* in terms of the GNU Library General Public License, Version 2 or later,
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* at your option.
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*/
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#ifndef _MC146818RTC_H
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#define _MC146818RTC_H
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#include <asm/io.h>
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#include <linux/rtc.h> /* get the user-level API */
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#include <asm/mc146818rtc.h> /* register access macros */
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#include <linux/bcd.h>
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#include <linux/delay.h>
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#include <linux/pm-trace.h>
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#ifdef __KERNEL__
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#include <linux/spinlock.h> /* spinlock_t */
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extern spinlock_t rtc_lock; /* serialize CMOS RAM access */
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/* Some RTCs extend the mc146818 register set to support alarms of more
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* than 24 hours in the future; or dates that include a century code.
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* This platform_data structure can pass this information to the driver.
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*
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* Also, some platforms need suspend()/resume() hooks to kick in special
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* handling of wake alarms, e.g. activating ACPI BIOS hooks or setting up
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* a separate wakeup alarm used by some almost-clone chips.
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*/
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struct cmos_rtc_board_info {
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void (*wake_on)(struct device *dev);
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void (*wake_off)(struct device *dev);
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u32 flags;
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#define CMOS_RTC_FLAGS_NOFREQ (1 << 0)
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int address_space;
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u8 rtc_day_alarm; /* zero, or register index */
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u8 rtc_mon_alarm; /* zero, or register index */
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u8 rtc_century; /* zero, or register index */
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};
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#endif
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/**********************************************************************
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* register summary
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**********************************************************************/
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#define RTC_SECONDS 0
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#define RTC_SECONDS_ALARM 1
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#define RTC_MINUTES 2
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#define RTC_MINUTES_ALARM 3
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#define RTC_HOURS 4
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#define RTC_HOURS_ALARM 5
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/* RTC_*_alarm is always true if 2 MSBs are set */
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# define RTC_ALARM_DONT_CARE 0xC0
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#define RTC_DAY_OF_WEEK 6
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#define RTC_DAY_OF_MONTH 7
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#define RTC_MONTH 8
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#define RTC_YEAR 9
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/* control registers - Moto names
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*/
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#define RTC_REG_A 10
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#define RTC_REG_B 11
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#define RTC_REG_C 12
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#define RTC_REG_D 13
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/**********************************************************************
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* register details
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**********************************************************************/
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#define RTC_FREQ_SELECT RTC_REG_A
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/* update-in-progress - set to "1" 244 microsecs before RTC goes off the bus,
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* reset after update (may take 1.984ms @ 32768Hz RefClock) is complete,
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* totalling to a max high interval of 2.228 ms.
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*/
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# define RTC_UIP 0x80
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# define RTC_DIV_CTL 0x70
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/* divider control: refclock values 4.194 / 1.049 MHz / 32.768 kHz */
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# define RTC_REF_CLCK_4MHZ 0x00
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# define RTC_REF_CLCK_1MHZ 0x10
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# define RTC_REF_CLCK_32KHZ 0x20
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/* 2 values for divider stage reset, others for "testing purposes only" */
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# define RTC_DIV_RESET1 0x60
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# define RTC_DIV_RESET2 0x70
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/* In AMD BKDG bit 5 and 6 are reserved, bit 4 is for select dv0 bank */
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# define RTC_AMD_BANK_SELECT 0x10
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/* Periodic intr. / Square wave rate select. 0=none, 1=32.8kHz,... 15=2Hz */
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# define RTC_RATE_SELECT 0x0F
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/**********************************************************************/
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#define RTC_CONTROL RTC_REG_B
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# define RTC_SET 0x80 /* disable updates for clock setting */
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# define RTC_PIE 0x40 /* periodic interrupt enable */
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# define RTC_AIE 0x20 /* alarm interrupt enable */
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# define RTC_UIE 0x10 /* update-finished interrupt enable */
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# define RTC_SQWE 0x08 /* enable square-wave output */
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# define RTC_DM_BINARY 0x04 /* all time/date values are BCD if clear */
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# define RTC_24H 0x02 /* 24 hour mode - else hours bit 7 means pm */
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# define RTC_DST_EN 0x01 /* auto switch DST - works f. USA only */
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/**********************************************************************/
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#define RTC_INTR_FLAGS RTC_REG_C
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/* caution - cleared by read */
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# define RTC_IRQF 0x80 /* any of the following 3 is active */
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# define RTC_PF 0x40
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# define RTC_AF 0x20
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# define RTC_UF 0x10
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/**********************************************************************/
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#define RTC_VALID RTC_REG_D
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# define RTC_VRT 0x80 /* valid RAM and time */
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/**********************************************************************/
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#ifndef ARCH_RTC_LOCATION /* Override by <asm/mc146818rtc.h>? */
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#define RTC_IO_EXTENT 0x8
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#define RTC_IO_EXTENT_USED 0x2
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#define RTC_IOMAPPED 1 /* Default to I/O mapping. */
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#else
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#define RTC_IO_EXTENT_USED RTC_IO_EXTENT
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#endif /* ARCH_RTC_LOCATION */
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bool mc146818_does_rtc_work(void);
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int mc146818_get_time(struct rtc_time *time);
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int mc146818_set_time(struct rtc_time *time);
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bool mc146818_avoid_UIP(void (*callback)(unsigned char seconds, void *param),
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void *param);
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#endif /* _MC146818RTC_H */
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