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alpha: Reorganize rtc handling 

Discontinue use of GENERIC_CMOS_UPDATE; rely on the RTC subsystem.

The marvel platform requires that the rtc only be touched from the
boot cpu.  This had been partially implemented with hooks for
get/set_rtc_time, but read/update_persistent_clock were not handled.
Move the hooks from the machine_vec to a special rtc_class_ops struct.

We had read_persistent_clock managing the epoch against which the
rtc hw is based, but this didn't apply to get_rtc_time or set_rtc_time.
This resulted in incorrect values when hwclock(8) gets involved.

Allow the epoch to be set from the kernel command-line, overriding
the autodetection, which is doomed to fail in 2020.  Further, by
implementing the rtc ioctl function, we can expose this epoch to
userland.

Elide the alarm functions that RTC_DRV_CMOS implements.  This was
highly questionable on Alpha, since the interrupt is used by the
system timer.

Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2013-07-13 15:49:45 -07:00 committed by Matt Turner
parent 7f3bbb82e0
commit 85d0b3a573
11 changed files with 337 additions and 223 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/alpha/Kconfig
View File

@ -17,7 +17,6 @@ config ALPHA
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select GENERIC_SMP_IDLE_THREAD
select GENERIC_CMOS_UPDATE
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select HAVE_MOD_ARCH_SPECIFIC

4
arch/alpha/include/asm/machvec.h
View File

@ -33,6 +33,7 @@ struct alpha_machine_vector
int nr_irqs;
int rtc_port;
int rtc_boot_cpu_only;
unsigned int max_asn;
unsigned long max_isa_dma_address;
unsigned long irq_probe_mask;
@ -95,9 +96,6 @@ struct alpha_machine_vector
struct _alpha_agp_info *(*agp_info)(void);
unsigned int (*rtc_get_time)(struct rtc_time *);
int (*rtc_set_time)(struct rtc_time *);
const char *vector_name;
/* NUMA information */

11
arch/alpha/include/asm/rtc.h
View File

@ -1,12 +1 @@
#ifndef _ALPHA_RTC_H
#define _ALPHA_RTC_H
#if defined(CONFIG_ALPHA_MARVEL) && defined(CONFIG_SMP) \
|| defined(CONFIG_ALPHA_GENERIC)
# define get_rtc_time alpha_mv.rtc_get_time
# define set_rtc_time alpha_mv.rtc_set_time
#endif
#include <asm-generic/rtc.h>
#endif

1
arch/alpha/kernel/Makefile
View File

@ -16,6 +16,7 @@ obj-$(CONFIG_PCI) += pci.o pci_iommu.o pci-sysfs.o
obj-$(CONFIG_SRM_ENV) += srm_env.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o
obj-$(CONFIG_RTC_DRV_ALPHA) += rtc.o
ifdef CONFIG_ALPHA_GENERIC

5
arch/alpha/kernel/machvec_impl.h
View File

@ -43,10 +43,7 @@
#define CAT1(x,y) x##y
#define CAT(x,y) CAT1(x,y)
#define DO_DEFAULT_RTC \
.rtc_port = 0x70, \
.rtc_get_time = common_get_rtc_time, \
.rtc_set_time = common_set_rtc_time
#define DO_DEFAULT_RTC .rtc_port = 0x70
#define DO_EV4_MMU \
.max_asn = EV4_MAX_ASN, \

2
arch/alpha/kernel/proto.h
View File

@ -144,8 +144,6 @@ extern void smp_percpu_timer_interrupt(struct pt_regs *);
extern irqreturn_t timer_interrupt(int irq, void *dev);
extern void common_init_rtc(void);
extern unsigned long est_cycle_freq;
extern unsigned int common_get_rtc_time(struct rtc_time *time);
extern int common_set_rtc_time(struct rtc_time *time);
/* smc37c93x.c */
extern void SMC93x_Init(void);

323
arch/alpha/kernel/rtc.c Normal file
View File

@ -0,0 +1,323 @@
/*
* linux/arch/alpha/kernel/rtc.c
*
* Copyright (C) 1991, 1992, 1995, 1999, 2000 Linus Torvalds
*
* This file contains date handling.
*/
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mc146818rtc.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <asm/rtc.h>
#include "proto.h"
/*
* Support for the RTC device.
*
* We don't want to use the rtc-cmos driver, because we don't want to support
* alarms, as that would be indistinguishable from timer interrupts.
*
* Further, generic code is really, really tied to a 1900 epoch. This is
* true in __get_rtc_time as well as the users of struct rtc_time e.g.
* rtc_tm_to_time. Thankfully all of the other epochs in use are later
* than 1900, and so it's easy to adjust.
*/
static unsigned long rtc_epoch;
static int __init
specifiy_epoch(char *str)
{
unsigned long epoch = simple_strtoul(str, NULL, 0);
if (epoch < 1900)
printk("Ignoring invalid user specified epoch %lu\n", epoch);
else
rtc_epoch = epoch;
return 1;
}
__setup("epoch=", specifiy_epoch);
static void __init
init_rtc_epoch(void)
{
int epoch, year, ctrl;
if (rtc_epoch != 0) {
/* The epoch was specified on the command-line. */
return;
}
/* Detect the epoch in use on this computer. */
ctrl = CMOS_READ(RTC_CONTROL);
year = CMOS_READ(RTC_YEAR);
if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
year = bcd2bin(year);
/* PC-like is standard; used for year >= 70 */
epoch = 1900;
if (year < 20) {
epoch = 2000;
} else if (year >= 20 && year < 48) {
/* NT epoch */
epoch = 1980;
} else if (year >= 48 && year < 70) {
/* Digital UNIX epoch */
epoch = 1952;
}
rtc_epoch = epoch;
printk(KERN_INFO "Using epoch %d for rtc year %d\n", epoch, year);
}
static int
alpha_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
__get_rtc_time(tm);
/* Adjust for non-default epochs. It's easier to depend on the
generic __get_rtc_time and adjust the epoch here than create
a copy of __get_rtc_time with the edits we need. */
if (rtc_epoch != 1900) {
int year = tm->tm_year;
/* Undo the century adjustment made in __get_rtc_time. */
if (year >= 100)
year -= 100;
year += rtc_epoch - 1900;
/* Redo the century adjustment with the epoch in place. */
if (year <= 69)
year += 100;
tm->tm_year = year;
}
return rtc_valid_tm(tm);
}
static int
alpha_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct rtc_time xtm;
if (rtc_epoch != 1900) {
xtm = *tm;
xtm.tm_year -= rtc_epoch - 1900;
tm = &xtm;
}
return __set_rtc_time(tm);
}
static int
alpha_rtc_set_mmss(struct device *dev, unsigned long nowtime)
{
int retval = 0;
int real_seconds, real_minutes, cmos_minutes;
unsigned char save_control, save_freq_select;
/* Note: This code only updates minutes and seconds. Comments
indicate this was to avoid messing with unknown time zones,
and with the epoch nonsense described above. In order for
this to work, the existing clock cannot be off by more than
15 minutes.
??? This choice is may be out of date. The x86 port does
not have problems with timezones, and the epoch processing has
now been fixed in alpha_set_rtc_time.
In either case, one can always force a full rtc update with
the userland hwclock program, so surely 15 minute accuracy
is no real burden. */
/* In order to set the CMOS clock precisely, we have to be called
500 ms after the second nowtime has started, because when
nowtime is written into the registers of the CMOS clock, it will
jump to the next second precisely 500 ms later. Check the Motorola
MC146818A or Dallas DS12887 data sheet for details. */
/* irq are locally disabled here */
spin_lock(&rtc_lock);
/* Tell the clock it's being set */
save_control = CMOS_READ(RTC_CONTROL);
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
/* Stop and reset prescaler */
save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
cmos_minutes = CMOS_READ(RTC_MINUTES);
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
cmos_minutes = bcd2bin(cmos_minutes);
real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1) {
/* correct for half hour time zone */
real_minutes += 30;
}
real_minutes %= 60;
if (abs(real_minutes - cmos_minutes) < 30) {
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
real_seconds = bin2bcd(real_seconds);
real_minutes = bin2bcd(real_minutes);
}
CMOS_WRITE(real_seconds,RTC_SECONDS);
CMOS_WRITE(real_minutes,RTC_MINUTES);
} else {
printk_once(KERN_NOTICE
"set_rtc_mmss: can't update from %d to %d\n",
cmos_minutes, real_minutes);
retval = -1;
}
/* The following flags have to be released exactly in this order,
* otherwise the DS12887 (popular MC146818A clone with integrated
* battery and quartz) will not reset the oscillator and will not
* update precisely 500 ms later. You won't find this mentioned in
* the Dallas Semiconductor data sheets, but who believes data
* sheets anyway ... -- Markus Kuhn
*/
CMOS_WRITE(save_control, RTC_CONTROL);
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
spin_unlock(&rtc_lock);
return retval;
}
static int
alpha_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case RTC_EPOCH_READ:
return put_user(rtc_epoch, (unsigned long __user *)arg);
case RTC_EPOCH_SET:
if (arg < 1900)
return -EINVAL;
rtc_epoch = arg;
return 0;
default:
return -ENOIOCTLCMD;
}
}
static const struct rtc_class_ops alpha_rtc_ops = {
.read_time = alpha_rtc_read_time,
.set_time = alpha_rtc_set_time,
.set_mmss = alpha_rtc_set_mmss,
.ioctl = alpha_rtc_ioctl,
};
/*
* Similarly, except do the actual CMOS access on the boot cpu only.
* This requires marshalling the data across an interprocessor call.
*/
#if defined(CONFIG_SMP) && \
(defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_MARVEL))
# define HAVE_REMOTE_RTC 1
union remote_data {
struct rtc_time *tm;
unsigned long now;
long retval;
};
static void
do_remote_read(void *data)
{
union remote_data *x = data;
x->retval = alpha_rtc_read_time(NULL, x->tm);
}
static int
remote_read_time(struct device *dev, struct rtc_time *tm)
{
union remote_data x;
if (smp_processor_id() != boot_cpuid) {
x.tm = tm;
smp_call_function_single(boot_cpuid, do_remote_read, &x, 1);
return x.retval;
}
return alpha_rtc_read_time(NULL, tm);
}
static void
do_remote_set(void *data)
{
union remote_data *x = data;
x->retval = alpha_rtc_set_time(NULL, x->tm);
}
static int
remote_set_time(struct device *dev, struct rtc_time *tm)
{
union remote_data x;
if (smp_processor_id() != boot_cpuid) {
x.tm = tm;
smp_call_function_single(boot_cpuid, do_remote_set, &x, 1);
return x.retval;
}
return alpha_rtc_set_time(NULL, tm);
}
static void
do_remote_mmss(void *data)
{
union remote_data *x = data;
x->retval = alpha_rtc_set_mmss(NULL, x->now);
}
static int
remote_set_mmss(struct device *dev, unsigned long now)
{
union remote_data x;
if (smp_processor_id() != boot_cpuid) {
x.now = now;
smp_call_function_single(boot_cpuid, do_remote_mmss, &x, 1);
return x.retval;
}
return alpha_rtc_set_mmss(NULL, now);
}
static const struct rtc_class_ops remote_rtc_ops = {
.read_time = remote_read_time,
.set_time = remote_set_time,
.set_mmss = remote_set_mmss,
.ioctl = alpha_rtc_ioctl,
};
#endif
static int __init
alpha_rtc_init(void)
{
const struct rtc_class_ops *ops;
struct platform_device *pdev;
struct rtc_device *rtc;
const char *name;
init_rtc_epoch();
name = "rtc-alpha";
ops = &alpha_rtc_ops;
#ifdef HAVE_REMOTE_RTC
if (alpha_mv.rtc_boot_cpu_only)
ops = &remote_rtc_ops;
#endif
pdev = platform_device_register_simple(name, -1, NULL, 0);
rtc = devm_rtc_device_register(&pdev->dev, name, ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
platform_set_drvdata(pdev, rtc);
return 0;
}
device_initcall(alpha_rtc_init);

2
arch/alpha/kernel/sys_jensen.c
View File

@ -224,8 +224,6 @@ struct alpha_machine_vector jensen_mv __initmv = {
.machine_check = jensen_machine_check,
.max_isa_dma_address = ALPHA_MAX_ISA_DMA_ADDRESS,
.rtc_port = 0x170,
.rtc_get_time = common_get_rtc_time,
.rtc_set_time = common_set_rtc_time,
.nr_irqs = 16,
.device_interrupt = jensen_device_interrupt,

55
arch/alpha/kernel/sys_marvel.c
View File

@ -22,7 +22,6 @@
#include <asm/hwrpb.h>
#include <asm/tlbflush.h>
#include <asm/vga.h>
#include <asm/rtc.h>
#include "proto.h"
#include "err_impl.h"
@ -400,57 +399,6 @@ marvel_init_rtc(void)
init_rtc_irq();
}
struct marvel_rtc_time {
struct rtc_time *time;
int retval;
};
#ifdef CONFIG_SMP
static void
smp_get_rtc_time(void *data)
{
struct marvel_rtc_time *mrt = data;
mrt->retval = __get_rtc_time(mrt->time);
}
static void
smp_set_rtc_time(void *data)
{
struct marvel_rtc_time *mrt = data;
mrt->retval = __set_rtc_time(mrt->time);
}
#endif
static unsigned int
marvel_get_rtc_time(struct rtc_time *time)
{
#ifdef CONFIG_SMP
struct marvel_rtc_time mrt;
if (smp_processor_id() != boot_cpuid) {
mrt.time = time;
smp_call_function_single(boot_cpuid, smp_get_rtc_time, &mrt, 1);
return mrt.retval;
}
#endif
return __get_rtc_time(time);
}
static int
marvel_set_rtc_time(struct rtc_time *time)
{
#ifdef CONFIG_SMP
struct marvel_rtc_time mrt;
if (smp_processor_id() != boot_cpuid) {
mrt.time = time;
smp_call_function_single(boot_cpuid, smp_set_rtc_time, &mrt, 1);
return mrt.retval;
}
#endif
return __set_rtc_time(time);
}
static void
marvel_smp_callin(void)
{
@ -492,8 +440,7 @@ struct alpha_machine_vector marvel_ev7_mv __initmv = {
.vector_name = "MARVEL/EV7",
DO_EV7_MMU,
.rtc_port = 0x70,
.rtc_get_time = marvel_get_rtc_time,
.rtc_set_time = marvel_set_rtc_time,
.rtc_boot_cpu_only = 1,
DO_MARVEL_IO,
.machine_check = marvel_machine_check,
.max_isa_dma_address = ALPHA_MAX_ISA_DMA_ADDRESS,

146
arch/alpha/kernel/time.c
View File

@ -3,13 +3,7 @@
*
* Copyright (C) 1991, 1992, 1995, 1999, 2000 Linus Torvalds
*
* This file contains the PC-specific time handling details:
* reading the RTC at bootup, etc..
* 1994-07-02 Alan Modra
* fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
* 1995-03-26 Markus Kuhn
* fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
* precision CMOS clock update
* This file contains the clocksource time handling.
* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
* "A Kernel Model for Precision Timekeeping" by Dave Mills
* 1997-01-09 Adrian Sun
@ -21,9 +15,6 @@
* 1999-04-16 Thorsten Kranzkowski (dl8bcu@gmx.net)
* fixed algorithm in do_gettimeofday() for calculating the precise time
* from processor cycle counter (now taking lost_ticks into account)
* 2000-08-13 Jan-Benedict Glaw <jbglaw@lug-owl.de>
* Fixed time_init to be aware of epoches != 1900. This prevents
* booting up in 2048 for me;) Code is stolen from rtc.c.
* 2003-06-03 R. Scott Bailey <scott.bailey@eds.com>
* Tighten sanity in time_init from 1% (10,000 PPM) to 250 PPM
*/
@ -46,7 +37,6 @@
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/hwrpb.h>
#include <asm/rtc.h>
#include <linux/mc146818rtc.h>
#include <linux/time.h>
@ -56,8 +46,6 @@
#include "proto.h"
#include "irq_impl.h"
static int set_rtc_mmss(unsigned long);
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
@ -108,53 +96,6 @@ static inline __u32 rpcc(void)
return __builtin_alpha_rpcc();
}
int update_persistent_clock(struct timespec now)
{
return set_rtc_mmss(now.tv_sec);
}
void read_persistent_clock(struct timespec *ts)
{
unsigned int year, mon, day, hour, min, sec, epoch;
sec = CMOS_READ(RTC_SECONDS);
min = CMOS_READ(RTC_MINUTES);
hour = CMOS_READ(RTC_HOURS);
day = CMOS_READ(RTC_DAY_OF_MONTH);
mon = CMOS_READ(RTC_MONTH);
year = CMOS_READ(RTC_YEAR);
if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
sec = bcd2bin(sec);
min = bcd2bin(min);
hour = bcd2bin(hour);
day = bcd2bin(day);
mon = bcd2bin(mon);
year = bcd2bin(year);
}
/* PC-like is standard; used for year >= 70 */
epoch = 1900;
if (year < 20)
epoch = 2000;
else if (year >= 20 && year < 48)
/* NT epoch */
epoch = 1980;
else if (year >= 48 && year < 70)
/* Digital UNIX epoch */
epoch = 1952;
printk(KERN_INFO "Using epoch = %d\n", epoch);
if ((year += epoch) < 1970)
year += 100;
ts->tv_sec = mktime(year, mon, day, hour, min, sec);
ts->tv_nsec = 0;
}
/*
* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "xtime_update()" routine every clocktick
@ -243,16 +184,6 @@ common_init_rtc(void)
init_rtc_irq();
}
unsigned int common_get_rtc_time(struct rtc_time *time)
{
return __get_rtc_time(time);
}
int common_set_rtc_time(struct rtc_time *time)
{
return __set_rtc_time(time);
}
/* Validate a computed cycle counter result against the known bounds for
the given processor core. There's too much brokenness in the way of
timing hardware for any one method to work everywhere. :-(
@ -453,78 +384,3 @@ time_init(void)
/* Startup the timer source. */
alpha_mv.init_rtc();
}
/*
* In order to set the CMOS clock precisely, set_rtc_mmss has to be
* called 500 ms after the second nowtime has started, because when
* nowtime is written into the registers of the CMOS clock, it will
* jump to the next second precisely 500 ms later. Check the Motorola
* MC146818A or Dallas DS12887 data sheet for details.
*
* BUG: This routine does not handle hour overflow properly; it just
* sets the minutes. Usually you won't notice until after reboot!
*/
static int
set_rtc_mmss(unsigned long nowtime)
{
int retval = 0;
int real_seconds, real_minutes, cmos_minutes;
unsigned char save_control, save_freq_select;
/* irq are locally disabled here */
spin_lock(&rtc_lock);
/* Tell the clock it's being set */
save_control = CMOS_READ(RTC_CONTROL);
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
/* Stop and reset prescaler */
save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
cmos_minutes = CMOS_READ(RTC_MINUTES);
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
cmos_minutes = bcd2bin(cmos_minutes);
/*
* since we're only adjusting minutes and seconds,
* don't interfere with hour overflow. This avoids
* messing with unknown time zones but requires your
* RTC not to be off by more than 15 minutes
*/
real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) {
/* correct for half hour time zone */
real_minutes += 30;
}
real_minutes %= 60;
if (abs(real_minutes - cmos_minutes) < 30) {
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
real_seconds = bin2bcd(real_seconds);
real_minutes = bin2bcd(real_minutes);
}
CMOS_WRITE(real_seconds,RTC_SECONDS);
CMOS_WRITE(real_minutes,RTC_MINUTES);
} else {
printk_once(KERN_NOTICE
"set_rtc_mmss: can't update from %d to %d\n",
cmos_minutes, real_minutes);
retval = -1;
}
/* The following flags have to be released exactly in this order,
* otherwise the DS12887 (popular MC146818A clone with integrated
* battery and quartz) will not reset the oscillator and will not
* update precisely 500 ms later. You won't find this mentioned in
* the Dallas Semiconductor data sheets, but who believes data
* sheets anyway ... -- Markus Kuhn
*/
CMOS_WRITE(save_control, RTC_CONTROL);
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
spin_unlock(&rtc_lock);
return retval;
}

10
drivers/rtc/Kconfig
View File

@ -626,7 +626,7 @@ comment "Platform RTC drivers"
config RTC_DRV_CMOS
tristate "PC-style 'CMOS'"
depends on X86 || ALPHA || ARM || M32R || ATARI || PPC || MIPS || SPARC64
depends on X86 || ARM || M32R || ATARI || PPC || MIPS || SPARC64
default y if X86
help
Say "yes" here to get direct support for the real time clock
@ -643,6 +643,14 @@ config RTC_DRV_CMOS
This driver can also be built as a module. If so, the module
will be called rtc-cmos.
config RTC_DRV_ALPHA
bool "Alpha PC-style CMOS"
depends on ALPHA
default y
help
Direct support for the real-time clock found on every Alpha
system, specifically MC146818 compatibles. If in doubt, say Y.
config RTC_DRV_VRTC
tristate "Virtual RTC for Intel MID platforms"
depends on X86_INTEL_MID