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linux_dsm_epyc7002/drivers/rtc/rtc-ds1511.c
Atsushi Nemoto ba4f3e47cb rtc-ds1511: fix races around device registration 
- Call dev_set_drvdata before rtc device creation.

- Use its own spinlock instead of rtc->irq_lock.  Because pdata->rtc
  must be initialized to use the irq_lock (pdata->rtc->irq_lock).  There
  is a small window which rtc methods can be called before pdata->rtc is
  initialized.

  And there is no need use the irq_lock to protect hardware registers.
  The driver's own spinlock shoule be enough.

- Check pdata->rtc before calling rtc_update_irq.

- Use {alarm,update}_irq_enable and remove ioctl routine.

- Use devres APIs and simplify error/remove path.

These fixes are ported from ds1553 driver and just compile-tested only.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Andrew Sharp <andy.sharp@lsi.com>
Cc: Thomas Hommel <thomas.hommel@gefanuc.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:19:59 -08:00

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/*
* An rtc driver for the Dallas DS1511
*
* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
* Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Real time clock driver for the Dallas 1511 chip, which also
* contains a watchdog timer. There is a tiny amount of code that
* platform code could use to mess with the watchdog device a little
* bit, but not a full watchdog driver.
*/
#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#define DRV_VERSION "0.6"
enum ds1511reg {
DS1511_SEC = 0x0,
DS1511_MIN = 0x1,
DS1511_HOUR = 0x2,
DS1511_DOW = 0x3,
DS1511_DOM = 0x4,
DS1511_MONTH = 0x5,
DS1511_YEAR = 0x6,
DS1511_CENTURY = 0x7,
DS1511_AM1_SEC = 0x8,
DS1511_AM2_MIN = 0x9,
DS1511_AM3_HOUR = 0xa,
DS1511_AM4_DATE = 0xb,
DS1511_WD_MSEC = 0xc,
DS1511_WD_SEC = 0xd,
DS1511_CONTROL_A = 0xe,
DS1511_CONTROL_B = 0xf,
DS1511_RAMADDR_LSB = 0x10,
DS1511_RAMDATA = 0x13
};
#define DS1511_BLF1 0x80
#define DS1511_BLF2 0x40
#define DS1511_PRS 0x20
#define DS1511_PAB 0x10
#define DS1511_TDF 0x08
#define DS1511_KSF 0x04
#define DS1511_WDF 0x02
#define DS1511_IRQF 0x01
#define DS1511_TE 0x80
#define DS1511_CS 0x40
#define DS1511_BME 0x20
#define DS1511_TPE 0x10
#define DS1511_TIE 0x08
#define DS1511_KIE 0x04
#define DS1511_WDE 0x02
#define DS1511_WDS 0x01
#define DS1511_RAM_MAX 0xff
#define RTC_CMD DS1511_CONTROL_B
#define RTC_CMD1 DS1511_CONTROL_A
#define RTC_ALARM_SEC DS1511_AM1_SEC
#define RTC_ALARM_MIN DS1511_AM2_MIN
#define RTC_ALARM_HOUR DS1511_AM3_HOUR
#define RTC_ALARM_DATE DS1511_AM4_DATE
#define RTC_SEC DS1511_SEC
#define RTC_MIN DS1511_MIN
#define RTC_HOUR DS1511_HOUR
#define RTC_DOW DS1511_DOW
#define RTC_DOM DS1511_DOM
#define RTC_MON DS1511_MONTH
#define RTC_YEAR DS1511_YEAR
#define RTC_CENTURY DS1511_CENTURY
#define RTC_TIE DS1511_TIE
#define RTC_TE DS1511_TE
struct rtc_plat_data {
struct rtc_device *rtc;
void __iomem *ioaddr; /* virtual base address */
int size; /* amount of memory mapped */
int irq;
unsigned int irqen;
int alrm_sec;
int alrm_min;
int alrm_hour;
int alrm_mday;
spinlock_t lock;
};
static DEFINE_SPINLOCK(ds1511_lock);
static __iomem char *ds1511_base;
static u32 reg_spacing = 1;
static noinline void
rtc_write(uint8_t val, uint32_t reg)
{
writeb(val, ds1511_base + (reg * reg_spacing));
}
static inline void
rtc_write_alarm(uint8_t val, enum ds1511reg reg)
{
rtc_write((val | 0x80), reg);
}
static noinline uint8_t
rtc_read(enum ds1511reg reg)
{
return readb(ds1511_base + (reg * reg_spacing));
}
static inline void
rtc_disable_update(void)
{
rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
}
static void
rtc_enable_update(void)
{
rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
}
/*
* #define DS1511_WDOG_RESET_SUPPORT
*
* Uncomment this if you want to use these routines in
* some platform code.
*/
#ifdef DS1511_WDOG_RESET_SUPPORT
/*
* just enough code to set the watchdog timer so that it
* will reboot the system
*/
void
ds1511_wdog_set(unsigned long deciseconds)
{
/*
* the wdog timer can take 99.99 seconds
*/
deciseconds %= 10000;
/*
* set the wdog values in the wdog registers
*/
rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
/*
* set wdog enable and wdog 'steering' bit to issue a reset
*/
rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD);
}
void
ds1511_wdog_disable(void)
{
/*
* clear wdog enable and wdog 'steering' bits
*/
rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
/*
* clear the wdog counter
*/
rtc_write(0, DS1511_WD_MSEC);
rtc_write(0, DS1511_WD_SEC);
}
#endif
/*
* set the rtc chip's idea of the time.
* stupidly, some callers call with year unmolested;
* and some call with year = year - 1900. thanks.
*/
static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
{
u8 mon, day, dow, hrs, min, sec, yrs, cen;
unsigned long flags;
/*
* won't have to change this for a while
*/
if (rtc_tm->tm_year < 1900) {
rtc_tm->tm_year += 1900;
}
if (rtc_tm->tm_year < 1970) {
return -EINVAL;
}
yrs = rtc_tm->tm_year % 100;
cen = rtc_tm->tm_year / 100;
mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */
day = rtc_tm->tm_mday;
dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
hrs = rtc_tm->tm_hour;
min = rtc_tm->tm_min;
sec = rtc_tm->tm_sec;
if ((mon > 12) || (day == 0)) {
return -EINVAL;
}
if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) {
return -EINVAL;
}
if ((hrs >= 24) || (min >= 60) || (sec >= 60)) {
return -EINVAL;
}
/*
* each register is a different number of valid bits
*/
sec = bin2bcd(sec) & 0x7f;
min = bin2bcd(min) & 0x7f;
hrs = bin2bcd(hrs) & 0x3f;
day = bin2bcd(day) & 0x3f;
mon = bin2bcd(mon) & 0x1f;
yrs = bin2bcd(yrs) & 0xff;
cen = bin2bcd(cen) & 0xff;
spin_lock_irqsave(&ds1511_lock, flags);
rtc_disable_update();
rtc_write(cen, RTC_CENTURY);
rtc_write(yrs, RTC_YEAR);
rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
rtc_write(day, RTC_DOM);
rtc_write(hrs, RTC_HOUR);
rtc_write(min, RTC_MIN);
rtc_write(sec, RTC_SEC);
rtc_write(dow, RTC_DOW);
rtc_enable_update();
spin_unlock_irqrestore(&ds1511_lock, flags);
return 0;
}
static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
{
unsigned int century;
unsigned long flags;
spin_lock_irqsave(&ds1511_lock, flags);
rtc_disable_update();
rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
century = rtc_read(RTC_CENTURY);
rtc_enable_update();
spin_unlock_irqrestore(&ds1511_lock, flags);
rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
century = bcd2bin(century) * 100;
/*
* Account for differences between how the RTC uses the values
* and how they are defined in a struct rtc_time;
*/
century += rtc_tm->tm_year;
rtc_tm->tm_year = century - 1900;
rtc_tm->tm_mon--;
if (rtc_valid_tm(rtc_tm) < 0) {
dev_err(dev, "retrieved date/time is not valid.\n");
rtc_time_to_tm(0, rtc_tm);
}
return 0;
}
/*
* write the alarm register settings
*
* we only have the use to interrupt every second, otherwise
* known as the update interrupt, or the interrupt if the whole
* date/hours/mins/secs matches. the ds1511 has many more
* permutations, but the kernel doesn't.
*/
static void
ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
{
unsigned long flags;
spin_lock_irqsave(&pdata->lock, flags);
rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
RTC_ALARM_DATE);
rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
RTC_ALARM_HOUR);
rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
RTC_ALARM_MIN);
rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
RTC_ALARM_SEC);
rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
rtc_read(RTC_CMD1); /* clear interrupts */
spin_unlock_irqrestore(&pdata->lock, flags);
}
static int
ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
pdata->alrm_mday = alrm->time.tm_mday;
pdata->alrm_hour = alrm->time.tm_hour;
pdata->alrm_min = alrm->time.tm_min;
pdata->alrm_sec = alrm->time.tm_sec;
if (alrm->enabled) {
pdata->irqen |= RTC_AF;
}
ds1511_rtc_update_alarm(pdata);
return 0;
}
static int
ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
return 0;
}
static irqreturn_t
ds1511_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = dev_id;
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
unsigned long events = 0;
spin_lock(&pdata->lock);
/*
* read and clear interrupt
*/
if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
events = RTC_IRQF;
if (rtc_read(RTC_ALARM_SEC) & 0x80)
events |= RTC_UF;
else
events |= RTC_AF;
if (likely(pdata->rtc))
rtc_update_irq(pdata->rtc, 1, events);
}
spin_unlock(&pdata->lock);
return events ? IRQ_HANDLED : IRQ_NONE;
}
static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
if (enabled)
pdata->irqen |= RTC_AF;
else
pdata->irqen &= ~RTC_AF;
ds1511_rtc_update_alarm(pdata);
return 0;
}
static int ds1511_rtc_update_irq_enable(struct device *dev,
unsigned int enabled)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
if (enabled)
pdata->irqen |= RTC_UF;
else
pdata->irqen &= ~RTC_UF;
ds1511_rtc_update_alarm(pdata);
return 0;
}
static const struct rtc_class_ops ds1511_rtc_ops = {
.read_time = ds1511_rtc_read_time,
.set_time = ds1511_rtc_set_time,
.read_alarm = ds1511_rtc_read_alarm,
.set_alarm = ds1511_rtc_set_alarm,
.alarm_irq_enable = ds1511_rtc_alarm_irq_enable,
.update_irq_enable = ds1511_rtc_update_irq_enable,
};
static ssize_t
ds1511_nvram_read(struct kobject *kobj, struct bin_attribute *ba,
char *buf, loff_t pos, size_t size)
{
ssize_t count;
/*
* if count is more than one, turn on "burst" mode
* turn it off when you're done
*/
if (size > 1) {
rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
}
if (pos > DS1511_RAM_MAX) {
pos = DS1511_RAM_MAX;
}
if (size + pos > DS1511_RAM_MAX + 1) {
size = DS1511_RAM_MAX - pos + 1;
}
rtc_write(pos, DS1511_RAMADDR_LSB);
for (count = 0; size > 0; count++, size--) {
*buf++ = rtc_read(DS1511_RAMDATA);
}
if (count > 1) {
rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
}
return count;
}
static ssize_t
ds1511_nvram_write(struct kobject *kobj, struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t size)
{
ssize_t count;
/*
* if count is more than one, turn on "burst" mode
* turn it off when you're done
*/
if (size > 1) {
rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
}
if (pos > DS1511_RAM_MAX) {
pos = DS1511_RAM_MAX;
}
if (size + pos > DS1511_RAM_MAX + 1) {
size = DS1511_RAM_MAX - pos + 1;
}
rtc_write(pos, DS1511_RAMADDR_LSB);
for (count = 0; size > 0; count++, size--) {
rtc_write(*buf++, DS1511_RAMDATA);
}
if (count > 1) {
rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
}
return count;
}
static struct bin_attribute ds1511_nvram_attr = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUGO,
},
.size = DS1511_RAM_MAX,
.read = ds1511_nvram_read,
.write = ds1511_nvram_write,
};
static int __devinit
ds1511_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
struct resource *res;
struct rtc_plat_data *pdata;
int ret = 0;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
return -ENODEV;
}
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
pdata->size = res->end - res->start + 1;
if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
pdev->name))
return -EBUSY;
ds1511_base = devm_ioremap(&pdev->dev, res->start, pdata->size);
if (!ds1511_base)
return -ENOMEM;
pdata->ioaddr = ds1511_base;
pdata->irq = platform_get_irq(pdev, 0);
/*
* turn on the clock and the crystal, etc.
*/
rtc_write(0, RTC_CMD);
rtc_write(0, RTC_CMD1);
/*
* clear the wdog counter
*/
rtc_write(0, DS1511_WD_MSEC);
rtc_write(0, DS1511_WD_SEC);
/*
* start the clock
*/
rtc_enable_update();
/*
* check for a dying bat-tree
*/
if (rtc_read(RTC_CMD1) & DS1511_BLF1) {
dev_warn(&pdev->dev, "voltage-low detected.\n");
}
spin_lock_init(&pdata->lock);
platform_set_drvdata(pdev, pdata);
/*
* if the platform has an interrupt in mind for this device,
* then by all means, set it
*/
if (pdata->irq > 0) {
rtc_read(RTC_CMD1);
if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
pdata->irq = 0;
}
}
rtc = rtc_device_register(pdev->name, &pdev->dev, &ds1511_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
pdata->rtc = rtc;
ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
if (ret)
rtc_device_unregister(pdata->rtc);
return ret;
}
static int __devexit
ds1511_rtc_remove(struct platform_device *pdev)
{
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
rtc_device_unregister(pdata->rtc);
if (pdata->irq > 0) {
/*
* disable the alarm interrupt
*/
rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
rtc_read(RTC_CMD1);
}
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:ds1511");
static struct platform_driver ds1511_rtc_driver = {
.probe = ds1511_rtc_probe,
.remove = __devexit_p(ds1511_rtc_remove),
.driver = {
.name = "ds1511",
.owner = THIS_MODULE,
},
};
static int __init
ds1511_rtc_init(void)
{
return platform_driver_register(&ds1511_rtc_driver);
}
static void __exit
ds1511_rtc_exit(void)
{
platform_driver_unregister(&ds1511_rtc_driver);
}
module_init(ds1511_rtc_init);
module_exit(ds1511_rtc_exit);
MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
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