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linux/drivers/rtc/rtc-ds1511.c
Vladimir Zapolskiy 8ccba14233 rtc: ds1511: clean up ds1511_nvram_read()/ds1511_nvram_write() 
The change removes redundant sysfs binary file boundary checks, since
this task is already done on caller side in fs/sysfs/file.c

The change enables burst mode of access to SRAM for any read()/write()
operations, it is worth to mention that this may influence on
userspace, for instance prior to the change

  read(fd, buf, 1);
  read(fd, buf + 1, 1);

and

  read(fd, buf, 2);

sequences of syscalls over DS1511's sysfs "nvram" fd led to different
DS1511 state changes and/or buf content, if some userspace applications
are written specifically for DS1511 and exploit this strange
"feature", they may be impacted.

Also the change corrects NVRAM size accessible to userspace from 255
bytes to 256 bytes.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2015-09-05 13:19:10 +02:00

541 lines
13 KiB
C
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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/gfp.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/module.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 0x100
#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 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(rtc_read(RTC_CMD) | 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;
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 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,
};
static ssize_t
ds1511_nvram_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *ba,
char *buf, loff_t pos, size_t size)
{
ssize_t count;
rtc_write(pos, DS1511_RAMADDR_LSB);
for (count = 0; count < size; count++)
*buf++ = rtc_read(DS1511_RAMDATA);
return count;
}
static ssize_t
ds1511_nvram_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t size)
{
ssize_t count;
rtc_write(pos, DS1511_RAMADDR_LSB);
for (count = 0; count < size; count++)
rtc_write(*buf++, DS1511_RAMDATA);
return count;
}
static struct bin_attribute ds1511_nvram_attr = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
},
.size = DS1511_RAM_MAX,
.read = ds1511_nvram_read,
.write = ds1511_nvram_write,
};
static int ds1511_rtc_probe(struct platform_device *pdev)
{
struct resource *res;
struct rtc_plat_data *pdata;
int ret = 0;
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ds1511_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(ds1511_base))
return PTR_ERR(ds1511_base);
pdata->ioaddr = ds1511_base;
pdata->irq = platform_get_irq(pdev, 0);
/*
* turn on the clock and the crystal, etc.
*/
rtc_write(DS1511_BME, 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);
pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
&ds1511_rtc_ops, THIS_MODULE);
if (IS_ERR(pdata->rtc))
return PTR_ERR(pdata->rtc);
/*
* 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_SHARED, pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
pdata->irq = 0;
}
}
ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
if (ret)
dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
ds1511_nvram_attr.attr.name);
return 0;
}
static int 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);
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 = ds1511_rtc_remove,
.driver = {
.name = "ds1511",
},
};
module_platform_driver(ds1511_rtc_driver);
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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