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linux/drivers/rtc/rtc-zynqmp.c
Alexandre Belloni c9a1dd673f rtc: zynqmp: initialize fract_tick 
fract_tick is used uninitialized when fract_offset is 0

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20220727100018.3301470-1-alexandre.belloni@bootlin.com
2022-08-08 20:35:41 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver
*
* Copyright (C) 2015 Xilinx, Inc.
*
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
/* RTC Registers */
#define RTC_SET_TM_WR 0x00
#define RTC_SET_TM_RD 0x04
#define RTC_CALIB_WR 0x08
#define RTC_CALIB_RD 0x0C
#define RTC_CUR_TM 0x10
#define RTC_CUR_TICK 0x14
#define RTC_ALRM 0x18
#define RTC_INT_STS 0x20
#define RTC_INT_MASK 0x24
#define RTC_INT_EN 0x28
#define RTC_INT_DIS 0x2C
#define RTC_CTRL 0x40
#define RTC_FR_EN BIT(20)
#define RTC_FR_DATSHIFT 16
#define RTC_TICK_MASK 0xFFFF
#define RTC_INT_SEC BIT(0)
#define RTC_INT_ALRM BIT(1)
#define RTC_OSC_EN BIT(24)
#define RTC_BATT_EN BIT(31)
#define RTC_CALIB_DEF 0x7FFF
#define RTC_CALIB_MASK 0x1FFFFF
#define RTC_ALRM_MASK BIT(1)
#define RTC_MSEC 1000
#define RTC_FR_MASK 0xF0000
#define RTC_FR_MAX_TICKS 16
#define RTC_PPB 1000000000LL
#define RTC_MIN_OFFSET -32768000
#define RTC_MAX_OFFSET 32767000
struct xlnx_rtc_dev {
struct rtc_device *rtc;
void __iomem *reg_base;
int alarm_irq;
int sec_irq;
struct clk *rtc_clk;
unsigned int freq;
};
static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long new_time;
/*
* The value written will be updated after 1 sec into the
* seconds read register, so we need to program time +1 sec
* to get the correct time on read.
*/
new_time = rtc_tm_to_time64(tm) + 1;
writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
/*
* Clear the rtc interrupt status register after setting the
* time. During a read_time function, the code should read the
* RTC_INT_STATUS register and if bit 0 is still 0, it means
* that one second has not elapsed yet since RTC was set and
* the current time should be read from SET_TIME_READ register;
* otherwise, CURRENT_TIME register is read to report the time
*/
writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS);
return 0;
}
static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
u32 status;
unsigned long read_time;
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
status = readl(xrtcdev->reg_base + RTC_INT_STS);
if (status & RTC_INT_SEC) {
/*
* RTC has updated the CURRENT_TIME with the time written into
* SET_TIME_WRITE register.
*/
read_time = readl(xrtcdev->reg_base + RTC_CUR_TM);
} else {
/*
* Time written in SET_TIME_WRITE has not yet updated into
* the seconds read register, so read the time from the
* SET_TIME_WRITE instead of CURRENT_TIME register.
* Since we add +1 sec while writing, we need to -1 sec while
* reading.
*/
read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1;
}
rtc_time64_to_tm(read_time, tm);
return 0;
}
static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time);
alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM;
return 0;
}
static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned int status;
ulong timeout;
timeout = jiffies + msecs_to_jiffies(RTC_MSEC);
if (enabled) {
while (1) {
status = readl(xrtcdev->reg_base + RTC_INT_STS);
if (!((status & RTC_ALRM_MASK) == RTC_ALRM_MASK))
break;
if (time_after_eq(jiffies, timeout)) {
dev_err(dev, "Time out occur, while clearing alarm status bit\n");
return -ETIMEDOUT;
}
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS);
}
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN);
} else {
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
}
return 0;
}
static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long alarm_time;
alarm_time = rtc_tm_to_time64(&alrm->time);
writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM));
xlnx_rtc_alarm_irq_enable(dev, alrm->enabled);
return 0;
}
static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev)
{
u32 rtc_ctrl;
/* Enable RTC switch to battery when VCC_PSAUX is not available */
rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL);
rtc_ctrl |= RTC_BATT_EN;
writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL);
}
static int xlnx_rtc_read_offset(struct device *dev, long *offset)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long long rtc_ppb = RTC_PPB;
unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
unsigned int calibval;
long offset_val;
calibval = readl(xrtcdev->reg_base + RTC_CALIB_RD);
/* Offset with seconds ticks */
offset_val = calibval & RTC_TICK_MASK;
offset_val = offset_val - RTC_CALIB_DEF;
offset_val = offset_val * tick_mult;
/* Offset with fractional ticks */
if (calibval & RTC_FR_EN)
offset_val += ((calibval & RTC_FR_MASK) >> RTC_FR_DATSHIFT)
* (tick_mult / RTC_FR_MAX_TICKS);
*offset = offset_val;
return 0;
}
static int xlnx_rtc_set_offset(struct device *dev, long offset)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long long rtc_ppb = RTC_PPB;
unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
unsigned char fract_tick = 0;
unsigned int calibval;
short int max_tick;
int fract_offset;
if (offset < RTC_MIN_OFFSET || offset > RTC_MAX_OFFSET)
return -ERANGE;
/* Number ticks for given offset */
max_tick = div_s64_rem(offset, tick_mult, &fract_offset);
/* Number fractional ticks for given offset */
if (fract_offset) {
if (fract_offset < 0) {
fract_offset = fract_offset + tick_mult;
max_tick--;
}
if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) {
for (fract_tick = 1; fract_tick < 16; fract_tick++) {
if (fract_offset <=
(fract_tick *
(tick_mult / RTC_FR_MAX_TICKS)))
break;
}
}
}
/* Zynqmp RTC uses second and fractional tick
* counters for compensation
*/
calibval = max_tick + RTC_CALIB_DEF;
if (fract_tick)
calibval |= RTC_FR_EN;
calibval |= (fract_tick << RTC_FR_DATSHIFT);
writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
return 0;
}
static const struct rtc_class_ops xlnx_rtc_ops = {
.set_time = xlnx_rtc_set_time,
.read_time = xlnx_rtc_read_time,
.read_alarm = xlnx_rtc_read_alarm,
.set_alarm = xlnx_rtc_set_alarm,
.alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
.read_offset = xlnx_rtc_read_offset,
.set_offset = xlnx_rtc_set_offset,
};
static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
{
struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id;
unsigned int status;
status = readl(xrtcdev->reg_base + RTC_INT_STS);
/* Check if interrupt asserted */
if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
return IRQ_NONE;
/* Disable RTC_INT_ALRM interrupt only */
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
if (status & RTC_INT_ALRM)
rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static int xlnx_rtc_probe(struct platform_device *pdev)
{
struct xlnx_rtc_dev *xrtcdev;
int ret;
xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
if (!xrtcdev)
return -ENOMEM;
platform_set_drvdata(pdev, xrtcdev);
xrtcdev->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(xrtcdev->rtc))
return PTR_ERR(xrtcdev->rtc);
xrtcdev->rtc->ops = &xlnx_rtc_ops;
xrtcdev->rtc->range_max = U32_MAX;
xrtcdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(xrtcdev->reg_base))
return PTR_ERR(xrtcdev->reg_base);
xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm");
if (xrtcdev->alarm_irq < 0)
return xrtcdev->alarm_irq;
ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq,
xlnx_rtc_interrupt, 0,
dev_name(&pdev->dev), xrtcdev);
if (ret) {
dev_err(&pdev->dev, "request irq failed\n");
return ret;
}
xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec");
if (xrtcdev->sec_irq < 0)
return xrtcdev->sec_irq;
ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq,
xlnx_rtc_interrupt, 0,
dev_name(&pdev->dev), xrtcdev);
if (ret) {
dev_err(&pdev->dev, "request irq failed\n");
return ret;
}
/* Getting the rtc_clk info */
xrtcdev->rtc_clk = devm_clk_get_optional(&pdev->dev, "rtc_clk");
if (IS_ERR(xrtcdev->rtc_clk)) {
if (PTR_ERR(xrtcdev->rtc_clk) != -EPROBE_DEFER)
dev_warn(&pdev->dev, "Device clock not found.\n");
}
xrtcdev->freq = clk_get_rate(xrtcdev->rtc_clk);
if (!xrtcdev->freq) {
ret = of_property_read_u32(pdev->dev.of_node, "calibration",
&xrtcdev->freq);
if (ret)
xrtcdev->freq = RTC_CALIB_DEF;
}
ret = readl(xrtcdev->reg_base + RTC_CALIB_RD);
if (!ret)
writel(xrtcdev->freq, (xrtcdev->reg_base + RTC_CALIB_WR));
xlnx_init_rtc(xrtcdev);
device_init_wakeup(&pdev->dev, 1);
return devm_rtc_register_device(xrtcdev->rtc);
}
static int xlnx_rtc_remove(struct platform_device *pdev)
{
xlnx_rtc_alarm_irq_enable(&pdev->dev, 0);
device_init_wakeup(&pdev->dev, 0);
return 0;
}
static int __maybe_unused xlnx_rtc_suspend(struct device *dev)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(xrtcdev->alarm_irq);
else
xlnx_rtc_alarm_irq_enable(dev, 0);
return 0;
}
static int __maybe_unused xlnx_rtc_resume(struct device *dev)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(xrtcdev->alarm_irq);
else
xlnx_rtc_alarm_irq_enable(dev, 1);
return 0;
}
static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume);
static const struct of_device_id xlnx_rtc_of_match[] = {
{.compatible = "xlnx,zynqmp-rtc" },
{ }
};
MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match);
static struct platform_driver xlnx_rtc_driver = {
.probe = xlnx_rtc_probe,
.remove = xlnx_rtc_remove,
.driver = {
.name = KBUILD_MODNAME,
.pm = &xlnx_rtc_pm_ops,
.of_match_table = xlnx_rtc_of_match,
},
};
module_platform_driver(xlnx_rtc_driver);
MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver");
MODULE_AUTHOR("Xilinx Inc.");
MODULE_LICENSE("GPL v2");
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