linux/drivers/rtc/rtc-ep93xx.c
Nikita Shubin 00c33482bb rtc: ep93xx: Fix NULL pointer dereference in ep93xx_rtc_read_time
Mismatch in probe platform_set_drvdata set's and method's that call
dev_get_platdata will result in "Unable to handle kernel NULL pointer
dereference", let's use according method for getting driver data after
platform_set_drvdata.

8<--- cut here ---
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = (ptrval)
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 5.9.10-00003-g723e101e0037-dirty #4
Hardware name: Technologic Systems TS-72xx SBC
PC is at ep93xx_rtc_read_time+0xc/0x2c
LR is at __rtc_read_time+0x4c/0x8c
[...]
[<c02b01c8>] (ep93xx_rtc_read_time) from [<c02ac38c>] (__rtc_read_time+0x4c/0x8c)
[<c02ac38c>] (__rtc_read_time) from [<c02ac3f8>] (rtc_read_time+0x2c/0x4c)
[<c02ac3f8>] (rtc_read_time) from [<c02acc54>] (__rtc_read_alarm+0x28/0x358)
[<c02acc54>] (__rtc_read_alarm) from [<c02abd80>] (__rtc_register_device+0x124/0x2ec)
[<c02abd80>] (__rtc_register_device) from [<c02b028c>] (ep93xx_rtc_probe+0xa4/0xac)
[<c02b028c>] (ep93xx_rtc_probe) from [<c026424c>] (platform_drv_probe+0x24/0x5c)
[<c026424c>] (platform_drv_probe) from [<c0262918>] (really_probe+0x218/0x374)
[<c0262918>] (really_probe) from [<c0262da0>] (device_driver_attach+0x44/0x60)
[<c0262da0>] (device_driver_attach) from [<c0262e70>] (__driver_attach+0xb4/0xc0)
[<c0262e70>] (__driver_attach) from [<c0260d44>] (bus_for_each_dev+0x68/0xac)
[<c0260d44>] (bus_for_each_dev) from [<c026223c>] (driver_attach+0x18/0x24)
[<c026223c>] (driver_attach) from [<c0261dd8>] (bus_add_driver+0x150/0x1b4)
[<c0261dd8>] (bus_add_driver) from [<c026342c>] (driver_register+0xb0/0xf4)
[<c026342c>] (driver_register) from [<c0264210>] (__platform_driver_register+0x30/0x48)
[<c0264210>] (__platform_driver_register) from [<c04cb9ac>] (ep93xx_rtc_driver_init+0x10/0x1c)
[<c04cb9ac>] (ep93xx_rtc_driver_init) from [<c000973c>] (do_one_initcall+0x7c/0x1c0)
[<c000973c>] (do_one_initcall) from [<c04b9ecc>] (kernel_init_freeable+0x168/0x1ac)
[<c04b9ecc>] (kernel_init_freeable) from [<c03b2228>] (kernel_init+0x8/0xf4)
[<c03b2228>] (kernel_init) from [<c00082c0>] (ret_from_fork+0x14/0x34)
Exception stack(0xc441dfb0 to 0xc441dff8)
dfa0:                                     00000000 00000000 00000000 00000000
dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
dfe0: 00000000 00000000 00000000 00000000 00000013 00000000
Code: e12fff1e e92d4010 e590303c e1a02001 (e5933000)
---[ end trace c914d6030eaa95c8 ]---

Fixes: b809d192eb ("rtc: ep93xx: stop setting platform_data")
Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201201095507.10317-1-nikita.shubin@maquefel.me
2020-12-03 23:49:31 +01:00

164 lines
4.0 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* A driver for the RTC embedded in the Cirrus Logic EP93XX processors
* Copyright (c) 2006 Tower Technologies
*
* Author: Alessandro Zummo <a.zummo@towertech.it>
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/gfp.h>
#define EP93XX_RTC_DATA 0x000
#define EP93XX_RTC_MATCH 0x004
#define EP93XX_RTC_STATUS 0x008
#define EP93XX_RTC_STATUS_INTR BIT(0)
#define EP93XX_RTC_LOAD 0x00C
#define EP93XX_RTC_CONTROL 0x010
#define EP93XX_RTC_CONTROL_MIE BIT(0)
#define EP93XX_RTC_SWCOMP 0x108
#define EP93XX_RTC_SWCOMP_DEL_MASK 0x001f0000
#define EP93XX_RTC_SWCOMP_DEL_SHIFT 16
#define EP93XX_RTC_SWCOMP_INT_MASK 0x0000ffff
#define EP93XX_RTC_SWCOMP_INT_SHIFT 0
struct ep93xx_rtc {
void __iomem *mmio_base;
struct rtc_device *rtc;
};
static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,
unsigned short *delete)
{
struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
unsigned long comp;
comp = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);
if (preload)
*preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
>> EP93XX_RTC_SWCOMP_INT_SHIFT;
if (delete)
*delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
>> EP93XX_RTC_SWCOMP_DEL_SHIFT;
return 0;
}
static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
unsigned long time;
time = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);
rtc_time64_to_tm(time, tm);
return 0;
}
static int ep93xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
unsigned long secs = rtc_tm_to_time64(tm);
writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);
return 0;
}
static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
{
unsigned short preload, delete;
ep93xx_rtc_get_swcomp(dev, &preload, &delete);
seq_printf(seq, "preload\t\t: %d\n", preload);
seq_printf(seq, "delete\t\t: %d\n", delete);
return 0;
}
static const struct rtc_class_ops ep93xx_rtc_ops = {
.read_time = ep93xx_rtc_read_time,
.set_time = ep93xx_rtc_set_time,
.proc = ep93xx_rtc_proc,
};
static ssize_t comp_preload_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
unsigned short preload;
ep93xx_rtc_get_swcomp(dev->parent, &preload, NULL);
return sprintf(buf, "%d\n", preload);
}
static DEVICE_ATTR_RO(comp_preload);
static ssize_t comp_delete_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
unsigned short delete;
ep93xx_rtc_get_swcomp(dev->parent, NULL, &delete);
return sprintf(buf, "%d\n", delete);
}
static DEVICE_ATTR_RO(comp_delete);
static struct attribute *ep93xx_rtc_attrs[] = {
&dev_attr_comp_preload.attr,
&dev_attr_comp_delete.attr,
NULL
};
static const struct attribute_group ep93xx_rtc_sysfs_files = {
.attrs = ep93xx_rtc_attrs,
};
static int ep93xx_rtc_probe(struct platform_device *pdev)
{
struct ep93xx_rtc *ep93xx_rtc;
int err;
ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
if (!ep93xx_rtc)
return -ENOMEM;
ep93xx_rtc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(ep93xx_rtc->mmio_base))
return PTR_ERR(ep93xx_rtc->mmio_base);
platform_set_drvdata(pdev, ep93xx_rtc);
ep93xx_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(ep93xx_rtc->rtc))
return PTR_ERR(ep93xx_rtc->rtc);
ep93xx_rtc->rtc->ops = &ep93xx_rtc_ops;
ep93xx_rtc->rtc->range_max = U32_MAX;
err = rtc_add_group(ep93xx_rtc->rtc, &ep93xx_rtc_sysfs_files);
if (err)
return err;
return devm_rtc_register_device(ep93xx_rtc->rtc);
}
static struct platform_driver ep93xx_rtc_driver = {
.driver = {
.name = "ep93xx-rtc",
},
.probe = ep93xx_rtc_probe,
};
module_platform_driver(ep93xx_rtc_driver);
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("EP93XX RTC driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ep93xx-rtc");