[ Upstream commit
8c0826756744c0ac1df600a5e4cca1a341b13101 ]
Super-IO accesses may fail on a system with no or unmapped LPC bus.
Also, other drivers may attempt to access the LPC bus at the same time,
resulting in undefined behavior.
Use request_muxed_region() to ensure that IO access on the requested
address space is supported, and to ensure that access by multiple drivers
is synchronized.
Fixes:
8d5d45fb1468 ("I2C: Move hwmon drivers (2/3)")
Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: John Garry <john.garry@huawei.com>
Cc: John Garry <john.garry@huawei.com>
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
superio_outb(0x07, ld);
}
-static inline void superio_enter(void)
+static inline int superio_enter(void)
{
+ if (!request_muxed_region(REG, 2, DRVNAME))
+ return -EBUSY;
+
outb(0x55, REG);
+ return 0;
}
static inline void superio_exit(void)
{
outb(0xAA, REG);
+ release_region(REG, 2);
}
#define SUPERIO_REG_DEVID 0x20
u8 id, rev;
char *name;
unsigned short addr;
+ int err;
+
+ err = superio_enter();
+ if (err)
+ return err;
- superio_enter();
id = force_id ? force_id : superio_inb(SUPERIO_REG_DEVID);
switch (id) {