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authorGuenter Roeck <linux@roeck-us.net>2019-04-05 17:44:41 +0200
committerGuenter Roeck <linux@roeck-us.net>2019-04-16 02:19:53 +0200
commite95fd518d05bfc087da6fcdea4900a57cfb083bd (patch)
tree1f75021e709148ab6392db5524681f3a344fb6dd /drivers/hwmon/w83627hf.c
parenthwmon: (smsc47m1) Use request_muxed_region for Super-IO accesses (diff)
downloadlinux-e95fd518d05bfc087da6fcdea4900a57cfb083bd.tar.xz
linux-e95fd518d05bfc087da6fcdea4900a57cfb083bd.zip
hwmon: (w83627hf) Use request_muxed_region for Super-IO accesses
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: b72656dbc491 ("hwmon: (w83627hf) Stop using globals for I/O port numbers") Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/w83627hf.c')
-rw-r--r--drivers/hwmon/w83627hf.c42
1 files changed, 37 insertions, 5 deletions
diff --git a/drivers/hwmon/w83627hf.c b/drivers/hwmon/w83627hf.c
index 97bbf1af11e8..7ca53a28c305 100644
--- a/drivers/hwmon/w83627hf.c
+++ b/drivers/hwmon/w83627hf.c
@@ -130,17 +130,23 @@ superio_select(struct w83627hf_sio_data *sio, int ld)
outb(ld, sio->sioaddr + 1);
}
-static inline void
+static inline int
superio_enter(struct w83627hf_sio_data *sio)
{
+ if (!request_muxed_region(sio->sioaddr, 2, DRVNAME))
+ return -EBUSY;
+
outb(0x87, sio->sioaddr);
outb(0x87, sio->sioaddr);
+
+ return 0;
}
static inline void
superio_exit(struct w83627hf_sio_data *sio)
{
outb(0xAA, sio->sioaddr);
+ release_region(sio->sioaddr, 2);
}
#define W627_DEVID 0x52
@@ -1254,7 +1260,7 @@ static DEVICE_ATTR_RO(name);
static int __init w83627hf_find(int sioaddr, unsigned short *addr,
struct w83627hf_sio_data *sio_data)
{
- int err = -ENODEV;
+ int err;
u16 val;
static __initconst char *const names[] = {
@@ -1266,7 +1272,11 @@ static int __init w83627hf_find(int sioaddr, unsigned short *addr,
};
sio_data->sioaddr = sioaddr;
- superio_enter(sio_data);
+ err = superio_enter(sio_data);
+ if (err)
+ return err;
+
+ err = -ENODEV;
val = force_id ? force_id : superio_inb(sio_data, DEVID);
switch (val) {
case W627_DEVID:
@@ -1619,9 +1629,21 @@ static int w83627thf_read_gpio5(struct platform_device *pdev)
struct w83627hf_sio_data *sio_data = dev_get_platdata(&pdev->dev);
int res = 0xff, sel;
- superio_enter(sio_data);
+ if (superio_enter(sio_data)) {
+ /*
+ * Some other driver reserved the address space for itself.
+ * We don't want to fail driver instantiation because of that,
+ * so display a warning and keep going.
+ */
+ dev_warn(&pdev->dev,
+ "Can not read VID data: Failed to enable SuperIO access\n");
+ return res;
+ }
+
superio_select(sio_data, W83627HF_LD_GPIO5);
+ res = 0xff;
+
/* Make sure these GPIO pins are enabled */
if (!(superio_inb(sio_data, W83627THF_GPIO5_EN) & (1<<3))) {
dev_dbg(&pdev->dev, "GPIO5 disabled, no VID function\n");
@@ -1652,7 +1674,17 @@ static int w83687thf_read_vid(struct platform_device *pdev)
struct w83627hf_sio_data *sio_data = dev_get_platdata(&pdev->dev);
int res = 0xff;
- superio_enter(sio_data);
+ if (superio_enter(sio_data)) {
+ /*
+ * Some other driver reserved the address space for itself.
+ * We don't want to fail driver instantiation because of that,
+ * so display a warning and keep going.
+ */
+ dev_warn(&pdev->dev,
+ "Can not read VID data: Failed to enable SuperIO access\n");
+ return res;
+ }
+
superio_select(sio_data, W83627HF_LD_HWM);
/* Make sure these GPIO pins are enabled */