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Commit e95fd518 authored by Guenter Roeck's avatar Guenter Roeck
Browse files

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: b72656db ("hwmon: (w83627hf) Stop using globals for I/O port numbers")
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent d6410408

drivers/hwmon/w83627hf.c

+37 −5
Original line number Diff line number Diff line
@@ -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 */