3.16.74-rc1 review patch. If anyone has any objections, please let me know.
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From: Guenter Roeck linux@roeck-us.net
commit e95fd518d05bfc087da6fcdea4900a57cfb083bd upstream.
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 Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/hwmon/w83627hf.c | 42 +++++++++++++++++++++++++++++++++++----- 1 file changed, 37 insertions(+), 5 deletions(-)
--- a/drivers/hwmon/w83627hf.c +++ b/drivers/hwmon/w83627hf.c @@ -130,17 +130,23 @@ superio_select(struct w83627hf_sio_data 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 @@ -1273,7 +1279,7 @@ static DEVICE_ATTR(name, S_IRUGO, show_n 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[] = { @@ -1285,7 +1291,11 @@ static int __init w83627hf_find(int sioa };
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: @@ -1639,9 +1649,21 @@ static int w83627thf_read_gpio5(struct p 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"); @@ -1672,7 +1694,17 @@ static int w83687thf_read_vid(struct pla 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 */