Implement superio access locking

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/nct6775.c b/nct6775.c
index 29bde779ff0654093f35d7ed41e8e84eb5f96ede..fc65ad1bbad74b97be9cdd2d64c7a5c18bf097e1 100644 (file)
--- a/nct6775.c
+++ b/nct6775.c
@@ -117,11 +117,19 @@ superio_select(int ioreg, int ld)
        outb(ld, ioreg + 1);
 }
 
-static inline void
+static inline int
 superio_enter(int ioreg)
 {
+       /*
+        * Try to reserve <ioreg> and <ioreg + 1> for exclusive access.
+        */
+        if (!request_muxed_region(ioreg, 2, DRVNAME))
+               return -EBUSY;
+
        outb(0x87, ioreg);
        outb(0x87, ioreg);
+
+       return 0;
 }
 
 static inline void
@@ -130,6 +138,7 @@ superio_exit(int ioreg)
        outb(0xaa, ioreg);
        outb(0x02, ioreg);
        outb(0x02, ioreg + 1);
+       release_region(ioreg, 2);
 }
 
 /*
@@ -2862,6 +2871,7 @@ clear_caseopen(struct device *dev, struct device_attribute *attr,
        int nr = to_sensor_dev_attr(attr)->index - INTRUSION_ALARM_BASE;
        unsigned long val;
        u8 reg;
+       int ret;
 
        if (kstrtoul(buf, 10, &val) || val != 0)
                return -EINVAL;
@@ -2873,7 +2883,10 @@ clear_caseopen(struct device *dev, struct device_attribute *attr,
         * The CR registers are the same for all chips, and not all chips
         * support clearing the caseopen status through "regular" registers.
         */
-       superio_enter(sio_data->sioreg);
+       ret = superio_enter(sio_data->sioreg);
+       if (ret)
+               goto error;
+
        superio_select(sio_data->sioreg, NCT6775_LD_ACPI);
        reg = superio_inb(sio_data->sioreg, NCT6775_REG_CR_CASEOPEN_CLR[nr]);
        reg |= NCT6775_CR_CASEOPEN_CLR_MASK[nr];
@@ -2883,10 +2896,11 @@ clear_caseopen(struct device *dev, struct device_attribute *attr,
        superio_exit(sio_data->sioreg);
 
        data->valid = 0;        /* Force cache refresh */
-
+       ret = count;
+error:
        mutex_unlock(&data->update_lock);
 
-       return count;
+       return ret;
 }
 
 static struct sensor_device_attribute sda_caseopen[] = {
@@ -2999,15 +3013,18 @@ static inline void __devinit nct6775_init_device(struct nct6775_data *data)
        }
 }
 
-static void __devinit
+static int __devinit
 nct6775_check_fan_inputs(const struct nct6775_sio_data *sio_data,
                         struct nct6775_data *data)
 {
        int regval;
        bool fan3pin, fan3min, fan4pin, fan4min, fan5pin;
        bool pwm3pin, pwm4pin, pwm5pin;
+       int ret;
 
-       superio_enter(sio_data->sioreg);
+       ret = superio_enter(sio_data->sioreg);
+       if (ret)
+               return ret;
 
        /* fan4 and fan5 share some pins with the GPIO and serial flash */
        if (data->kind == nct6775) {
@@ -3074,6 +3091,8 @@ nct6775_check_fan_inputs(const struct nct6775_sio_data *sio_data,
        data->has_fan_min |= (fan4min << 3) | (fan5pin << 4);
 
        data->has_pwm = 0x03 | (pwm3pin << 2) | (pwm4pin << 3) | (pwm5pin << 4);
+
+       return 0;
 }
 
 static int __devinit nct6775_probe(struct platform_device *pdev)
@@ -3473,7 +3492,10 @@ static int __devinit nct6775_probe(struct platform_device *pdev)
        nct6775_init_device(data);
 
        data->vrm = vid_which_vrm();
-       superio_enter(sio_data->sioreg);
+       err = superio_enter(sio_data->sioreg);
+       if (err)
+               return err;
+
        /*
         * Read VID value
         * We can get the VID input values directly at logical device D 0xe3.
@@ -3508,7 +3530,9 @@ static int __devinit nct6775_probe(struct platform_device *pdev)
        if (err)
                return err;
 
-       nct6775_check_fan_inputs(sio_data, data);
+       err = nct6775_check_fan_inputs(sio_data, data);
+       if (err)
+               goto exit_remove;
 
        /* Read fan clock dividers immediately */
        nct6775_update_fan_div_common(dev, data);
@@ -3688,8 +3712,11 @@ static int __init nct6775_find(int sioaddr, unsigned short *addr,
 
        u16 val;
        const char *sio_name;
+       int err;
 
-       superio_enter(sioaddr);
+       err = superio_enter(sioaddr);
+       if (err)
+               return err;
 
        if (force_id)
                val = force_id;