ssb: add locking around gpio register accesses

The GPIOs are access through some registers in the chip common core or
over extif. We need locking around these GPIO accesses, all GPIOs are
accessed through the same registers and parallel writes will cause
problems.

Signed-off-by: Hauke Mehrtens <[e-mail]>
Patchwork: http://patchwork.linux-mips.org/patch/4590
Acked-by: Florian Fainelli <[e-mail]>

drivers/ssb/driver_chipcommon.c

···
 {
 	if (!cc->dev)
 		return; /* We don't have a ChipCommon */
+
+	spin_lock_init(&cc->gpio_lock);
+
 	if (cc->dev->id.revision >= 11)
 		cc->status = chipco_read32(cc, SSB_CHIPCO_CHIPSTAT);
 	ssb_dprintk(KERN_INFO PFX "chipcommon status is 0x%x\n", cc->status);
···
 
 u32 ssb_chipco_gpio_out(struct ssb_chipcommon *cc, u32 mask, u32 value)
 {
-	return chipco_write32_masked(cc, SSB_CHIPCO_GPIOOUT, mask, value);
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&cc->gpio_lock, flags);
+	res = chipco_write32_masked(cc, SSB_CHIPCO_GPIOOUT, mask, value);
+	spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+	return res;
 }
 
 u32 ssb_chipco_gpio_outen(struct ssb_chipcommon *cc, u32 mask, u32 value)
 {
-	return chipco_write32_masked(cc, SSB_CHIPCO_GPIOOUTEN, mask, value);
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&cc->gpio_lock, flags);
+	res = chipco_write32_masked(cc, SSB_CHIPCO_GPIOOUTEN, mask, value);
+	spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+	return res;
 }
 
 u32 ssb_chipco_gpio_control(struct ssb_chipcommon *cc, u32 mask, u32 value)
 {
-	return chipco_write32_masked(cc, SSB_CHIPCO_GPIOCTL, mask, value);
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&cc->gpio_lock, flags);
+	res = chipco_write32_masked(cc, SSB_CHIPCO_GPIOCTL, mask, value);
+	spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+	return res;
 }
 EXPORT_SYMBOL(ssb_chipco_gpio_control);
 
 u32 ssb_chipco_gpio_intmask(struct ssb_chipcommon *cc, u32 mask, u32 value)
 {
-	return chipco_write32_masked(cc, SSB_CHIPCO_GPIOIRQ, mask, value);
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&cc->gpio_lock, flags);
+	res = chipco_write32_masked(cc, SSB_CHIPCO_GPIOIRQ, mask, value);
+	spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+	return res;
 }
 
 u32 ssb_chipco_gpio_polarity(struct ssb_chipcommon *cc, u32 mask, u32 value)
 {
-	return chipco_write32_masked(cc, SSB_CHIPCO_GPIOPOL, mask, value);
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&cc->gpio_lock, flags);
+	res = chipco_write32_masked(cc, SSB_CHIPCO_GPIOPOL, mask, value);
+	spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+	return res;
 }
 
 u32 ssb_chipco_gpio_pullup(struct ssb_chipcommon *cc, u32 mask, u32 value)
 {
+	unsigned long flags;
+	u32 res = 0;
+
 	if (cc->dev->id.revision < 20)
 		return 0xffffffff;
 
-	return chipco_write32_masked(cc, SSB_CHIPCO_GPIOPULLUP, mask, value);
+	spin_lock_irqsave(&cc->gpio_lock, flags);
+	res = chipco_write32_masked(cc, SSB_CHIPCO_GPIOPULLUP, mask, value);
+	spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+	return res;
 }
 
 u32 ssb_chipco_gpio_pulldown(struct ssb_chipcommon *cc, u32 mask, u32 value)
 {
+	unsigned long flags;
+	u32 res = 0;
+
 	if (cc->dev->id.revision < 20)
 		return 0xffffffff;
 
-	return chipco_write32_masked(cc, SSB_CHIPCO_GPIOPULLDOWN, mask, value);
+	spin_lock_irqsave(&cc->gpio_lock, flags);
+	res = chipco_write32_masked(cc, SSB_CHIPCO_GPIOPULLDOWN, mask, value);
+	spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+	return res;
 }
 
 #ifdef CONFIG_SSB_SERIAL

drivers/ssb/driver_extif.c

···
 	extif_write32(extif, SSB_EXTIF_WATCHDOG, ticks);
 }
 
+void ssb_extif_init(struct ssb_extif *extif)
+{
+	if (!extif->dev)
+		return; /* We don't have a Extif core */
+	spin_lock_init(&extif->gpio_lock);
+}
+
 u32 ssb_extif_gpio_in(struct ssb_extif *extif, u32 mask)
 {
 	return extif_read32(extif, SSB_EXTIF_GPIO_IN) & mask;
···
 
 u32 ssb_extif_gpio_out(struct ssb_extif *extif, u32 mask, u32 value)
 {
-	return extif_write32_masked(extif, SSB_EXTIF_GPIO_OUT(0),
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&extif->gpio_lock, flags);
+	res = extif_write32_masked(extif, SSB_EXTIF_GPIO_OUT(0),
 				   mask, value);
+	spin_unlock_irqrestore(&extif->gpio_lock, flags);
+
+	return res;
 }
 
 u32 ssb_extif_gpio_outen(struct ssb_extif *extif, u32 mask, u32 value)
 {
-	return extif_write32_masked(extif, SSB_EXTIF_GPIO_OUTEN(0),
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&extif->gpio_lock, flags);
+	res = extif_write32_masked(extif, SSB_EXTIF_GPIO_OUTEN(0),
 				   mask, value);
+	spin_unlock_irqrestore(&extif->gpio_lock, flags);
+
+	return res;
 }
 
 u32 ssb_extif_gpio_polarity(struct ssb_extif *extif, u32 mask, u32 value)
 {
-	return extif_write32_masked(extif, SSB_EXTIF_GPIO_INTPOL, mask, value);
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&extif->gpio_lock, flags);
+	res = extif_write32_masked(extif, SSB_EXTIF_GPIO_INTPOL, mask, value);
+	spin_unlock_irqrestore(&extif->gpio_lock, flags);
+
+	return res;
 }
 
 u32 ssb_extif_gpio_intmask(struct ssb_extif *extif, u32 mask, u32 value)
 {
-	return extif_write32_masked(extif, SSB_EXTIF_GPIO_INTMASK, mask, value);
+	unsigned long flags;
+	u32 res = 0;
+
+	spin_lock_irqsave(&extif->gpio_lock, flags);
+	res = extif_write32_masked(extif, SSB_EXTIF_GPIO_INTMASK, mask, value);
+	spin_unlock_irqrestore(&extif->gpio_lock, flags);
+
+	return res;
 }

drivers/ssb/main.c

···
 	if (err)
 		goto err_pcmcia_exit;
 	ssb_chipcommon_init(&bus->chipco);
+	ssb_extif_init(&bus->extif);
 	ssb_mipscore_init(&bus->mipscore);
 	err = ssb_fetch_invariants(bus, get_invariants);
 	if (err) {

drivers/ssb/ssb_private.h

···
 extern u32 ssb_pmu_get_cpu_clock(struct ssb_chipcommon *cc);
 extern u32 ssb_pmu_get_controlclock(struct ssb_chipcommon *cc);
 
+#ifdef CONFIG_SSB_DRIVER_EXTIF
+extern void ssb_extif_init(struct ssb_extif *extif);
+#else
+static inline void ssb_extif_init(struct ssb_extif *extif)
+{
+}
+#endif
+
 #endif /* LINUX_SSB_PRIVATE_H_ */

include/linux/ssb/ssb_driver_chipcommon.h

···
 	u32 status;
 	/* Fast Powerup Delay constant */
 	u16 fast_pwrup_delay;
+	spinlock_t gpio_lock;
 	struct ssb_chipcommon_pmu pmu;
 };
 

include/linux/ssb/ssb_driver_extif.h

···
 
 struct ssb_extif {
 	struct ssb_device *dev;
+	spinlock_t gpio_lock;
 };
 
 static inline bool ssb_extif_available(struct ssb_extif *extif)