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[PATCH 1/8] bcma: add locking around GPIO register accesses

To: john@phrozen.org, ralf@linux-mips.org
Subject: [PATCH 1/8] bcma: add locking around GPIO register accesses
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Mon, 19 Nov 2012 23:57:50 +0100
Cc: linux-mips@linux-mips.org, linux-wireless@vger.kernel.org, florian@openwrt.org, zajec5@gmail.com, m@bues.ch, Hauke Mehrtens <hauke@hauke-m.de>
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The GPIOs are access through some registers in the chip common core.
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 <hauke@hauke-m.de>
---
 drivers/bcma/driver_chipcommon.c            |   56 ++++++++++++++++++++++++---
 include/linux/bcma/bcma_driver_chipcommon.h |    3 ++
 2 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/drivers/bcma/driver_chipcommon.c b/drivers/bcma/driver_chipcommon.c
index a4c3ebc..9b34316 100644
--- a/drivers/bcma/driver_chipcommon.c
+++ b/drivers/bcma/driver_chipcommon.c
@@ -30,6 +30,8 @@ void bcma_core_chipcommon_init(struct bcma_drv_cc *cc)
        if (cc->setup_done)
                return;
 
+       spin_lock_init(&cc->gpio_lock);
+
        if (cc->core->id.rev >= 11)
                cc->status = bcma_cc_read32(cc, BCMA_CC_CHIPSTAT);
        cc->capabilities = bcma_cc_read32(cc, BCMA_CC_CAP);
@@ -79,33 +81,75 @@ u32 bcma_chipco_irq_status(struct bcma_drv_cc *cc, u32 mask)
 
 u32 bcma_chipco_gpio_in(struct bcma_drv_cc *cc, u32 mask)
 {
-       return bcma_cc_read32(cc, BCMA_CC_GPIOIN) & mask;
+       unsigned long flags;
+       u32 res;
+
+       spin_lock_irqsave(&cc->gpio_lock, flags);
+       res = bcma_cc_read32(cc, BCMA_CC_GPIOIN) & mask;
+       spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+       return res;
 }
 
 u32 bcma_chipco_gpio_out(struct bcma_drv_cc *cc, u32 mask, u32 value)
 {
-       return bcma_cc_write32_masked(cc, BCMA_CC_GPIOOUT, mask, value);
+       unsigned long flags;
+       u32 res;
+
+       spin_lock_irqsave(&cc->gpio_lock, flags);
+       res = bcma_cc_write32_masked(cc, BCMA_CC_GPIOOUT, mask, value);
+       spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+       return res;
 }
 
 u32 bcma_chipco_gpio_outen(struct bcma_drv_cc *cc, u32 mask, u32 value)
 {
-       return bcma_cc_write32_masked(cc, BCMA_CC_GPIOOUTEN, mask, value);
+       unsigned long flags;
+       u32 res;
+
+       spin_lock_irqsave(&cc->gpio_lock, flags);
+       res = bcma_cc_write32_masked(cc, BCMA_CC_GPIOOUTEN, mask, value);
+       spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+       return res;
 }
 
 u32 bcma_chipco_gpio_control(struct bcma_drv_cc *cc, u32 mask, u32 value)
 {
-       return bcma_cc_write32_masked(cc, BCMA_CC_GPIOCTL, mask, value);
+       unsigned long flags;
+       u32 res;
+
+       spin_lock_irqsave(&cc->gpio_lock, flags);
+       res = bcma_cc_write32_masked(cc, BCMA_CC_GPIOCTL, mask, value);
+       spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+       return res;
 }
 EXPORT_SYMBOL_GPL(bcma_chipco_gpio_control);
 
 u32 bcma_chipco_gpio_intmask(struct bcma_drv_cc *cc, u32 mask, u32 value)
 {
-       return bcma_cc_write32_masked(cc, BCMA_CC_GPIOIRQ, mask, value);
+       unsigned long flags;
+       u32 res;
+
+       spin_lock_irqsave(&cc->gpio_lock, flags);
+       res = bcma_cc_write32_masked(cc, BCMA_CC_GPIOIRQ, mask, value);
+       spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+       return res;
 }
 
 u32 bcma_chipco_gpio_polarity(struct bcma_drv_cc *cc, u32 mask, u32 value)
 {
-       return bcma_cc_write32_masked(cc, BCMA_CC_GPIOPOL, mask, value);
+       unsigned long flags;
+       u32 res;
+
+       spin_lock_irqsave(&cc->gpio_lock, flags);
+       res = bcma_cc_write32_masked(cc, BCMA_CC_GPIOPOL, mask, value);
+       spin_unlock_irqrestore(&cc->gpio_lock, flags);
+
+       return res;
 }
 
 #ifdef CONFIG_BCMA_DRIVER_MIPS
diff --git a/include/linux/bcma/bcma_driver_chipcommon.h 
b/include/linux/bcma/bcma_driver_chipcommon.h
index 1cf1749..a085d98 100644
--- a/include/linux/bcma/bcma_driver_chipcommon.h
+++ b/include/linux/bcma/bcma_driver_chipcommon.h
@@ -567,6 +567,9 @@ struct bcma_drv_cc {
        int nr_serial_ports;
        struct bcma_serial_port serial_ports[4];
 #endif /* CONFIG_BCMA_DRIVER_MIPS */
+
+       /* Lock for GPIO register access. */
+       spinlock_t gpio_lock;
 };
 
 /* Register access */
-- 
1.7.10.4


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