Staging: ipack/bridges/tpci200: Protect device registers with spinlock.

Some of the device registers are accessed from both interrupt and
non-interrupt context.  To ensure proper read-modify-write modification
of these registers we can not use the  "global" tpci200 mutex.  Instead
a spin-lock is used.

Signed-off-by: Jens Taprogge <jens.taprogge@taprogge.org>
Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/ipack/bridges/tpci200.c b/drivers/staging/ipack/bridges/tpci200.c
index 9ce577a..b1ddbe3 100644 (file)
--- a/drivers/staging/ipack/bridges/tpci200.c
+++ b/drivers/staging/ipack/bridges/tpci200.c
@@ -53,30 +53,22 @@ static struct tpci200_board *check_slot(struct ipack_device *dev)
        return tpci200;
 }
 
-static void __tpci200_clear_mask(__le16 __iomem *addr, u16 mask)
-{
-       iowrite16(ioread16(addr) & (~mask), addr);
-}
-
 static void tpci200_clear_mask(struct tpci200_board *tpci200,
                               __le16 __iomem *addr, u16 mask)
 {
-       mutex_lock(&tpci200->mutex);
-       __tpci200_clear_mask(addr, mask);
-       mutex_unlock(&tpci200->mutex);
-}
-
-static void __tpci200_set_mask(__le16 __iomem *addr, u16 mask)
-{
-       iowrite16(ioread16(addr) | mask, addr);
+       unsigned long flags;
+       spin_lock_irqsave(&tpci200->regs_lock, flags);
+       iowrite16(ioread16(addr) & (~mask), addr);
+       spin_unlock_irqrestore(&tpci200->regs_lock, flags);
 }
 
 static void tpci200_set_mask(struct tpci200_board *tpci200,
                             __le16 __iomem *addr, u16 mask)
 {
-       mutex_lock(&tpci200->mutex);
-       __tpci200_set_mask(addr, mask);
-       mutex_unlock(&tpci200->mutex);
+       unsigned long flags;
+       spin_lock_irqsave(&tpci200->regs_lock, flags);
+       iowrite16(ioread16(addr) | mask, addr);
+       spin_unlock_irqrestore(&tpci200->regs_lock, flags);
 }
 
 static void tpci200_unregister(struct tpci200_board *tpci200)
@@ -143,7 +135,7 @@ static irqreturn_t tpci200_interrupt(int irq, void *dev_id)
                                dev_info(&tpci200->info->pdev->dev,
                                         "No registered ISR for slot [%d:%d]!. IRQ will be disabled.\n",
                                         tpci200->number, i);
-                               __tpci200_clear_mask(
+                               tpci200_clear_mask(tpci200,
                                        &tpci200->info->interface_regs->control[i],
                                        TPCI200_INT0_EN | TPCI200_INT1_EN);
                        }
@@ -213,6 +205,9 @@ static int tpci200_register(struct tpci200_board *tpci200)
                                           TPCI200_MEM8_SPACE_BAR),
                        TPCI200_MEM8_SIZE);
 
+       /* Initialize lock that protects interface_regs */
+       spin_lock_init(&tpci200->regs_lock);
+
        ioidint_base = pci_resource_start(tpci200->info->pdev,
                                          TPCI200_IO_ID_INT_SPACES_BAR);
        mem_base = pci_resource_start(tpci200->info->pdev,
@@ -272,7 +267,7 @@ out_disable_pci:
 static int __tpci200_request_irq(struct tpci200_board *tpci200,
                                 struct ipack_device *dev)
 {
-       __tpci200_set_mask(
+       tpci200_set_mask(tpci200,
                        &tpci200->info->interface_regs->control[dev->slot],
                        TPCI200_INT0_EN | TPCI200_INT1_EN);
        return 0;
@@ -281,7 +276,7 @@ static int __tpci200_request_irq(struct tpci200_board *tpci200,
 static void __tpci200_free_irq(struct tpci200_board *tpci200,
                               struct ipack_device *dev)
 {
-       __tpci200_clear_mask(
+       tpci200_clear_mask(tpci200,
                        &tpci200->info->interface_regs->control[dev->slot],
                        TPCI200_INT0_EN | TPCI200_INT1_EN);
 }

diff --git a/drivers/staging/ipack/bridges/tpci200.h b/drivers/staging/ipack/bridges/tpci200.h
index 75a5dcc..b8e9826 100644 (file)
--- a/drivers/staging/ipack/bridges/tpci200.h
+++ b/drivers/staging/ipack/bridges/tpci200.h
@@ -163,6 +163,7 @@ struct tpci200_infos {
 struct tpci200_board {
        unsigned int            number;
        struct mutex            mutex;
+       spinlock_t              regs_lock;
        struct tpci200_slot     *slots;
        struct tpci200_infos    *info;
 };