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Subject[PATCH 11/24] Staging: ipack/bridges/tpci200: Protect device registers with spinlock.
Date
From: Jens Taprogge <jens.taprogge@taprogge.org>

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>
---
drivers/staging/ipack/bridges/tpci200.c | 33 +++++++++++++------------------
drivers/staging/ipack/bridges/tpci200.h | 1 +
2 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/drivers/staging/ipack/bridges/tpci200.c b/drivers/staging/ipack/bridges/tpci200.c
index 9ce577a..b1ddbe3 100644
--- 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
--- 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;
};
--
1.7.10.4


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