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| author | AnilKumar Ch <anilkumar@ti.com> | 2012-05-23 17:45:10 +0530 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2012-06-03 18:59:19 +0200 |
| commit | 148c87c89e1a8863d3d965179f3ab1a06490569e (patch) | |
| tree | df4bb7144955153698b0515fd84230da2178ace2 /drivers/net/can | |
| parent | 617caccebe451716df21c069b079d5936ed7b0f3 (diff) | |
| download | linux-stable-148c87c89e1a8863d3d965179f3ab1a06490569e.tar.gz linux-stable-148c87c89e1a8863d3d965179f3ab1a06490569e.tar.bz2 linux-stable-148c87c89e1a8863d3d965179f3ab1a06490569e.zip | |
can: c_can: fix an interrupt thrash issue with c_can driver
This patch fixes an interrupt thrash issue with c_can driver.
In c_can_isr() function interrupts are disabled and enabled only in
c_can_poll() function. c_can_isr() & c_can_poll() both read the
irqstatus flag. However, irqstatus is always read as 0 in c_can_poll()
because all C_CAN interrupts are disabled in c_can_isr(). This causes
all interrupts to be re-enabled in c_can_poll() which in turn causes
another interrupt since the event is not really handled. This keeps
happening causing a flood of interrupts.
To fix this, read the irqstatus register in isr and use the same cached
value in the poll function.
Cc: stable@kernel.org # 2.6.39+
Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'drivers/net/can')
| -rw-r--r-- | drivers/net/can/c_can/c_can.c | 7 | ||||
| -rw-r--r-- | drivers/net/can/c_can/c_can.h | 1 |
2 files changed, 4 insertions, 4 deletions
diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 9ac28df3c896..fa016214c52f 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -952,7 +952,7 @@ static int c_can_poll(struct napi_struct *napi, int quota) struct net_device *dev = napi->dev; struct c_can_priv *priv = netdev_priv(dev); - irqstatus = priv->read_reg(priv, &priv->regs->interrupt); + irqstatus = priv->irqstatus; if (!irqstatus) goto end; @@ -1030,12 +1030,11 @@ end: static irqreturn_t c_can_isr(int irq, void *dev_id) { - u16 irqstatus; struct net_device *dev = (struct net_device *)dev_id; struct c_can_priv *priv = netdev_priv(dev); - irqstatus = priv->read_reg(priv, &priv->regs->interrupt); - if (!irqstatus) + priv->irqstatus = priv->read_reg(priv, &priv->regs->interrupt); + if (!priv->irqstatus) return IRQ_NONE; /* disable all interrupts and schedule the NAPI */ diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h index 9b7fbef3d09a..5f32d34af507 100644 --- a/drivers/net/can/c_can/c_can.h +++ b/drivers/net/can/c_can/c_can.h @@ -76,6 +76,7 @@ struct c_can_priv { unsigned int tx_next; unsigned int tx_echo; void *priv; /* for board-specific data */ + u16 irqstatus; }; struct net_device *alloc_c_can_dev(void); |