diff options
author | AnilKumar Ch <anilkumar@ti.com> | 2012-05-23 08:15:10 -0400 |
---|---|---|
committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2012-06-03 12:59:19 -0400 |
commit | 148c87c89e1a8863d3d965179f3ab1a06490569e (patch) | |
tree | df4bb7144955153698b0515fd84230da2178ace2 /drivers/net | |
parent | 617caccebe451716df21c069b079d5936ed7b0f3 (diff) |
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')
-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 9ac28df3c89..fa016214c52 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) | |||
952 | struct net_device *dev = napi->dev; | 952 | struct net_device *dev = napi->dev; |
953 | struct c_can_priv *priv = netdev_priv(dev); | 953 | struct c_can_priv *priv = netdev_priv(dev); |
954 | 954 | ||
955 | irqstatus = priv->read_reg(priv, &priv->regs->interrupt); | 955 | irqstatus = priv->irqstatus; |
956 | if (!irqstatus) | 956 | if (!irqstatus) |
957 | goto end; | 957 | goto end; |
958 | 958 | ||
@@ -1030,12 +1030,11 @@ end: | |||
1030 | 1030 | ||
1031 | static irqreturn_t c_can_isr(int irq, void *dev_id) | 1031 | static irqreturn_t c_can_isr(int irq, void *dev_id) |
1032 | { | 1032 | { |
1033 | u16 irqstatus; | ||
1034 | struct net_device *dev = (struct net_device *)dev_id; | 1033 | struct net_device *dev = (struct net_device *)dev_id; |
1035 | struct c_can_priv *priv = netdev_priv(dev); | 1034 | struct c_can_priv *priv = netdev_priv(dev); |
1036 | 1035 | ||
1037 | irqstatus = priv->read_reg(priv, &priv->regs->interrupt); | 1036 | priv->irqstatus = priv->read_reg(priv, &priv->regs->interrupt); |
1038 | if (!irqstatus) | 1037 | if (!priv->irqstatus) |
1039 | return IRQ_NONE; | 1038 | return IRQ_NONE; |
1040 | 1039 | ||
1041 | /* disable all interrupts and schedule the NAPI */ | 1040 | /* 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 9b7fbef3d09..5f32d34af50 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 { | |||
76 | unsigned int tx_next; | 76 | unsigned int tx_next; |
77 | unsigned int tx_echo; | 77 | unsigned int tx_echo; |
78 | void *priv; /* for board-specific data */ | 78 | void *priv; /* for board-specific data */ |
79 | u16 irqstatus; | ||
79 | }; | 80 | }; |
80 | 81 | ||
81 | struct net_device *alloc_c_can_dev(void); | 82 | struct net_device *alloc_c_can_dev(void); |