From 617caccebe451716df21c069b079d5936ed7b0f3 Mon Sep 17 00:00:00 2001 From: AnilKumar Ch Date: Wed, 23 May 2012 17:45:09 +0530 Subject: can: c_can: fix "BUG! echo_skb is occupied!" during transmit This patch fixes an issue with transmit routine, which causes "can_put_echo_skb: BUG! echo_skb is occupied!" message when using "cansequence -p" on D_CAN controller. In c_can driver, while transmitting packets tx_echo flag holds the no of can frames put for transmission into the hardware. As the comment above c_can_do_tx() indicates, if we find any packet which is not transmitted then we should stop looking for more. In the current implementation this is not taken care of causing the said message. Also, fix the condition used to find if the packet is transmitted or not. Current code skips the first tx message object and ends up checking one extra invalid object. While at it, fix the comment on top of c_can_do_tx() to use the terminology "packet" instead of "package" since it is more standard. Cc: stable@kernel.org # 2.6.39+ Signed-off-by: AnilKumar Ch Acked-by: Wolfgang Grandegger Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 536bda072a1..9ac28df3c89 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -686,7 +686,7 @@ static int c_can_get_berr_counter(const struct net_device *dev, * * We iterate from priv->tx_echo to priv->tx_next and check if the * packet has been transmitted, echo it back to the CAN framework. - * If we discover a not yet transmitted package, stop looking for more. + * If we discover a not yet transmitted packet, stop looking for more. */ static void c_can_do_tx(struct net_device *dev) { @@ -698,7 +698,7 @@ static void c_can_do_tx(struct net_device *dev) for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) { msg_obj_no = get_tx_echo_msg_obj(priv); val = c_can_read_reg32(priv, &priv->regs->txrqst1); - if (!(val & (1 << msg_obj_no))) { + if (!(val & (1 << (msg_obj_no - 1)))) { can_get_echo_skb(dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); stats->tx_bytes += priv->read_reg(priv, @@ -706,6 +706,8 @@ static void c_can_do_tx(struct net_device *dev) & IF_MCONT_DLC_MASK; stats->tx_packets++; c_can_inval_msg_object(dev, 0, msg_obj_no); + } else { + break; } } -- cgit v1.2.3-70-g09d2 From 148c87c89e1a8863d3d965179f3ab1a06490569e Mon Sep 17 00:00:00 2001 From: AnilKumar Ch Date: Wed, 23 May 2012 17:45:10 +0530 Subject: 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 Acked-by: Wolfgang Grandegger Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 7 +++---- 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) 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 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 { unsigned int tx_next; unsigned int tx_echo; void *priv; /* for board-specific data */ + u16 irqstatus; }; struct net_device *alloc_c_can_dev(void); -- cgit v1.2.3-70-g09d2 From f461f27a4436dbe691908fe08b867ef888848cc3 Mon Sep 17 00:00:00 2001 From: AnilKumar Ch Date: Wed, 23 May 2012 17:45:11 +0530 Subject: can: c_can: fix race condition in c_can_open() Fix the issue of C_CAN interrupts getting disabled forever when canconfig utility is used multiple times. According to NAPI usage we disable all the hardware interrupts in ISR and re-enable them in poll(). Current implementation calls napi_enable() after hardware interrupts are enabled. If we get any interrupts between these two steps then we do not process those interrupts because napi is not enabled. Mostly these interrupts come because of STATUS is not 0x7 or ERROR interrupts. If napi_enable() happens before HW interrupts enabled then c_can_poll() function will be called eventual re-enabling. This patch moves the napi_enable() call before interrupts enabled. Cc: stable@kernel.org # 2.6.39+ Signed-off-by: AnilKumar Ch Acked-by: Wolfgang Grandegger Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index fa016214c52..8dc84d66eea 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -1064,10 +1064,11 @@ static int c_can_open(struct net_device *dev) goto exit_irq_fail; } + napi_enable(&priv->napi); + /* start the c_can controller */ c_can_start(dev); - napi_enable(&priv->napi); netif_start_queue(dev); return 0; -- cgit v1.2.3-70-g09d2 From dc605dbdb8dd152448ccb8d4c4d5bd9439965a20 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Wed, 30 May 2012 13:25:55 -0700 Subject: can: cc770: Fix likely misuse of | for & Using | with a constant is always true. Likely this should have be &. Signed-off-by: Joe Perches Signed-off-by: Marc Kleine-Budde --- drivers/net/can/cc770/cc770_platform.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/can/cc770/cc770_platform.c b/drivers/net/can/cc770/cc770_platform.c index 53115eee807..688371cda37 100644 --- a/drivers/net/can/cc770/cc770_platform.c +++ b/drivers/net/can/cc770/cc770_platform.c @@ -154,7 +154,7 @@ static int __devinit cc770_get_platform_data(struct platform_device *pdev, struct cc770_platform_data *pdata = pdev->dev.platform_data; priv->can.clock.freq = pdata->osc_freq; - if (priv->cpu_interface | CPUIF_DSC) + if (priv->cpu_interface & CPUIF_DSC) priv->can.clock.freq /= 2; priv->clkout = pdata->cor; priv->bus_config = pdata->bcr; -- cgit v1.2.3-70-g09d2