Thread (1 message) 1 message, 1 author, 2010-06-18

Re: [PATCH] socketcan: add a driver for FlexCAN controllers.

From: Wolfgang Grandegger <hidden>
Date: 2010-06-18 11:53:03
Subsystem: can network drivers, the rest · Maintainers: Marc Kleine-Budde, Vincent Mailhol, Linus Torvalds

Possibly related (same subject, not in this thread)

On 06/18/2010 01:21 PM, Marc Kleine-Budde wrote:
Wolfgang Grandegger wrote:
quoted
On 06/18/2010 12:44 PM, Marc Kleine-Budde wrote:
quoted
Wolfgang Grandegger wrote:
quoted
On 06/18/2010 12:16 PM, Marc Kleine-Budde wrote:
quoted
Wolfgang Grandegger wrote:
quoted
Hi Hans-Jürgen,

On 06/17/2010 12:52 PM, Hans J. Koch wrote:
quoted
This adds a driver for FlexCAN based CAN controllers,
e.g. found in Freescale i.MX35 SoCs.

The original version of this driver was posted by Sascha Hauer in July 2009:
http://kerneltrap.org/mailarchive/linux-netdev/2009/7/29/6251621

I took this version, added NAPI support, and fixed some problems found
during testing. Well, here is the result. Please review.
I briefly browsed the patch and various bits and pieces are missing or
not correctly implemented. Marc already pointed out a few of them:

- I do not find can_put/get_echo_skb functions in the code. How is
  IFF_ECHO supposed to work?
the driver uses hardware loopback
OK, then

  dev = alloc_candev(sizeof(struct flexcan_priv), 0);

should be used (and TX_ECHO_SKB_MAX removed) in Hans-Jürgens driver.
quoted
quoted
- Support for CAN_CTRLMODE_BERR_REPORTING and do_get_berr_counter()
  seems to be missing.

- Make use of alloc_can_skb() and alloc_can_err_skb().
the last two points are already addressed in my version of the driver.
I do not see support for CAN_CTRLMODE_BERR_REPORTING in your driver
(which has nothing to do with do_get_berr_counter).
oh yes...sorry, got confused.

However I implemented CAN_CTRLMODE_BERR_REPORTING, i.e. turning of the
bit error interrupts by default. This has the effect that no bus warning
and bus passive interrupt was signalled.

I should add a comment to my driver.
I'm confused, CAN_CTRLMODE_BERR_REPORTING means that the user can enable
bus error reporting, which seems not be handled in the driver your sent.
See:

http://lxr.linux.no/linux/drivers/net/can/sja1000/sja1000.c#L134
http://lxr.linux.no/linux/drivers/net/can/sja1000/sja1000.c#L588
Which interrupts does "IRQ_BEI" include? What should
CAN_CTRLMODE_BERR_REPORTING do?

Looking at:
http://lxr.linux.no/linux+v2.6.34/drivers/net/can/sja1000/sja1000.c#L393
it seems that BEI on the SJA just effects bit, form and stuff errors.
Yes, it effects *bus errors*... actually the one you handle in
at91_poll_err_frame(). Especially the AT91_IRQ_AERR does cause the
infamous interrupt flooding (which is, btw, not treated correctly as
bus error in your driver).
If I disable the corresponding interrupt in the flexcan. This is
ERR_MSK, (1 << 14 in CTRL), I don't get error warning or error passive
interrupts either. I'm not sure about the bus off interrupt.
Hm, my understanding is that you can disable those bus error
interrupts individually via AT91_IRQ_ERR_FRAME.
From my point of view this is not that what CAN_CTRLMODE_BERR_REPORTING
should do, is it?
It should *not* disable state change interrupts, of course. I have
started to fix some issues in the at91 driver some time ago, which 
I have attached below.

Wolfgang.

---
diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index a2f29a3..ad36b59 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -164,6 +164,7 @@ struct at91_priv {
 	void __iomem		*reg_base;
 
 	u32			reg_sr;
+	u32			reg_ie_napi;
 	unsigned int		tx_next;
 	unsigned int		tx_echo;
 	unsigned int		rx_next;
@@ -273,7 +274,7 @@ static int at91_set_bittiming(struct net_device *dev)
 static void at91_chip_start(struct net_device *dev)
 {
 	struct at91_priv *priv = netdev_priv(dev);
-	u32 reg_mr, reg_ier;
+	u32 reg_mr;
 
 	/* disable interrupts */
 	at91_write(priv, AT91_IDR, AT91_IRQ_ALL);
@@ -290,10 +291,12 @@ static void at91_chip_start(struct net_device *dev)
 
 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
 
-	/* Enable interrupts */
-	reg_ier = AT91_IRQ_MB_RX | AT91_IRQ_ERRP | AT91_IRQ_ERR_FRAME;
+	/* enable interrupts */
+	priv->reg_ir_napi = AT91_IRQ_MB_RX;
+	if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
+		priv->reg_ir_napi |= AT91_IRQ_ERR_FRAME;
 	at91_write(priv, AT91_IDR, AT91_IRQ_ALL);
-	at91_write(priv, AT91_IER, reg_ier);
+	at91_write(priv, AT91_IER, priv->reg_ir_napi | AT91_IRQ_ERRP);
 }
 
 static void at91_chip_stop(struct net_device *dev, enum can_state state)
@@ -604,20 +607,21 @@ static void at91_poll_err_frame(struct net_device *dev,
 {
 	struct at91_priv *priv = netdev_priv(dev);
 
+	priv->can.can_stats.bus_error++;
+	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
 	/* CRC error */
 	if (reg_sr & AT91_IRQ_CERR) {
 		dev_dbg(dev->dev.parent, "CERR irq\n");
 		dev->stats.rx_errors++;
-		priv->can.can_stats.bus_error++;
-		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+		cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ |
+			CAN_ERR_PROT_LOC_CRC_DEL;
 	}
 
 	/* Stuffing Error */
 	if (reg_sr & AT91_IRQ_SERR) {
 		dev_dbg(dev->dev.parent, "SERR irq\n");
 		dev->stats.rx_errors++;
-		priv->can.can_stats.bus_error++;
-		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 		cf->data[2] |= CAN_ERR_PROT_STUFF;
 	}
 
@@ -626,14 +630,13 @@ static void at91_poll_err_frame(struct net_device *dev,
 		dev_dbg(dev->dev.parent, "AERR irq\n");
 		dev->stats.tx_errors++;
 		cf->can_id |= CAN_ERR_ACK;
+		cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
 	}
 
 	/* Form error */
 	if (reg_sr & AT91_IRQ_FERR) {
 		dev_dbg(dev->dev.parent, "FERR irq\n");
 		dev->stats.rx_errors++;
-		priv->can.can_stats.bus_error++;
-		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 		cf->data[2] |= CAN_ERR_PROT_FORM;
 	}
 
@@ -641,9 +644,7 @@ static void at91_poll_err_frame(struct net_device *dev,
 	if (reg_sr & AT91_IRQ_BERR) {
 		dev_dbg(dev->dev.parent, "BERR irq\n");
 		dev->stats.tx_errors++;
-		priv->can.can_stats.bus_error++;
-		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
-		cf->data[2] |= CAN_ERR_PROT_BIT;
+		cf->data[2] |= CAN_ERR_PROT_BIT0 | CAN_ERR_PROT_BIT1;
 	}
 }
 
@@ -662,7 +663,6 @@ static int at91_poll_err(struct net_device *dev, int quota, u32 reg_sr)
 	at91_poll_err_frame(dev, cf, reg_sr);
 	netif_receive_skb(skb);
 
-	dev->last_rx = jiffies;
 	dev->stats.rx_packets++;
 	dev->stats.rx_bytes += cf->can_dlc;
 
@@ -688,12 +688,10 @@ static int at91_poll(struct napi_struct *napi, int quota)
 		work_done += at91_poll_err(dev, quota - work_done, reg_sr);
 
 	if (work_done < quota) {
-		/* enable IRQs for frame errors and all mailboxes >= rx_next */
-		u32 reg_ier = AT91_IRQ_ERR_FRAME;
-		reg_ier |= AT91_IRQ_MB_RX & ~AT91_MB_RX_MASK(priv->rx_next);
-
 		napi_complete(napi);
-		at91_write(priv, AT91_IER, reg_ier);
+		/* enable IRQs for frame errors and all mailboxes >= rx_next */
+		at91_write(priv, AT91_IER, priv->reg_ir_napi &
+			   ~AT91_MB_RX_MASK(priv->rx_next));
 	}
 
 	return work_done;
@@ -899,7 +897,6 @@ static void at91_irq_err(struct net_device *dev)
 	at91_irq_err_state(dev, cf, new_state);
 	netif_rx(skb);
 
-	dev->last_rx = jiffies;
 	dev->stats.rx_packets++;
 	dev->stats.rx_bytes += cf->can_dlc;
 
@@ -933,8 +930,7 @@ static irqreturn_t at91_irq(int irq, void *dev_id)
 		 * save for later use.
 		 */
 		priv->reg_sr = reg_sr;
-		at91_write(priv, AT91_IDR,
-			   AT91_IRQ_MB_RX | AT91_IRQ_ERR_FRAME);
+		at91_write(priv, AT91_IDR, priv->reg_ir_napi);
 		napi_schedule(&priv->napi);
 	}
 
@@ -1073,7 +1069,8 @@ static int __init at91_can_probe(struct platform_device *pdev)
 	priv->can.bittiming_const = &at91_bittiming_const;
 	priv->can.do_set_bittiming = at91_set_bittiming;
 	priv->can.do_set_mode = at91_set_mode;
-	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
+	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
+ 		CAN_CTRLMODE_BERR_REPORTING;
 	priv->reg_base = addr;
 	priv->dev = dev;
 	priv->clk = clk;
diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 145b1a7..77b5fbc 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -89,8 +89,8 @@ static int sja1000_probe_chip(struct net_device *dev)
 	struct sja1000_priv *priv = netdev_priv(dev);
 
 	if (priv->reg_base && (priv->read_reg(priv, 0) == 0xFF)) {
-		printk(KERN_INFO "%s: probing @0x%lX failed\n",
-		       DRV_NAME, dev->base_addr);
+		dev_info(dev->dev.parent, "probing @0x%p failed\n",
+			 priv->reg_base);
 		return 0;
 	}
 	return -1;
@@ -254,7 +254,7 @@ static void chipset_init(struct net_device *dev)
  * [  can-id ] [flags] [len] [can data (up to 8 bytes]
  */
 static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
-					    struct net_device *dev)
+				      struct net_device *dev)
 {
 	struct sja1000_priv *priv = netdev_priv(dev);
 	struct can_frame *cf = (struct can_frame *)skb->data;
@@ -602,9 +602,9 @@ void free_sja1000dev(struct net_device *dev)
 EXPORT_SYMBOL_GPL(free_sja1000dev);
 
 static const struct net_device_ops sja1000_netdev_ops = {
-       .ndo_open               = sja1000_open,
-       .ndo_stop               = sja1000_close,
-       .ndo_start_xmit         = sja1000_start_xmit,
+	.ndo_open = sja1000_open,
+	.ndo_stop = sja1000_close,
+	.ndo_start_xmit = sja1000_start_xmit,
 };
 
 int register_sja1000dev(struct net_device *dev)
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