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Date: Tue, 11 Jan 2011 11:28:08 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Socketcan-core@...ts.berlios.de
Cc: netdev@...r.kernel.org, Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH 3/3] can: at91_can: make can_id of mailbox 0 configurable
Due to a chip bug (errata 50.2.6.3 & 50.3.5.3 in
"AT91SAM9263 Preliminary 6249H-ATARM-27-Jul-09") the contents of mailbox
0 may be send under certain conditions (even if disabled or in rx mode).
The workaround in the errata suggests not to use the mailbox and load it
with a unused identifier.
This patch implements the second part of the workaround. A sysfs entry
"mb0_id" is introduced. While the interface is down it can be used to
configure the can_id of mailbox 0. The default value id 0x7ff.
In order to use an extended can_id add the CAN_EFF_FLAG (0x80000000U)
to the can_id. Example:
- standard id 0x7ff:
echo 0x7ff > /sys/class/net/can0/mb0_id
- extended if 0x1fffffff:
echo 0x9fffffff > /sys/class/net/can0/mb0_id
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
drivers/net/can/at91_can.c | 90 ++++++++++++++++++++++++++++++++++++++++---
1 files changed, 83 insertions(+), 7 deletions(-)
diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 16e45a5..2532b96 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -30,6 +30,7 @@
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>
+#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/string.h>
@@ -169,6 +170,8 @@ struct at91_priv {
struct clk *clk;
struct at91_can_data *pdata;
+
+ canid_t mb0_id;
};
static struct can_bittiming_const at91_bittiming_const = {
@@ -221,6 +224,18 @@ static inline void set_mb_mode(const struct at91_priv *priv, unsigned int mb,
set_mb_mode_prio(priv, mb, mode, 0);
}
+static inline u32 at91_can_id_to_reg_mid(canid_t can_id)
+{
+ u32 reg_mid;
+
+ if (can_id & CAN_EFF_FLAG)
+ reg_mid = (can_id & CAN_EFF_MASK) | AT91_MID_MIDE;
+ else
+ reg_mid = (can_id & CAN_SFF_MASK) << 18;
+
+ return reg_mid;
+}
+
/*
* Swtich transceiver on or off
*/
@@ -234,6 +249,7 @@ static void at91_setup_mailboxes(struct net_device *dev)
{
struct at91_priv *priv = netdev_priv(dev);
unsigned int i;
+ u32 reg_mid;
/*
* Due to a chip bug (errata 50.2.6.3 & 50.3.5.3) the first
@@ -242,8 +258,13 @@ static void at91_setup_mailboxes(struct net_device *dev)
* overwrite option. The overwrite flag indicates a FIFO
* overflow.
*/
- for (i = 0; i < AT91_MB_RX_FIRST; i++)
+ reg_mid = at91_can_id_to_reg_mid(priv->mb0_id);
+ for (i = 0; i < AT91_MB_RX_FIRST; i++) {
set_mb_mode(priv, i, AT91_MB_MODE_DISABLED);
+ at91_write(priv, AT91_MID(i), reg_mid);
+ at91_write(priv, AT91_MCR(i), 0x0); /* clear dlc */
+ }
+
for (i = AT91_MB_RX_FIRST; i < AT91_MB_RX_LAST; i++)
set_mb_mode(priv, i, AT91_MB_MODE_RX);
set_mb_mode(priv, AT91_MB_RX_LAST, AT91_MB_MODE_RX_OVRWR);
@@ -378,12 +399,7 @@ static netdev_tx_t at91_start_xmit(struct sk_buff *skb, struct net_device *dev)
netdev_err(dev, "BUG! TX buffer full when queue awake!\n");
return NETDEV_TX_BUSY;
}
-
- if (cf->can_id & CAN_EFF_FLAG)
- reg_mid = (cf->can_id & CAN_EFF_MASK) | AT91_MID_MIDE;
- else
- reg_mid = (cf->can_id & CAN_SFF_MASK) << 18;
-
+ reg_mid = at91_can_id_to_reg_mid(cf->can_id);
reg_mcr = ((cf->can_id & CAN_RTR_FLAG) ? AT91_MCR_MRTR : 0) |
(cf->can_dlc << 16) | AT91_MCR_MTCR;
@@ -1047,6 +1063,64 @@ static const struct net_device_ops at91_netdev_ops = {
.ndo_start_xmit = at91_start_xmit,
};
+static ssize_t at91_sysfs_show_mb0_id(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct at91_priv *priv = netdev_priv(to_net_dev(dev));
+
+ if (priv->mb0_id & CAN_EFF_FLAG)
+ return snprintf(buf, PAGE_SIZE, "0x%08x\n", priv->mb0_id);
+ else
+ return snprintf(buf, PAGE_SIZE, "0x%03x\n", priv->mb0_id);
+}
+
+static ssize_t at91_sysfs_set_mb0_id(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct net_device *ndev = to_net_dev(dev);
+ struct at91_priv *priv = netdev_priv(ndev);
+ unsigned long can_id;
+ ssize_t ret;
+ int err;
+
+ rtnl_lock();
+
+ if (ndev->flags & IFF_UP) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ err = strict_strtoul(buf, 0, &can_id);
+ if (err) {
+ ret = err;
+ goto out;
+ }
+
+ if (can_id & CAN_EFF_FLAG)
+ can_id &= CAN_EFF_MASK | CAN_EFF_FLAG;
+ else
+ can_id &= CAN_SFF_MASK;
+
+ priv->mb0_id = can_id;
+ ret = count;
+
+ out:
+ rtnl_unlock();
+ return ret;
+}
+
+static DEVICE_ATTR(mb0_id, S_IWUGO | S_IRUGO,
+ at91_sysfs_show_mb0_id, at91_sysfs_set_mb0_id);
+
+static struct attribute *at91_sysfs_attrs[] = {
+ &dev_attr_mb0_id.attr,
+ NULL,
+};
+
+static struct attribute_group at91_sysfs_attr_group = {
+ .attrs = at91_sysfs_attrs,
+};
+
static int __devinit at91_can_probe(struct platform_device *pdev)
{
struct net_device *dev;
@@ -1092,6 +1166,7 @@ static int __devinit at91_can_probe(struct platform_device *pdev)
dev->netdev_ops = &at91_netdev_ops;
dev->irq = irq;
dev->flags |= IFF_ECHO;
+ dev->sysfs_groups[0] = &at91_sysfs_attr_group;
priv = netdev_priv(dev);
priv->can.clock.freq = clk_get_rate(clk);
@@ -1103,6 +1178,7 @@ static int __devinit at91_can_probe(struct platform_device *pdev)
priv->dev = dev;
priv->clk = clk;
priv->pdata = pdev->dev.platform_data;
+ priv->mb0_id = 0x7ff;
netif_napi_add(dev, &priv->napi, at91_poll, AT91_NAPI_WEIGHT);
--
1.7.2.3
--
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