2 files changed, 108 insertions, 7 deletions

diff --git a/Documentation/ABI/testing/sysfs-platform-at91 b/Documentation/ABI/testing/sysfs-platform-at91
new file mode 100644
index 000000000000..4cc6a865ae66
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-at91
@@ -0,0 +1,25 @@
+What:           /sys/devices/platform/at91_can/net/<iface>/mb0_id
+Date:           January 2011
+KernelVersion:  2.6.38
+Contact:        Marc Kleine-Budde <kernel@pengutronix.de>
+Description:
+                Value representing the can_id of mailbox 0.
+
+                Default: 0x7ff (standard frame)
+
+                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 an unused identifier.
+
+                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 id 0x1fffffff:
+                echo 0x9fffffff > /sys/class/net/can0/mb0_id
diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 16e45a51cbb3..2532b9631538 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);