diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-platform-at91 | 25 | ||||
| -rw-r--r-- | drivers/net/can/at91_can.c | 138 |
2 files changed, 137 insertions, 26 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 7ef83d06f7ed..2532b9631538 100644 --- a/drivers/net/can/at91_can.c +++ b/drivers/net/can/at91_can.c @@ -2,7 +2,7 @@ * at91_can.c - CAN network driver for AT91 SoC CAN controller * * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de> - * (C) 2008, 2009, 2010 by Marc Kleine-Budde <kernel@pengutronix.de> + * (C) 2008, 2009, 2010, 2011 by Marc Kleine-Budde <kernel@pengutronix.de> * * This software may be distributed under the terms of the GNU General * Public License ("GPL") version 2 as distributed in the 'COPYING' @@ -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> @@ -40,22 +41,23 @@ #include <mach/board.h> -#define AT91_NAPI_WEIGHT 12 +#define AT91_NAPI_WEIGHT 11 /* * RX/TX Mailbox split * don't dare to touch */ -#define AT91_MB_RX_NUM 12 +#define AT91_MB_RX_NUM 11 #define AT91_MB_TX_SHIFT 2 -#define AT91_MB_RX_FIRST 0 +#define AT91_MB_RX_FIRST 1 #define AT91_MB_RX_LAST (AT91_MB_RX_FIRST + AT91_MB_RX_NUM - 1) #define AT91_MB_RX_MASK(i) ((1 << (i)) - 1) #define AT91_MB_RX_SPLIT 8 #define AT91_MB_RX_LOW_LAST (AT91_MB_RX_SPLIT - 1) -#define AT91_MB_RX_LOW_MASK (AT91_MB_RX_MASK(AT91_MB_RX_SPLIT)) +#define AT91_MB_RX_LOW_MASK (AT91_MB_RX_MASK(AT91_MB_RX_SPLIT) & \ + ~AT91_MB_RX_MASK(AT91_MB_RX_FIRST)) #define AT91_MB_TX_NUM (1 << AT91_MB_TX_SHIFT) #define AT91_MB_TX_FIRST (AT91_MB_RX_LAST + 1) @@ -168,6 +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 = { @@ -220,6 +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 */ @@ -233,12 +249,22 @@ static void at91_setup_mailboxes(struct net_device *dev) { struct at91_priv *priv = netdev_priv(dev); unsigned int i; + u32 reg_mid; /* - * The first 12 mailboxes are used as a reception FIFO. The - * last mailbox is configured with overwrite option. The - * overwrite flag indicates a FIFO overflow. + * Due to a chip bug (errata 50.2.6.3 & 50.3.5.3) the first + * mailbox is disabled. The next 11 mailboxes are used as a + * reception FIFO. The last mailbox is configured with + * overwrite option. The overwrite flag indicates a FIFO + * overflow. */ + 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); @@ -254,7 +280,8 @@ static void at91_setup_mailboxes(struct net_device *dev) set_mb_mode_prio(priv, i, AT91_MB_MODE_TX, 0); /* Reset tx and rx helper pointers */ - priv->tx_next = priv->tx_echo = priv->rx_next = 0; + priv->tx_next = priv->tx_echo = 0; + priv->rx_next = AT91_MB_RX_FIRST; } static int at91_set_bittiming(struct net_device *dev) @@ -372,12 +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; @@ -539,27 +561,31 @@ static void at91_read_msg(struct net_device *dev, unsigned int mb) * * Theory of Operation: * - * 12 of the 16 mailboxes on the chip are reserved for RX. we split - * them into 2 groups. The lower group holds 8 and upper 4 mailboxes. + * 11 of the 16 mailboxes on the chip are reserved for RX. we split + * them into 2 groups. The lower group holds 7 and upper 4 mailboxes. * * Like it or not, but the chip always saves a received CAN message * into the first free mailbox it finds (starting with the * lowest). This makes it very difficult to read the messages in the * right order from the chip. This is how we work around that problem: * - * The first message goes into mb nr. 0 and issues an interrupt. All + * The first message goes into mb nr. 1 and issues an interrupt. All * rx ints are disabled in the interrupt handler and a napi poll is * scheduled. We read the mailbox, but do _not_ reenable the mb (to * receive another message). * * lower mbxs upper - * ______^______ __^__ - * / \ / \ + * ____^______ __^__ + * / \ / \ * +-+-+-+-+-+-+-+-++-+-+-+-+ - * |x|x|x|x|x|x|x|x|| | | | | + * | |x|x|x|x|x|x|x|| | | | | * +-+-+-+-+-+-+-+-++-+-+-+-+ * 0 0 0 0 0 0 0 0 0 0 1 1 \ mail * 0 1 2 3 4 5 6 7 8 9 0 1 / box + * ^ + * | + * \ + * unused, due to chip bug * * The variable priv->rx_next points to the next mailbox to read a * message from. As long we're in the lower mailboxes we just read the @@ -590,10 +616,10 @@ static int at91_poll_rx(struct net_device *dev, int quota) "order of incoming frames cannot be guaranteed\n"); again: - for (mb = find_next_bit(addr, AT91_MB_RX_NUM, priv->rx_next); - mb < AT91_MB_RX_NUM && quota > 0; + for (mb = find_next_bit(addr, AT91_MB_RX_LAST + 1, priv->rx_next); + mb < AT91_MB_RX_LAST + 1 && quota > 0; reg_sr = at91_read(priv, AT91_SR), - mb = find_next_bit(addr, AT91_MB_RX_NUM, ++priv->rx_next)) { + mb = find_next_bit(addr, AT91_MB_RX_LAST + 1, ++priv->rx_next)) { at91_read_msg(dev, mb); /* reactivate mailboxes */ @@ -610,8 +636,8 @@ static int at91_poll_rx(struct net_device *dev, int quota) /* upper group completed, look again in lower */ if (priv->rx_next > AT91_MB_RX_LOW_LAST && - quota > 0 && mb >= AT91_MB_RX_NUM) { - priv->rx_next = 0; + quota > 0 && mb > AT91_MB_RX_LAST) { + priv->rx_next = AT91_MB_RX_FIRST; goto again; } @@ -1037,6 +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; @@ -1082,6 +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); @@ -1093,6 +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); |
