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Merge branch 'can/at91_can-for-net-2.6' of git://git.pengutronix.de/git/mkl/linux-2.6

This commit is contained in:
David S. Miller 2011-01-24 15:16:11 -08:00
parent fd0273c503 3a5655a5b5
commit 5955e75247
2 changed files with 137 additions and 26 deletions
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25
Documentation/ABI/testing/sysfs-platform-at91 Normal file
View File

@ -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

138
drivers/net/can/at91_can.c
View File

@ -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);