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can: c_can: Make it SMP safe 

The hardware has two message control interfaces, but the code only uses the
first one. So on SMP the following can be observed:

CPU0 	       	CPU1
rx_poll()
  write IF1	xmit()
		write IF1
  write IF1

That results in corrupted message object configurations. The TX/RX is not
globally serialized it's only serialized on a core.

Simple solution: Let RX use IF1 and TX use IF2 and all is good.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Thomas Gleixner 2014-03-18 17:19:09 +00:00 committed by Marc Kleine-Budde
parent 5bb9cbaa62
commit 640916db2b
1 changed files with 21 additions and 15 deletions
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36
drivers/net/can/c_can/c_can.c
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@ -132,6 +132,12 @@
#define IF_MCONT_EOB BIT(7) #define IF_MCONT_EOB BIT(7)
#define IF_MCONT_DLC_MASK 0xf #define IF_MCONT_DLC_MASK 0xf
/*
* Use IF1 for RX and IF2 for TX
*/
#define IF_RX 0
#define IF_TX 1
/* /*
* IFx register masks: * IFx register masks:
* allow easy operation on 16-bit registers when the * allow easy operation on 16-bit registers when the
@ -420,7 +426,7 @@ static void c_can_handle_lost_msg_obj(struct net_device *dev,
priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface),
IF_MCONT_CLR_MSGLST); IF_MCONT_CLR_MSGLST);
c_can_object_put(dev, 0, objno, IF_COMM_CONTROL); c_can_object_put(dev, iface, objno, IF_COMM_CONTROL);
/* create an error msg */ /* create an error msg */
skb = alloc_can_err_skb(dev, &frame); skb = alloc_can_err_skb(dev, &frame);
@ -551,7 +557,7 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
msg_obj_no = get_tx_next_msg_obj(priv); msg_obj_no = get_tx_next_msg_obj(priv);
/* prepare message object for transmission */ /* prepare message object for transmission */
c_can_write_msg_object(dev, 0, frame, msg_obj_no); c_can_write_msg_object(dev, IF_TX, frame, msg_obj_no);
can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
/* /*
@ -634,14 +640,14 @@ static void c_can_configure_msg_objects(struct net_device *dev)
/* first invalidate all message objects */ /* first invalidate all message objects */
for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++) for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)
c_can_inval_msg_object(dev, 0, i); c_can_inval_msg_object(dev, IF_RX, i);
/* setup receive message objects */ /* setup receive message objects */
for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++) for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)
c_can_setup_receive_object(dev, 0, i, 0, 0, c_can_setup_receive_object(dev, IF_RX, i, 0, 0,
(IF_MCONT_RXIE | IF_MCONT_UMASK) & ~IF_MCONT_EOB); (IF_MCONT_RXIE | IF_MCONT_UMASK) & ~IF_MCONT_EOB);
c_can_setup_receive_object(dev, 0, C_CAN_MSG_OBJ_RX_LAST, 0, 0, c_can_setup_receive_object(dev, IF_RX, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
IF_MCONT_EOB | IF_MCONT_RXIE | IF_MCONT_UMASK); IF_MCONT_EOB | IF_MCONT_RXIE | IF_MCONT_UMASK);
} }
@ -792,13 +798,13 @@ static void c_can_do_tx(struct net_device *dev)
if (!(val & (1 << (msg_obj_no - 1)))) { if (!(val & (1 << (msg_obj_no - 1)))) {
can_get_echo_skb(dev, can_get_echo_skb(dev,
msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
c_can_object_get(dev, 0, msg_obj_no, IF_COMM_ALL); c_can_object_get(dev, IF_TX, msg_obj_no, IF_COMM_ALL);
stats->tx_bytes += priv->read_reg(priv, stats->tx_bytes += priv->read_reg(priv,
C_CAN_IFACE(MSGCTRL_REG, 0)) C_CAN_IFACE(MSGCTRL_REG, IF_TX))
& IF_MCONT_DLC_MASK; & IF_MCONT_DLC_MASK;
stats->tx_packets++; stats->tx_packets++;
can_led_event(dev, CAN_LED_EVENT_TX); can_led_event(dev, CAN_LED_EVENT_TX);
c_can_inval_msg_object(dev, 0, msg_obj_no); c_can_inval_msg_object(dev, IF_TX, msg_obj_no);
} else { } else {
break; break;
} }
@ -850,13 +856,13 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota)
while ((msg_obj = ffs(val)) && quota > 0) { while ((msg_obj = ffs(val)) && quota > 0) {
val &= ~BIT(msg_obj - 1); val &= ~BIT(msg_obj - 1);
c_can_object_get(dev, 0, msg_obj, IF_COMM_ALL & c_can_object_get(dev, IF_RX, msg_obj, IF_COMM_ALL &
~IF_COMM_TXRQST); ~IF_COMM_TXRQST);
msg_ctrl_save = priv->read_reg(priv, msg_ctrl_save = priv->read_reg(priv,
C_CAN_IFACE(MSGCTRL_REG, 0)); C_CAN_IFACE(MSGCTRL_REG, IF_RX));
if (msg_ctrl_save & IF_MCONT_MSGLST) { if (msg_ctrl_save & IF_MCONT_MSGLST) {
c_can_handle_lost_msg_obj(dev, 0, msg_obj); c_can_handle_lost_msg_obj(dev, IF_RX, msg_obj);
num_rx_pkts++; num_rx_pkts++;
quota--; quota--;
continue; continue;
@ -869,19 +875,19 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota)
continue; continue;
/* read the data from the message object */ /* read the data from the message object */
c_can_read_msg_object(dev, 0, msg_ctrl_save); c_can_read_msg_object(dev, IF_RX, msg_ctrl_save);
if (msg_obj < C_CAN_MSG_RX_LOW_LAST) if (msg_obj < C_CAN_MSG_RX_LOW_LAST)
c_can_mark_rx_msg_obj(dev, 0, c_can_mark_rx_msg_obj(dev, IF_RX,
msg_ctrl_save, msg_obj); msg_ctrl_save, msg_obj);
else if (msg_obj > C_CAN_MSG_RX_LOW_LAST) else if (msg_obj > C_CAN_MSG_RX_LOW_LAST)
/* activate this msg obj */ /* activate this msg obj */
c_can_activate_rx_msg_obj(dev, 0, c_can_activate_rx_msg_obj(dev, IF_RX,
msg_ctrl_save, msg_obj); msg_ctrl_save, msg_obj);
else if (msg_obj == C_CAN_MSG_RX_LOW_LAST) else if (msg_obj == C_CAN_MSG_RX_LOW_LAST)
/* activate all lower message objects */ /* activate all lower message objects */
c_can_activate_all_lower_rx_msg_obj(dev, c_can_activate_all_lower_rx_msg_obj(dev,
0, msg_ctrl_save); IF_RX, msg_ctrl_save);
num_rx_pkts++; num_rx_pkts++;
quota--; quota--;