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Message-Id: <1396388550-23081-8-git-send-email-mkl@pengutronix.de>
Date: Tue, 1 Apr 2014 23:42:21 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, linux-can@...r.kernel.org,
kernel@...gutronix.de, Thomas Gleixner <tglx@...utronix.de>,
Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH 07/16] can: c_can: Make it SMP safe
From: Thomas Gleixner <tglx@...utronix.de>
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@...utronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
drivers/net/can/c_can/c_can.c | 36 +++++++++++++++++++++---------------
1 file changed, 21 insertions(+), 15 deletions(-)
diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 4d08a32..38f9ada 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -133,6 +133,12 @@
#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:
* allow easy operation on 16-bit registers when the
* argument is 32-bit instead
@@ -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),
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 */
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);
/* 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);
/*
@@ -634,14 +640,14 @@ static void c_can_configure_msg_objects(struct net_device *dev)
/* first invalidate all message objects */
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 */
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);
- 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);
}
@@ -792,13 +798,13 @@ static void c_can_do_tx(struct net_device *dev)
if (!(val & (1 << (msg_obj_no - 1)))) {
can_get_echo_skb(dev,
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,
- C_CAN_IFACE(MSGCTRL_REG, 0))
+ C_CAN_IFACE(MSGCTRL_REG, IF_TX))
& IF_MCONT_DLC_MASK;
stats->tx_packets++;
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 {
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) {
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);
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) {
- c_can_handle_lost_msg_obj(dev, 0, msg_obj);
+ c_can_handle_lost_msg_obj(dev, IF_RX, msg_obj);
num_rx_pkts++;
quota--;
continue;
@@ -869,19 +875,19 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota)
continue;
/* 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)
- c_can_mark_rx_msg_obj(dev, 0,
+ c_can_mark_rx_msg_obj(dev, IF_RX,
msg_ctrl_save, msg_obj);
else if (msg_obj > C_CAN_MSG_RX_LOW_LAST)
/* 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);
else if (msg_obj == C_CAN_MSG_RX_LOW_LAST)
/* activate all lower message objects */
c_can_activate_all_lower_rx_msg_obj(dev,
- 0, msg_ctrl_save);
+ IF_RX, msg_ctrl_save);
num_rx_pkts++;
quota--;
--
1.9.0.279.gdc9e3eb
--
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