Skip to content

Commit

Permalink
can: xilinx_can: fix recovery from error states not being propagated
Browse files Browse the repository at this point in the history 
The xilinx_can driver contains no mechanism for propagating recovery
from CAN_STATE_ERROR_WARNING and CAN_STATE_ERROR_PASSIVE.

Add such a mechanism by factoring the handling of
XCAN_STATE_ERROR_PASSIVE and XCAN_STATE_ERROR_WARNING out of
xcan_err_interrupt and checking for recovery after RX and TX if the
interface is in one of those states.

Tested with the integrated CAN on Zynq-7000 SoC.

Fixes: b1201e4 ("can: xilinx CAN controller support")
Signed-off-by: Anssi Hannula <[email protected]>
Cc: <[email protected]>
Signed-off-by: Marc Kleine-Budde <[email protected]>
  • Loading branch information
@anssih @marckleinebudde
anssih authored and marckleinebudde committed Jul 23, 2018
1 parent 32852c5 commit 877e0b7
Showing 1 changed file with 127 additions and 28 deletions.
155 changes: 127 additions & 28 deletions drivers/net/can/xilinx_can.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
*
* Copyright (C) 2012 - 2014 Xilinx, Inc.
* Copyright (C) 2009 PetaLogix. All rights reserved.
* Copyright (C) 2017 Sandvik Mining and Construction Oy
*
* Description:
* This driver is developed for Axi CAN IP and for Zynq CANPS Controller.
Expand Down Expand Up @@ -529,6 +530,123 @@ static int xcan_rx(struct net_device *ndev)
return 1;
}

/**
* xcan_current_error_state - Get current error state from HW
* @ndev: Pointer to net_device structure
*
* Checks the current CAN error state from the HW. Note that this
* only checks for ERROR_PASSIVE and ERROR_WARNING.
*
* Return:
* ERROR_PASSIVE or ERROR_WARNING if either is active, ERROR_ACTIVE
* otherwise.
*/
static enum can_state xcan_current_error_state(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
u32 status = priv->read_reg(priv, XCAN_SR_OFFSET);

if ((status & XCAN_SR_ESTAT_MASK) == XCAN_SR_ESTAT_MASK)
return CAN_STATE_ERROR_PASSIVE;
else if (status & XCAN_SR_ERRWRN_MASK)
return CAN_STATE_ERROR_WARNING;
else
return CAN_STATE_ERROR_ACTIVE;
}

/**
* xcan_set_error_state - Set new CAN error state
* @ndev: Pointer to net_device structure
* @new_state: The new CAN state to be set
* @cf: Error frame to be populated or NULL
*
* Set new CAN error state for the device, updating statistics and
* populating the error frame if given.
*/
static void xcan_set_error_state(struct net_device *ndev,
enum can_state new_state,
struct can_frame *cf)
{
struct xcan_priv *priv = netdev_priv(ndev);
u32 ecr = priv->read_reg(priv, XCAN_ECR_OFFSET);
u32 txerr = ecr & XCAN_ECR_TEC_MASK;
u32 rxerr = (ecr & XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT;

priv->can.state = new_state;

if (cf) {
cf->can_id |= CAN_ERR_CRTL;
cf->data[6] = txerr;
cf->data[7] = rxerr;
}

switch (new_state) {
case CAN_STATE_ERROR_PASSIVE:
priv->can.can_stats.error_passive++;
if (cf)
cf->data[1] = (rxerr > 127) ?
CAN_ERR_CRTL_RX_PASSIVE :
CAN_ERR_CRTL_TX_PASSIVE;
break;
case CAN_STATE_ERROR_WARNING:
priv->can.can_stats.error_warning++;
if (cf)
cf->data[1] |= (txerr > rxerr) ?
CAN_ERR_CRTL_TX_WARNING :
CAN_ERR_CRTL_RX_WARNING;
break;
case CAN_STATE_ERROR_ACTIVE:
if (cf)
cf->data[1] |= CAN_ERR_CRTL_ACTIVE;
break;
default:
/* non-ERROR states are handled elsewhere */
WARN_ON(1);
break;
}
}

/**
* xcan_update_error_state_after_rxtx - Update CAN error state after RX/TX
* @ndev: Pointer to net_device structure
*
* If the device is in a ERROR-WARNING or ERROR-PASSIVE state, check if
* the performed RX/TX has caused it to drop to a lesser state and set
* the interface state accordingly.
*/
static void xcan_update_error_state_after_rxtx(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
enum can_state old_state = priv->can.state;
enum can_state new_state;

/* changing error state due to successful frame RX/TX can only
* occur from these states
*/
if (old_state != CAN_STATE_ERROR_WARNING &&
old_state != CAN_STATE_ERROR_PASSIVE)
return;

new_state = xcan_current_error_state(ndev);

if (new_state != old_state) {
struct sk_buff *skb;
struct can_frame *cf;

skb = alloc_can_err_skb(ndev, &cf);

xcan_set_error_state(ndev, new_state, skb ? cf : NULL);

if (skb) {
struct net_device_stats *stats = &ndev->stats;

stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
netif_rx(skb);
}
}
}

/**
* xcan_err_interrupt - error frame Isr
* @ndev: net_device pointer
Expand All @@ -544,16 +662,12 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr)
struct net_device_stats *stats = &ndev->stats;
struct can_frame *cf;
struct sk_buff *skb;
u32 err_status, status, txerr = 0, rxerr = 0;
u32 err_status;

skb = alloc_can_err_skb(ndev, &cf);

err_status = priv->read_reg(priv, XCAN_ESR_OFFSET);
priv->write_reg(priv, XCAN_ESR_OFFSET, err_status);
txerr = priv->read_reg(priv, XCAN_ECR_OFFSET) & XCAN_ECR_TEC_MASK;
rxerr = ((priv->read_reg(priv, XCAN_ECR_OFFSET) &
XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT);
status = priv->read_reg(priv, XCAN_SR_OFFSET);

if (isr & XCAN_IXR_BSOFF_MASK) {
priv->can.state = CAN_STATE_BUS_OFF;
Expand All @@ -563,28 +677,10 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr)
can_bus_off(ndev);
if (skb)
cf->can_id |= CAN_ERR_BUSOFF;
} else if ((status & XCAN_SR_ESTAT_MASK) == XCAN_SR_ESTAT_MASK) {
priv->can.state = CAN_STATE_ERROR_PASSIVE;
priv->can.can_stats.error_passive++;
if (skb) {
cf->can_id |= CAN_ERR_CRTL;
cf->data[1] = (rxerr > 127) ?
CAN_ERR_CRTL_RX_PASSIVE :
CAN_ERR_CRTL_TX_PASSIVE;
cf->data[6] = txerr;
cf->data[7] = rxerr;
}
} else if (status & XCAN_SR_ERRWRN_MASK) {
priv->can.state = CAN_STATE_ERROR_WARNING;
priv->can.can_stats.error_warning++;
if (skb) {
cf->can_id |= CAN_ERR_CRTL;
cf->data[1] |= (txerr > rxerr) ?
CAN_ERR_CRTL_TX_WARNING :
CAN_ERR_CRTL_RX_WARNING;
cf->data[6] = txerr;
cf->data[7] = rxerr;
}
} else {
enum can_state new_state = xcan_current_error_state(ndev);

xcan_set_error_state(ndev, new_state, skb ? cf : NULL);
}

/* Check for Arbitration lost interrupt */
Expand Down Expand Up @@ -713,8 +809,10 @@ static int xcan_rx_poll(struct napi_struct *napi, int quota)
isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
}

if (work_done)
if (work_done) {
can_led_event(ndev, CAN_LED_EVENT_RX);
xcan_update_error_state_after_rxtx(ndev);
}

if (work_done < quota) {
napi_complete_done(napi, work_done);
Expand Down Expand Up @@ -745,6 +843,7 @@ static void xcan_tx_interrupt(struct net_device *ndev, u32 isr)
isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
}
can_led_event(ndev, CAN_LED_EVENT_TX);
xcan_update_error_state_after_rxtx(ndev);
netif_wake_queue(ndev);
}

Expand Down

0 comments on commit 877e0b7

Please sign in to comment.