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authorIra W. Snyder <iws@ovro.caltech.edu>2012-07-18 15:33:17 -0700
committerMarc Kleine-Budde <mkl@pengutronix.de>2012-07-20 17:49:05 +0200
commit30df5888e4a244093c1b403b55ef889c97824f7b (patch)
tree0a72a7baf1848b142cefb54ced268d600af655c8 /drivers/net
parent83702f69272e4591a91a27eb58eade1bcd361dae (diff)
can: janz-ican3: avoid firmware lockup caused by infinite bus error quota
If the bus error quota is set to infinite and the host CPU cannot keep up, the Janz VMOD-ICAN3 firmware will stop responding to control messages until the controller is reset. The firmware will automatically stop sending bus error messages when the quota is reached, and will only resume sending bus error messages when the quota is re-set to a positive value. This limitation is worked around by setting the bus error quota to one message, and then re-setting the quota to one message every time a bus error message is received. By doing this, the firmware never stops responding to control messages. The CAN bus can be reset without a hard-reset of the controller card. Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/can/janz-ican3.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/net/can/janz-ican3.c b/drivers/net/can/janz-ican3.c
index 47f8f6b4fef..e06ec403521 100644
--- a/drivers/net/can/janz-ican3.c
+++ b/drivers/net/can/janz-ican3.c
@@ -972,6 +972,16 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
stats->rx_errors++;
}
+ /*
+ * The controller automatically disables bus-error interrupts
+ * and therefore we must re-enable them.
+ */
+ ret = ican3_set_buserror(mod, 1);
+ if (ret) {
+ dev_err(mod->dev, "unable to re-enable bus-error\n");
+ return ret;
+ }
+
/* bus error reporting is off, return immediately */
if (!(mod->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
return 0;
@@ -1451,7 +1461,7 @@ static int __devinit ican3_startup_module(struct ican3_dev *mod)
}
/* default to "bus errors enabled" */
- ret = ican3_set_buserror(mod, ICAN3_BUSERR_QUOTA_MAX);
+ ret = ican3_set_buserror(mod, 1);
if (ret) {
dev_err(mod->dev, "unable to set bus-error\n");
return ret;