From 30df5888e4a244093c1b403b55ef889c97824f7b Mon Sep 17 00:00:00 2001 From: "Ira W. Snyder" Date: Wed, 18 Jul 2012 15:33:17 -0700 Subject: 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 Signed-off-by: Marc Kleine-Budde --- drivers/net/can/janz-ican3.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/janz-ican3.c b/drivers/net/can/janz-ican3.c index 47f8f6b4fef9..e06ec403521a 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; -- cgit v1.2.3