From 3cb3eaac52c0f145d895f4b6c22834d5f02b8569 Mon Sep 17 00:00:00 2001 From: Kurt Van Dijck Date: Tue, 1 Oct 2019 09:40:36 +0200 Subject: can: c_can: c_can_poll(): only read status register after status IRQ When the status register is read without the status IRQ pending, the chip may not raise the interrupt line for an upcoming status interrupt and the driver may miss a status interrupt. It is critical that the BUSOFF status interrupt is forwarded to the higher layers, since no more interrupts will follow without intervention. Thanks to Wolfgang and Joe for bringing up the first idea. Signed-off-by: Kurt Van Dijck Cc: Wolfgang Grandegger Cc: Joe Burmeister Fixes: fa39b54ccf28 ("can: c_can: Get rid of pointless interrupts") Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) (limited to 'drivers/net/can/c_can/c_can.c') diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 606b7d8ffe13..9b61bfbea6cd 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -97,6 +97,9 @@ #define BTR_TSEG2_SHIFT 12 #define BTR_TSEG2_MASK (0x7 << BTR_TSEG2_SHIFT) +/* interrupt register */ +#define INT_STS_PENDING 0x8000 + /* brp extension register */ #define BRP_EXT_BRPE_MASK 0x0f #define BRP_EXT_BRPE_SHIFT 0 @@ -1029,10 +1032,16 @@ static int c_can_poll(struct napi_struct *napi, int quota) u16 curr, last = priv->last_status; int work_done = 0; - priv->last_status = curr = priv->read_reg(priv, C_CAN_STS_REG); - /* Ack status on C_CAN. D_CAN is self clearing */ - if (priv->type != BOSCH_D_CAN) - priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED); + /* Only read the status register if a status interrupt was pending */ + if (atomic_xchg(&priv->sie_pending, 0)) { + priv->last_status = curr = priv->read_reg(priv, C_CAN_STS_REG); + /* Ack status on C_CAN. D_CAN is self clearing */ + if (priv->type != BOSCH_D_CAN) + priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED); + } else { + /* no change detected ... */ + curr = last; + } /* handle state changes */ if ((curr & STATUS_EWARN) && (!(last & STATUS_EWARN))) { @@ -1083,10 +1092,16 @@ static irqreturn_t c_can_isr(int irq, void *dev_id) { struct net_device *dev = (struct net_device *)dev_id; struct c_can_priv *priv = netdev_priv(dev); + int reg_int; - if (!priv->read_reg(priv, C_CAN_INT_REG)) + reg_int = priv->read_reg(priv, C_CAN_INT_REG); + if (!reg_int) return IRQ_NONE; + /* save for later use */ + if (reg_int & INT_STS_PENDING) + atomic_set(&priv->sie_pending, 1); + /* disable all interrupts and schedule the NAPI */ c_can_irq_control(priv, false); napi_schedule(&priv->napi); -- cgit From 23c5a9488f076bab336177cd1d1a366bd8ddf087 Mon Sep 17 00:00:00 2001 From: Jeroen Hofstee Date: Tue, 1 Oct 2019 21:01:20 +0000 Subject: can: c_can: D_CAN: c_can_chip_config(): perform a sofware reset on open When the CAN interface is closed it the hardwre is put in power down mode, but does not reset the error counters / state. Reset the D_CAN on open, so the reported state and the actual state match. According to [1], the C_CAN module doesn't have the software reset. [1] http://www.bosch-semiconductors.com/media/ip_modules/pdf_2/c_can_fd8/users_manual_c_can_fd8_r210_1.pdf Signed-off-by: Jeroen Hofstee Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'drivers/net/can/c_can/c_can.c') diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 9b61bfbea6cd..24c6015f6c92 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -52,6 +52,7 @@ #define CONTROL_EX_PDR BIT(8) /* control register */ +#define CONTROL_SWR BIT(15) #define CONTROL_TEST BIT(7) #define CONTROL_CCE BIT(6) #define CONTROL_DISABLE_AR BIT(5) @@ -572,6 +573,26 @@ static void c_can_configure_msg_objects(struct net_device *dev) IF_MCONT_RCV_EOB); } +static int c_can_software_reset(struct net_device *dev) +{ + struct c_can_priv *priv = netdev_priv(dev); + int retry = 0; + + if (priv->type != BOSCH_D_CAN) + return 0; + + priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_SWR | CONTROL_INIT); + while (priv->read_reg(priv, C_CAN_CTRL_REG) & CONTROL_SWR) { + msleep(20); + if (retry++ > 100) { + netdev_err(dev, "CCTRL: software reset failed\n"); + return -EIO; + } + } + + return 0; +} + /* * Configure C_CAN chip: * - enable/disable auto-retransmission @@ -581,6 +602,11 @@ static void c_can_configure_msg_objects(struct net_device *dev) static int c_can_chip_config(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); + int err; + + err = c_can_software_reset(dev); + if (err) + return err; /* enable automatic retransmission */ priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_ENABLE_AR); -- cgit From 6f12001ad5e79d0a0b08c599731d45c34cafd376 Mon Sep 17 00:00:00 2001 From: Jeroen Hofstee Date: Tue, 1 Oct 2019 21:01:24 +0000 Subject: can: c_can: C_CAN: add bus recovery events While the state is updated when the error counters increase and decrease, there is no event when the bus recovers and the error counters decrease again. So add that event as well. Change the state going downward to be ERROR_PASSIVE -> ERROR_WARNING -> ERROR_ACTIVE instead of directly to ERROR_ACTIVE again. Signed-off-by: Jeroen Hofstee Acked-by: Kurt Van Dijck Tested-by: Kurt Van Dijck Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) (limited to 'drivers/net/can/c_can/c_can.c') diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 24c6015f6c92..8e9f5620c9a2 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -915,6 +915,9 @@ static int c_can_handle_state_change(struct net_device *dev, struct can_berr_counter bec; switch (error_type) { + case C_CAN_NO_ERROR: + priv->can.state = CAN_STATE_ERROR_ACTIVE; + break; case C_CAN_ERROR_WARNING: /* error warning state */ priv->can.can_stats.error_warning++; @@ -945,6 +948,13 @@ static int c_can_handle_state_change(struct net_device *dev, ERR_CNT_RP_SHIFT; switch (error_type) { + case C_CAN_NO_ERROR: + /* error warning state */ + cf->can_id |= CAN_ERR_CRTL; + cf->data[1] = CAN_ERR_CRTL_ACTIVE; + cf->data[6] = bec.txerr; + cf->data[7] = bec.rxerr; + break; case C_CAN_ERROR_WARNING: /* error warning state */ cf->can_id |= CAN_ERR_CRTL; @@ -1089,11 +1099,17 @@ static int c_can_poll(struct napi_struct *napi, int quota) /* handle bus recovery events */ if ((!(curr & STATUS_BOFF)) && (last & STATUS_BOFF)) { netdev_dbg(dev, "left bus off state\n"); - priv->can.state = CAN_STATE_ERROR_ACTIVE; + work_done += c_can_handle_state_change(dev, C_CAN_ERROR_PASSIVE); } + if ((!(curr & STATUS_EPASS)) && (last & STATUS_EPASS)) { netdev_dbg(dev, "left error passive state\n"); - priv->can.state = CAN_STATE_ERROR_ACTIVE; + work_done += c_can_handle_state_change(dev, C_CAN_ERROR_WARNING); + } + + if ((!(curr & STATUS_EWARN)) && (last & STATUS_EWARN)) { + netdev_dbg(dev, "left error warning state\n"); + work_done += c_can_handle_state_change(dev, C_CAN_NO_ERROR); } /* handle lec errors on the bus */ -- cgit