diff options
Diffstat (limited to 'drivers/net/can/c_can')
| -rw-r--r-- | drivers/net/can/c_can/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/net/can/c_can/c_can.c | 62 |
2 files changed, 55 insertions, 14 deletions
diff --git a/drivers/net/can/c_can/Kconfig b/drivers/net/can/c_can/Kconfig index 61ffc12d8fd8..8ab7103d4f44 100644 --- a/drivers/net/can/c_can/Kconfig +++ b/drivers/net/can/c_can/Kconfig @@ -14,6 +14,13 @@ config CAN_C_CAN_PLATFORM SPEAr1310 and SPEAr320 evaluation boards & TI (www.ti.com) boards like am335x, dm814x, dm813x and dm811x. +config CAN_C_CAN_STRICT_FRAME_ORDERING + bool "Force a strict RX CAN frame order (may cause frame loss)" + ---help--- + The RX split buffer prevents packet reordering but can cause packet + loss. Only enable this option when you accept to lose CAN frames + in favour of getting the received CAN frames in the correct order. + config CAN_C_CAN_PCI tristate "Generic PCI Bus based C_CAN/D_CAN driver" depends on PCI diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 09cb68772737..c1a8684ed1c8 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -791,18 +791,39 @@ static u32 c_can_adjust_pending(u32 pend) return pend & ~((1 << lasts) - 1); } +static inline void c_can_rx_object_get(struct net_device *dev, u32 obj) +{ +#ifdef CONFIG_CAN_C_CAN_STRICT_FRAME_ORDERING + if (obj < C_CAN_MSG_RX_LOW_LAST) + c_can_object_get(dev, IF_RX, obj, IF_COMM_RCV_LOW); + else +#endif + c_can_object_get(dev, IF_RX, obj, IF_COMM_RCV_HIGH); +} + +static inline void c_can_rx_finalize(struct net_device *dev, + struct c_can_priv *priv, u32 obj) +{ +#ifdef CONFIG_CAN_C_CAN_STRICT_FRAME_ORDERING + if (obj < C_CAN_MSG_RX_LOW_LAST) + priv->rxmasked |= BIT(obj - 1); + else if (obj == C_CAN_MSG_RX_LOW_LAST) { + priv->rxmasked = 0; + /* activate all lower message objects */ + c_can_activate_all_lower_rx_msg_obj(dev, IF_RX); + } +#endif +} + static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv, u32 pend, int quota) { - u32 pkts = 0, ctrl, obj, mcmd; + u32 pkts = 0, ctrl, obj; while ((obj = ffs(pend)) && quota > 0) { pend &= ~BIT(obj - 1); - mcmd = obj < C_CAN_MSG_RX_LOW_LAST ? - IF_COMM_RCV_LOW : IF_COMM_RCV_HIGH; - - c_can_object_get(dev, IF_RX, obj, mcmd); + c_can_rx_object_get(dev, obj); ctrl = priv->read_reg(priv, C_CAN_IFACE(MSGCTRL_REG, IF_RX)); if (ctrl & IF_MCONT_MSGLST) { @@ -824,13 +845,7 @@ static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv, /* read the data from the message object */ c_can_read_msg_object(dev, IF_RX, ctrl); - if (obj < C_CAN_MSG_RX_LOW_LAST) - priv->rxmasked |= BIT(obj - 1); - else if (obj == C_CAN_MSG_RX_LOW_LAST) { - priv->rxmasked = 0; - /* activate all lower message objects */ - c_can_activate_all_lower_rx_msg_obj(dev, IF_RX); - } + c_can_rx_finalize(dev, priv, obj); pkts++; quota--; @@ -839,6 +854,16 @@ static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv, return pkts; } +static inline u32 c_can_get_pending(struct c_can_priv *priv) +{ + u32 pend = priv->read_reg(priv, C_CAN_NEWDAT1_REG); + +#ifdef CONFIG_CAN_C_CAN_STRICT_FRAME_ORDERING + pend &= ~priv->rxmasked; +#endif + return pend; +} + /* * theory of operation: * @@ -848,6 +873,8 @@ static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv, * has arrived. To work-around this issue, we keep two groups of message * objects whose partitioning is defined by C_CAN_MSG_OBJ_RX_SPLIT. * + * If CONFIG_CAN_C_CAN_STRICT_FRAME_ORDERING = y + * * To ensure in-order frame reception we use the following * approach while re-activating a message object to receive further * frames: @@ -860,6 +887,14 @@ static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv, * - if the current message object number is greater than * C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of * only this message object. + * + * This can cause packet loss! + * + * If CONFIG_CAN_C_CAN_STRICT_FRAME_ORDERING = n + * + * We clear the newdat bit right away. + * + * This can result in packet reordering when the readout is slow. */ static int c_can_do_rx_poll(struct net_device *dev, int quota) { @@ -875,8 +910,7 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota) while (quota > 0) { if (!pend) { - pend = priv->read_reg(priv, C_CAN_NEWDAT1_REG); - pend &= ~priv->rxmasked; + pend = c_can_get_pending(priv); if (!pend) break; /* |
