As the first step to handle remote's RX window, store the skb in a sk_buff_head list, instead of sending a message immediately when pushed by Greybus.
skbs are still sent out straight away, but now there is a place to store away if the remote's RX window is too small.
Signed-off-by: Damien Riégel damien.riegel@silabs.com --- drivers/greybus/cpc/cpc.h | 10 ++++++---- drivers/greybus/cpc/cport.c | 21 ++++++++++++--------- drivers/greybus/cpc/host.c | 4 +++- drivers/greybus/cpc/protocol.c | 25 ++++++++++++++++++++++++- 4 files changed, 45 insertions(+), 15 deletions(-)
diff --git a/drivers/greybus/cpc/cpc.h b/drivers/greybus/cpc/cpc.h index 725fd7f4afc..f1669585c45 100644 --- a/drivers/greybus/cpc/cpc.h +++ b/drivers/greybus/cpc/cpc.h @@ -9,15 +9,15 @@ #include <linux/device.h> #include <linux/greybus.h> #include <linux/mutex.h> +#include <linux/skbuff.h> #include <linux/types.h>
-struct sk_buff; - /** * struct cpc_cport - CPC cport * @id: cport ID * @cpc_hd: pointer to the CPC host device this cport belongs to * @lock: mutex to synchronize accesses to tcb and other attributes + * @holding_queue: list of frames queued to be sent * @tcb: Transmission Control Block */ struct cpc_cport { @@ -26,6 +26,8 @@ struct cpc_cport { struct cpc_host_device *cpc_hd; struct mutex lock; /* Synchronize access to state variables */
+ struct sk_buff_head holding_queue; + /* * @ack: current acknowledge number * @seq: current sequence number @@ -42,7 +44,7 @@ void cpc_cport_release(struct cpc_cport *cport); void cpc_cport_pack(struct gb_operation_msg_hdr *gb_hdr, u16 cport_id); u16 cpc_cport_unpack(struct gb_operation_msg_hdr *gb_hdr);
-int cpc_cport_transmit(struct cpc_cport *cport, struct sk_buff *skb); +void cpc_cport_transmit(struct cpc_cport *cport, struct sk_buff *skb);
struct cpc_skb_cb { struct cpc_cport *cport; @@ -58,7 +60,7 @@ struct cpc_skb_cb {
#define CPC_SKB_CB(__skb) ((struct cpc_skb_cb *)&((__skb)->cb[0]))
-void cpc_protocol_prepare_header(struct sk_buff *skb, u8 ack); void cpc_protocol_on_data(struct cpc_cport *cport, struct sk_buff *skb); +void __cpc_protocol_write_head(struct cpc_cport *cport);
#endif diff --git a/drivers/greybus/cpc/cport.c b/drivers/greybus/cpc/cport.c index 35a148abbed..f850da7acfb 100644 --- a/drivers/greybus/cpc/cport.c +++ b/drivers/greybus/cpc/cport.c @@ -7,7 +7,6 @@ #include <linux/skbuff.h>
#include "cpc.h" -#include "host.h"
/** * cpc_cport_tcb_reset() - Reset cport's TCB to initial values. @@ -38,15 +37,23 @@ struct cpc_cport *cpc_cport_alloc(u16 cport_id, gfp_t gfp_mask) cpc_cport_tcb_reset(cport);
mutex_init(&cport->lock); + skb_queue_head_init(&cport->holding_queue);
return cport; }
void cpc_cport_release(struct cpc_cport *cport) { + skb_queue_purge(&cport->holding_queue); kfree(cport); }
+static void cpc_cport_queue_skb(struct cpc_cport *cport, struct sk_buff *skb) +{ + __skb_header_release(skb); + __skb_queue_tail(&cport->holding_queue, skb); +} + /** * cpc_cport_pack() - Pack CPort ID into Greybus Operation Message header. * @gb_hdr: Greybus operation message header. @@ -73,11 +80,9 @@ u16 cpc_cport_unpack(struct gb_operation_msg_hdr *gb_hdr) * @cport: cport. * @skb: skb to be transmitted. */ -int cpc_cport_transmit(struct cpc_cport *cport, struct sk_buff *skb) +void cpc_cport_transmit(struct cpc_cport *cport, struct sk_buff *skb) { - struct cpc_host_device *cpc_hd = cport->cpc_hd; struct gb_operation_msg_hdr *gb_hdr; - u8 ack;
/* Inject cport ID in Greybus header */ gb_hdr = (struct gb_operation_msg_hdr *)skb->data; @@ -89,11 +94,9 @@ int cpc_cport_transmit(struct cpc_cport *cport, struct sk_buff *skb) CPC_SKB_CB(skb)->cpc_flags = CPC_SKB_FLAG_REQ_ACK;
cport->tcb.seq++; - ack = cport->tcb.ack; + + cpc_cport_queue_skb(cport, skb); + __cpc_protocol_write_head(cport);
mutex_unlock(&cport->lock); - - cpc_protocol_prepare_header(skb, ack); - - return cpc_hd_send_skb(cpc_hd, skb); } diff --git a/drivers/greybus/cpc/host.c b/drivers/greybus/cpc/host.c index 7f0579fde26..ec43d33dfc6 100644 --- a/drivers/greybus/cpc/host.c +++ b/drivers/greybus/cpc/host.c @@ -62,7 +62,9 @@ static int cpc_hd_message_send(struct cpc_host_device *cpc_hd, u16 cport_id, CPC_SKB_CB(skb)->cport = cport; CPC_SKB_CB(skb)->gb_message = message;
- return cpc_cport_transmit(cport, skb); + cpc_cport_transmit(cport, skb); + + return 0; }
static int cpc_hd_cport_allocate(struct cpc_host_device *cpc_hd, int cport_id, unsigned long flags) diff --git a/drivers/greybus/cpc/protocol.c b/drivers/greybus/cpc/protocol.c index b4dd4e173a1..ef8ff0cac24 100644 --- a/drivers/greybus/cpc/protocol.c +++ b/drivers/greybus/cpc/protocol.c @@ -14,7 +14,7 @@ static bool cpc_skb_is_sequenced(struct sk_buff *skb) return CPC_SKB_CB(skb)->cpc_flags & CPC_SKB_FLAG_REQ_ACK; }
-void cpc_protocol_prepare_header(struct sk_buff *skb, u8 ack) +static void cpc_protocol_prepare_header(struct sk_buff *skb, u8 ack) { struct cpc_header *hdr;
@@ -84,3 +84,26 @@ void cpc_protocol_on_data(struct cpc_cport *cport, struct sk_buff *skb) greybus_data_rcvd(cport->cpc_hd->gb_hd, cport->id, skb->data, skb->len); } } + +static void __cpc_protocol_write_skb(struct cpc_cport *cport, struct sk_buff *skb, u8 ack) +{ + cpc_protocol_prepare_header(skb, ack); + + cpc_hd_send_skb(cport->cpc_hd, skb); +} + +/* Write skbs at the head of holding queue */ +void __cpc_protocol_write_head(struct cpc_cport *cport) +{ + struct sk_buff *skb; + u8 ack; + + ack = cport->tcb.ack; + + /* For each SKB in the holding queue, clone it and pass it to lower layer */ + while ((skb = skb_peek(&cport->holding_queue))) { + skb_unlink(skb, &cport->holding_queue); + + __cpc_protocol_write_skb(cport, skb, ack); + } +}