Commit 35e60bfd authored by Peter Crosthwaite's avatar Peter Crosthwaite Committed by Edgar E. Iglesias
Browse files

stream: Add flow control API 



Add basic flow control to stream. A stream slave may return short, indicating
that it is not capable of accepting any more data at the present time. Polling
or a callback can be used via the can_push() function to determine when the
slave can receive again.

Signed-off-by: default avatarPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: default avatarEdgar E. Iglesias <edgar.iglesias@gmail.com>
parent 210914e2

hw/core/stream.c

+11 −2
Original line number Diff line number Diff line 
#include "hw/stream.h"



void

size_t

stream_push(StreamSlave *sink, uint8_t *buf, size_t len, uint32_t *app)

{

    StreamSlaveClass *k =  STREAM_SLAVE_GET_CLASS(sink);



    k->push(sink, buf, len, app);

    return k->push(sink, buf, len, app);

}



bool

stream_can_push(StreamSlave *sink, StreamCanPushNotifyFn notify,

                void *notify_opaque)

{

    StreamSlaveClass *k =  STREAM_SLAVE_GET_CLASS(sink);



    return k->can_push ? k->can_push(sink, notify, notify_opaque) : true;

}



static const TypeInfo stream_slave_info = {

hw/dma/xilinx_axidma.c

+2 −1
Original line number Diff line number Diff line
@@ -381,7 +381,7 @@ static void xilinx_axidma_reset(DeviceState *dev) 
    }

}



static void

static size_t

xilinx_axidma_data_stream_push(StreamSlave *obj, unsigned char *buf, size_t len,

                               uint32_t *app)

{
@@ -393,6 +393,7 @@ xilinx_axidma_data_stream_push(StreamSlave *obj, unsigned char *buf, size_t len, 
    }

    stream_process_s2mem(s, buf, len, app);

    stream_update_irq(s);

    return len;

}



static uint64_t axidma_read(void *opaque, hwaddr addr,

hw/net/xilinx_axienet.c

+5 −3
Original line number Diff line number Diff line
@@ -815,7 +815,7 @@ static void eth_cleanup(NetClientState *nc) 
    g_free(s);

}



static void

static size_t

xilinx_axienet_data_stream_push(StreamSlave *obj, uint8_t *buf, size_t size,

                                uint32_t *hdr)

{
@@ -824,13 +824,13 @@ xilinx_axienet_data_stream_push(StreamSlave *obj, uint8_t *buf, size_t size, 


    /* TX enable ?  */

    if (!(s->tc & TC_TX)) {

        return;

        return size;

    }



    /* Jumbo or vlan sizes ?  */

    if (!(s->tc & TC_JUM)) {

        if (size > 1518 && size <= 1522 && !(s->tc & TC_VLAN)) {

            return;

            return size;

        }

    }
@@ -858,6 +858,8 @@ xilinx_axienet_data_stream_push(StreamSlave *obj, uint8_t *buf, size_t size, 
    s->stats.tx_bytes += size;

    s->regs[R_IS] |= IS_TX_COMPLETE;

    enet_update_irq(s);



    return size;

}



static NetClientInfo net_xilinx_enet_info = {

include/hw/stream.h

+30 −3
Original line number Diff line number Diff line
@@ -18,14 +18,41 @@ typedef struct StreamSlave { 
    Object Parent;

} StreamSlave;



typedef void (*StreamCanPushNotifyFn)(void *opaque);



typedef struct StreamSlaveClass {

    InterfaceClass parent;



    void (*push)(StreamSlave *obj, unsigned char *buf, size_t len,

    /**

     * can push - determine if a stream slave is capable of accepting at least

     * one byte of data. Returns false if cannot accept. If not implemented, the

     * slave is assumed to always be capable of recieveing.

     * @notify: Optional callback that the slave will call when the slave is

     * capable of recieving again. Only called if false is returned.

     * @notify_opaque: opaque data to pass to notify call.

     */

    bool (*can_push)(StreamSlave *obj, StreamCanPushNotifyFn notify,

                     void *notify_opaque);

    /**

     * push - push data to a Stream slave. The number of bytes pushed is

     * returned. If the slave short returns, the master must wait before trying

     * again, the slave may continue to just return 0 waiting for the vm time to

     * advance. The can_push() function can be used to trap the point in time

     * where the slave is ready to recieve again, otherwise polling on a QEMU

     * timer will work.

     * @obj: Stream slave to push to

     * @buf: Data to write

     * @len: Maximum number of bytes to write

     */

    size_t (*push)(StreamSlave *obj, unsigned char *buf, size_t len,

                                                    uint32_t *app);

} StreamSlaveClass;



void

size_t

stream_push(StreamSlave *sink, uint8_t *buf, size_t len, uint32_t *app);



bool

stream_can_push(StreamSlave *sink, StreamCanPushNotifyFn notify,

                void *notify_opaque);





#endif /* STREAM_H */