greybus: loopback: add sink to loopback protocol

Loopback sink command will operate as an amalgam of the ping and tranfer
operations. Sink will send an ACK'd variable size operation over greybus.
Unlike the transfer type which transmits the received data back, the sink
type will simply ACK without sending the received data back.

This patch adds the kernel side of the sink command.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/greybus_protocols.h b/drivers/staging/greybus/greybus_protocols.h
index 9823d16..d3cce68 100644 (file)
--- a/drivers/staging/greybus/greybus_protocols.h
+++ b/drivers/staging/greybus/greybus_protocols.h
@@ -668,6 +668,7 @@ struct gb_uart_serial_state_request {
 #define        GB_LOOPBACK_TYPE_PROTOCOL_VERSION       0x01
 #define        GB_LOOPBACK_TYPE_PING                   0x02
 #define        GB_LOOPBACK_TYPE_TRANSFER               0x03
+#define GB_LOOPBACK_TYPE_SINK                  0x04
 
 struct gb_loopback_transfer_request {
        __le32  len;

diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c
index bdbebd6..678690f 100644 (file)
--- a/drivers/staging/greybus/loopback.c
+++ b/drivers/staging/greybus/loopback.c
@@ -114,6 +114,7 @@ static void gb_loopback_check_attr(struct gb_loopback *gb)
        switch (gb->type) {
        case GB_LOOPBACK_TYPE_PING:
        case GB_LOOPBACK_TYPE_TRANSFER:
+       case GB_LOOPBACK_TYPE_SINK:
                break;
        default:
                gb->type = 0;
@@ -164,6 +165,31 @@ static struct attribute *loopback_attrs[] = {
 };
 ATTRIBUTE_GROUPS(loopback);
 
+static int gb_loopback_sink(struct gb_loopback *gb,
+                               struct timeval *tping, u32 len)
+{
+       struct timeval ts, te;
+       u64 elapsed_nsecs;
+       struct gb_loopback_transfer_request *request;
+       int retval;
+
+       request = kmalloc(len + sizeof(*request), GFP_KERNEL);
+       if (!request)
+               return -ENOMEM;
+
+       request->len = cpu_to_le32(len);
+
+       do_gettimeofday(&ts);
+       retval = gb_operation_sync(gb->connection, GB_LOOPBACK_TYPE_SINK,
+                                  request, len + sizeof(*request), NULL, 0);
+       do_gettimeofday(&te);
+       elapsed_nsecs = timeval_to_ns(&te) - timeval_to_ns(&ts);
+       *tping = ns_to_timeval(elapsed_nsecs);
+
+       kfree(request);
+       return retval;
+}
+
 static int gb_loopback_transfer(struct gb_loopback *gb,
                                struct timeval *tping, u32 len)
 {
@@ -235,6 +261,7 @@ static int gb_loopback_request_recv(u8 type, struct gb_operation *operation)
                        "module-initiated version operation\n");
                return -EINVAL;
        case GB_LOOPBACK_TYPE_PING:
+       case GB_LOOPBACK_TYPE_SINK:
                return 0;
        case GB_LOOPBACK_TYPE_TRANSFER:
                if (operation->request->payload_size < sizeof(*request)) {
@@ -345,6 +372,8 @@ static int gb_loopback_fn(void *data)
                        error = gb_loopback_ping(gb, &tlat);
                else if (gb->type == GB_LOOPBACK_TYPE_TRANSFER)
                        error = gb_loopback_transfer(gb, &tlat, gb->size);
+               else if (gb->type == GB_LOOPBACK_TYPE_SINK)
+                       error = gb_loopback_sink(gb, &tlat, gb->size);
                if (error)
                        gb->error++;
                if (gb->ts.tv_usec == 0 && gb->ts.tv_sec == 0) {