usb: musb: introduce dma_channel.rx_packet_done

The musb/cppi41 glue layer is capable of handling transactions that span
over more than one USB packet by reloading the DMA descriptors
partially. An urb is considered completed when either its transfer
buffer has been filled entirely (actual_length ==
transfer_buffer_length) or if a packet in the stream has less bytes than
the endpoint's wMaxPacketSize.

Once one of the above conditions is met, musb_dma_completion() is called
from cppi41_trans_done(). However, the final decision whether or not to
return the urb to its owner is made by the core and its determination of
the variable 'done' in musb_host_rx(). This code has currently no way of
knowing what the size of the last packet was, and whether or not to
give back the urb due to a short read.

Fix this by introducing a new boolean flag in 'struct dma_channel', and
set it from musb_cppi41.c. If set, it will make the core do what the
DMA layer decided and complete the urb.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

3 files changed, 5 insertions, 1 deletions

diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
index 7b8bbf53127e..4187ef1fab29 100644
--- a/drivers/usb/musb/musb_cppi41.c
+++ b/drivers/usb/musb/musb_cppi41.c
@@ -139,6 +139,7 @@ static void cppi41_trans_done(struct cppi41_dma_channel *cppi41_channel)
                 cppi41_channel->channel.actual_len =
                         cppi41_channel->transferred;
                 cppi41_channel->channel.status = MUSB_DMA_STATUS_FREE;
+                cppi41_channel->channel.rx_packet_done = true;
                 musb_dma_completion(musb, hw_ep->epnum, cppi41_channel->is_tx);
         } else {
                 /* next iteration, reload */
@@ -450,6 +451,7 @@ static bool cppi41_configure_channel(struct dma_channel *channel,
         dma_desc->callback = cppi41_dma_callback;
         dma_desc->callback_param = channel;
         cppi41_channel->cookie = dma_desc->tx_submit(dma_desc);
+        cppi41_channel->channel.rx_packet_done = false;
 
         save_rx_toggle(cppi41_channel);
         dma_async_issue_pending(dc);
diff --git a/drivers/usb/musb/musb_dma.h b/drivers/usb/musb/musb_dma.h
index 1345a4ff041a..1d44faa86252 100644
--- a/drivers/usb/musb/musb_dma.h
+++ b/drivers/usb/musb/musb_dma.h
@@ -129,6 +129,7 @@ struct dma_channel {
         size_t                  actual_len;
         enum dma_channel_status status;
         bool                    desired_mode;
+        bool                    rx_packet_done;
 };
 
 /*
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 3381fa56db29..88435cd7fe3d 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -1737,7 +1737,8 @@ void musb_host_rx(struct musb *musb, u8 epnum)
                 /* done if urb buffer is full or short packet is recd */
                 done = (urb->actual_length + xfer_len >=
                                 urb->transfer_buffer_length
-                        || dma->actual_len < qh->maxpacket);
+                        || dma->actual_len < qh->maxpacket
+                        || dma->rx_packet_done);
                 }
 
                 /* send IN token for next packet, without AUTOREQ */