[PATCH v5 5/6] usb: musb: gadget: implement optional explicit status stage

From: Paul Elder
Date: Wed Jan 09 2019 - 02:10:10 EST


Implement the mechanism for optional explicit status stage for the MUSB
driver. This allows a function driver to specify what to reply for the
status stage. The functionality for an implicit status stage is
retained.

Signed-off-by: Paul Elder <paul.elder@xxxxxxxxxxxxxxxx>
v1 Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
v1 Acked-by: Bin Liu <b-liu@xxxxxx>
---
Changes from v4:

- call usb_gadget_control_complete before usb_gadget_giveback_request
- set musb ep0 state to statusin in ep0_send_ack
- make sure to not double-write musb register in ep0_rxstate, since
musb_g_ep0_giveback will take care of writing them

No change from v3

Changes from v2:
- update call to usb_gadget_control_complete to include status
- since sending STALL from the function driver is now done with
usb_ep_set_halt, there is no need for the internal ep0_send_response to
take a stall/ack parameter; remove the parameter and make the function
only send ack, and remove checking for the status reply in the
usb_request for the status stage

Changes from v1:
- obvious change to implement v2 mechanism laid out by 4/6 of this
series (send_response, and musb_g_ep0_send_response function has
been removed, call to usb_gadget_control_complete has been added)
- ep0_send_response's ack argument has been changed from stall
- last_packet flag in ep0_rxstate has been removed, since it is equal to
req != NULL

drivers/usb/musb/musb_gadget.c | 2 ++
drivers/usb/musb/musb_gadget_ep0.c | 29 +++++++++++++++++++++++++++--
2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 496643f54faa..ff83578c181f 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -144,6 +144,8 @@ __acquires(ep->musb->lock)
unmap_dma_buffer(req, musb);

trace_musb_req_gb(req);
+ if (req->ep->end_point.address == 0)
+ usb_gadget_control_complete(&musb->g, &req->request);
usb_gadget_giveback_request(&req->ep->end_point, &req->request);
spin_lock(&musb->lock);
ep->busy = busy;
diff --git a/drivers/usb/musb/musb_gadget_ep0.c b/drivers/usb/musb/musb_gadget_ep0.c
index 91a5027b5c1f..dc5abdf9d49e 100644
--- a/drivers/usb/musb/musb_gadget_ep0.c
+++ b/drivers/usb/musb/musb_gadget_ep0.c
@@ -458,6 +458,25 @@ __acquires(musb->lock)
return handled;
}

+static int ep0_send_ack(struct musb *musb)
+{
+ void __iomem *regs = musb->control_ep->regs;
+ u16 csr;
+
+ if (musb->ep0_state != MUSB_EP0_STAGE_RX &&
+ musb->ep0_state != MUSB_EP0_STAGE_STATUSIN)
+ return -EINVAL;
+
+ csr = MUSB_CSR0_P_DATAEND | MUSB_CSR0_P_SVDRXPKTRDY;
+
+ musb_ep_select(musb->mregs, 0);
+ musb_writew(regs, MUSB_CSR0, csr);
+
+ musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
+
+ return 0;
+}
+
/* we have an ep0out data packet
* Context: caller holds controller lock
*/
@@ -504,12 +523,15 @@ static void ep0_rxstate(struct musb *musb)
if (req) {
musb->ackpend = csr;
musb_g_ep0_giveback(musb, req);
+ if (req->explicit_status)
+ return;
if (!musb->ackpend)
return;
musb->ackpend = 0;
+ } else {
+ musb_ep_select(musb->mregs, 0);
+ musb_writew(regs, MUSB_CSR0, csr);
}
- musb_ep_select(musb->mregs, 0);
- musb_writew(regs, MUSB_CSR0, csr);
}

/*
@@ -939,6 +961,9 @@ musb_g_ep0_queue(struct usb_ep *e, struct usb_request *r, gfp_t gfp_flags)
case MUSB_EP0_STAGE_ACKWAIT: /* zero-length data */
status = 0;
break;
+ case MUSB_EP0_STAGE_STATUSIN:
+ status = ep0_send_ack(musb);
+ goto cleanup;
default:
musb_dbg(musb, "ep0 request queued in state %d",
musb->ep0_state);
--
2.20.1