From: Pierre Le Magourou <plemagourou@xxxxxxxxxxxxxxxxxxxx>
We can't wait for END_OF_TRANSFER event in dwc3_gadget_ep_dequeue()
because it can be called in an interruption context.
TRBs are now cleared after the END_OF_TRANSFER completion, in the
interrupt handler.
Signed-off-by: Pierre Le Magourou <plemagourou@xxxxxxxxxxxxxxxxxxxx>
---
drivers/usb/dwc3/core.h | 14 ++++++
drivers/usb/dwc3/gadget.c | 122 +++++++++++++++++++++++++++-------------------
2 files changed, 85 insertions(+), 51 deletions(-)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 7a217a36c36b..5e2070183e3a 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -627,6 +627,7 @@ struct dwc3_event_buffer {
* @wait_end_transfer: wait_queue_head_t for waiting on End Transfer complete
* @lock: spinlock for endpoint request queue traversal
* @regs: pointer to first endpoint register
+ * @pending_trb: pointer to pending TRB structure
* @trb_pool: array of transaction buffers
* @trb_pool_dma: dma address of @trb_pool
* @trb_enqueue: enqueue 'pointer' into TRB array
@@ -654,6 +655,7 @@ struct dwc3_ep {
void __iomem *regs;
struct dwc3_trb *trb_pool;
+ struct dwc3_pending_trb *pending_trb;
dma_addr_t trb_pool_dma;
struct dwc3 *dwc;
@@ -777,6 +779,18 @@ struct dwc3_trb {
u32 ctrl;
} __packed;
+/**
+ * struct dwc3_pending_trb
+ * @dirty_trb: pointer to TRB waiting for END_TRANSFER completion
+ * @extra_trb: true if extra TRB was set to align transfer
+ * @num_pending_sgs: number of pending SGs
+ */
+struct dwc3_pending_trb {
+ struct dwc3_trb *dirty_trb;
+ bool extra_trb;
+ unsigned int num_pending_sgs;
+};
+
/**
* struct dwc3_hwparams - copy of HWPARAMS registers
* @hwparams0: GHWPARAMS0
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 69bf137aab37..dd1f2b74723b 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1341,6 +1341,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
struct dwc3_ep *dep = to_dwc3_ep(ep);
struct dwc3 *dwc = dep->dwc;
+ struct dwc3_pending_trb *p_trb;
unsigned long flags;
int ret = 0;
@@ -1367,63 +1368,29 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
* If request was already started, this means we had to
* stop the transfer. With that we also need to ignore
* all TRBs used by the request, however TRBs can only
- * be modified after completion of END_TRANSFER
- * command. So what we do here is that we wait for
- * END_TRANSFER completion and only after that, we jump
- * over TRBs by clearing HWO and incrementing dequeue
- * pointer.
+ * be modified after completion of END_TRANSFER command.
*
- * Note that we have 2 possible types of transfers here:
- *
- * i) Linear buffer request
- * ii) SG-list based request
- *
- * SG-list based requests will have r->num_pending_sgs
- * set to a valid number (> 0). Linear requests,
- * normally use a single TRB.
- *
- * For each of these two cases, if r->unaligned flag is
- * set, one extra TRB has been used to align transfer
- * size to wMaxPacketSize.
- *
- * All of these cases need to be taken into
- * consideration so we don't mess up our TRB ring
- * pointers.
+ * Don't wait for END_TRANSFER completion here because
+ * dwc3_gadget_ep_dequeue() can be called from within
+ * the controller's interrupt handler. Save the TRB
+ * pointer, the number of pending sgs, and the
+ * extra_trb flag, so that TRBs HWO can be cleared and
+ * dequeue pointer incremented when the END_TRANSFER
+ * completion is received.
*/
- wait_event_lock_irq(dep->wait_end_transfer,
- !(dep->flags & DWC3_EP_END_TRANSFER_PENDING),
- dwc->lock);
if (!r->trb)
goto out0;
- if (r->num_pending_sgs) {
- struct dwc3_trb *trb;
- int i = 0;
-
- for (i = 0; i < r->num_pending_sgs; i++) {
- trb = r->trb + i;
- trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
- dwc3_ep_inc_deq(dep);
- }
-
- if (r->unaligned || r->zero) {
- trb = r->trb + r->num_pending_sgs + 1;
- trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
- dwc3_ep_inc_deq(dep);
- }
- } else {
- struct dwc3_trb *trb = r->trb;
-
- trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
- dwc3_ep_inc_deq(dep);
-
- if (r->unaligned || r->zero) {
- trb = r->trb + 1;
- trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
- dwc3_ep_inc_deq(dep);
- }
- }
+ p_trb = kzalloc(sizeof(*p_trb), GFP_KERNEL|GFP_ATOMIC);
+ p_trb->dirty_trb = r->trb;
+ p_trb->num_pending_sgs = r->num_pending_sgs;
+
+ if (r->unaligned || r->zero)
+ p_trb->extra_trb = true;
+
+ dep->pending_trb = p_trb;
+
goto out1;
}
dev_err(dwc->dev, "request %pK was not queued to %s\n",
@@ -2430,6 +2397,56 @@ static void dwc3_gadget_endpoint_transfer_not_ready(struct dwc3_ep *dep,
__dwc3_gadget_start_isoc(dep);
}
+/* Clear HWO and increment dequeue pointer.
+ *
+ * 2 types of transfers are possible:
+ *
+ * i) Linear buffer request
+ * ii) SG-list based request
+ *
+ * SG-list based requests have p_trb->num_pending_sgs set to a valid number
+ * (> 0). Linear requests, normally use a single TRB.
+ *
+ * For each of these two cases, if p_trb->extra_trb flag is set, one
+ * extra TRB has been used to align transfer size to wMaxPacketSize.
+ *
+ * All of these cases need to be taken into consideration so TRB ring pointers
+ * are not messed up.
+ */
+static void dwc3_clear_pending_trbs(struct dwc3_ep *dep)
+{
+ struct dwc3_pending_trb *p_trb = dep->pending_trb;
+ struct dwc3_trb *trb;
+
+ if (p_trb->num_pending_sgs) {
+ int i;
+
+ for (i = 0; i < p_trb->num_pending_sgs; i++) {
+ trb = p_trb->dirty_trb + i;
+ trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
+ dwc3_ep_inc_deq(dep);
+ }
+
+ if (p_trb->extra_trb) {
+ trb = p_trb->dirty_trb + p_trb->num_pending_sgs + 1;
+ trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
+ dwc3_ep_inc_deq(dep);
+ }
+ } else {
+ trb = p_trb->dirty_trb;
+ trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
+ dwc3_ep_inc_deq(dep);
+
+ if (p_trb->extra_trb) {
+ trb = p_trb->dirty_trb + 1;
+ trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
+ dwc3_ep_inc_deq(dep);
+ }
+ }
+ kfree(p_trb);
+ dep->pending_trb = NULL;
+}
+
static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
const struct dwc3_event_depevt *event)
{
@@ -2466,6 +2483,9 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
if (cmd == DWC3_DEPCMD_ENDTRANSFER) {
dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
wake_up(&dep->wait_end_transfer);
+
+ if (dep->pending_trb)
+ dwc3_clear_pending_trbs(dep);
}
break;
case DWC3_DEPEVT_STREAMEVT:
--
2.16.2
--
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