From: Dom Cobley <popcornmix@xxxxxxxxx>
Add the NAK holdoff patch from the downstream Raspberry Pi kernel.
This allows the transfer scheduler to better handle "cheeky devices
that just hold off using NAKs".
[original patch from Dom Cobley]
Signed-off-by: Dom Cobley <popcornmix@xxxxxxxxx>
[adapted to dwc2 driver by Paul Zimmerman]
Signed-off-by: Paul Zimmerman <paulz@xxxxxxxxxxxx>
---
drivers/staging/dwc2/core.h | 2 ++
drivers/staging/dwc2/hcd.c | 20 ++++++++++++++++++++
drivers/staging/dwc2/hcd.h | 2 ++
drivers/staging/dwc2/hcd_intr.c | 24 ++++++++++++++++++++++--
drivers/staging/dwc2/hcd_queue.c | 19 +++++++++++++++----
5 files changed, 61 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/dwc2/core.h b/drivers/staging/dwc2/core.h
index e5b4dc8..d65e8a5 100644
--- a/drivers/staging/dwc2/core.h
+++ b/drivers/staging/dwc2/core.h
@@ -292,6 +292,7 @@ struct dwc2_core_params {
* @otg_port: OTG port number
* @frame_list: Frame list
* @frame_list_dma: Frame list DMA address
+ * @next_sched_frame: Next scheduled frame, used by the NAK holdoff code
*/
struct dwc2_hsotg {
struct device *dev;
@@ -365,6 +366,7 @@ struct dwc2_hsotg {
u8 otg_port;
u32 *frame_list;
dma_addr_t frame_list_dma;
+ int next_sched_frame;
/* DWC OTG HW Release versions */
#define DWC2_CORE_REV_2_71a 0x4f54271a
diff --git a/drivers/staging/dwc2/hcd.c b/drivers/staging/dwc2/hcd.c
index 32b52ad..3a4ff79 100644
--- a/drivers/staging/dwc2/hcd.c
+++ b/drivers/staging/dwc2/hcd.c
@@ -890,6 +890,24 @@ enum dwc2_transaction_type dwc2_hcd_select_transactions(
if (list_empty(&hsotg->free_hc_list))
break;
qh = list_entry(qh_ptr, struct dwc2_qh, qh_list_entry);
+
+ /*
+ * Check to see if this is a NAK'd retransmit, in which case
+ * ignore for retransmission. We hold off on bulk
+ * retransmissions to reduce NAK interrupt overhead for
+ * cheeky devices that just hold off using NAKs.
+ */
+ if (dwc2_full_frame_num(qh->nak_frame) ==
+ dwc2_full_frame_num(dwc2_hcd_get_frame_number(hsotg))) {
+ /* Make interrupt run on next frame (i.e. 8 uframes) */
+ hsotg->next_sched_frame = ((qh->nak_frame + 8) & ~7) &
+ HFNUM_MAX_FRNUM;
+ qh_ptr = qh_ptr->next;
+ continue;
+ } else {
+ qh->nak_frame = 0xffff;
+ }
+
dwc2_assign_and_init_hc(hsotg, qh);
/*
@@ -2914,6 +2932,8 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg, int irq,
hsotg->hc_ptr_array[i] = channel;
}
+ hsotg->next_sched_frame = 0;
+
/* Initialize hsotg start work */
INIT_DELAYED_WORK(&hsotg->start_work, dwc2_hcd_start_func);
diff --git a/drivers/staging/dwc2/hcd.h b/drivers/staging/dwc2/hcd.h
index 3b06024..4f9f6c5 100644
--- a/drivers/staging/dwc2/hcd.h
+++ b/drivers/staging/dwc2/hcd.h
@@ -238,6 +238,7 @@ enum dwc2_transaction_type {
* @interval: Interval between transfers in (micro)frames
* @sched_frame: (Micro)frame to initialize a periodic transfer.
* The transfer executes in the following (micro)frame.
+ * @nak_frame: Internal variable used by the NAK holdoff code
* @start_split_frame: (Micro)frame at which last start split was initialized
* @ntd: Actual number of transfer descriptors in a list
* @dw_align_buf: Used instead of original buffer if its physical address
@@ -271,6 +272,7 @@ struct dwc2_qh {
u16 usecs;
u16 interval;
u16 sched_frame;
+ u16 nak_frame;
u16 start_split_frame;
u16 ntd;
u8 *dw_align_buf;
diff --git a/drivers/staging/dwc2/hcd_intr.c b/drivers/staging/dwc2/hcd_intr.c
index 9e68ef1..b190d2b 100644
--- a/drivers/staging/dwc2/hcd_intr.c
+++ b/drivers/staging/dwc2/hcd_intr.c
@@ -118,9 +118,10 @@ static void dwc2_hc_handle_tt_clear(struct dwc2_hsotg *hsotg,
*/
static void dwc2_sof_intr(struct dwc2_hsotg *hsotg)
{
+ enum dwc2_transaction_type tr_type;
struct list_head *qh_entry;
struct dwc2_qh *qh;
- enum dwc2_transaction_type tr_type;
+ int next_sched_frame = -1;
#ifdef DEBUG_SOF
dev_vdbg(hsotg->dev, "--Start of Frame Interrupt--\n");
@@ -135,14 +136,23 @@ static void dwc2_sof_intr(struct dwc2_hsotg *hsotg)
while (qh_entry != &hsotg->periodic_sched_inactive) {
qh = list_entry(qh_entry, struct dwc2_qh, qh_list_entry);
qh_entry = qh_entry->next;
- if (dwc2_frame_num_le(qh->sched_frame, hsotg->frame_number))
+ if (dwc2_frame_num_le(qh->sched_frame, hsotg->frame_number)) {
/*
* Move QH to the ready list to be executed next
* (micro)frame
*/
list_move(&qh->qh_list_entry,
&hsotg->periodic_sched_ready);
+ } else {
+ if (next_sched_frame < 0 ||
+ dwc2_frame_num_le(qh->sched_frame,
+ next_sched_frame))
+ next_sched_frame = qh->sched_frame;
+ }
}
+
+ hsotg->next_sched_frame = next_sched_frame;
+
tr_type = dwc2_hcd_select_transactions(hsotg);
if (tr_type != DWC2_TRANSACTION_NONE)
dwc2_hcd_queue_transactions(hsotg, tr_type);
@@ -1205,6 +1215,16 @@ static void dwc2_hc_nak_intr(struct dwc2_hsotg *hsotg,
chnum);
/*
+ * When we get bulk NAKs then remember this so we holdoff on this qh
+ * until the beginning of the next frame
+ */
+ switch (dwc2_hcd_get_pipe_type(&qtd->urb->pipe_info)) {
+ case USB_ENDPOINT_XFER_BULK:
+ chan->qh->nak_frame = dwc2_hcd_get_frame_number(hsotg);
+ break;
+ }
+
+ /*
* Handle NAK for IN/OUT SSPLIT/CSPLIT transfers, bulk, control, and
* interrupt. Re-start the SSPLIT transfer.
*/
diff --git a/drivers/staging/dwc2/hcd_queue.c b/drivers/staging/dwc2/hcd_queue.c
index 5461e3b..262e11f 100644
--- a/drivers/staging/dwc2/hcd_queue.c
+++ b/drivers/staging/dwc2/hcd_queue.c
@@ -83,6 +83,7 @@ static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
dev_speed = dwc2_host_get_speed(hsotg, urb->priv);
dwc2_host_hub_info(hsotg, urb->priv, &hub_addr, &hub_port);
+ qh->nak_frame = 0xffff;
if ((dev_speed == USB_SPEED_LOW || dev_speed == USB_SPEED_FULL) &&
hub_addr != 0 && hub_addr != 1) {
@@ -391,13 +392,18 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
return status;
}
- if (hsotg->core_params->dma_desc_enable > 0)
+ if (hsotg->core_params->dma_desc_enable > 0) {
/* Don't rely on SOF and start in ready schedule */
list_add_tail(&qh->qh_list_entry, &hsotg->periodic_sched_ready);
- else
+ } else {
+ if (list_empty(&hsotg->periodic_sched_inactive) ||
+ dwc2_frame_num_le(qh->sched_frame, hsotg->next_sched_frame))
+ hsotg->next_sched_frame = qh->sched_frame;
+
/* Always start in inactive schedule */
list_add_tail(&qh->qh_list_entry,
&hsotg->periodic_sched_inactive);
+ }
/* Reserve periodic channel */
hsotg->periodic_channels++;
@@ -581,12 +587,17 @@ void dwc2_hcd_qh_deactivate(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
* Remove from periodic_sched_queued and move to
* appropriate queue
*/
- if (qh->sched_frame == frame_number)
+ if (qh->sched_frame == frame_number) {
list_move(&qh->qh_list_entry,
&hsotg->periodic_sched_ready);
- else
+ } else {
+ if (!dwc2_frame_num_le(hsotg->next_sched_frame,
+ qh->sched_frame))
+ hsotg->next_sched_frame =
+ qh->sched_frame;
list_move(&qh->qh_list_entry,
&hsotg->periodic_sched_inactive);
+ }
}
}
}
--
1.8.2.rc0.16.g20a599e
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