usb_ep_{dis,en}able() calling context (was: Re: [PATCH 2/3] usb: dwc3: gadget: wait for End Transfer to complete)

Message ID CAMz4kuKysBckKPjFeGSHGCxCJvHu1-AzcAbRxyc8fif3tpz-FA@mail.gmail.com
State New
Headers show

Commit Message

Baolin Wang Oct. 20, 2016, 7:44 a.m.
Hi,

On 19 October 2016 at 18:09, Felipe Balbi <felipe.balbi@linux.intel.com> wrote:
>

> Hi,

>

> Baolin Wang <baolin.wang@linaro.org> writes:

>>

>> We should not check the DWC3_EP_ENABLED flag, since we will clear all

>> flags in __dwc3_gadget_ep_disable() after setting

>> DWC3_EP_END_TRANSFER_PENDING flags in dwc3_stop_active_transfer().

>

> good catch.

>

>>

>>> +

>>> +               if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING))

>>> +                       continue;

>>

>> Ditto.

>

> yeah, END_TRANSFER_PENDING should only be cleared by command completion,

> so ep_disable needs to be patched.

>

>>> +

>>> +               wait_event_lock_irq(dep->wait_end_transfer,

>>> +                               !(dep->flags & DWC3_EP_END_TRANSFER_PENDING),

>>> +                               dwc->lock);

>>> +       }

>>>  }

>>>

>>>  static int dwc3_gadget_stop(struct usb_gadget *g)

>>> @@ -2171,6 +2189,7 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,

>>>  {

>>>         struct dwc3_ep          *dep;

>>>         u8                      epnum = event->endpoint_number;

>>> +       u8                      cmd;

>>

>> Here we should add below modification, or the event can not be handled.

>>

>> - if (!(dep->flags & DWC3_EP_ENABLED))

>> + if (!(dep->flags & DWC3_EP_ENABLED) &&

>> + !(dep->flags & DWC3_EP_END_TRANSFER_PENDING))

>> return;

>

> this seems unnecessary to me. The only interrupt with a disabled

> endpoint should be due to END_TRANSFER cmd completion. In fact, I'm now

> thinking that maybe usb_ep_disable() should also block until EndTransfer

> completes.

>

> This would means replacing wake_up() with wake_up_all()

>

>>> I'll run some tests with this in a couple hours.

>>

>> I would like to send out new version based on my original patch

>> according to your suggestion, or you can send out new version I can

>> help to test. Thanks.

>

> From ce24ab50d57a18287a99ea776e9bdc7d5cfd282c Mon Sep 17 00:00:00 2001

> From: Baolin Wang <baolin.wang@linaro.org>

> Date: Thu, 13 Oct 2016 14:09:47 +0300

> Subject: [PATCH] usb: dwc3: gadget: wait for End Transfer to complete

>

> Instead of just delaying for 100us, we should

> actually wait for End Transfer Command Complete

> interrupt before moving on. Note that this should

> only be done if we're dealing with one of the core

> revisions that actually require the interrupt before

> moving on.

>

> [ felipe.balbi@linux.intel.com: minor improvements ]

>

> NYET-Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

> ---

>  drivers/usb/dwc3/core.h   |  8 ++++++++

>  drivers/usb/dwc3/gadget.c | 40 +++++++++++++++++++++++++++++++++++++---

>  2 files changed, 45 insertions(+), 3 deletions(-)

>

> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h

> index 5fc437021ac7..0cb3b78d28b7 100644

> --- a/drivers/usb/dwc3/core.h

> +++ b/drivers/usb/dwc3/core.h

> @@ -26,6 +26,7 @@

>  #include <linux/dma-mapping.h>

>  #include <linux/mm.h>

>  #include <linux/debugfs.h>

> +#include <linux/wait.h>

>

>  #include <linux/usb/ch9.h>

>  #include <linux/usb/gadget.h>

> @@ -505,6 +506,7 @@ struct dwc3_event_buffer {

>   * @endpoint: usb endpoint

>   * @pending_list: list of pending requests for this endpoint

>   * @started_list: list of started requests on this endpoint

> + * @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

>   * @trb_pool: array of transaction buffers

> @@ -530,6 +532,8 @@ struct dwc3_ep {

>         struct list_head        pending_list;

>         struct list_head        started_list;

>

> +       wait_queue_head_t       wait_end_transfer;

> +

>         spinlock_t              lock;

>         void __iomem            *regs;

>

> @@ -546,6 +550,7 @@ struct dwc3_ep {

>  #define DWC3_EP_BUSY           (1 << 4)

>  #define DWC3_EP_PENDING_REQUEST        (1 << 5)

>  #define DWC3_EP_MISSED_ISOC    (1 << 6)

> +#define DWC3_EP_END_TRANSFER_PENDING (1 << 7)

>

>         /* This last one is specific to EP0 */

>  #define DWC3_EP0_DIR_IN                (1 << 31)

> @@ -1050,6 +1055,9 @@ struct dwc3_event_depevt {

>  #define DEPEVT_TRANSFER_BUS_EXPIRY     2

>

>         u32     parameters:16;

> +

> +/* For Command Complete Events */

> +#define DEPEVT_PARAMETER_CMD(n) (((n) & (0xf << 8)) >> 8)

>  } __packed;

>

>  /**

> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c

> index 3b53a5714df4..bc985f8571c6 100644

> --- a/drivers/usb/dwc3/gadget.c

> +++ b/drivers/usb/dwc3/gadget.c

> @@ -598,6 +598,8 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep,

>                 reg |= DWC3_DALEPENA_EP(dep->number);

>                 dwc3_writel(dwc->regs, DWC3_DALEPENA, reg);

>

> +               init_waitqueue_head(&dep->wait_end_transfer);

> +

>                 if (usb_endpoint_xfer_control(desc))

>                         return 0;

>

> @@ -772,6 +774,10 @@ static int dwc3_gadget_ep_disable(struct usb_ep *ep)

>                                         dep->name))

>                 return 0;

>

> +       if (dep->flags & DWC3_EP_END_TRANSFER_PENDING)

> +               wait_event(dep->wait_end_transfer,

> +                               !(dep->flags & DWC3_EP_END_TRANSFER_PENDING));

> +


We will set DWC3_EP_END_TRANSFER_PENDING flag in
dwc3_stop_active_transfer() function (function stack:
dwc3_gadget_ep_disable()--->__dwc3_gadget_ep_disable()--->dwc3_remove_requests()---->dwc3_stop_active_transfer()),
but it will cleane all flags in __dwc3_gadget_ep_disable() function.
So when issuing __dwc3_gadget_stop(), we can not check
DWC3_EP_END_TRANSFER_PENDING flag to wait for command complete event.

>         spin_lock_irqsave(&dwc->lock, flags);

>         ret = __dwc3_gadget_ep_disable(dep);

>         spin_unlock_irqrestore(&dwc->lock, flags);

> @@ -1782,13 +1788,30 @@ static int dwc3_gadget_start(struct usb_gadget *g,

>  }

>

>  static void __dwc3_gadget_stop(struct dwc3 *dwc)

> +__releases(&dwc->lock) __acquires(&dwc->lock)

>  {

> +       int                     epnum;

> +

>         if (pm_runtime_suspended(dwc->dev))

>                 return;

>

>         dwc3_gadget_disable_irq(dwc);

>         __dwc3_gadget_ep_disable(dwc->eps[0]);

>         __dwc3_gadget_ep_disable(dwc->eps[1]);

> +

> +       for (epnum = 2; epnum < DWC3_ENDPOINTS_NUM; epnum++) {

> +               struct dwc3_ep  *dep = dwc->eps[epnum];

> +

> +               if (!(dep->flags & DWC3_EP_ENABLED))

> +                       continue;

> +

> +               if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING))

> +                       continue;

> +

> +               wait_event_lock_irq(dep->wait_end_transfer,

> +                               !(dep->flags & DWC3_EP_END_TRANSFER_PENDING),

> +                               dwc->lock);

> +       }


When gadget suspend to stop gadget, we will never get the command
complete event, since we will exit the dwc3 core. Thus we can move
this checking into dwc3_gadget_stop() and we will clean the
DWC3_EP_END_TRANSFER_PENDING flag when re-enable the endpoint.

I did one patch based on your patch which did some modification, and I
tested the usb function changing and suspend/resume, it can work well.
Could you check it if it is OK? Thanks.
From 6fdb5cd4216755f07bb1a1e5d081e269046c60c6 Mon Sep 17 00:00:00 2001
Message-Id: <6fdb5cd4216755f07bb1a1e5d081e269046c60c6.1476949020.git.baolin.wang@linaro.org>
From: Baolin Wang <baolin.wang@linaro.org>

Date: Thu, 20 Oct 2016 15:35:54 +0800
Subject: [PATCH v1] usb: dwc3: gadget: wait for End Transfer to complete

Instead of just delaying for 100us, we should
actually wait for End Transfer Command Complete
interrupt before moving on. Note that this should
only be done if we're dealing with one of the core
revisions that actually require the interrupt before
moving on.

[ felipe.balbi@linux.intel.com: minor improvements ]

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

---
 drivers/usb/dwc3/core.h   |    8 ++++++++
 drivers/usb/dwc3/gadget.c |   47 +++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 51 insertions(+), 4 deletions(-)

  /*
@@ -2277,8 +2314,10 @@ static void dwc3_stop_active_transfer(struct
dwc3 *dwc, u32 epnum, bool force)
  dep->resource_index = 0;
  dep->flags &= ~DWC3_EP_BUSY;

- if (dwc3_is_usb31(dwc) || dwc->revision < DWC3_REVISION_310A)
+ if (dwc3_is_usb31(dwc) || dwc->revision < DWC3_REVISION_310A) {
+ dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
  udelay(100);
+ }
 }

 static void dwc3_stop_active_transfers(struct dwc3 *dwc)
-- 
1.7.9.5

-- 
Baolin.wang
Best Regards
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch hide | download patch | download mbox

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 23765a1..c5fd862 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -26,6 +26,7 @@ 
 #include <linux/dma-mapping.h>
 #include <linux/mm.h>
 #include <linux/debugfs.h>
+#include <linux/wait.h>

 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
@@ -496,6 +497,7 @@  struct dwc3_event_buffer {
  * @endpoint: usb endpoint
  * @pending_list: list of pending requests for this endpoint
  * @started_list: list of started requests on this endpoint
+ * @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
  * @trb_pool: array of transaction buffers
@@ -521,6 +523,8 @@  struct dwc3_ep {
  struct list_head pending_list;
  struct list_head started_list;

+ wait_queue_head_t wait_end_transfer;
+
  spinlock_t lock;
  void __iomem *regs;

@@ -537,6 +541,7 @@  struct dwc3_ep {
 #define DWC3_EP_BUSY (1 << 4)
 #define DWC3_EP_PENDING_REQUEST (1 << 5)
 #define DWC3_EP_MISSED_ISOC (1 << 6)
+#define DWC3_EP_END_TRANSFER_PENDING (1 << 7)

  /* This last one is specific to EP0 */
 #define DWC3_EP0_DIR_IN (1 << 31)
@@ -1044,6 +1049,9 @@  struct dwc3_event_depevt {
 #define DEPEVT_TRANSFER_BUS_EXPIRY 2

  u32 parameters:16;
+
+/* For Command Complete Events */
+#define DEPEVT_PARAMETER_CMD(n) (((n) & (0xf << 8)) >> 8)
 } __packed;

 /**
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 3722c90..018611d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -570,11 +570,14 @@  static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep,
  dep->comp_desc = comp_desc;
  dep->type = usb_endpoint_type(desc);
  dep->flags |= DWC3_EP_ENABLED;
+ dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;

  reg = dwc3_readl(dwc->regs, DWC3_DALEPENA);
  reg |= DWC3_DALEPENA_EP(dep->number);
  dwc3_writel(dwc->regs, DWC3_DALEPENA, reg);

+ init_waitqueue_head(&dep->wait_end_transfer);
+
  if (usb_endpoint_xfer_control(desc))
  return 0;

@@ -647,7 +650,7 @@  static int __dwc3_gadget_ep_disable(struct dwc3_ep *dep)
  dep->endpoint.desc = NULL;
  dep->comp_desc = NULL;
  dep->type = 0;
- dep->flags = 0;
+ dep->flags &= DWC3_EP_END_TRANSFER_PENDING;

  return 0;
 }
@@ -1736,10 +1739,34 @@  static int dwc3_gadget_stop(struct usb_gadget *g)
 {
  struct dwc3 *dwc = gadget_to_dwc(g);
  unsigned long flags;
+ int epnum;

  spin_lock_irqsave(&dwc->lock, flags);
  __dwc3_gadget_stop(dwc);
  dwc->gadget_driver = NULL;
+
+ for (epnum = 2; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
+ struct dwc3_ep  *dep = dwc->eps[epnum];
+
+ /*
+ * If the dwc3 core has been in suspend state, we will never get
+ * the command complete event, thus ignore.
+ */
+ if (pm_runtime_suspended(dwc->dev))
+ break;
+
+ if (!dep)
+ continue;
+
+ if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING))
+ continue;
+
+
+ wait_event_lock_irq(dep->wait_end_transfer,
+    !(dep->flags & DWC3_EP_END_TRANSFER_PENDING),
+    dwc->lock);
+ }
+
  spin_unlock_irqrestore(&dwc->lock, flags);

  free_irq(dwc->irq_gadget, dwc->ev_buf);
@@ -2105,10 +2132,12 @@  static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 {
  struct dwc3_ep *dep;
  u8 epnum = event->endpoint_number;
+ u8 cmd;

  dep = dwc->eps[epnum];

- if (!(dep->flags & DWC3_EP_ENABLED))
+ if (!(dep->flags & DWC3_EP_ENABLED) &&
+    !(dep->flags & DWC3_EP_END_TRANSFER_PENDING))
  return;

  if (epnum == 0 || epnum == 1) {
@@ -2180,6 +2209,13 @@  static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
  dwc3_trace(trace_dwc3_gadget, "%s FIFO Overrun", dep->name);
  break;
  case DWC3_DEPEVT_EPCMDCMPLT:
+ cmd = DEPEVT_PARAMETER_CMD(event->parameters);
+
+ if (cmd == DWC3_DEPCMD_ENDTRANSFER) {
+ dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
+ wake_up(&dep->wait_end_transfer);
+ }
+
  dwc3_trace(trace_dwc3_gadget, "Endpoint Command Complete");
  break;
  }
@@ -2233,7 +2269,8 @@  static void dwc3_stop_active_transfer(struct
dwc3 *dwc, u32 epnum, bool force)

  dep = dwc->eps[epnum];

- if (!dep->resource_index)
+ if ((dep->flags & DWC3_EP_END_TRANSFER_PENDING) ||
+    !dep->resource_index)
  return;