On 2026-08-10 15:26, Anshul Dalal wrote:
> On Mon Aug 10, 2026 at 1:52 PM IST, Anders Roxell wrote:
> > On 2026-08-06 18:47, Anshul Dalal wrote:
> >> On Thu, 16 Jul 2026 15:41:30 +0200, Anders Roxell
> >> <[email protected]> wrote:
> >> > [...]
[...]
> >
> > And in dwc3_gadget_uboot_handle_interrupt(), same file:
> >
> > - struct dwc3_event_buffer *evt;
> > - dwc3_thread_interrupt(0, dwc);
> > + struct dwc3_event_buffer *evt = dwc->ev_buf;
> > + dwc3_thread_interrupt(0, evt);
>
> Thanks for the pointers Anders but I encounter a similar failure even
> with the diff you suggested. I enabled some logging for the SPL by
> defining the DEBUG macro in the following files (dfu.c spl.c spl_ram.c
> dwc3-am62.c composite.c g_dnl.c).
Hi Anshul,
Good news. I found two more bugs on top of the two I already sent you
(the event buffer and allow_connect). With all four the device
enumerates.
>
> Failure logs:
>
> U-Boot SPL 2026.07-00860-g5a9b7a715be2 (Aug 10 2026 - 15:06:27 +0530)
> SYSFW ABI: 4.0 (firmware rev 0x000c '12.1.0--v12.01.00 (Clever Cat)')
> Set clock rates for '/a53@0', CPU: 1250MHz at Speed Grade 'V'
> SPL initial stack usage: 17104 bytes
> SPL malloc() before relocation used 0x64d0 bytes (25 KB)
> >>SPL: board_init_r()
> spl_init
> Trying to boot from DFU
> g_dnl_register: g_dnl_driver.name = usb_dnl_dfu
> g_dnl_bind: gadget: 0x81c44a98 cdev: 0x81c66bc0
> usb_add_config: adding config #1 'usb_dnload'/81c67cc0
> g_dnl_do_config: configuration: 0x81c67cc0 composite dev: 0x81c66bc0
> adding 'dfu'/81c67d34 to config 'usb_dnload'/81c67cc0
> cfg 1/81c67cc0 speeds: high full
> usb_add_config: interface 0 = dfu/81c67d34
> g_dnl_bind: calling usb_gadget_connect for controller 'dwc3-gadget'
> usb_dnl_dfu: ready
>
> <CTRL-C> from user
>
> unbind function 'dfu'/81c67d34
> g_dnl_unbind: calling usb_gadget_disconnect for controller 'dwc3-gadget'
> Legacy image
> u_boot_pos = ffffffff
> Raw boot image support not enabled, proceeding to other boot methods
> Error: -22
> SPL: Unsupported Boot Device!
> SPL: failed to boot from all boot devices
> ### ERROR ### Please RESET the board ###
>
> Succes logs (same debug symbols ontop of main branch):
>
> U-Boot SPL 2026.10-rc1-00209-g0bdd5e5daf95 (Aug 10 2026 - 14:58:28
> +0530)
> SYSFW ABI: 4.0 (firmware rev 0x000c '12.1.0--v12.01.00 (Clever Cat)')
> Set clock rates for '/a53@0', CPU: 1250MHz at Speed Grade 'V'
> SPL initial stack usage: 17104 bytes
> SPL malloc() before relocation used 0x64d0 bytes (25 KB)
> >>SPL: board_init_r()
> spl_init
> Trying to boot from DFU
> g_dnl_register: g_dnl_driver.name = usb_dnl_dfu
> g_dnl_bind: gadget: 0x81c44aa4 cdev: 0x81c4af40
> usb_add_config: adding config #1 'usb_dnload'/81c4c040
> g_dnl_do_config: configuration: 0x81c4c040 composite dev: 0x81c4af40
> adding 'dfu'/81c4c0b4 to config 'usb_dnload'/81c4c040
> cfg 1/81c4c040 speeds: high full
> usb_add_config: interface 0 = dfu/81c4c0b4
> g_dnl_bind: calling usb_gadget_connect for controller 'dwc3-gadget'
> usb_dnl_dfu: ready
> composite_suspend: suspend
> set_config: high speed config #1: usb_dnload
> non-core control reqa1.03 v0000 i0000 l6
> non-core control req21.01 v0000 i0000 l4096
> ...(repeated)
> #non-core control reqa1.03 v0000 i0000 l6
> non-core control reqa1.03 v0000 i0000 l6
> DOWNLOAD ... OK
> Ctrl+C to exit ...
>
> I'm not that familiar with the DW3 driver, let me know if you need me to
> test with any further changes.
>
> >
> > evt was used there without being set as well.
> >
> > All of this is in v6 that I plan to send out. I have no AM62p and it is
> > only compile tested, so please try it on your board so we know if it
> > solves your issue before I send out v6.
>
> I was able to reproduce the issue on beagleplay since it uses the same
> DWC3. You can try it locally if you have that board with you by
> resetting to DFU mode from U-Boot prompt:
>
> => mw.w 43000030 53; res
I could not use the mw.w 43000030 53; res trick on the BeagleBoard-X15
that I found. But I can run DFU directly, it is the same DWC3 gadget
path you hit.
How I tested on x15:
env set dfu_alt_info "${dfu_alt_info_ram}"
dfu 0 ram 0
On the host dfu-util finds it:
Found DFU: [0451:d022] ... name="kernel"/"fdt"/"ramdisk"
The two new bugs:
3. udc-core never sets dwc->async_callbacks. So the gadget setup() is
never called and every GET_DESCRIPTOR returns -EINVAL.
4. ep0. The trb and the ep0 buffers are normal cached memory. In u-boot
dma_alloc_coherent is not coherent, so nothing keeps them in sync with
the controller dma. The resync dropped the manual flush and invalidate,
so the controller reads a stale trb and stale buffers.
The patch below is only 3 and 4. Keep the first two you already have,
this goes on top. It is against v5. I built it and tested it on x15,
it works.
Can you test it on BeaglePlay with your reset trick? These fixes will
be part of the coming usb_dwc3_sync_v6 branch.
Cheers,
Anders
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 0a4f69cbc28a..2ba05fc3f573 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -54,6 +54,9 @@ static void dwc3_ep0_prepare_one_trb(struct dwc3_ep *dep,
else
trb->ctrl |= (DWC3_TRB_CTRL_IOC
| DWC3_TRB_CTRL_LST);
+
+ dwc3_flush_cache((uintptr_t)buf_dma, len);
+ dwc3_flush_cache((uintptr_t)trb, sizeof(*trb));
}
static int dwc3_ep0_start_trans(struct dwc3_ep *dep)
@@ -811,6 +814,8 @@ static void dwc3_ep0_inspect_setup(struct dwc3 *dwc,
int ret = -EINVAL;
u32 len;
+ dwc3_invalidate_cache((uintptr_t)ctrl, sizeof(*ctrl));
+
if (!dwc->gadget_driver || !dwc->softconnect || !dwc->connected)
goto out;
@@ -856,6 +861,8 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
dwc->ep0_next_event = DWC3_EP0_NRDY_STATUS;
trb = dwc->ep0_trb;
+ dwc3_invalidate_cache((uintptr_t)trb, sizeof(*trb) * 2);
+
r = next_request(&ep0->pending_list);
if (!r)
return;
@@ -873,6 +880,9 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
length = trb->size & DWC3_TRB_SIZE_MASK;
transferred = ur->length - length;
+
+ if (ur->buf && !r->direction)
+ dwc3_invalidate_cache((uintptr_t)ur->dma, ur->length);
ur->actual += transferred;
if ((IS_ALIGNED(ur->length, ep0->endpoint.maxpacket) &&
diff --git a/drivers/usb/gadget/udc/udc-core.c
b/drivers/usb/gadget/udc/udc-core.c
index 6355931f9ff1..f03ff937dfde 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -941,6 +941,8 @@ static inline void usb_gadget_udc_set_speed(struct usb_udc
*udc,
gadget->ops->udc_set_speed(gadget, s);
}
+static inline void usb_gadget_enable_async_callbacks(struct usb_udc *udc);
+
static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver
*driver)
{
int ret;
@@ -960,6 +962,7 @@ static int udc_bind_to_driver(struct usb_udc *udc, struct
usb_gadget_driver *dri
driver->unbind(udc->gadget);
goto err1;
}
+ usb_gadget_enable_async_callbacks(udc);
udc->allow_connect = true;
usb_gadget_connect(udc->gadget);
@@ -1156,6 +1159,7 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
udc->driver->function);
udc->allow_connect = false;
+ usb_gadget_disable_async_callbacks(udc);
usb_gadget_disconnect(udc->gadget);
udc->driver->disconnect(udc->gadget);
udc->driver->unbind(udc->gadget);
