dcd/musb: defer EP0 SETUP during DATA_IN/STATUS race by HiFiPhile · Pull Request #3643 · hathach/tinyusb

HiFiPhile · 2026-05-14T17:41:33Z

Handle cases where a new SETUP arrives before the previous control transfer fully completes by buffering the SETUP and replaying it after status completion. Split EP0 DATA state into DATA_IN/DATA_OUT and finalize pending status-out completion before processing deferred SETUP.

Take care these 2 cases if new SETUP packet arrived while old control transfer is not finished yet. This could happen in following scenarios when CPU load is high:

Status IN/OUT finished, IRQ and new setup packet IRQ arrive at the same time.
Data IN finished and status OUT is received, both IRQs and new setup packet IRQ arrive at the same time.

Supercede #3626

Tested intensively with DFU example with Interrupt turned on/off every 20ms simulating high CP load:

diff --git a/examples/device/dfu/src/main.c b/examples/device/dfu/src/main.c
index fb3c22630..d4e75a44b 100644
--- a/examples/device/dfu/src/main.c
+++ b/examples/device/dfu/src/main.c
@@ -45,6 +45,7 @@
 #include "bsp/board_api.h"
 #include "tusb.h"
 
+#include "device/dcd.h"
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF PROTYPES
 //--------------------------------------------------------------------+
@@ -65,6 +66,7 @@ enum {
 static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED;
 
 void led_blinking_task(void);
+static void musb_test(void);
 
 /*------------- MAIN -------------*/
 int main(void) {
@@ -79,6 +81,7 @@ int main(void) {
   while (1) {
     tud_task(); // tinyusb device task
     led_blinking_task();
+    musb_test();
   }
 }
 
@@ -86,6 +89,26 @@ int main(void) {
 // Device callbacks
 //--------------------------------------------------------------------+
 
+// on off usb interrupt 20ms for testing
+static void musb_test(void) {
+  static uint32_t start_ms  = 0;
+  static bool irq_enabled = true;
+
+  if (tusb_time_millis_api() - start_ms < 20) {
+    return; // not enough time
+  }
+
+  if (irq_enabled) {
+    dcd_int_disable(0);
+    tusb_time_delay_ms_api(20);
+    dcd_int_enable(0);
+  } else {
+  }
+
+  irq_enabled = !irq_enabled;
+  start_ms += 20;
+}
+
 // Invoked when device is mounted
 void tud_mount_cb(void) {
   blink_interval_ms = BLINK_MOUNTED;
@@ -122,7 +145,7 @@ uint32_t tud_dfu_get_timeout_cb(uint8_t alt, uint8_t state) {
     // For this example
     // - Atl0 Flash is fast : 1   ms
     // - Alt1 EEPROM is slow: 100 ms
-    return (alt == 0) ? 1 : 100;
+    return (alt == 0) ? 0 : 0;
   } else if (state == DFU_MANIFEST) {
     // since we don't buffer entire image and do any flashing in manifest stage
     return 0;
@@ -142,9 +165,9 @@ void tud_dfu_download_cb(uint8_t alt, uint16_t block_num, const uint8_t *data, u
 
   //printf("\r\nReceived Alt %u BlockNum %u of length %u\r\n", alt, wBlockNum, length);
 
-  for (uint16_t i = 0; i < length; i++) {
-    printf("%c", data[i]);
-  }
+  //for (uint16_t i = 0; i < length; i++) {
+  //  printf("%c", data[i]);
+  //}
 
   // flashing op for download complete without error
   tud_dfu_finish_flashing(DFU_STATUS_OK);

Copilot

Pull request overview

This PR updates the Mentor MUSB device controller (DCD) EP0 control-transfer state machine to better handle a race where a new SETUP arrives before the prior control transfer has fully completed (typically under high CPU load). It also adjusts MUSB port headers to avoid multiple-definition linkage issues around MUSB_BASES.

Changes:

Split EP0 DATA state into explicit DATA_IN / DATA_OUT states and add buffering of a “deferred” SETUP request to replay after status completion.
Add logic to complete pending STATUS stages before dispatching the deferred SETUP.
Make MUSB_BASES static const in MUSB port headers to prevent ODR/multiple-definition problems.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/portable/mentor/musb/musb_ti.h	Make `MUSB_BASES` `static const` to avoid multiple definitions across translation units.
src/portable/mentor/musb/musb_max32.h	Same `MUSB_BASES` linkage fix for the MAX32 port.
src/portable/mentor/musb/dcd_musb.c	Rework EP0 control-transfer state machine and add deferred-SETUP buffering/replay to handle SETUP vs status/data completion races.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

github-actions · 2026-05-14T17:55:22Z

Size Difference Report

Because TinyUSB code size varies by port and configuration, the metrics below represent the averaged totals across all example builds.

Note: If there is no change, only one value is shown.

Changes >1% in size

file	.text	.bss	size	% diff
dcd_musb.c	2226 ➙ 2451 (+225)	171 ➙ 179 (+8)	2396 ➙ 2630 (+234)	+9.8%
TOTAL	2226 ➙ 2451 (+225)	171 ➙ 179 (+8)	2396 ➙ 2630 (+234)	+9.8%

Changes <1% in size

No entries.

No changes

file	.text	.rodata	.data	.bss	size	% diff
audio_device.c	2896	0	1259	1625	4515	+0.0%
cdc_device.c	1239	16	1092	735	1972	+0.0%
cdc_host.c	6381	487	15	985	7579	+0.0%
dcd_ch32_usbfs.c	1475	0	0	2444	3919	+0.0%
dcd_ch32_usbhs.c	1468	0	0	448	1916	+0.0%
dcd_ci_fs.c	1924	0	0	1290	3214	+0.0%
dcd_ci_hs.c	1758	0	0	1344	2535	+0.0%
dcd_da146xx.c	3067	0	0	144	3211	+0.0%
dcd_dwc2.c	4261	19	0	265	4544	+0.0%
dcd_eptri.c	2272	0	0	259	2531	+0.0%
dcd_ft9xx.c	3280	0	0	172	3452	+0.0%
dcd_khci.c	1952	0	0	1290	3242	+0.0%
dcd_lpc17_40.c	1478	0	0	648	1802	+0.0%
dcd_lpc_ip3511.c	1463	0	0	264	1683	+0.0%
dcd_mm32f327x_otg.c	1477	0	0	1290	2767	+0.0%
dcd_msp430x5xx.c	1799	0	0	176	1975	+0.0%
dcd_nrf5x.c	2940	0	0	292	3232	+0.0%
dcd_nuc120.c	1095	0	0	78	1173	+0.0%
dcd_nuc121.c	1168	0	0	101	1270	+0.0%
dcd_nuc505.c	0	0	1532	157	1689	+0.0%
dcd_rp2040.c	841	0	764	653	2258	+0.0%
dcd_rusb2.c	2917	0	0	156	3073	+0.0%
dcd_samd.c	1036	0	0	266	1302	+0.0%
dcd_samg.c	1321	0	0	72	1393	+0.0%
dcd_stm32_fsdev.c	2558	0	0	291	2849	+0.0%
dfu_device.c	777	28	712	138	914	+0.0%
dfu_rt_device.c	157	0	134	0	157	+0.0%
dwc2_common.c	603	22	0	0	615	+0.0%
ecm_rndis_device.c	1059	0	1	2759	3818	+0.0%
ehci.c	2763	0	0	6172	7701	+0.0%
fsdev_common.c	180	0	0	0	180	+0.0%
hcd_ch32_usbfs.c	2485	0	0	498	2983	+0.0%
hcd_ci_hs.c	180	0	0	0	180	+0.0%
hcd_dwc2.c	5014	25	1	513	5552	+0.0%
hcd_khci.c	2442	0	0	449	2891	+0.0%
hcd_musb.c	3070	0	0	157	3228	+0.0%
hcd_pio_usb.c	262	0	240	0	502	+0.0%
hcd_rp2040.c	2000	17	4	321	2342	+0.0%
hcd_rusb2.c	2923	0	0	245	3168	+0.0%
hcd_samd.c	2220	0	0	324	2544	+0.0%
hcd_stm32_fsdev.c	3256	0	1	420	3677	+0.0%
hid_device.c	1125	44	997	119	1244	+0.0%
hid_host.c	1240	0	0	1251	2491	+0.0%
hub.c	1384	8	8	30	1418	+0.0%
midi_device.c	1151	0	1007	624	1773	+0.0%
midi_host.c	1341	7	7	3635	4979	+0.0%
msc_device.c	2517	108	2281	806	3323	+0.0%
msc_host.c	1638	0	0	394	2033	+0.0%
mtp_device.c	1706	22	739	588	2302	+0.0%
ncm_device.c	1757	28	815	4310	6080	+0.0%
ohci.c	1919	0	0	2464	4383	+0.0%
printer_device.c	830	0	706	566	1394	+0.0%
rp2040_usb.c	378	35	631	11	1055	+0.0%
rusb2_common.c	160	0	16	0	176	+0.0%
tusb.c	450	0	383	3	452	+0.0%
tusb_fifo.c	847	0	483	0	842	+0.0%
typec_stm32.c	820	8	2	12	842	+0.0%
usbc.c	420	2	20	166	608	+0.0%
usbd.c	3522	58	91	355	3941	+0.0%
usbh.c	4668	57	111	1032	5832	+0.0%
usbtmc_device.c	2196	24	68	316	2544	+0.0%
vendor_device.c	641	0	534	565	1204	+0.0%
video_device.c	4443	5	1235	479	4914	+0.0%
TOTAL	116610	1020	15889	45167	163378	+0.0%

github-actions · 2026-05-14T18:23:04Z

MemBrowse Memory Report

Top 10 targets by memory change (%) (out of 2253 targets) View Project Dashboard →

target	.text	.rodata	.data	.bss	total	% diff
msp_exp432e401y/dfu_runtime	8,592 → 8,832 (+240)	—	—	1,048 → 1,056 (+8)	10,372 → 10,620 (+248)	+2.4%
msp_exp432e401y/hid_generic_inout	9,644 → 9,884 (+240)	—	—	1,252 → 1,260 (+8)	11,628 → 11,876 (+248)	+2.1%
msp_exp432e401y/hid_multiple_interface	10,428 → 10,668 (+240)	—	—	1,128 → 1,136 (+8)	12,288 → 12,536 (+248)	+2.0%
msp_exp432e401y/hid_boot_interface	10,440 → 10,680 (+240)	—	—	1,128 → 1,136 (+8)	12,300 → 12,548 (+248)	+2.0%
msp_exp432e401y/hid_composite	10,652 → 10,892 (+240)	—	—	1,116 → 1,124 (+8)	12,500 → 12,748 (+248)	+2.0%
msp_exp432e401y/midi_test	10,748 → 10,988 (+240)	—	—	1,248 → 1,256 (+8)	12,728 → 12,976 (+248)	+1.9%
ek_tm4c123gxl/dfu_runtime	8,540 → 8,780 (+240)	—	—	612 → 620 (+8)	13,316 → 13,564 (+248)	+1.9%
msp_exp432e401y/cdc_dual_ports	11,592 → 11,832 (+240)	—	—	1,432 → 1,440 (+8)	13,756 → 14,004 (+248)	+1.8%
msp_exp432e401y/printer_to_cdc	11,716 → 11,956 (+240)	—	—	1,412 → 1,420 (+8)	13,852 → 14,100 (+248)	+1.8%
msp_exp432e401y/webusb_serial	12,096 → 12,336 (+240)	—	—	1,420 → 1,428 (+8)	14,248 → 14,496 (+248)	+1.7%

Handle cases where a new SETUP arrives before the previous control transfer fully completes by buffering the SETUP and replaying it after status completion. Split EP0 DATA state into DATA_IN/DATA_OUT and finalize pending status-out completion before processing deferred SETUP. Signed-off-by: HiFiPhile <admin@hifiphile.com>

Signed-off-by: HiFiPhile <admin@hifiphile.com>

Copilot AI review requested due to automatic review settings May 14, 2026 17:41

github-actions Bot added the Prio Higher label May 14, 2026

Copilot started reviewing on behalf of HiFiPhile May 14, 2026 17:42 View session

HiFiPhile force-pushed the musb_ep0_race branch from f0eafce to 75dcec2 Compare May 14, 2026 17:45

Copilot AI reviewed May 14, 2026

View reviewed changes

Comment thread src/portable/mentor/musb/dcd_musb.c Outdated

Comment thread src/portable/mentor/musb/dcd_musb.c

HiFiPhile force-pushed the musb_ep0_race branch from 75dcec2 to da1f953 Compare May 14, 2026 18:05

HiFiPhile force-pushed the musb_ep0_race branch from da1f953 to c4cd6c8 Compare May 14, 2026 21:50

fix test hung

ae61e6c

Signed-off-by: HiFiPhile <admin@hifiphile.com>

This was referenced May 15, 2026

dwc2: preserve EP0 status completion before SETUP #3634

Draft

DFU on an MUSB-based controller (MSPM0) #3415

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

dcd/musb: defer EP0 SETUP during DATA_IN/STATUS race#3643

dcd/musb: defer EP0 SETUP during DATA_IN/STATUS race#3643
HiFiPhile wants to merge 2 commits into
masterfrom
musb_ep0_race

HiFiPhile commented May 14, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Uh oh!

github-actions Bot commented May 14, 2026 •

edited

Loading

Uh oh!

github-actions Bot commented May 14, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Conversation

HiFiPhile commented May 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

Uh oh!

github-actions Bot commented May 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Size Difference Report

Changes >1% in size

Changes <1% in size

Uh oh!

github-actions Bot commented May 14, 2026

MemBrowse Memory Report

Top 10 targets by memory change (%) (out of 2253 targets) View Project Dashboard →

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

HiFiPhile commented May 14, 2026 •

edited

Loading

github-actions Bot commented May 14, 2026 •

edited

Loading