[Do Not Merge] Introduce DWC2_I_WANT_FS_ON_HS_BOARD hack

[ceedriic]

Describe the PR
This is a proof-of-concept patch to support Full-Speed USB on DWC2 on a board with High-Speed ULPI

Additional context
I've a stm32h747 board with a high-speed external PHY.
But for testing/reliability purposes I want to limit the speed to Full-Speed.

I tried with:

#define BOARD_TUH_MAX_SPEED OPT_MODE_HIGH_SPEED
#define CFG_TUH_MAX_SPEED OPT_MODE_FULL_SPEED

In my tusb_config.h, but with bad results (hang in trying to setup the low-speed phy)

This patch is just a proof-of-concept that it is not too difficult to make that work, In the hope that someone can clean that up :)

[github-actions]

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

No entries.

Changes <1% in size

No entries.

No changes

file	.text	.rodata	.data	.bss	size	% diff
audio_device.c	2855	0	1248	1679	4529	+0.0%
cdc_device.c	1331	16	20	670	2000	+0.0%
cdc_host.c	6596	487	15	1539	8357	+0.0%
dcd_ch32_usbfs.c	1472	0	0	2444	3916	+0.0%
dcd_ch32_usbhs.c	1648	0	0	448	2096	+0.0%
dcd_ci_fs.c	1925	0	0	1290	3215	+0.0%
dcd_ci_hs.c	1762	0	0	1280	2530	+0.0%
dcd_da146xx.c	3067	0	0	144	3211	+0.0%
dcd_dwc2.c	4160	25	0	263	4447	+0.0%
dcd_eptri.c	2270	0	0	259	2529	+0.0%
dcd_khci.c	1953	0	0	1290	3243	+0.0%
dcd_lpc17_40.c	1470	0	0	648	1794	+0.0%
dcd_lpc_ip3511.c	1463	0	0	264	1639	+0.0%
dcd_mm32f327x_otg.c	1478	0	0	1290	2768	+0.0%
dcd_msp430x5xx.c	1796	0	0	176	1972	+0.0%
dcd_musb.c	2079	0	0	160	2239	+0.0%
dcd_nrf5x.c	2919	0	0	292	3211	+0.0%
dcd_nuc120.c	1093	0	0	78	1171	+0.0%
dcd_nuc121.c	1167	0	0	101	1268	+0.0%
dcd_nuc505.c	0	0	1529	157	1686	+0.0%
dcd_rp2040.c	736	20	580	1029	2365	+0.0%
dcd_rusb2.c	2917	0	0	156	3073	+0.0%
dcd_samd.c	1032	0	0	266	1298	+0.0%
dcd_samg.c	1319	0	0	72	1391	+0.0%
dcd_stm32_fsdev.c	2556	0	0	291	2847	+0.0%
dfu_device.c	744	28	712	184	929	+0.0%
dfu_rt_device.c	157	0	134	0	156	+0.0%
dwc2_common.c	594	29	0	0	610	+0.0%
ecm_rndis_device.c	1037	0	1	2272	3310	+0.0%
ehci.c	2761	0	0	5970	7537	+0.0%
fsdev_common.c	180	0	0	0	180	+0.0%
hcd_ch32_usbfs.c	2484	0	0	498	2982	+0.0%
hcd_ci_hs.c	190	0	0	0	190	+0.0%
hcd_dwc2.c	4893	30	0	512	5434	+0.0%
hcd_khci.c	2442	0	0	449	2891	+0.0%
hcd_musb.c	3073	0	0	157	3230	+0.0%
hcd_pio_usb.c	262	0	240	0	502	+0.0%
hcd_rp2040.c	936	73	420	512	1941	+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	3282	0	1	420	3703	+0.0%
hid_device.c	1120	44	997	115	1235	+0.0%
hid_host.c	1206	0	0	1250	2456	+0.0%
hub.c	1235	8	8	29	1268	+0.0%
midi_device.c	1129	0	991	596	1723	+0.0%
midi_host.c	1353	7	7	3740	5097	+0.0%
msc_device.c	2506	108	2274	538	3044	+0.0%
msc_host.c	1589	0	0	394	1984	+0.0%
mtp_device.c	1622	22	1385	578	2208	+0.0%
ncm_device.c	1517	28	1408	5824	7354	+0.0%
ohci.c	1942	0	0	2414	4356	+0.0%
rp2040_usb.c	124	70	574	4	772	+0.0%
rusb2_common.c	160	0	16	0	176	+0.0%
tusb.c	418	0	359	3	420	+0.0%
tusb_fifo.c	844	0	477	0	839	+0.0%
typec_stm32.c	820	8	2	12	842	+0.0%
usbc.c	420	2	20	166	608	+0.0%
usbd.c	3179	57	90	276	3519	+0.0%
usbd_control.c	524	0	474	78	601	+0.0%
usbh.c	4374	60	63	954	5415	+0.0%
usbtmc_device.c	2178	24	70	294	2504	+0.0%
vendor_device.c	636	0	538	470	1105	+0.0%
video_device.c	4402	6	1851	471	4865	+0.0%
TOTAL	112540	1152	16504	46035	160493	+0.0%

[hathach]

why not use the built-in FS PHY instead ? does the mcu only has 1 phy, and that is used by the other usb controller ?

[ceedriic]

why not use the built-in FS PHY instead ? does the mcu only has 1 phy, and that is used by the other usb controller ?

You're right, I could use the built-in FS PHY of the MCU, but the board has been designed with the USB3315C external PHY, to be high-speed capable. So the built-in FS PHY pins are not connected.

At the moment, for some reasons I'm trying to understand, high-speed devices do not enumerate on that board with the latest TinyUSB, but full-speed devices work well. So with this patch I'm able to run high-speed devices in full speed mode.