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rk27xx: keep interrupt and bulk endpoints in separate groups

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USB mass storage writes ran at 0.03 MB/s in the firmware - to the NAND
and to the SD card alike - while the bootloader, with the same driver,
wrote the same NAND at 2 MB/s. The firmware adds a HID interface, and
without it writes ran at full speed.

The UDC's endpoints come in groups of three - bulk OUT, bulk IN,
interrupt IN: 1-3, 4-6 and so on - and allocation handed out the first
free endpoint of each type, so HID's interrupt endpoint 3 landed in the
group of mass storage's bulk endpoints 1 and 2. The host polls it every
16 ms, the idle endpoint NAKs, and each poll costs the group's bulk
traffic: writes advanced about one packet per poll. Polled every 125 us
instead, they all but stopped; moved to endpoint 6, in a group of its
own, they ran at 2.36 MB/s, as without HID.

Never give an interrupt endpoint a group with bulk endpoints in use, or
the other way round, whichever class asks first. Since which endpoints
are available then depends on what is already allocated, the driver
tracks the allocation itself - option 2 of usb_drv.h, as usb-designware
does - with its context in usb-rk27xx.h, which usb_core.c includes before
usb_drv.h. HID keeps working.

Tested on a generic rk2705 with ums_stress.py over USB mass storage to
the SD card: 0.03 MB/s with HID on endpoint 3, 2.36 MB/s with it on
endpoint 6 - the allocation this change produces for mass storage plus
HID. (Measured with the driver's earlier allocator, before the USB core
took allocation over; this carries the same rule into the new scheme.)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Change-Id: Ib80ed206a3705f2c76fc8457b5c0a54d60a46402
This commit is contained in:
Marcin Bukat 2026-09-25 20:24:05 +02:00
parent 4dcb5bae9d
commit d3893ead3a
3 changed files with 85 additions and 12 deletions
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37
firmware/export/usb-rk27xx.h Normal file
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
*
* Copyright (C) 2026 by Marcin Bukat
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef __USB_RK27XX_H__
#define __USB_RK27XX_H__
#include <stdint.h>
#include "cpu.h" /* USB_NUM_ENDPOINTS */
/* rk27xx UDC endpoint allocation: which endpoints may be allocated depends
* on what else is - interrupt and bulk endpoints never share a group of
* three - so the driver tracks the allocation itself (usb_drv.h, option 2;
* usb-drv-rk27xx.c). Include before usb_drv.h. */
struct usb_drv_ep_alloc_ctx_rk27xx
{
int8_t type[USB_NUM_ENDPOINTS][2];
int max_packet_size[USB_NUM_ENDPOINTS][2];
};
#define usb_drv_ep_alloc_ctx usb_drv_ep_alloc_ctx_rk27xx
#endif /* __USB_RK27XX_H__ */