Mike R
USB device stack, with KL25Z fixes for USB 3.0 hosts and sleep/resume interrupt handling
Dependents: frdm_Slider_Keyboard idd_hw2_figlax_PanType idd_hw2_appachu_finger_chording idd_hw3_AngieWangAntonioDeLimaFernandesDanielLim_BladeSymphony ... more
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USBDevice
by 
mbed official
This is an overhauled version of the standard mbed USB device-side driver library, with bug fixes for KL25Z devices. It greatly improves reliability and stability of USB on the KL25Z, especially with devices using multiple endpoints concurrently.
I've had some nagging problems with the base mbed implementation for a long time, manifesting as occasional random disconnects that required rebooting the device. Recently (late 2015), I started implementing a USB device on the KL25Z that used multiple endpoints, and suddenly the nagging, occasional problems turned into frequent and predictable crashes. This forced me to delve into the USB stack and figure out what was really going on. Happily, the frequent crashes made it possible to track down and fix the problems. This new version is working very reliably in my testing - the random disconnects seem completely eradicated, even under very stressful conditions for the device.
Summary
- Overall stability improvements
- USB 3.0 host support
- Stalled endpoint fixes
- Sleep/resume notifications
- Smaller memory footprint
- General code cleanup
Update - 2/15/2016
My recent fixes introduced a new problem that made the initial connection fail most of the time on certain hosts. It's not clear if the common thread was a particular type of motherboard or USB chip set, or a specific version of Windows, or what, but several people ran into it. We tracked the problem down to the "stall" fixes in the earlier updates, which we now know weren't quite the right fixes after all. The latest update (2/15/2016) fixes this. It has new and improved "unstall" handling that so far works well with diverse hosts.
Race conditions and overall stability
The base mbed KL25Z implementation has a lot of problems with "race conditions" - timing problems that can happen when hardware interrupts occur at inopportune moments. The library shares a bunch of static variable data between interrupt handler context and regular application context. This isn't automatically a bad thing, but it does require careful coordination to make sure that the interrupt handler doesn't corrupt data that the other code was in the middle of updating when an interrupt occurs. The base mbed code, though, doesn't do any of the necessary coordination. This makes it kind of amazing that the base code worked at all for anyone, but I guess the interrupt rate is low enough in most applications that the glitch rate was below anyone's threshold to seriously investigate.
This overhaul adds the necessary coordination for the interrupt handlers to protect against these data corruptions. I think it's very solid now, and hopefully entirely free of the numerous race conditions in the old code. It's always hard to be certain that you've fixed every possible bug like this because they strike (effectively) at random, but I'm pretty confident: my test application was reliably able to trigger glitches in the base code in a matter of minutes, but the same application (with the overhauled library) now runs for days on end without dropping the connection.
Stalled endpoint fixes
USB has a standard way of handling communications errors called a "stall", which basically puts the connection into an error mode to let both sides know that they need to reset their internal states and sync up again. The original mbed version of the USB device library doesn't seem to have the necessary code to recover from this condition properly. The KL25Z hardware does some of the work, but it also seems to require the software to take some steps to "un-stall" the connection. (I keep saying "seems to" because the hardware reference material is very sketchy about all of this. Most of what I've figured out is from observing the device in action with a Windows host.) This new version adds code to do the necessary re-syncing and get the connection going again, automatically, and transparently to the user.
USB 3.0 Hosts
The original mbed code sometimes didn't work when connecting to hosts with USB 3.0 ports. This didn't affect every host, but it affected many of them. The common element seemed to be the Intel Haswell chip set on the host, but there may be other chip sets affected as well. In any case, the problem affected many PCs from the Windows 7 and 8 generation, as well as many Macs. It was possible to work around the problem by avoiding USB 3.0 ports - you could use a USB 2 port on the host, or plug a USB 2 hub between the host and device. But I wanted to just fix the problem and eliminate the need for such workarounds. This modified version of the library has such a fix, which so far has worked for everyone who's tried.
Sleep/resume notifications
This modified version also contains an innocuous change to the KL25Z USB HAL code to handle sleep and resume interrupts with calls to suspendStateChanged(). The original KL25Z code omitted these calls (and in fact didn't even enable the interrupts), but I think this was an unintentional oversight - the notifier function is part of the generic API, and other supported boards all implement it. I use this feature in my own application so that I can distinguish sleep mode from actual disconnects and handle the two conditions correctly.
Smaller memory footprint
The base mbed version of the code allocates twice as much memory for USB buffers as it really needed to. It looks like the original developers intended to implement the KL25Z USB hardware's built-in double-buffering mechanism, but they ultimately abandoned that effort. But they left in the double memory allocation. This version removes that and allocates only what's actually needed. The USB buffers aren't that big (128 bytes per endpoint), so this doesn't save a ton of memory, but even a little memory is pretty precious on this machine given that it only has 16K.
(I did look into adding the double-buffering support that the original developers abandoned, but after some experimentation I decided they were right to skip it. It just doesn't seem to mesh well with the design of the rest of the mbed USB code. I think it would take a major rewrite to make it work, and it doesn't seem worth the effort given that most applications don't need it - it would only benefit applications that are moving so much data through USB that they're pushing the limits of the CPU. And even for those, I think it would be a lot simpler to build a purely software-based buffer rotation mechanism.)
General code cleanup
The KL25Z HAL code in this version has greatly expanded commentary and a lot of general cleanup. Some of the hardware constants were given the wrong symbolic names (e.g., EVEN and ODD were reversed), and many were just missing (written as hard-coded numbers without explanation). I fixed the misnomers and added symbolic names for formerly anonymous numbers. Hopefully the next person who has to overhaul this code will at least have an easier time understanding what I thought I was doing!
USBDevice/USBRegs_STM32.h
- Committer:
- mjr
- Date:
- 2017-03-17
- Revision:
- 54:2e181d51495a
- Parent:
- 25:7c72828865f3
File content as of revision 54:2e181d51495a:
/**
******************************************************************************
* @file usb_regs.h
* @author MCD Application Team
* @version V2.1.0
* @date 19-March-2012
* @brief hardware registers
******************************************************************************
* @attention
*
* <h2><center>© COPYRIGHT 2012 STMicroelectronics</center></h2>
*
* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.st.com/software_license_agreement_liberty_v2
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************
*/
#ifndef __USB_OTG_REGS_H__
#define __USB_OTG_REGS_H__
typedef struct //000h
{
__IO uint32_t GOTGCTL; /* USB_OTG Control and Status Register 000h*/
__IO uint32_t GOTGINT; /* USB_OTG Interrupt Register 004h*/
__IO uint32_t GAHBCFG; /* Core AHB Configuration Register 008h*/
__IO uint32_t GUSBCFG; /* Core USB Configuration Register 00Ch*/
__IO uint32_t GRSTCTL; /* Core Reset Register 010h*/
__IO uint32_t GINTSTS; /* Core Interrupt Register 014h*/
__IO uint32_t GINTMSK; /* Core Interrupt Mask Register 018h*/
__IO uint32_t GRXSTSR; /* Receive Sts Q Read Register 01Ch*/
__IO uint32_t GRXSTSP; /* Receive Sts Q Read & POP Register 020h*/
__IO uint32_t GRXFSIZ; /* Receive FIFO Size Register 024h*/
__IO uint32_t DIEPTXF0_HNPTXFSIZ; /* EP0 / Non Periodic Tx FIFO Size Register 028h*/
__IO uint32_t HNPTXSTS; /* Non Periodic Tx FIFO/Queue Sts reg 02Ch*/
uint32_t Reserved30[2]; /* Reserved 030h*/
__IO uint32_t GCCFG; /* General Purpose IO Register 038h*/
__IO uint32_t CID; /* User ID Register 03Ch*/
uint32_t Reserved40[48]; /* Reserved 040h-0FFh*/
__IO uint32_t HPTXFSIZ; /* Host Periodic Tx FIFO Size Reg 100h*/
__IO uint32_t DIEPTXF[3];/* dev Periodic Transmit FIFO */
}
USB_OTG_GREGS;
typedef struct // 800h
{
__IO uint32_t DCFG; /* dev Configuration Register 800h*/
__IO uint32_t DCTL; /* dev Control Register 804h*/
__IO uint32_t DSTS; /* dev Status Register (RO) 808h*/
uint32_t Reserved0C; /* Reserved 80Ch*/
__IO uint32_t DIEPMSK; /* dev IN Endpoint Mask 810h*/
__IO uint32_t DOEPMSK; /* dev OUT Endpoint Mask 814h*/
__IO uint32_t DAINT; /* dev All Endpoints Itr Reg 818h*/
__IO uint32_t DAINTMSK; /* dev All Endpoints Itr Mask 81Ch*/
uint32_t Reserved20; /* Reserved 820h*/
uint32_t Reserved9; /* Reserved 824h*/
__IO uint32_t DVBUSDIS; /* dev VBUS discharge Register 828h*/
__IO uint32_t DVBUSPULSE; /* dev VBUS Pulse Register 82Ch*/
__IO uint32_t DTHRCTL; /* dev thr 830h*/
__IO uint32_t DIEPEMPMSK; /* dev empty msk 834h*/
}
USB_OTG_DREGS;
typedef struct
{
__IO uint32_t DIEPCTL; /* dev IN Endpoint Control Reg 900h + (ep_num * 20h) + 00h*/
uint32_t Reserved04; /* Reserved 900h + (ep_num * 20h) + 04h*/
__IO uint32_t DIEPINT; /* dev IN Endpoint Itr Reg 900h + (ep_num * 20h) + 08h*/
uint32_t Reserved0C; /* Reserved 900h + (ep_num * 20h) + 0Ch*/
__IO uint32_t DIEPTSIZ; /* IN Endpoint Txfer Size 900h + (ep_num * 20h) + 10h*/
uint32_t Reserved14;
__IO uint32_t DTXFSTS;/*IN Endpoint Tx FIFO Status Reg 900h + (ep_num * 20h) + 18h*/
uint32_t Reserved1C; /* Reserved 900h+(ep_num*20h)+1Ch-900h+ (ep_num * 20h) + 1Ch*/
}
USB_OTG_INEPREGS;
typedef struct
{
__IO uint32_t DOEPCTL; /* dev OUT Endpoint Control Reg B00h + (ep_num * 20h) + 00h*/
uint32_t Reserved04; /* Reserved B00h + (ep_num * 20h) + 04h*/
__IO uint32_t DOEPINT; /* dev OUT Endpoint Itr Reg B00h + (ep_num * 20h) + 08h*/
uint32_t Reserved0C; /* Reserved B00h + (ep_num * 20h) + 0Ch*/
__IO uint32_t DOEPTSIZ; /* dev OUT Endpoint Txfer Size B00h + (ep_num * 20h) + 10h*/
uint32_t Reserved14[3];
}
USB_OTG_OUTEPREGS;
typedef struct
{
__IO uint32_t HCFG; /* Host Configuration Register 400h*/
__IO uint32_t HFIR; /* Host Frame Interval Register 404h*/
__IO uint32_t HFNUM; /* Host Frame Nbr/Frame Remaining 408h*/
uint32_t Reserved40C; /* Reserved 40Ch*/
__IO uint32_t HPTXSTS; /* Host Periodic Tx FIFO/ Queue Status 410h*/
__IO uint32_t HAINT; /* Host All Channels Interrupt Register 414h*/
__IO uint32_t HAINTMSK; /* Host All Channels Interrupt Mask 418h*/
}
USB_OTG_HREGS;
typedef struct
{
__IO uint32_t HCCHAR;
__IO uint32_t HCSPLT;
__IO uint32_t HCINT;
__IO uint32_t HCINTMSK;
__IO uint32_t HCTSIZ;
uint32_t Reserved[3];
}
USB_OTG_HC_REGS;
typedef struct
{
USB_OTG_GREGS GREGS;
uint32_t RESERVED0[188];
USB_OTG_HREGS HREGS;
uint32_t RESERVED1[9];
__IO uint32_t HPRT;
uint32_t RESERVED2[47];
USB_OTG_HC_REGS HC_REGS[8];
uint32_t RESERVED3[128];
USB_OTG_DREGS DREGS;
uint32_t RESERVED4[50];
USB_OTG_INEPREGS INEP_REGS[4];
uint32_t RESERVED5[96];
USB_OTG_OUTEPREGS OUTEP_REGS[4];
uint32_t RESERVED6[160];
__IO uint32_t PCGCCTL;
uint32_t RESERVED7[127];
__IO uint32_t FIFO[4][1024];
}
USB_OTG_CORE_REGS;
#define OTG_FS_BASE (AHB2PERIPH_BASE + 0x0000)
#define OTG_FS ((USB_OTG_CORE_REGS *) OTG_FS_BASE)
#endif //__USB_OTG_REGS_H__
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/