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!
USBMSD/USBMSD.cpp
- Committer:
- mjr
- Date:
- 2017-03-17
- Revision:
- 54:2e181d51495a
- Parent:
- 49:03527ce6840e
File content as of revision 54:2e181d51495a:
/* Copyright (c) 2010-2011 mbed.org, MIT License
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software
* and associated documentation files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
* BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "stdint.h"
#include "USBMSD.h"
#define DISK_OK 0x00
#define NO_INIT 0x01
#define NO_DISK 0x02
#define WRITE_PROTECT 0x04
#define CBW_Signature 0x43425355
#define CSW_Signature 0x53425355
// SCSI Commands
#define TEST_UNIT_READY 0x00
#define REQUEST_SENSE 0x03
#define FORMAT_UNIT 0x04
#define INQUIRY 0x12
#define MODE_SELECT6 0x15
#define MODE_SENSE6 0x1A
#define START_STOP_UNIT 0x1B
#define MEDIA_REMOVAL 0x1E
#define READ_FORMAT_CAPACITIES 0x23
#define READ_CAPACITY 0x25
#define READ10 0x28
#define WRITE10 0x2A
#define VERIFY10 0x2F
#define READ12 0xA8
#define WRITE12 0xAA
#define MODE_SELECT10 0x55
#define MODE_SENSE10 0x5A
// MSC class specific requests
#define MSC_REQUEST_RESET 0xFF
#define MSC_REQUEST_GET_MAX_LUN 0xFE
#define DEFAULT_CONFIGURATION (1)
// max packet size
#define MAX_PACKET MAX_PACKET_SIZE_EPBULK
// CSW Status
enum Status {
CSW_PASSED,
CSW_FAILED,
CSW_ERROR,
};
USBMSD::USBMSD(uint16_t vendor_id, uint16_t product_id, uint16_t product_release): USBDevice(vendor_id, product_id, product_release) {
stage = READ_CBW;
memset((void *)&cbw, 0, sizeof(CBW));
memset((void *)&csw, 0, sizeof(CSW));
page = NULL;
}
USBMSD::~USBMSD() {
disconnect();
}
// Called in ISR context to process a class specific request
bool USBMSD::USBCallback_request(void) {
bool success = false;
CONTROL_TRANSFER * transfer = getTransferPtr();
static uint8_t maxLUN[1] = {0};
if (transfer->setup.bmRequestType.Type == CLASS_TYPE) {
switch (transfer->setup.bRequest) {
case MSC_REQUEST_RESET:
reset();
success = true;
break;
case MSC_REQUEST_GET_MAX_LUN:
transfer->remaining = 1;
transfer->ptr = maxLUN;
transfer->direction = DEVICE_TO_HOST;
success = true;
break;
default:
break;
}
}
return success;
}
bool USBMSD::connect(bool blocking) {
//disk initialization
if (disk_status() & NO_INIT) {
if (disk_initialize()) {
return false;
}
}
// get number of blocks
BlockCount = disk_sectors();
// get memory size
MemorySize = disk_size();
if (BlockCount > 0) {
BlockSize = MemorySize / BlockCount;
if (BlockSize != 0) {
delete [] page;
page = new uint8_t[BlockSize];
if (page == NULL)
return false;
}
} else {
return false;
}
//connect the device
USBDevice::connect(blocking);
return true;
}
void USBMSD::disconnect() {
//De-allocate MSD page size:
delete [] page;
page = NULL;
USBDevice::disconnect();
}
void USBMSD::reset() {
stage = READ_CBW;
}
// Called in ISR context called when a data is received
bool USBMSD::EP2_OUT_callback() {
uint32_t size = 0;
uint8_t buf[MAX_PACKET_SIZE_EPBULK];
readEP(EPBULK_OUT, buf, &size, MAX_PACKET_SIZE_EPBULK);
switch (stage) {
// the device has to decode the CBW received
case READ_CBW:
CBWDecode(buf, size);
break;
// the device has to receive data from the host
case PROCESS_CBW:
switch (cbw.CB[0]) {
case WRITE10:
case WRITE12:
memoryWrite(buf, size);
break;
case VERIFY10:
memoryVerify(buf, size);
break;
}
break;
// an error has occured: stall endpoint and send CSW
default:
stallEndpoint(EPBULK_OUT);
csw.Status = CSW_ERROR;
sendCSW();
break;
}
//reactivate readings on the OUT bulk endpoint
readStart(EPBULK_OUT, MAX_PACKET_SIZE_EPBULK);
return true;
}
// Called in ISR context when a data has been transferred
bool USBMSD::EP2_IN_callback() {
switch (stage) {
// the device has to send data to the host
case PROCESS_CBW:
switch (cbw.CB[0]) {
case READ10:
case READ12:
memoryRead();
break;
}
break;
//the device has to send a CSW
case SEND_CSW:
sendCSW();
break;
// the host has received the CSW -> we wait a CBW
case WAIT_CSW:
stage = READ_CBW;
break;
// an error has occured
default:
stallEndpoint(EPBULK_IN);
sendCSW();
break;
}
return true;
}
void USBMSD::memoryWrite (uint8_t * buf, uint16_t size) {
if ((addr + size) > MemorySize) {
size = MemorySize - addr;
stage = ERROR;
stallEndpoint(EPBULK_OUT);
}
// we fill an array in RAM of 1 block before writing it in memory
for (int i = 0; i < size; i++)
page[addr%BlockSize + i] = buf[i];
// if the array is filled, write it in memory
if (!((addr + size)%BlockSize)) {
if (!(disk_status() & WRITE_PROTECT)) {
disk_write(page, addr/BlockSize);
}
}
addr += size;
length -= size;
csw.DataResidue -= size;
if ((!length) || (stage != PROCESS_CBW)) {
csw.Status = (stage == ERROR) ? CSW_FAILED : CSW_PASSED;
sendCSW();
}
}
void USBMSD::memoryVerify (uint8_t * buf, uint16_t size) {
uint32_t n;
if ((addr + size) > MemorySize) {
size = MemorySize - addr;
stage = ERROR;
stallEndpoint(EPBULK_OUT);
}
// beginning of a new block -> load a whole block in RAM
if (!(addr%BlockSize))
disk_read(page, addr/BlockSize);
// info are in RAM -> no need to re-read memory
for (n = 0; n < size; n++) {
if (page[addr%BlockSize + n] != buf[n]) {
memOK = false;
break;
}
}
addr += size;
length -= size;
csw.DataResidue -= size;
if ( !length || (stage != PROCESS_CBW)) {
csw.Status = (memOK && (stage == PROCESS_CBW)) ? CSW_PASSED : CSW_FAILED;
sendCSW();
}
}
bool USBMSD::inquiryRequest (void) {
uint8_t inquiry[] = { 0x00, 0x80, 0x00, 0x01,
36 - 4, 0x80, 0x00, 0x00,
'M', 'B', 'E', 'D', '.', 'O', 'R', 'G',
'M', 'B', 'E', 'D', ' ', 'U', 'S', 'B', ' ', 'D', 'I', 'S', 'K', ' ', ' ', ' ',
'1', '.', '0', ' ',
};
if (!write(inquiry, sizeof(inquiry))) {
return false;
}
return true;
}
bool USBMSD::readFormatCapacity() {
uint8_t capacity[] = { 0x00, 0x00, 0x00, 0x08,
(uint8_t)((BlockCount >> 24) & 0xff),
(uint8_t)((BlockCount >> 16) & 0xff),
(uint8_t)((BlockCount >> 8) & 0xff),
(uint8_t)((BlockCount >> 0) & 0xff),
0x02,
(uint8_t)((BlockSize >> 16) & 0xff),
(uint8_t)((BlockSize >> 8) & 0xff),
(uint8_t)((BlockSize >> 0) & 0xff),
};
if (!write(capacity, sizeof(capacity))) {
return false;
}
return true;
}
bool USBMSD::readCapacity (void) {
uint8_t capacity[] = {
(uint8_t)(((BlockCount - 1) >> 24) & 0xff),
(uint8_t)(((BlockCount - 1) >> 16) & 0xff),
(uint8_t)(((BlockCount - 1) >> 8) & 0xff),
(uint8_t)(((BlockCount - 1) >> 0) & 0xff),
(uint8_t)((BlockSize >> 24) & 0xff),
(uint8_t)((BlockSize >> 16) & 0xff),
(uint8_t)((BlockSize >> 8) & 0xff),
(uint8_t)((BlockSize >> 0) & 0xff),
};
if (!write(capacity, sizeof(capacity))) {
return false;
}
return true;
}
bool USBMSD::write (uint8_t * buf, uint16_t size) {
if (size >= cbw.DataLength) {
size = cbw.DataLength;
}
stage = SEND_CSW;
if (!writeNB(EPBULK_IN, buf, size, MAX_PACKET_SIZE_EPBULK)) {
return false;
}
csw.DataResidue -= size;
csw.Status = CSW_PASSED;
return true;
}
bool USBMSD::modeSense6 (void) {
uint8_t sense6[] = { 0x03, 0x00, 0x00, 0x00 };
if (!write(sense6, sizeof(sense6))) {
return false;
}
return true;
}
void USBMSD::sendCSW() {
csw.Signature = CSW_Signature;
writeNB(EPBULK_IN, (uint8_t *)&csw, sizeof(CSW), MAX_PACKET_SIZE_EPBULK);
stage = WAIT_CSW;
}
bool USBMSD::requestSense (void) {
uint8_t request_sense[] = {
0x70,
0x00,
0x05, // Sense Key: illegal request
0x00,
0x00,
0x00,
0x00,
0x0A,
0x00,
0x00,
0x00,
0x00,
0x30,
0x01,
0x00,
0x00,
0x00,
0x00,
};
if (!write(request_sense, sizeof(request_sense))) {
return false;
}
return true;
}
void USBMSD::fail() {
csw.Status = CSW_FAILED;
sendCSW();
}
void USBMSD::CBWDecode(uint8_t * buf, uint16_t size) {
if (size == sizeof(cbw)) {
memcpy((uint8_t *)&cbw, buf, size);
if (cbw.Signature == CBW_Signature) {
csw.Tag = cbw.Tag;
csw.DataResidue = cbw.DataLength;
if ((cbw.CBLength < 1) || (cbw.CBLength > 16) ) {
fail();
} else {
switch (cbw.CB[0]) {
case TEST_UNIT_READY:
testUnitReady();
break;
case REQUEST_SENSE:
requestSense();
break;
case INQUIRY:
inquiryRequest();
break;
case MODE_SENSE6:
modeSense6();
break;
case READ_FORMAT_CAPACITIES:
readFormatCapacity();
break;
case READ_CAPACITY:
readCapacity();
break;
case READ10:
case READ12:
if (infoTransfer()) {
if ((cbw.Flags & 0x80)) {
stage = PROCESS_CBW;
memoryRead();
} else {
stallEndpoint(EPBULK_OUT);
csw.Status = CSW_ERROR;
sendCSW();
}
}
break;
case WRITE10:
case WRITE12:
if (infoTransfer()) {
if (!(cbw.Flags & 0x80)) {
stage = PROCESS_CBW;
} else {
stallEndpoint(EPBULK_IN);
csw.Status = CSW_ERROR;
sendCSW();
}
}
break;
case VERIFY10:
if (!(cbw.CB[1] & 0x02)) {
csw.Status = CSW_PASSED;
sendCSW();
break;
}
if (infoTransfer()) {
if (!(cbw.Flags & 0x80)) {
stage = PROCESS_CBW;
memOK = true;
} else {
stallEndpoint(EPBULK_IN);
csw.Status = CSW_ERROR;
sendCSW();
}
}
break;
case MEDIA_REMOVAL:
csw.Status = CSW_PASSED;
sendCSW();
break;
default:
fail();
break;
}
}
}
}
}
void USBMSD::testUnitReady (void) {
if (cbw.DataLength != 0) {
if ((cbw.Flags & 0x80) != 0) {
stallEndpoint(EPBULK_IN);
} else {
stallEndpoint(EPBULK_OUT);
}
}
csw.Status = CSW_PASSED;
sendCSW();
}
void USBMSD::memoryRead (void) {
uint32_t n;
n = (length > MAX_PACKET) ? MAX_PACKET : length;
if ((addr + n) > MemorySize) {
n = MemorySize - addr;
stage = ERROR;
}
// we read an entire block
if (!(addr%BlockSize))
disk_read(page, addr/BlockSize);
// write data which are in RAM
writeNB(EPBULK_IN, &page[addr%BlockSize], n, MAX_PACKET_SIZE_EPBULK);
addr += n;
length -= n;
csw.DataResidue -= n;
if ( !length || (stage != PROCESS_CBW)) {
csw.Status = (stage == PROCESS_CBW) ? CSW_PASSED : CSW_FAILED;
stage = (stage == PROCESS_CBW) ? SEND_CSW : stage;
}
}
bool USBMSD::infoTransfer (void) {
uint32_t n;
// Logical Block Address of First Block
n = (cbw.CB[2] << 24) | (cbw.CB[3] << 16) | (cbw.CB[4] << 8) | (cbw.CB[5] << 0);
addr = n * BlockSize;
// Number of Blocks to transfer
switch (cbw.CB[0]) {
case READ10:
case WRITE10:
case VERIFY10:
n = (cbw.CB[7] << 8) | (cbw.CB[8] << 0);
break;
case READ12:
case WRITE12:
n = (cbw.CB[6] << 24) | (cbw.CB[7] << 16) | (cbw.CB[8] << 8) | (cbw.CB[9] << 0);
break;
}
length = n * BlockSize;
if (!cbw.DataLength) { // host requests no data
csw.Status = CSW_FAILED;
sendCSW();
return false;
}
if (cbw.DataLength != length) {
if ((cbw.Flags & 0x80) != 0) {
stallEndpoint(EPBULK_IN);
} else {
stallEndpoint(EPBULK_OUT);
}
csw.Status = CSW_FAILED;
sendCSW();
return false;
}
return true;
}
// Called in ISR context
// Set configuration. Return false if the
// configuration is not supported.
bool USBMSD::USBCallback_setConfiguration(uint8_t configuration) {
if (configuration != DEFAULT_CONFIGURATION) {
return false;
}
// Configure endpoints > 0
addEndpoint(EPBULK_IN, MAX_PACKET_SIZE_EPBULK);
addEndpoint(EPBULK_OUT, MAX_PACKET_SIZE_EPBULK);
//activate readings
readStart(EPBULK_OUT, MAX_PACKET_SIZE_EPBULK);
return true;
}
const uint8_t *USBMSD::stringIinterfaceDesc() {
static const uint8_t stringIinterfaceDescriptor[] = {
0x08, //bLength
STRING_DESCRIPTOR, //bDescriptorType 0x03
'M',0,'S',0,'D',0 //bString iInterface - MSD
};
return stringIinterfaceDescriptor;
}
const uint8_t *USBMSD::stringIproductDesc() {
static const uint8_t stringIproductDescriptor[] = {
0x12, //bLength
STRING_DESCRIPTOR, //bDescriptorType 0x03
'M',0,'b',0,'e',0,'d',0,' ',0,'M',0,'S',0,'D',0 //bString iProduct - Mbed Audio
};
return stringIproductDescriptor;
}
const uint8_t *USBMSD::configurationDesc() {
static const uint8_t configDescriptor[] = {
// Configuration 1
9, // bLength
2, // bDescriptorType
LSB(9 + 9 + 7 + 7), // wTotalLength
MSB(9 + 9 + 7 + 7),
0x01, // bNumInterfaces
0x01, // bConfigurationValue: 0x01 is used to select this configuration
0x00, // iConfiguration: no string to describe this configuration
0xC0, // bmAttributes
100, // bMaxPower, device power consumption is 100 mA
// Interface 0, Alternate Setting 0, MSC Class
9, // bLength
4, // bDescriptorType
0x00, // bInterfaceNumber
0x00, // bAlternateSetting
0x02, // bNumEndpoints
0x08, // bInterfaceClass
0x06, // bInterfaceSubClass
0x50, // bInterfaceProtocol
0x04, // iInterface
// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
7, // bLength
5, // bDescriptorType
PHY_TO_DESC(EPBULK_IN), // bEndpointAddress
0x02, // bmAttributes (0x02=bulk)
LSB(MAX_PACKET_SIZE_EPBULK),// wMaxPacketSize (LSB)
MSB(MAX_PACKET_SIZE_EPBULK),// wMaxPacketSize (MSB)
0, // bInterval
// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
7, // bLength
5, // bDescriptorType
PHY_TO_DESC(EPBULK_OUT), // bEndpointAddress
0x02, // bmAttributes (0x02=bulk)
LSB(MAX_PACKET_SIZE_EPBULK),// wMaxPacketSize (LSB)
MSB(MAX_PACKET_SIZE_EPBULK),// wMaxPacketSize (MSB)
0 // bInterval
};
return configDescriptor;
}