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usb: generic packet handler cleanup and documentation (Max Krasnyansky) 

A bit better documentation of the USB device API, namely
return codes.
Rewrite of usb_generic_handle_packet() to make it more
reable and easier to follow.

Signed-off-by: Max Krasnyansky <maxk@kernel.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5049 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2008-08-21 19:29:38 +00:00
parent 4b096fc9ec
commit 89b9b79f34
2 changed files with 183 additions and 125 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

273
hw/usb.c
View File

@ -3,6 +3,8 @@
*
* Copyright (c) 2005 Fabrice Bellard
*
* 2008 Generic packet handler rewrite by Max Krasnyansky
*
* 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
@ -30,6 +32,7 @@ void usb_attach(USBPort *port, USBDevice *dev)
}
/**********************/
/* generic USB device helpers (you are not forced to use them when
writing your USB device driver, but they help handling the
protocol)
@ -39,141 +42,164 @@ void usb_attach(USBPort *port, USBDevice *dev)
#define SETUP_STATE_DATA 1
#define SETUP_STATE_ACK 2
static int do_token_setup(USBDevice *s, USBPacket *p)
{
int request, value, index;
int ret = 0;
if (p->len != 8)
return USB_RET_STALL;
memcpy(s->setup_buf, p->data, 8);
s->setup_len = (s->setup_buf[7] << 8) | s->setup_buf[6];
s->setup_index = 0;
request = (s->setup_buf[0] << 8) | s->setup_buf[1];
value = (s->setup_buf[3] << 8) | s->setup_buf[2];
index = (s->setup_buf[5] << 8) | s->setup_buf[4];
if (s->setup_buf[0] & USB_DIR_IN) {
ret = s->handle_control(s, request, value, index,
s->setup_len, s->data_buf);
if (ret < 0)
return ret;
if (ret < s->setup_len)
s->setup_len = ret;
s->setup_state = SETUP_STATE_DATA;
} else {
if (s->setup_len == 0)
s->setup_state = SETUP_STATE_ACK;
else
s->setup_state = SETUP_STATE_DATA;
}
return ret;
}
static int do_token_in(USBDevice *s, USBPacket *p)
{
int request, value, index;
int ret = 0;
if (p->devep != 0)
return s->handle_data(s, p);
request = (s->setup_buf[0] << 8) | s->setup_buf[1];
value = (s->setup_buf[3] << 8) | s->setup_buf[2];
index = (s->setup_buf[5] << 8) | s->setup_buf[4];
switch(s->setup_state) {
case SETUP_STATE_ACK:
if (!(s->setup_buf[0] & USB_DIR_IN)) {
s->setup_state = SETUP_STATE_IDLE;
ret = s->handle_control(s, request, value, index,
s->setup_len, s->data_buf);
if (ret > 0)
return 0;
return ret;
}
/* return 0 byte */
return 0;
case SETUP_STATE_DATA:
if (s->setup_buf[0] & USB_DIR_IN) {
int len = s->setup_len - s->setup_index;
if (len > p->len)
len = p->len;
memcpy(p->data, s->data_buf + s->setup_index, len);
s->setup_index += len;
if (s->setup_index >= s->setup_len)
s->setup_state = SETUP_STATE_ACK;
return len;
}
s->setup_state = SETUP_STATE_IDLE;
return USB_RET_STALL;
default:
return USB_RET_STALL;
}
}
static int do_token_out(USBDevice *s, USBPacket *p)
{
if (p->devep != 0)
return s->handle_data(s, p);
switch(s->setup_state) {
case SETUP_STATE_ACK:
if (s->setup_buf[0] & USB_DIR_IN) {
s->setup_state = SETUP_STATE_IDLE;
/* transfer OK */
} else {
/* ignore additional output */
}
return 0;
case SETUP_STATE_DATA:
if (!(s->setup_buf[0] & USB_DIR_IN)) {
int len = s->setup_len - s->setup_index;
if (len > p->len)
len = p->len;
memcpy(s->data_buf + s->setup_index, p->data, len);
s->setup_index += len;
if (s->setup_index >= s->setup_len)
s->setup_state = SETUP_STATE_ACK;
return len;
}
s->setup_state = SETUP_STATE_IDLE;
return USB_RET_STALL;
default:
return USB_RET_STALL;
}
}
/*
* Generic packet handler.
* Called by the HC (host controller).
*
* Returns length of the transaction or one of the USB_RET_XXX codes.
*/
int usb_generic_handle_packet(USBDevice *s, USBPacket *p)
{
int l, ret = 0;
int len = p->len;
uint8_t *data = p->data;
switch(p->pid) {
case USB_MSG_ATTACH:
s->state = USB_STATE_ATTACHED;
break;
return 0;
case USB_MSG_DETACH:
s->state = USB_STATE_NOTATTACHED;
break;
return 0;
case USB_MSG_RESET:
s->remote_wakeup = 0;
s->addr = 0;
s->state = USB_STATE_DEFAULT;
s->handle_reset(s);
break;
case USB_TOKEN_SETUP:
if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
return USB_RET_NODEV;
if (len != 8)
goto fail;
memcpy(s->setup_buf, data, 8);
s->setup_len = (s->setup_buf[7] << 8) | s->setup_buf[6];
s->setup_index = 0;
if (s->setup_buf[0] & USB_DIR_IN) {
ret = s->handle_control(s,
(s->setup_buf[0] << 8) | s->setup_buf[1],
(s->setup_buf[3] << 8) | s->setup_buf[2],
(s->setup_buf[5] << 8) | s->setup_buf[4],
s->setup_len,
s->data_buf);
if (ret < 0)
return ret;
if (ret < s->setup_len)
s->setup_len = ret;
s->setup_state = SETUP_STATE_DATA;
} else {
if (s->setup_len == 0)
s->setup_state = SETUP_STATE_ACK;
else
s->setup_state = SETUP_STATE_DATA;
}
break;
case USB_TOKEN_IN:
if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
return USB_RET_NODEV;
switch(p->devep) {
case 0:
switch(s->setup_state) {
case SETUP_STATE_ACK:
if (!(s->setup_buf[0] & USB_DIR_IN)) {
s->setup_state = SETUP_STATE_IDLE;
ret = s->handle_control(s,
(s->setup_buf[0] << 8) | s->setup_buf[1],
(s->setup_buf[3] << 8) | s->setup_buf[2],
(s->setup_buf[5] << 8) | s->setup_buf[4],
s->setup_len,
s->data_buf);
if (ret > 0)
ret = 0;
} else {
/* return 0 byte */
}
break;
case SETUP_STATE_DATA:
if (s->setup_buf[0] & USB_DIR_IN) {
l = s->setup_len - s->setup_index;
if (l > len)
l = len;
memcpy(data, s->data_buf + s->setup_index, l);
s->setup_index += l;
if (s->setup_index >= s->setup_len)
s->setup_state = SETUP_STATE_ACK;
ret = l;
} else {
s->setup_state = SETUP_STATE_IDLE;
goto fail;
}
break;
default:
goto fail;
}
break;
default:
ret = s->handle_data(s, p);
break;
}
break;
case USB_TOKEN_OUT:
if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
return USB_RET_NODEV;
switch(p->devep) {
case 0:
switch(s->setup_state) {
case SETUP_STATE_ACK:
if (s->setup_buf[0] & USB_DIR_IN) {
s->setup_state = SETUP_STATE_IDLE;
/* transfer OK */
} else {
/* ignore additional output */
}
break;
case SETUP_STATE_DATA:
if (!(s->setup_buf[0] & USB_DIR_IN)) {
l = s->setup_len - s->setup_index;
if (l > len)
l = len;
memcpy(s->data_buf + s->setup_index, data, l);
s->setup_index += l;
if (s->setup_index >= s->setup_len)
s->setup_state = SETUP_STATE_ACK;
ret = l;
} else {
s->setup_state = SETUP_STATE_IDLE;
goto fail;
}
break;
default:
goto fail;
}
break;
default:
ret = s->handle_data(s, p);
break;
}
break;
default:
fail:
ret = USB_RET_STALL;
break;
return 0;
}
/* Rest of the PIDs must match our address */
if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
return USB_RET_NODEV;
switch (p->pid) {
case USB_TOKEN_SETUP:
return do_token_setup(s, p);
case USB_TOKEN_IN:
return do_token_in(s, p);
case USB_TOKEN_OUT:
return do_token_out(s, p);
default:
return USB_RET_STALL;
}
return ret;
}
/* XXX: fix overflow */
@ -200,5 +226,6 @@ void usb_send_msg(USBDevice *dev, int msg)
memset(&p, 0, sizeof(p));
p.pid = msg;
dev->handle_packet(dev, &p);
}
/* This _must_ be synchronous */
}

35
hw/usb.h
View File

@ -120,18 +120,49 @@ typedef struct USBPacket USBPacket;
/* definition of a USB device */
struct USBDevice {
void *opaque;
/*
* Process USB packet.
* Called by the HC (Host Controller).
*
* Returns length of the transaction
* or one of the USB_RET_XXX codes.
*/
int (*handle_packet)(USBDevice *dev, USBPacket *p);
/*
* Called when device is destroyed.
*/
void (*handle_destroy)(USBDevice *dev);
int speed;
/* The following fields are used by the generic USB device
layer. They are here just to avoid creating a new structure for
them. */
layer. They are here just to avoid creating a new structure
for them. */
/*
* Reset the device
*/
void (*handle_reset)(USBDevice *dev);
/*
* Process control request.
* Called from handle_packet().
*
* Returns length or one of the USB_RET_ codes.
*/
int (*handle_control)(USBDevice *dev, int request, int value,
int index, int length, uint8_t *data);
/*
* Process data transfers (both BULK and ISOC).
* Called from handle_packet().
*
* Returns length or one of the USB_RET_ codes.
*/
int (*handle_data)(USBDevice *dev, USBPacket *p);
uint8_t addr;
char devname[32];