qemu/hw/usb.c
aliguori 89b9b79f34 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
2008-08-21 19:29:38 +00:00

232 lines
6.1 KiB
C

/*
* QEMU USB emulation
*
* 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
* 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 "qemu-common.h"
#include "usb.h"
void usb_attach(USBPort *port, USBDevice *dev)
{
port->attach(port, dev);
}
/**********************/
/* generic USB device helpers (you are not forced to use them when
writing your USB device driver, but they help handling the
protocol)
*/
#define SETUP_STATE_IDLE 0
#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)
{
switch(p->pid) {
case USB_MSG_ATTACH:
s->state = USB_STATE_ATTACHED;
return 0;
case USB_MSG_DETACH:
s->state = USB_STATE_NOTATTACHED;
return 0;
case USB_MSG_RESET:
s->remote_wakeup = 0;
s->addr = 0;
s->state = USB_STATE_DEFAULT;
s->handle_reset(s);
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;
}
}
/* XXX: fix overflow */
int set_usb_string(uint8_t *buf, const char *str)
{
int len, i;
uint8_t *q;
q = buf;
len = strlen(str);
*q++ = 2 * len + 2;
*q++ = 3;
for(i = 0; i < len; i++) {
*q++ = str[i];
*q++ = 0;
}
return q - buf;
}
/* Send an internal message to a USB device. */
void usb_send_msg(USBDevice *dev, int msg)
{
USBPacket p;
memset(&p, 0, sizeof(p));
p.pid = msg;
dev->handle_packet(dev, &p);
/* This _must_ be synchronous */
}