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
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273
hw/usb.c
273
hw/usb.c
@ -3,6 +3,8 @@
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*
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* Copyright (c) 2005 Fabrice Bellard
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*
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* 2008 Generic packet handler rewrite by Max Krasnyansky
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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@ -30,6 +32,7 @@ void usb_attach(USBPort *port, USBDevice *dev)
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}
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/**********************/
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/* generic USB device helpers (you are not forced to use them when
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writing your USB device driver, but they help handling the
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protocol)
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@ -39,141 +42,164 @@ void usb_attach(USBPort *port, USBDevice *dev)
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#define SETUP_STATE_DATA 1
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#define SETUP_STATE_ACK 2
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static int do_token_setup(USBDevice *s, USBPacket *p)
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{
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int request, value, index;
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int ret = 0;
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if (p->len != 8)
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return USB_RET_STALL;
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memcpy(s->setup_buf, p->data, 8);
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s->setup_len = (s->setup_buf[7] << 8) | s->setup_buf[6];
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s->setup_index = 0;
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request = (s->setup_buf[0] << 8) | s->setup_buf[1];
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value = (s->setup_buf[3] << 8) | s->setup_buf[2];
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index = (s->setup_buf[5] << 8) | s->setup_buf[4];
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if (s->setup_buf[0] & USB_DIR_IN) {
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ret = s->handle_control(s, request, value, index,
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s->setup_len, s->data_buf);
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if (ret < 0)
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return ret;
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if (ret < s->setup_len)
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s->setup_len = ret;
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s->setup_state = SETUP_STATE_DATA;
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} else {
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if (s->setup_len == 0)
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s->setup_state = SETUP_STATE_ACK;
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else
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s->setup_state = SETUP_STATE_DATA;
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}
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return ret;
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}
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static int do_token_in(USBDevice *s, USBPacket *p)
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{
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int request, value, index;
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int ret = 0;
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if (p->devep != 0)
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return s->handle_data(s, p);
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request = (s->setup_buf[0] << 8) | s->setup_buf[1];
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value = (s->setup_buf[3] << 8) | s->setup_buf[2];
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index = (s->setup_buf[5] << 8) | s->setup_buf[4];
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switch(s->setup_state) {
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case SETUP_STATE_ACK:
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if (!(s->setup_buf[0] & USB_DIR_IN)) {
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s->setup_state = SETUP_STATE_IDLE;
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ret = s->handle_control(s, request, value, index,
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s->setup_len, s->data_buf);
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if (ret > 0)
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return 0;
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return ret;
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}
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/* return 0 byte */
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return 0;
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case SETUP_STATE_DATA:
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if (s->setup_buf[0] & USB_DIR_IN) {
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int len = s->setup_len - s->setup_index;
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if (len > p->len)
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len = p->len;
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memcpy(p->data, s->data_buf + s->setup_index, len);
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s->setup_index += len;
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if (s->setup_index >= s->setup_len)
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s->setup_state = SETUP_STATE_ACK;
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return len;
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}
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s->setup_state = SETUP_STATE_IDLE;
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return USB_RET_STALL;
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default:
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return USB_RET_STALL;
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}
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}
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static int do_token_out(USBDevice *s, USBPacket *p)
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{
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if (p->devep != 0)
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return s->handle_data(s, p);
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switch(s->setup_state) {
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case SETUP_STATE_ACK:
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if (s->setup_buf[0] & USB_DIR_IN) {
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s->setup_state = SETUP_STATE_IDLE;
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/* transfer OK */
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} else {
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/* ignore additional output */
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}
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return 0;
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case SETUP_STATE_DATA:
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if (!(s->setup_buf[0] & USB_DIR_IN)) {
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int len = s->setup_len - s->setup_index;
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if (len > p->len)
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len = p->len;
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memcpy(s->data_buf + s->setup_index, p->data, len);
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s->setup_index += len;
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if (s->setup_index >= s->setup_len)
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s->setup_state = SETUP_STATE_ACK;
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return len;
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}
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s->setup_state = SETUP_STATE_IDLE;
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return USB_RET_STALL;
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default:
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return USB_RET_STALL;
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}
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}
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/*
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* Generic packet handler.
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* Called by the HC (host controller).
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*
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* Returns length of the transaction or one of the USB_RET_XXX codes.
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*/
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int usb_generic_handle_packet(USBDevice *s, USBPacket *p)
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{
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int l, ret = 0;
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int len = p->len;
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uint8_t *data = p->data;
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switch(p->pid) {
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case USB_MSG_ATTACH:
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s->state = USB_STATE_ATTACHED;
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break;
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return 0;
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case USB_MSG_DETACH:
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s->state = USB_STATE_NOTATTACHED;
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break;
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return 0;
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case USB_MSG_RESET:
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s->remote_wakeup = 0;
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s->addr = 0;
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s->state = USB_STATE_DEFAULT;
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s->handle_reset(s);
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break;
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case USB_TOKEN_SETUP:
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if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
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return USB_RET_NODEV;
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if (len != 8)
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goto fail;
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memcpy(s->setup_buf, data, 8);
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s->setup_len = (s->setup_buf[7] << 8) | s->setup_buf[6];
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s->setup_index = 0;
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if (s->setup_buf[0] & USB_DIR_IN) {
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ret = s->handle_control(s,
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(s->setup_buf[0] << 8) | s->setup_buf[1],
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(s->setup_buf[3] << 8) | s->setup_buf[2],
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(s->setup_buf[5] << 8) | s->setup_buf[4],
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s->setup_len,
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s->data_buf);
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if (ret < 0)
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return ret;
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if (ret < s->setup_len)
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s->setup_len = ret;
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s->setup_state = SETUP_STATE_DATA;
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} else {
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if (s->setup_len == 0)
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s->setup_state = SETUP_STATE_ACK;
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else
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s->setup_state = SETUP_STATE_DATA;
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}
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break;
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case USB_TOKEN_IN:
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if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
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return USB_RET_NODEV;
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switch(p->devep) {
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case 0:
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switch(s->setup_state) {
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case SETUP_STATE_ACK:
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if (!(s->setup_buf[0] & USB_DIR_IN)) {
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s->setup_state = SETUP_STATE_IDLE;
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ret = s->handle_control(s,
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(s->setup_buf[0] << 8) | s->setup_buf[1],
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(s->setup_buf[3] << 8) | s->setup_buf[2],
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(s->setup_buf[5] << 8) | s->setup_buf[4],
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s->setup_len,
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s->data_buf);
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if (ret > 0)
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ret = 0;
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} else {
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/* return 0 byte */
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}
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break;
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case SETUP_STATE_DATA:
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if (s->setup_buf[0] & USB_DIR_IN) {
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l = s->setup_len - s->setup_index;
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if (l > len)
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l = len;
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memcpy(data, s->data_buf + s->setup_index, l);
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s->setup_index += l;
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if (s->setup_index >= s->setup_len)
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s->setup_state = SETUP_STATE_ACK;
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ret = l;
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} else {
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s->setup_state = SETUP_STATE_IDLE;
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goto fail;
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}
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break;
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default:
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goto fail;
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}
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break;
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default:
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ret = s->handle_data(s, p);
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break;
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}
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break;
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case USB_TOKEN_OUT:
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if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
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return USB_RET_NODEV;
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switch(p->devep) {
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case 0:
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switch(s->setup_state) {
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case SETUP_STATE_ACK:
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if (s->setup_buf[0] & USB_DIR_IN) {
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s->setup_state = SETUP_STATE_IDLE;
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/* transfer OK */
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} else {
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/* ignore additional output */
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}
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break;
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case SETUP_STATE_DATA:
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if (!(s->setup_buf[0] & USB_DIR_IN)) {
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l = s->setup_len - s->setup_index;
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if (l > len)
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l = len;
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memcpy(s->data_buf + s->setup_index, data, l);
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s->setup_index += l;
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if (s->setup_index >= s->setup_len)
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s->setup_state = SETUP_STATE_ACK;
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ret = l;
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} else {
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s->setup_state = SETUP_STATE_IDLE;
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goto fail;
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}
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break;
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default:
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goto fail;
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}
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break;
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default:
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ret = s->handle_data(s, p);
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break;
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}
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break;
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default:
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fail:
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ret = USB_RET_STALL;
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break;
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return 0;
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}
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/* Rest of the PIDs must match our address */
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if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
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return USB_RET_NODEV;
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switch (p->pid) {
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case USB_TOKEN_SETUP:
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return do_token_setup(s, p);
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case USB_TOKEN_IN:
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return do_token_in(s, p);
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case USB_TOKEN_OUT:
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return do_token_out(s, p);
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default:
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return USB_RET_STALL;
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}
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return ret;
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}
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/* XXX: fix overflow */
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@ -200,5 +226,6 @@ void usb_send_msg(USBDevice *dev, int msg)
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memset(&p, 0, sizeof(p));
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p.pid = msg;
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dev->handle_packet(dev, &p);
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}
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/* This _must_ be synchronous */
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}
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35
hw/usb.h
35
hw/usb.h
@ -120,18 +120,49 @@ typedef struct USBPacket USBPacket;
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/* definition of a USB device */
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struct USBDevice {
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void *opaque;
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/*
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* Process USB packet.
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* Called by the HC (Host Controller).
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*
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* Returns length of the transaction
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* or one of the USB_RET_XXX codes.
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*/
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int (*handle_packet)(USBDevice *dev, USBPacket *p);
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/*
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* Called when device is destroyed.
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*/
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void (*handle_destroy)(USBDevice *dev);
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int speed;
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/* The following fields are used by the generic USB device
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layer. They are here just to avoid creating a new structure for
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them. */
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layer. They are here just to avoid creating a new structure
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for them. */
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/*
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* Reset the device
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*/
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void (*handle_reset)(USBDevice *dev);
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/*
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* Process control request.
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* Called from handle_packet().
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*
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* Returns length or one of the USB_RET_ codes.
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*/
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int (*handle_control)(USBDevice *dev, int request, int value,
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int index, int length, uint8_t *data);
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/*
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* Process data transfers (both BULK and ISOC).
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* Called from handle_packet().
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*
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* Returns length or one of the USB_RET_ codes.
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*/
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int (*handle_data)(USBDevice *dev, USBPacket *p);
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uint8_t addr;
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char devname[32];
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