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/*
* usb/txhandler.c -- USB Transmission Handling
*
* Copyright (C) 2017 Tomasz Kramkowski <tk@the-tk.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <reg/usbotg.h>
#include <stdbool.h>
#include <stddef.h>
#include "bdt.h"
#include "txhandler.h"
/* puttx: place data in the current buffer descriptor */
static bool puttx(struct tx_ctx *tx, void *data, size_t size)
{
if (GET_BIT(tx->bdt[tx->odd].desc, BD_OWN))
return false;
tx->bdt[tx->odd].addr = data;
tx->bdt[tx->odd].desc = USB0_BD_INIT(size, tx->data01);
tx->odd = !tx->odd;
tx->data01 = !tx->data01;
return true;
}
/* tx_push: attempt to push rest of the current transmission into a BD */
bool tx_push(struct tx_ctx *tx)
{
size_t size = tx->size;
if (tx->data == NULL)
return false;
if (size > tx->max)
size = tx->max;
if (!puttx(tx, tx->data, size))
return false;
tx->data = (char *)tx->data + size;
tx->size -= size;
if (tx->size == 0 && size < tx->max)
tx->data = NULL;
return true;
}
/* tx_que: enqueue a transmission */
void tx_que(struct tx_ctx *tx, void *data, size_t size)
{
if (data == NULL || size == 0) {
puttx(tx, NULL, 0);
return;
}
tx->data = data;
tx->size = size;
while (tx_push(tx))
;
}
/* tx_isempty: check if there's nothing left to transmit */
bool tx_isempty(struct tx_ctx *tx)
{
return tx->data == NULL;
}
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