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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "atomic.h"
#include "common.h"
#include "config.h"
#include "link_defs.h"
#include "printf.h"
#include "registers.h"
#include "task.h"
#include "timer.h"
#include "util.h"
#include "usb.h"
#include "usb-stream.h"
/*
* The USB packet RAM is attached to the processor via the AHB2APB bridge. This
* bridge performs manipulations of read and write accesses as per the note in
* section 2.1 of RM0091. The upshot is that it is OK to read from the packet
* RAM using 8-bit or 16-bit accesses, but not 32-bit, and it is only really OK
* to write to the packet RAM using 16-bit accesses. Thus custom memcpy like
* routines need to be employed. Furthermore, reading from and writing to the
* RX and TX queues uses memcpy, which will try to do 32-bit accesses if it can.
* so we must read and write single bytes at a time and construct 16-bit
* accesses to the packet RAM.
*
* This could be improved by adding a set of operations on the queue to get
* a pointer and size of the largest contiguous free/full region, then that
* region could be operated on and a commit operation could be performed on
* the queue.
*/
static size_t rx_read(struct usb_stream_config const *config)
{
size_t count = btable_ep[config->endpoint].rx_count & 0x3ff;
if (count < queue_space(&config->rx)) {
usb_uint *buffer = config->rx_ram;
size_t i;
for (i = 0; i < count / 2; i++) {
usb_uint word = *buffer++;
uint8_t lsb = (word >> 0) & 0xff;
uint8_t msb = (word >> 8) & 0xff;
queue_add_unit(&config->rx, &lsb);
queue_add_unit(&config->rx, &msb);
}
if (count & 1) {
usb_uint word = *buffer++;
uint8_t lsb = (word >> 0) & 0xff;
queue_add_unit(&config->rx, &lsb);
}
return count;
}
return 0;
}
static size_t tx_write(struct usb_stream_config const *config)
{
usb_uint *buffer = config->tx_ram;
size_t count = MIN(USB_MAX_PACKET_SIZE, queue_count(&config->tx));
size_t i;
for (i = 0; i < count / 2; i++) {
uint8_t lsb;
uint8_t msb;
queue_remove_unit(&config->tx, &lsb);
queue_remove_unit(&config->tx, &msb);
*buffer++ = (msb << 8) | lsb;
}
if (count & 1) {
uint8_t lsb;
queue_remove_unit(&config->tx, &lsb);
*buffer++ = lsb;
}
btable_ep[config->endpoint].tx_count = count;
return count;
}
static size_t usb_read(struct in_stream const *stream,
uint8_t *buffer,
size_t count)
{
struct usb_stream_config const *config =
DOWNCAST(stream, struct usb_stream_config, in);
size_t read = QUEUE_REMOVE_UNITS(&config->rx, buffer, count);
if (config->state->rx_waiting && rx_read(config)) {
config->state->rx_waiting = 0;
STM32_TOGGLE_EP(config->endpoint, EP_RX_MASK, EP_RX_VALID, 0);
/*
* Make sure that the reader of this queue knows that there is
* more to read.
*/
in_stream_ready(&config->in);
/*
* If there is still space left in the callers buffer fill it
* up with the additional bytes just added to the queue.
*/
if (count - read > 0)
read += QUEUE_REMOVE_UNITS(&config->rx,
buffer + read,
count - read);
}
return read;
}
static int tx_valid(struct usb_stream_config const *config)
{
return (STM32_USB_EP(config->endpoint) & EP_TX_MASK) == EP_TX_VALID;
}
static size_t usb_write(struct out_stream const *stream,
uint8_t const *buffer,
size_t count)
{
struct usb_stream_config const *config =
DOWNCAST(stream, struct usb_stream_config, out);
size_t wrote = QUEUE_ADD_UNITS(&config->tx, buffer, count);
/*
* If we are not currently in a valid transmission state and we had
* something for the TX buffer, then mark the TX endpoint as valid.
*/
if (!tx_valid(config) && tx_write(config))
STM32_TOGGLE_EP(config->endpoint, EP_TX_MASK, EP_TX_VALID, 0);
return wrote;
}
static void usb_flush(struct out_stream const *stream)
{
struct usb_stream_config const *config =
DOWNCAST(stream, struct usb_stream_config, out);
while (tx_valid(config) || queue_count(&config->tx))
;
}
struct in_stream_ops const usb_stream_in_stream_ops = {
.read = usb_read,
};
struct out_stream_ops const usb_stream_out_stream_ops = {
.write = usb_write,
.flush = usb_flush,
};
void usb_stream_tx(struct usb_stream_config const *config)
{
if (tx_write(config))
STM32_TOGGLE_EP(config->endpoint, EP_TX_MASK, EP_TX_VALID, 0);
else
STM32_TOGGLE_EP(config->endpoint, 0, 0, 0);
out_stream_ready(&config->out);
}
void usb_stream_rx(struct usb_stream_config const *config)
{
if (rx_read(config)) {
/*
* RX packet consumed, mark the packet as VALID.
*/
STM32_TOGGLE_EP(config->endpoint, EP_RX_MASK, EP_RX_VALID, 0);
} else {
/*
* There is not enough space in the RX queue to receive this
* packet. Leave the RX endpoint in a NAK state, clear the
* interrupt, and indicate to the usb_read function that when
* there is enough space in the queue to hold it there is an
* RX packet waiting.
*/
config->state->rx_waiting = 1;
STM32_TOGGLE_EP(config->endpoint, 0, 0, 0);
}
in_stream_ready(&config->in);
}
void usb_stream_reset(struct usb_stream_config const *config)
{
int i = config->endpoint;
btable_ep[i].tx_addr = usb_sram_addr(config->tx_ram);
btable_ep[i].tx_count = 0;
btable_ep[i].rx_addr = usb_sram_addr(config->rx_ram);
btable_ep[i].rx_count = 0x8000 | ((USB_MAX_PACKET_SIZE / 32 - 1) << 10);
config->state->rx_waiting = 0;
STM32_USB_EP(i) = ((i << 0) | /* Endpoint Addr*/
(2 << 4) | /* TX NAK */
(0 << 9) | /* Bulk EP */
(3 << 12)); /* RX VALID */
}
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