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/* Copyright 2017 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "common.h"
#include "config.h"
#include "link_defs.h"
#include "registers.h"
#include "stddef.h"
#include "usb_api.h"
#include "usb_hw.h"
#include "usb_isochronous.h"
#include "util.h"
/* Console output macro */
#define CPRINTF(format, args...) cprintf(CC_USB, format, ##args)
#define CPRINTS(format, args...) cprints(CC_USB, format, ##args)
/*
* Currently, we only support TX direction for USB isochronous transfer.
*
* According to RM0091, isochronous transfer is always double buffered.
* Addresses of buffers are pointed by `btable_ep[<endpoint>].tx_addr` and
* `btable_ep[<endpoint>].rx_addr`.
*
* DTOG | USB Buffer | App Buffer
* -----+------------+-----------
* 0 | tx_addr | rx_addr
* 1 | rx_addr | tx_addr
*
* That is, when DTOG bit is 0 (see `get_tx_dtog()`), USB hardware will read
* from `tx_addr`, and our application can write new data to `rx_addr` at the
* same time.
*
* Number of bytes in each buffer shall be tracked by `tx_count` and `rx_count`
* respectively.
*
* `get_app_addr()`, `set_app_count()` help you to to select the correct
* variable to use by given DTOG value, which is available by `get_tx_dtog()`.
*/
/*
* Gets current DTOG value of given `config`.
*/
static int get_tx_dtog(struct usb_isochronous_config const *config)
{
return !!(STM32_USB_EP(config->endpoint) & EP_TX_DTOG);
}
/*
* Gets buffer address that can be used by software (application).
*
* The mapping between application buffer address and current TX DTOG value is
* shown in table above.
*/
static usb_uint *get_app_addr(struct usb_isochronous_config const *config,
int dtog_value)
{
return config->tx_ram[dtog_value];
}
/*
* Sets number of bytes written to application buffer.
*/
static void set_app_count(struct usb_isochronous_config const *config,
int dtog_value, usb_uint count)
{
if (dtog_value)
btable_ep[config->endpoint].tx_count = count;
else
btable_ep[config->endpoint].rx_count = count;
}
int usb_isochronous_write_buffer(struct usb_isochronous_config const *config,
const uint8_t *src, size_t n,
size_t dst_offset, int *buffer_id, int commit)
{
int dtog_value = get_tx_dtog(config);
usb_uint *buffer = get_app_addr(config, dtog_value);
uintptr_t ptr = usb_sram_addr(buffer);
if (*buffer_id == -1)
*buffer_id = dtog_value;
else if (dtog_value != *buffer_id)
return -EC_ERROR_TIMEOUT;
if (dst_offset > config->tx_size)
return -EC_ERROR_INVAL;
n = MIN(n, config->tx_size - dst_offset);
memcpy_to_usbram((void *)(ptr + dst_offset), src, n);
if (commit)
set_app_count(config, dtog_value, dst_offset + n);
return n;
}
void usb_isochronous_init(struct usb_isochronous_config const *config)
{
int ep = config->endpoint;
btable_ep[ep].tx_addr = usb_sram_addr(get_app_addr(config, 1));
btable_ep[ep].rx_addr = usb_sram_addr(get_app_addr(config, 0));
set_app_count(config, 0, 0);
set_app_count(config, 1, 0);
STM32_USB_EP(ep) = ((ep << 0) | /* Endpoint Addr */
EP_TX_VALID | /* start transmit */
(2 << 9) | /* ISO EP */
EP_RX_DISAB);
}
void usb_isochronous_event(struct usb_isochronous_config const *config,
enum usb_ep_event evt)
{
if (evt == USB_EVENT_RESET)
usb_isochronous_init(config);
}
void usb_isochronous_tx(struct usb_isochronous_config const *config)
{
/*
* Clear CTR_TX, note that EP_TX_VALID will *NOT* be cleared by
* hardware, so we don't need to toggle it.
*/
STM32_TOGGLE_EP(config->endpoint, 0, 0, 0);
/*
* Clear buffer count for buffer we just transmitted, so we do not
* transmit the data twice.
*/
set_app_count(config, get_tx_dtog(config), 0);
config->tx_callback(config);
}
int usb_isochronous_iface_handler(struct usb_isochronous_config const *config,
usb_uint *ep0_buf_rx, usb_uint *ep0_buf_tx)
{
int ret = -1;
if (ep0_buf_rx[0] ==
(USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_INTERFACE |
USB_REQ_SET_INTERFACE << 8)) {
ret = config->set_interface(ep0_buf_rx[1], ep0_buf_rx[2]);
if (ret == 0) {
/* ACK */
btable_ep[0].tx_count = 0;
STM32_TOGGLE_EP(0, EP_TX_RX_MASK, EP_TX_RX_VALID, 0);
}
}
return ret;
}
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