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/*
* Copyright (c) 2015 Freescale Semiconductor, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of Freescale Semiconductor nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**************************************************************************
* FILE NAME
*
* rpmsg_ext.c
*
* COMPONENT
*
* OpenAMP
*
* DESCRIPTION
*
* Main file for the RPMSG driver extension. This file implements APIs for
* achieving zero copy received message process and zero copy message
* transmission.
*
**************************************************************************/
#include "rpmsg_ext.h"
/*!
* @brief Holds the rx buffer for usage outside the receive callback.
*
* Calling this function prevents the RPMsg receive buffer from being released back to the pool
* of shmem buffers. This API can only be called at rx callback context (rpmsg_rx_cb_t). With this API,
* the application doesn't need to copy the message in rx callback. Instead, the rx buffer base address
* is saved in application context and further processed in application process. After the message
* is processed, the application can release the rx buffer for future reuse in vring by calling the
* rpmsg_release_rx_buffer() function.
*
* @param[in] rpdev The rpmsg channel
* @param[in] rxbuf RX buffer with message payload
*
* @see rpmsg_release_rx_buffer
*/
void rpmsg_hold_rx_buffer(struct rpmsg_channel *rpdev, void *rxbuf) {
struct rpmsg_hdr *rp_hdr = NULL;
if (!rpdev || !rxbuf)
return;
rp_hdr = RPMSG_HDR_FROM_BUF(rxbuf);
/* set held status to keep buffer */
rp_hdr->reserved |= RPMSG_BUF_HELD;
}
/*!
* @brief Releases the rx buffer for future reuse in vring.
*
* This API can be called at process context when the message in rx buffer is processed.
*
* @param rpdev - the rpmsg channel
* @param rxbuf - rx buffer with message payload
*
* @see rpmsg_hold_rx_buffer
*/
void rpmsg_release_rx_buffer(struct rpmsg_channel *rpdev, void *rxbuf) {
struct rpmsg_hdr *hdr;
struct remote_device *rdev;
struct rpmsg_hdr_reserved * reserved = NULL;
if (!rpdev || !rxbuf)
return;
rdev = rpdev->rdev;
hdr = RPMSG_HDR_FROM_BUF(rxbuf);
/* Get the pointer to the reserved field that contains buffer size and the index */
reserved = (struct rpmsg_hdr_reserved*)&hdr->reserved;
env_lock_mutex(rdev->lock);
/* Return used buffer, with total length (header length + buffer size). */
rpmsg_return_buffer(rdev, hdr, (unsigned long)reserved->totlen, reserved->idx);
env_unlock_mutex(rdev->lock);
}
/*!
* @brief Allocates the tx buffer for message payload.
*
* This API can only be called at process context to get the tx buffer in vring. By this way, the
* application can directly put its message into the vring tx buffer without copy from an application buffer.
* It is the application responsibility to correctly fill the allocated tx buffer by data and passing correct
* parameters to the rpmsg_send_nocopy() or rpmsg_sendto_nocopy() function to perform data no-copy-send mechanism.
*
* @param[in] rpdev Pointer to rpmsg channel
* @param[in] size Pointer to store tx buffer size
* @param[in] wait Boolean, wait or not for buffer to become available
*
* @return The tx buffer address on success and NULL on failure
*
* @see rpmsg_send_offchannel_nocopy
* @see rpmsg_sendto_nocopy
* @see rpmsg_send_nocopy
*/
void *rpmsg_alloc_tx_buffer(struct rpmsg_channel *rpdev, unsigned long *size, int wait) {
struct rpmsg_hdr *hdr;
struct remote_device *rdev;
unsigned short idx;
int buff_len, tick_count = 0;
if (!rpdev || !size)
return NULL;
rdev = rpdev->rdev;
env_lock_mutex(rdev->lock);
/* Get tx buffer from vring */
hdr = (struct rpmsg_hdr *) rpmsg_get_tx_buffer(rdev, &buff_len, &idx);
env_unlock_mutex(rdev->lock);
if (!hdr && !wait) {
return NULL;
} else {
while (!hdr) {
/*
* Wait parameter is true - pool the buffer for
* 15 secs as defined by the APIs.
*/
env_sleep_msec(RPMSG_TICKS_PER_INTERVAL);
env_lock_mutex(rdev->lock);
hdr = (struct rpmsg_hdr *) rpmsg_get_tx_buffer(rdev, &buff_len, &idx);
env_unlock_mutex(rdev->lock);
tick_count += RPMSG_TICKS_PER_INTERVAL;
if (tick_count >= (RPMSG_TICK_COUNT / RPMSG_TICKS_PER_INTERVAL)) {
return NULL;
}
}
/* Store buffer size and the index into the reserved field to be used when sending */
((struct rpmsg_hdr_reserved*)&hdr->reserved)->idx = idx;
((struct rpmsg_hdr_reserved*)&hdr->reserved)->totlen = buff_len;
/* Actual data buffer size is vring buffer size minus rpmsg header length */
*size = buff_len - offsetof(struct rpmsg_hdr, data);
return hdr->data;
}
}
/*!
* @brief Sends a message in tx buffer allocated by rpmsg_alloc_tx_buffer()
* using explicit src/dst addresses.
*
* This function sends txbuf of length len to the remote dst address,
* and uses src as the source address.
* The message will be sent to the remote processor which the rpdev
* channel belongs to.
* The application has to take the responsibility for:
* 1. tx buffer allocation (rpmsg_alloc_tx_buffer() )
* 2. filling the data to be sent into the pre-allocated tx buffer
* 3. not exceeding the buffer size when filling the data
* 4. data cache coherency
*
* After the rpmsg_send_offchannel_nocopy() function is issued the tx buffer is no more owned
* by the sending task and must not be touched anymore unless the rpmsg_send_offchannel_nocopy()
* function fails and returns an error. In that case the application should try
* to re-issue the rpmsg_send_offchannel_nocopy() again and if it is still not possible to send
* the message and the application wants to give it up from whatever reasons
* the rpmsg_release_rx_buffer function could be called,
* passing the pointer to the tx buffer to be released as a parameter.
*
* @param[in] rpdev The rpmsg channel
* @param[in] src Source address
* @param[in] dst Destination address
* @param[in] txbuf TX buffer with message filled
* @param[in] len Length of payload
*
* @return 0 on success and an appropriate error value on failure
*
* @see rpmsg_alloc_tx_buffer
* @see rpmsg_sendto_nocopy
* @see rpmsg_send_nocopy
*/
int rpmsg_send_offchannel_nocopy(struct rpmsg_channel *rpdev, unsigned long src, unsigned long dst,
void *txbuf, int len) {
struct rpmsg_hdr *hdr;
struct remote_device *rdev;
struct rpmsg_hdr_reserved * reserved = NULL;
int status;
if (!rpdev || !txbuf)
return RPMSG_ERR_PARAM;
rdev = rpdev->rdev;
hdr = RPMSG_HDR_FROM_BUF(txbuf);
/* Initialize RPMSG header. */
hdr->dst = dst;
hdr->src = src;
hdr->len = len;
hdr->flags = 0;
/* Get the pointer to the reserved field that contains buffer size and the index */
reserved = (struct rpmsg_hdr_reserved*)&hdr->reserved;
env_lock_mutex(rdev->lock);
status = rpmsg_enqueue_buffer(rdev, hdr, (unsigned long)reserved->totlen, reserved->idx);
if (status == RPMSG_SUCCESS) {
/* Let the other side know that there is a job to process. */
virtqueue_kick(rdev->tvq);
}
env_unlock_mutex(rdev->lock);
return status;
}
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