freebsd-skq/sys/dev/xdma/xdma_mbuf.c
br 8713fad4de Tune xDMA interface slightly:
o Move descriptors allocation to DMA engine driver
o Add generic xdma_request() routine
o Add less-generic scatter-gather application based on xdma interface

Typical operation flow in peripheral device driver is:

1. Get xDMA controller
sc->xdma_tx = xdma_ofw_get(sc->dev, "tx");

2. Allocate virtual channel
sc->xchan_tx = xdma_channel_alloc(sc->xdma_tx, caps);

3. Setup transfer status callback
xdma_setup_intr(sc->xchan_tx, my_tx_intr, sc, &sc->ih_tx);

4. Request a transfer(s)
ret = xdma_request(sc->xchan_tx, &req);

5. Free the channel
xdma_channel_free(sc->xdma_tx);

6. Free the controller
xdma_put(sc->xdma_tx);

Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D14971
2018-04-12 15:36:24 +00:00

155 lines
3.8 KiB
C

/*-
* Copyright (c) 2017-2018 Ruslan Bukin <br@bsdpad.com>
* All rights reserved.
*
* This software was developed by SRI International and the University of
* Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
* ("CTSRD"), as part of the DARPA CRASH research programme.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/sx.h>
#include <sys/mbuf.h>
#include <machine/bus.h>
#ifdef FDT
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#endif
#include <dev/xdma/xdma.h>
int
xdma_dequeue_mbuf(xdma_channel_t *xchan, struct mbuf **mp,
xdma_transfer_status_t *status)
{
struct xdma_request *xr;
struct xdma_request *xr_tmp;
QUEUE_OUT_LOCK(xchan);
TAILQ_FOREACH_SAFE(xr, &xchan->queue_out, xr_next, xr_tmp) {
TAILQ_REMOVE(&xchan->queue_out, xr, xr_next);
break;
}
QUEUE_OUT_UNLOCK(xchan);
if (xr == NULL)
return (-1);
*mp = xr->m;
status->error = xr->status.error;
status->transferred = xr->status.transferred;
xchan_bank_put(xchan, xr);
return (0);
}
int
xdma_enqueue_mbuf(xdma_channel_t *xchan, struct mbuf **mp,
uintptr_t addr, uint8_t src_width, uint8_t dst_width,
enum xdma_direction dir)
{
struct xdma_request *xr;
xdma_controller_t *xdma;
xdma = xchan->xdma;
xr = xchan_bank_get(xchan);
if (xr == NULL)
return (-1); /* No space is available yet. */
xr->direction = dir;
xr->m = *mp;
xr->req_type = XR_TYPE_MBUF;
if (dir == XDMA_MEM_TO_DEV) {
xr->dst_addr = addr;
xr->src_addr = 0;
} else {
xr->src_addr = addr;
xr->dst_addr = 0;
}
xr->src_width = src_width;
xr->dst_width = dst_width;
QUEUE_IN_LOCK(xchan);
TAILQ_INSERT_TAIL(&xchan->queue_in, xr, xr_next);
QUEUE_IN_UNLOCK(xchan);
return (0);
}
uint32_t
xdma_mbuf_chain_count(struct mbuf *m0)
{
struct mbuf *m;
uint32_t c;
c = 0;
for (m = m0; m != NULL; m = m->m_next)
c++;
return (c);
}
uint32_t
xdma_mbuf_defrag(xdma_channel_t *xchan, struct xdma_request *xr)
{
xdma_controller_t *xdma;
struct mbuf *m;
uint32_t c;
xdma = xchan->xdma;
c = xdma_mbuf_chain_count(xr->m);
if (c == 1)
return (c); /* Nothing to do. */
if (xchan->caps & XCHAN_CAP_BUSDMA) {
if ((xchan->caps & XCHAN_CAP_BUSDMA_NOSEG) || \
(c > xchan->maxnsegs)) {
if ((m = m_defrag(xr->m, M_NOWAIT)) == NULL) {
device_printf(xdma->dma_dev,
"%s: Can't defrag mbuf\n",
__func__);
return (c);
}
xr->m = m;
c = 1;
}
}
return (c);
}