freebsd-skq/sys/dev/ioat/ioat.h
Conrad Meyer 6ca07079af ioat(4): Add support for 'fence' bit with DMA_FENCE flag
Some classes of IOAT hardware prefetch reads.  DMA operations that
depend on the result of prior DMA operations must use the DMA_FENCE flag
to prevent stale reads.

(E.g., I've hit this personally on Broadwell-EP.  The Broadwell-DE has a
different IOAT unit that is documented to not pipeline DMA operations.)

Sponsored by:	EMC / Isilon Storage Division
2016-01-15 01:34:43 +00:00

162 lines
5.7 KiB
C

/*-
* Copyright (C) 2012 Intel Corporation
* 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.
*
* 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.
*/
__FBSDID("$FreeBSD$");
#ifndef __IOAT_H__
#define __IOAT_H__
#include <sys/param.h>
#include <machine/bus.h>
/*
* This file defines the public interface to the IOAT driver.
*/
/*
* Enables an interrupt for this operation. Typically, you would only enable
* this on the last operation in a group
*/
#define DMA_INT_EN 0x1
/*
* Like M_NOWAIT. Operations will return NULL if they cannot allocate a
* descriptor without blocking.
*/
#define DMA_NO_WAIT 0x2
/*
* Disallow prefetching the source of the following operation. Ordinarily, DMA
* operations can be pipelined on some hardware. E.g., operation 2's source
* may be prefetched before operation 1 completes.
*/
#define DMA_FENCE 0x4
#define DMA_ALL_FLAGS (DMA_INT_EN | DMA_NO_WAIT | DMA_FENCE)
/*
* Hardware revision number. Different hardware revisions support different
* features. For example, 3.2 cannot read from MMIO space, while 3.3 can.
*/
#define IOAT_VER_3_0 0x30
#define IOAT_VER_3_2 0x32
#define IOAT_VER_3_3 0x33
typedef void *bus_dmaengine_t;
struct bus_dmadesc;
typedef void (*bus_dmaengine_callback_t)(void *arg, int error);
/*
* Called first to acquire a reference to the DMA channel
*/
bus_dmaengine_t ioat_get_dmaengine(uint32_t channel_index);
/* Release the DMA channel */
void ioat_put_dmaengine(bus_dmaengine_t dmaengine);
/* Check the DMA engine's HW version */
int ioat_get_hwversion(bus_dmaengine_t dmaengine);
size_t ioat_get_max_io_size(bus_dmaengine_t dmaengine);
/*
* Set interrupt coalescing on a DMA channel.
*
* The argument is in microseconds. A zero value disables coalescing. Any
* other value delays interrupt generation for N microseconds to provide
* opportunity to coalesce multiple operations into a single interrupt.
*
* Returns an error status, or zero on success.
*
* - ERANGE if the given value exceeds the delay supported by the hardware.
* (All current hardware supports a maximum of 0x3fff microseconds delay.)
* - ENODEV if the hardware does not support interrupt coalescing.
*/
int ioat_set_interrupt_coalesce(bus_dmaengine_t dmaengine, uint16_t delay);
/*
* Return the maximum supported coalescing period, for use in
* ioat_set_interrupt_coalesce(). If the hardware does not support coalescing,
* returns zero.
*/
uint16_t ioat_get_max_coalesce_period(bus_dmaengine_t dmaengine);
/*
* Acquire must be called before issuing an operation to perform. Release is
* called after. Multiple operations can be issued within the context of one
* acquire and release
*/
void ioat_acquire(bus_dmaengine_t dmaengine);
void ioat_release(bus_dmaengine_t dmaengine);
/*
* Acquire_reserve can be called to ensure there is room for N descriptors. If
* it succeeds, the next N valid operations will successfully enqueue.
*
* It may fail with:
* - ENXIO if the channel is in an errored state, or the driver is being
* unloaded
* - EAGAIN if mflags included M_NOWAIT
*
* On failure, the caller does not hold the dmaengine.
*/
int ioat_acquire_reserve(bus_dmaengine_t dmaengine, unsigned n, int mflags);
/*
* Issue a blockfill operation. The 64-bit pattern 'fillpattern' is written to
* 'len' physically contiguous bytes at 'dst'.
*
* Only supported on devices with the BFILL capability.
*/
struct bus_dmadesc *ioat_blockfill(bus_dmaengine_t dmaengine, bus_addr_t dst,
uint64_t fillpattern, bus_size_t len, bus_dmaengine_callback_t callback_fn,
void *callback_arg, uint32_t flags);
/* Issues the copy data operation */
struct bus_dmadesc *ioat_copy(bus_dmaengine_t dmaengine, bus_addr_t dst,
bus_addr_t src, bus_size_t len, bus_dmaengine_callback_t callback_fn,
void *callback_arg, uint32_t flags);
/*
* Issue a copy data operation, with constraints:
* - src1, src2, dst1, dst2 are all page-aligned addresses
* - The quantity to copy is exactly 2 pages;
* - src1 -> dst1, src2 -> dst2
*
* Why use this instead of normal _copy()? You can copy two non-contiguous
* pages (src, dst, or both) with one descriptor.
*/
struct bus_dmadesc *ioat_copy_8k_aligned(bus_dmaengine_t dmaengine,
bus_addr_t dst1, bus_addr_t dst2, bus_addr_t src1, bus_addr_t src2,
bus_dmaengine_callback_t callback_fn, void *callback_arg, uint32_t flags);
/*
* Issues a null operation. This issues the operation to the hardware, but the
* hardware doesn't do anything with it.
*/
struct bus_dmadesc *ioat_null(bus_dmaengine_t dmaengine,
bus_dmaengine_callback_t callback_fn, void *callback_arg, uint32_t flags);
#endif /* __IOAT_H__ */