From owner-svn-src-head@FreeBSD.ORG Thu Dec 20 00:34:55 2012 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 9D0F954C; Thu, 20 Dec 2012 00:34:55 +0000 (UTC) (envelope-from cognet@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) by mx1.freebsd.org (Postfix) with ESMTP id 81A158FC13; Thu, 20 Dec 2012 00:34:55 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.5/8.14.5) with ESMTP id qBK0YtCk022551; Thu, 20 Dec 2012 00:34:55 GMT (envelope-from cognet@svn.freebsd.org) Received: (from cognet@localhost) by svn.freebsd.org (8.14.5/8.14.5/Submit) id qBK0YtUd022549; Thu, 20 Dec 2012 00:34:55 GMT (envelope-from cognet@svn.freebsd.org) Message-Id: <201212200034.qBK0YtUd022549@svn.freebsd.org> From: Olivier Houchard Date: Thu, 20 Dec 2012 00:34:55 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r244466 - in head/sys: kern sys X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 Dec 2012 00:34:55 -0000 Author: cognet Date: Thu Dec 20 00:34:54 2012 New Revision: 244466 URL: http://svnweb.freebsd.org/changeset/base/244466 Log: Create an architecture-agnostic buffer pool manager that uses uma(9) to manage a set of power-of-2 sized buffers for bus_dmamem_alloc(). This allows the caller to provide the back-end allocator uma allocator, allowing full control of the memory pages backing the pool. For convenience, it provides an optional builtin allocator that provides pages allocated with the VM_MEMATTR_UNCACHEABLE attribute, for managing pools of DMA buffers for BUS_DMA_COHERENT or BUS_DMA_NOCACHE. This also allows the caller to specify a minimum alignment, and it ensures that all buffers start on a boundary and have a length that's a multiple of that value, to avoid using buffers that trigger partial cache line flushes. Submitted by: Ian Lepore Added: head/sys/kern/subr_busdma_bufalloc.c (contents, props changed) head/sys/sys/busdma_bufalloc.h (contents, props changed) Added: head/sys/kern/subr_busdma_bufalloc.c ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/sys/kern/subr_busdma_bufalloc.c Thu Dec 20 00:34:54 2012 (r244466) @@ -0,0 +1,174 @@ +/*- + * Copyright (c) 2012 Ian Lepore + * 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. + */ + +#include +__FBSDID("$FreeBSD$"); + +/* + * Buffer allocation support routines for bus_dmamem_alloc implementations. + */ + +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +/* + * We manage buffer zones up to a page in size. Buffers larger than a page can + * be managed by one of the kernel's page-oriented memory allocation routines as + * efficiently as what we can do here. Also, a page is the largest size for + * which we can g'tee contiguity when using uma, and contiguity is one of the + * requirements we have to fulfill. + */ +#define MIN_ZONE_BUFSIZE 32 +#define MAX_ZONE_BUFSIZE PAGE_SIZE + +/* + * The static array of 12 bufzones is big enough to handle all the zones for the + * smallest supported allocation size of 32 through the largest supported page + * size of 64K. If you up the biggest page size number, up the array size too. + * Basically the size of the array needs to be log2(maxsize)-log2(minsize)+1, + * but I don't know of an easy way to express that as a compile-time constant. + */ +#if PAGE_SIZE > 65536 +#error Unsupported page size +#endif + +struct busdma_bufalloc { + bus_size_t min_size; + size_t num_zones; + struct busdma_bufzone buf_zones[12]; +}; + +busdma_bufalloc_t +busdma_bufalloc_create(const char *name, bus_size_t minimum_alignment, + uma_alloc alloc_func, uma_free free_func, u_int32_t zcreate_flags) +{ + struct busdma_bufalloc *ba; + struct busdma_bufzone *bz; + int i; + bus_size_t cursize; + + ba = malloc(sizeof(struct busdma_bufalloc), M_DEVBUF, + M_ZERO | M_WAITOK); + + ba->min_size = MAX(MIN_ZONE_BUFSIZE, minimum_alignment); + + /* + * Each uma zone is created with an alignment of size-1, meaning that + * the alignment is equal to the size (I.E., 64 byte buffers are aligned + * to 64 byte boundaries, etc). This allows for a fast efficient test + * when deciding whether a pool buffer meets the constraints of a given + * tag used for allocation: the buffer is usable if tag->alignment <= + * bufzone->size. + */ + for (i = 0, bz = ba->buf_zones, cursize = ba->min_size; + i < nitems(ba->buf_zones) && cursize <= MAX_ZONE_BUFSIZE; + ++i, ++bz, cursize <<= 1) { + snprintf(bz->name, sizeof(bz->name), "dma %.10s %lu", + name, cursize); + bz->size = cursize; + bz->umazone = uma_zcreate(bz->name, bz->size, + NULL, NULL, NULL, NULL, bz->size - 1, zcreate_flags); + if (bz->umazone == NULL) { + busdma_bufalloc_destroy(ba); + return (NULL); + } + if (alloc_func != NULL) + uma_zone_set_allocf(bz->umazone, alloc_func); + if (free_func != NULL) + uma_zone_set_freef(bz->umazone, free_func); + ++ba->num_zones; + } + + return (ba); +} + +void +busdma_bufalloc_destroy(busdma_bufalloc_t ba) +{ + struct busdma_bufzone *bz; + int i; + + if (ba == NULL) + return; + + for (i = 0, bz = ba->buf_zones; i < ba->num_zones; ++i, ++bz) { + uma_zdestroy(bz->umazone); + } + + free(ba, M_DEVBUF); +} + +struct busdma_bufzone * +busdma_bufalloc_findzone(busdma_bufalloc_t ba, bus_size_t size) +{ + struct busdma_bufzone *bz; + int i; + + if (size > MAX_ZONE_BUFSIZE) + return (NULL); + + for (i = 0, bz = ba->buf_zones; i < ba->num_zones; ++i, ++bz) { + if (bz->size >= size) + return (bz); + } + + panic("Didn't find a buffer zone of the right size"); +} + +void * +busdma_bufalloc_alloc_uncacheable(uma_zone_t zone, int size, u_int8_t *pflag, + int wait) +{ +#ifdef VM_MEMATTR_UNCACHEABLE + + /* Inform UMA that this allocator uses kernel_map/object. */ + *pflag = UMA_SLAB_KERNEL; + + return ((void *)kmem_alloc_attr(kernel_map, size, wait, 0, + BUS_SPACE_MAXADDR, VM_MEMATTR_UNCACHEABLE)); + +#else + + panic("VM_MEMATTR_UNCACHEABLE unavailable"); + +#endif /* VM_MEMATTR_UNCACHEABLE */ +} + +void +busdma_bufalloc_free_uncacheable(void *item, int size, u_int8_t pflag) +{ + + kmem_free(kernel_map, (vm_offset_t)item, size); +} + Added: head/sys/sys/busdma_bufalloc.h ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/sys/sys/busdma_bufalloc.h Thu Dec 20 00:34:54 2012 (r244466) @@ -0,0 +1,118 @@ +/*- + * Copyright (c) 2012 Ian Lepore + * 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. + */ + +/* + * $FreeBSD$ + */ + +/* + * A buffer pool manager, for use by a platform's busdma implementation. + */ + +#ifndef _MACHINE_BUSDMA_BUFALLOC_H_ +#define _MACHINE_BUSDMA_BUFALLOC_H_ + +#include +#include + +/* + * Information about a buffer zone, returned by busdma_bufalloc_findzone(). + */ +struct busdma_bufzone { + bus_size_t size; + uma_zone_t umazone; + char name[24]; +}; + +/* + * Opaque handle type returned by busdma_bufalloc_create(). + */ +struct busdma_bufalloc; +typedef struct busdma_bufalloc *busdma_bufalloc_t; + +/* + * Create an allocator that manages a pool of DMA buffers. + * + * The allocator manages a collection of uma(9) zones of buffers in power-of-two + * sized increments ranging from minimum_alignment to the platform's PAGE_SIZE. + * The buffers within each zone are aligned on boundaries corresponding to the + * buffer size, and thus by implication each buffer is contiguous within a page + * and does not cross a power of two boundary larger than the buffer size. + * These rules are intended to make it easy for a busdma implementation to + * check whether a tag's constraints allow use of a buffer from the allocator. + * + * minimum_alignment is also the minimum buffer allocation size. For platforms + * with software-assisted cache coherency, this is typically the data cache line + * size (and MUST not be smaller than the cache line size). + * + * name appears in zone stats as 'dma name nnnnn' where 'dma' is fixed and + * 'nnnnn' is the size of buffers in that zone. + * + * If if the alloc/free function pointers are NULL, the regular uma internal + * allocators are used (I.E., you get "plain old kernel memory"). On a platform + * with an exclusion zone that applies to all DMA operations, a custom allocator + * could be used to ensure no buffer memory is ever allocated from that zone, + * allowing the bus_dmamem_alloc() implementation to make the assumption that + * buffers provided by the allocation could never lead to the need for a bounce. + */ +busdma_bufalloc_t busdma_bufalloc_create(const char *name, + bus_size_t minimum_alignment, + uma_alloc uma_alloc_func, uma_free uma_free_func, + u_int32_t uma_zcreate_flags); + +/* + * Destroy an allocator created by busdma_bufalloc_create(). + * Safe to call with a NULL pointer. + */ +void busdma_bufalloc_destroy(busdma_bufalloc_t ba); + +/* + * Return a pointer to the busdma_bufzone that should be used to allocate or + * free a buffer of the given size. Returns NULL if the size is larger than the + * largest zone handled by the allocator. + */ +struct busdma_bufzone * busdma_bufalloc_findzone(busdma_bufalloc_t ba, + bus_size_t size); + +/* + * These built-in allocation routines are available for managing a pools of + * uncacheable memory on platforms that support VM_MEMATTR_UNCACHEABLE. + * + * Allocation is done using kmem_alloc_attr() with these parameters: + * lowaddr = 0 + * highaddr = BUS_SPACE_MAXADDR + * memattr = VM_MEMATTR_UNCACHEABLE. + * + * If your platform has no exclusion region (lowaddr/highaddr), and its pmap + * routines support pmap_page_set_memattr() and the VM_MEMATTR_UNCACHEABLE flag + * you can probably use these when you need uncacheable buffers. + */ +void * busdma_bufalloc_alloc_uncacheable(uma_zone_t zone, int size, + u_int8_t *pflag, int wait); +void busdma_bufalloc_free_uncacheable(void *item, int size, u_int8_t pflag); + +#endif /* _MACHINE_BUSDMA_BUFALLOC_H_ */ +