Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753090Ab0LQEQl (ORCPT ); Thu, 16 Dec 2010 23:16:41 -0500 Received: from ganesha.gnumonks.org ([213.95.27.120]:37584 "EHLO ganesha.gnumonks.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752064Ab0LQEQi (ORCPT ); Thu, 16 Dec 2010 23:16:38 -0500 From: KyongHo Cho To: KyongHo Cho Cc: Kyungmin Park , Kukjin Kim , Inho Lee , Inki Dae , Andrew Morton , Ankita Garg , Daniel Walker , Johan MOSSBERG , KAMEZAWA Hiroyuki , Marek Szyprowski , Mel Gorman , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-samsung-soc@vger.kernel.org, Michal Nazarewicz Subject: [RFCv2,7/8] mm: vcm: vcm-cma: VCM CMA driver added Date: Fri, 17 Dec 2010 12:56:26 +0900 Message-Id: <1292558187-17348-8-git-send-email-pullip.cho@samsung.com> X-Mailer: git-send-email 1.6.2.5 In-Reply-To: <1292558187-17348-7-git-send-email-pullip.cho@samsung.com> References: <1292558187-17348-1-git-send-email-pullip.cho@samsung.com> <1292558187-17348-2-git-send-email-pullip.cho@samsung.com> <1292558187-17348-3-git-send-email-pullip.cho@samsung.com> <1292558187-17348-4-git-send-email-pullip.cho@samsung.com> <1292558187-17348-5-git-send-email-pullip.cho@samsung.com> <1292558187-17348-6-git-send-email-pullip.cho@samsung.com> <1292558187-17348-7-git-send-email-pullip.cho@samsung.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6993 Lines: 232 From: Michal Nazarewicz This commit adds a VCM driver that instead of using real hardware MMU emulates one and uses CMA for allocating contiguous memory chunks. Signed-off-by: Michal Nazarewicz Signed-off-by: Kyungmin Park --- Documentation/virtual-contiguous-memory.txt | 12 +++- include/linux/vcm-cma.h | 38 ++++++++++ mm/Kconfig | 14 ++++ mm/Makefile | 1 + mm/vcm-cma.c | 99 +++++++++++++++++++++++++++ 5 files changed, 163 insertions(+), 1 deletions(-) create mode 100644 include/linux/vcm-cma.h create mode 100644 mm/vcm-cma.c diff --git a/Documentation/virtual-contiguous-memory.txt b/Documentation/virtual-contiguous-memory.txt index 070685b..46edaee 100644 --- a/Documentation/virtual-contiguous-memory.txt +++ b/Documentation/virtual-contiguous-memory.txt @@ -552,7 +552,17 @@ well: If one uses vcm_unbind() then vcm_bind() on the same reservation, physical memory pair should also work. -There are no One-to-One drivers at this time. +*** VCM CMA + +VCM CMA driver is a One-to-One driver which uses CMA (see +[[file:contiguous-memory.txt][contiguous-memory.txt]]) to allocate physically contiguous memory. VCM +CMA context is created by calling: + + struct vcm *__must_check + vcm_cma_create(const char *regions, dma_addr_t alignment); + +Its first argument is the list of regions that CMA should try to +allocate memory from. The second argument is required alignment. * Writing a VCM driver diff --git a/include/linux/vcm-cma.h b/include/linux/vcm-cma.h new file mode 100644 index 0000000..57c2cc9 --- /dev/null +++ b/include/linux/vcm-cma.h @@ -0,0 +1,38 @@ +/* + * Virtual Contiguous Memory driver for CMA header + * Copyright (c) 2010 by Samsung Electronics. + * Written by Michal Nazarewicz (m.nazarewicz@samsung.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License or (at your optional) any later version of the license. + */ + +/* + * See Documentation/virtual-contiguous-memory.txt for details. + */ + +#ifndef __LINUX_VCM_CMA_H +#define __LINUX_VCM_CMA_H + +#include + +struct vcm; + +/** + * vcm_cma_create() - creates a VCM context that fakes a hardware MMU + * @ctx: the cma context that is defined by the machine's implementation. + * from. + * @alignment: required alignment of allocations. + * + * This creates VCM context that can be used on platforms with no + * hardware MMU or for devices that aro conected to the bus directly. + * Because it does not represent real MMU it has some limitations: + * basically, vcm_alloc(), vcm_reserve() and vcm_bind() are likely to + * fail so vcm_make_binding() should be used instead. + */ +struct vcm *__must_check +vcm_cma_create(struct cma *ctx, unsigned long alignment); + +#endif diff --git a/mm/Kconfig b/mm/Kconfig index 53328d2..5cd25e7 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -390,6 +390,20 @@ config VCM_O2O it if you are going to build external modules that will use this functionality. +config VCM_CMA + bool "VCM CMA driver" + depends on VCM && CMA + select VCM_O2O + help + This enables VCM driver that instead of using a real hardware + MMU fakes one and uses a direct mapping. It provides a subset + of functionalities of a real MMU but if drivers limits their + use of VCM to only supported operations they can work on + both systems with and without MMU with no changes. + + For more information see + . If unsure, say "n". + # # UP and nommu archs use km based percpu allocator # diff --git a/mm/Makefile b/mm/Makefile index b96a6cb..6663fc2 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -44,3 +44,4 @@ obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o obj-$(CONFIG_CMA) += cma.o obj-$(CONFIG_VCM) += vcm.o +obj-$(CONFIG_VCM_CMA) += vcm-cma.o diff --git a/mm/vcm-cma.c b/mm/vcm-cma.c new file mode 100644 index 0000000..dcdc751 --- /dev/null +++ b/mm/vcm-cma.c @@ -0,0 +1,99 @@ +/* + * Virtual Contiguous Memory driver for CMA + * Copyright (c) 2010 by Samsung Electronics. + * Written by Michal Nazarewicz (m.nazarewicz@samsung.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License or (at your optional) any later version of the license. + */ + +/* + * See Documentation/virtual-contiguous-memory.txt for details. + */ + +#include +#include +#include +#include +#include +#include + +struct vcm_cma { + struct vcm_o2o o2o; + struct cma *ctx; + unsigned long alignment; +}; + +struct vcm_cma_phys { + struct cm *chunk; + struct vcm_phys phys; +}; + +static void vcm_cma_free(struct vcm_phys *_phys) +{ + struct vcm_cma_phys *phys = + container_of(_phys, struct vcm_cma_phys, phys); + cm_unpin(phys->chunk); + cm_free(phys->chunk); + kfree(phys); +} + +static struct vcm_phys * +vcm_cma_phys(struct vcm *vcm, resource_size_t size, unsigned flags) +{ + struct vcm_cma *cma = container_of(vcm, struct vcm_cma, o2o.vcm); + struct vcm_cma_phys *phys; + struct cm *chunk; + + phys = kmalloc(sizeof *phys + sizeof *phys->phys.parts, GFP_KERNEL); + if (!phys) + return ERR_PTR(-ENOMEM); + + chunk = cm_alloc(cma->ctx, size, cma->alignment); + if (IS_ERR(chunk)) { + kfree(phys); + return ERR_CAST(chunk); + } + + phys->chunk = chunk; + phys->phys.count = 1; + phys->phys.free = vcm_cma_free; + phys->phys.parts->start = cm_pin(chunk); + phys->phys.parts->size = size; + return &phys->phys; +} + +struct vcm *__must_check +vcm_cma_create(struct cma *ctx, unsigned long alignment) +{ + static const struct vcm_o2o_driver driver = { + .phys = vcm_cma_phys, + }; + + struct vcm_cma *cma; + struct vcm *vcm; + + if (alignment & (alignment - 1)) + return ERR_PTR(-EINVAL); + + cma = kmalloc(sizeof *cma, GFP_KERNEL); + if (!cma) + return ERR_PTR(-ENOMEM); + + cma->o2o.driver = &driver; + /* dummy size and start address! + * to be accepted by vcm_init() + * vcm_cma does not use these members. + */ + cma->o2o.vcm.start = 0; + cma->o2o.vcm.size = PAGE_SIZE; + cma->ctx = ctx; + cma->alignment = alignment; + vcm = vcm_o2o_init(&cma->o2o); + if (IS_ERR(vcm)) + kfree(cma); + return vcm; +} +EXPORT_SYMBOL_GPL(vcm_cma_create); -- 1.6.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/