RE: [PATCH v4 03/12] intel-ipu3: Add IOMMU based dmamap support

["Zhi, Yong" <yong.zhi@intel.com>]

Hi, Sakari,

> -----Original Message-----
> From: Sakari Ailus [mailto:sakari.ailus@iki.fi]
> Sent: Friday, October 20, 2017 2:20 AM
> To: Zhi, Yong <yong.zhi@intel.com>
> Cc: linux-media@vger.kernel.org; sakari.ailus@linux.intel.com; Zheng, Jian
> Xu <jian.xu.zheng@intel.com>; Mani, Rajmohan
> <rajmohan.mani@intel.com>; Toivonen, Tuukka
> <tuukka.toivonen@intel.com>; Hu, Jerry W <jerry.w.hu@intel.com>;
> arnd@arndb.de; hch@lst.de; robin.murphy@arm.com; iommu@lists.linux-
> foundation.org; Tomasz Figa <tfiga@chromium.org>
> Subject: Re: [PATCH v4 03/12] intel-ipu3: Add IOMMU based dmamap
> support
> 
> Hi Yong,
> 
> On Tue, Oct 17, 2017 at 10:48:59PM -0500, Yong Zhi wrote:
> > From: Tomasz Figa <tfiga@chromium.org>
> >
> > This patch adds driver to support IPU3-specific MMU-aware memory
> > alloc/free and sg mapping functions.
> >
> > Signed-off-by: Tomasz Figa <tfiga@chromium.org>
> > Signed-off-by: Yong Zhi <yong.zhi@intel.com>
> > ---
> >  drivers/media/pci/intel/ipu3/Kconfig       |   7 +
> >  drivers/media/pci/intel/ipu3/Makefile      |   2 +-
> >  drivers/media/pci/intel/ipu3/ipu3-dmamap.c | 342
> > +++++++++++++++++++++++++++++
> > drivers/media/pci/intel/ipu3/ipu3-dmamap.h |  33 +++
> >  4 files changed, 383 insertions(+), 1 deletion(-)  create mode 100644
> > drivers/media/pci/intel/ipu3/ipu3-dmamap.c
> >  create mode 100644 drivers/media/pci/intel/ipu3/ipu3-dmamap.h
> >
> > diff --git a/drivers/media/pci/intel/ipu3/Kconfig
> > b/drivers/media/pci/intel/ipu3/Kconfig
> > index 46ff138f3e50..d7dab52dc881 100644
> > --- a/drivers/media/pci/intel/ipu3/Kconfig
> > +++ b/drivers/media/pci/intel/ipu3/Kconfig
> > @@ -26,3 +26,10 @@ config INTEL_IPU3_MMU
> >  	---help---
> >  	  For IPU3, this option enables its MMU driver to translate its internal
> >  	  virtual address to 39 bits wide physical address for 64GBytes space
> access.
> > +
> > +config INTEL_IPU3_DMAMAP
> > +	tristate
> > +	default n
> > +	select IOMMU_IOVA
> > +	---help---
> > +	  This is IPU3 IOMMU domain specific DMA driver.
> > diff --git a/drivers/media/pci/intel/ipu3/Makefile
> > b/drivers/media/pci/intel/ipu3/Makefile
> > index 91cac9cb7401..651773231496 100644
> > --- a/drivers/media/pci/intel/ipu3/Makefile
> > +++ b/drivers/media/pci/intel/ipu3/Makefile
> > @@ -13,4 +13,4 @@
> >
> >  obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
> >  obj-$(CONFIG_INTEL_IPU3_MMU) += ipu3-mmu.o
> > -
> > +obj-$(CONFIG_INTEL_IPU3_DMAMAP) += ipu3-dmamap.o
> > diff --git a/drivers/media/pci/intel/ipu3/ipu3-dmamap.c
> > b/drivers/media/pci/intel/ipu3/ipu3-dmamap.c
> > new file mode 100644
> > index 000000000000..e54bd9dfa302
> > --- /dev/null
> > +++ b/drivers/media/pci/intel/ipu3/ipu3-dmamap.c
> > @@ -0,0 +1,342 @@
> > +/*
> > + * Copyright (c) 2017 Intel Corporation.
> > + * Copyright (C) 2017 Google, Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > +version
> > + * 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + */
> > +
> > +#include <linux/dma-direction.h>
> > +#include <linux/highmem.h>
> > +#include <linux/iommu.h>
> > +#include <linux/iova.h>
> > +#include <linux/module.h>
> > +#include <linux/slab.h>
> > +#include <linux/types.h>
> > +#include <linux/version.h>
> 
> Do you need this for something?
> 

Ouch, will remove the un-needed headers.

> > +#include <linux/vmalloc.h>
> > +
> > +#include "ipu3-css-pool.h"
> > +#include "ipu3.h"
> > +
> > +/*
> > + * Based on arch/arm64/mm/dma-mapping.c, with simplifications
> > +possible due
> > + * to driver-specific character of this file.
> > + */
> > +
> > +static int dma_direction_to_prot(enum dma_data_direction dir, bool
> > +coherent) {
> > +	int prot = coherent ? IOMMU_CACHE : 0;
> > +
> > +	switch (dir) {
> > +	case DMA_BIDIRECTIONAL:
> > +		return prot | IOMMU_READ | IOMMU_WRITE;
> > +	case DMA_TO_DEVICE:
> > +		return prot | IOMMU_READ;
> > +	case DMA_FROM_DEVICE:
> > +		return prot | IOMMU_WRITE;
> > +	default:
> > +		return 0;
> > +	}
> > +}
> > +
> > +/*
> > + * Free a buffer allocated by ipu3_dmamap_alloc_buffer()  */ static
> > +void ipu3_dmamap_free_buffer(struct page **pages,
> > +				    size_t size)
> > +{
> > +	int count = size >> PAGE_SHIFT;
> > +
> > +	while (count--)
> > +		__free_page(pages[count]);
> > +	kvfree(pages);
> > +}
> > +
> > +/*
> > + * Based on the implementation of __iommu_dma_alloc_pages()
> > + * defined in drivers/iommu/dma-iommu.c  */ static struct page
> > +**ipu3_dmamap_alloc_buffer(size_t size,
> > +					      unsigned long order_mask,
> > +					      gfp_t gfp)
> > +{
> > +	struct page **pages;
> > +	unsigned int i = 0, count = size >> PAGE_SHIFT;
> > +	const gfp_t high_order_gfp = __GFP_NOWARN | __GFP_NORETRY;
> > +
> > +	/* Allocate mem for array of page ptrs */
> > +	pages = kvmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
> > +
> > +	if (!pages)
> > +		return NULL;
> > +
> > +	order_mask &= (2U << MAX_ORDER) - 1;
> > +	if (!order_mask)
> > +		return NULL;
> > +
> > +	gfp |= __GFP_NOWARN | __GFP_HIGHMEM | __GFP_ZERO;
> > +
> > +	while (count) {
> > +		struct page *page = NULL;
> > +		unsigned int order_size;
> > +
> > +		for (order_mask &= (2U << __fls(count)) - 1;
> > +		     order_mask; order_mask &= ~order_size) {
> > +			unsigned int order = __fls(order_mask);
> > +
> > +			order_size = 1U << order;
> > +			page = alloc_pages((order_mask - order_size) ?
> > +					   gfp | high_order_gfp : gfp, order);
> > +			if (!page)
> > +				continue;
> > +			if (!order)
> > +				break;
> > +			if (!PageCompound(page)) {
> > +				split_page(page, order);
> > +				break;
> > +			}
> > +
> > +			__free_pages(page, order);
> > +		}
> > +		if (!page) {
> > +			ipu3_dmamap_free_buffer(pages, i << PAGE_SHIFT);
> > +			return NULL;
> > +		}
> > +		count -= order_size;
> > +		while (order_size--)
> > +			pages[i++] = page++;
> > +	}
> > +
> > +	return pages;
> > +}
> > +
> > +/**
> > + * ipu3_dmamap_alloc - allocate and map a buffer into KVA
> > + * @dev: struct device pointer
> > + * @map: struct to store mapping variables
> > + * @len: size required
> > + *
> > + * Return KVA on success or NULL on failure  */ void
> > +*ipu3_dmamap_alloc(struct imgu_device *imgu, struct ipu3_css_map
> *map,
> > +			size_t len)
> > +{
> > +	unsigned long shift = iova_shift(&imgu->iova_domain);
> > +	unsigned int alloc_sizes = imgu->domain->pgsize_bitmap;
> > +	size_t size = PAGE_ALIGN(len);
> > +	struct page **pages;
> > +	dma_addr_t iovaddr;
> > +	struct iova *iova;
> > +	int i, rval;
> > +
> > +	if (WARN(!(&imgu->pci_dev->dev),
> > +		 "cannot create IOMMU mapping for unknown device\n"))
> > +		return NULL;
> > +
> > +	dev_dbg(&imgu->pci_dev->dev, "%s: allocating %zu\n", __func__,
> > +size);
> > +
> > +	iova = alloc_iova(&imgu->iova_domain, size >> shift,
> > +			  imgu->domain->geometry.aperture_end >> shift, 0);
> > +	if (!iova)
> > +		return NULL;
> > +
> > +	pages = ipu3_dmamap_alloc_buffer(size, alloc_sizes >> PAGE_SHIFT,
> > +					 GFP_KERNEL);
> > +	if (!pages)
> > +		goto out_free_iova;
> > +
> > +	/* Call IOMMU driver to setup pgt */
> > +	iovaddr = iova_dma_addr(&imgu->iova_domain, iova);
> > +	for (i = 0; i < size / PAGE_SIZE; ++i) {
> > +		rval = iommu_map(imgu->domain, iovaddr,
> > +				 page_to_phys(pages[i]), PAGE_SIZE, 0);
> 
> In the current implementation, you don't have much benefit from the use of
> the IOMMU framework left: it's more or less a wrapper between this and the
> MMU driver.
> 
> Could you remove it, and use the MMU driver directly?
> 
> Neither should need to be a separate module anymore.
> 

Ok, will remove the dependency on IOMMU framework and use MMU directly for next update.

> > +		if (rval)
> > +			goto out_unmap;
> > +
> > +		iovaddr += PAGE_SIZE;
> > +	}
> > +
> > +	/* Now grab a virtual region */
> > +	map->vma = __get_vm_area(size, VM_USERMAP, VMALLOC_START,
> VMALLOC_END);
> > +	if (!map->vma)
> > +		goto out_unmap;
> > +
> > +	map->vma->pages = pages;
> > +	/* And map it in KVA */
> > +	if (map_vm_area(map->vma, PAGE_KERNEL, pages))
> > +		goto out_vunmap;
> > +
> > +	map->size = size;
> > +	map->daddr = iova_dma_addr(&imgu->iova_domain, iova);
> > +	map->vaddr = map->vma->addr;
> > +
> > +	dev_dbg(&imgu->pci_dev->dev, "%s: allocated %zu @ IOVA %pad @
> VA %p\n",
> > +		__func__, size, &map->daddr, map->vma->addr);
> > +
> > +	return map->vma->addr;
> > +
> > +out_vunmap:
> > +	vunmap(map->vma->addr);
> > +
> > +out_unmap:
> > +	ipu3_dmamap_free_buffer(pages, size);
> > +	iommu_unmap(imgu->domain, iova_dma_addr(&imgu-
> >iova_domain, iova),
> > +		    i * PAGE_SIZE);
> > +	map->vma = NULL;
> > +
> > +out_free_iova:
> > +	__free_iova(&imgu->iova_domain, iova);
> > +
> > +	return NULL;
> > +}
> > +EXPORT_SYMBOL_GPL(ipu3_dmamap_alloc);
> > +
> > +void ipu3_dmamap_unmap(struct imgu_device *imgu, struct
> ipu3_css_map
> > +*map) {
> > +	struct iova *iova;
> > +
> > +	iova = find_iova(&imgu->iova_domain,
> > +			 iova_pfn(&imgu->iova_domain, map->daddr));
> > +	if (WARN_ON(!iova))
> > +		return;
> > +
> > +	iommu_unmap(imgu->domain, iova_dma_addr(&imgu-
> >iova_domain, iova),
> > +		    iova_size(iova) << iova_shift(&imgu->iova_domain));
> > +
> > +	__free_iova(&imgu->iova_domain, iova); }
> > +EXPORT_SYMBOL_GPL(ipu3_dmamap_unmap);
> > +
> > +/*
> > + * Counterpart of ipu3_dmamap_alloc
> > + */
> > +void ipu3_dmamap_free(struct imgu_device *imgu, struct ipu3_css_map
> > +*map) {
> > +	struct vm_struct *area = map->vma;
> > +
> > +	dev_dbg(&imgu->pci_dev->dev, "%s: freeing %zu @ IOVA %pad @
> VA %p\n",
> > +		__func__, map->size, &map->daddr, map->vaddr);
> > +
> > +	if (!map->vaddr)
> > +		return;
> > +
> > +	ipu3_dmamap_unmap(imgu, map);
> > +
> > +	if (WARN_ON(!area) || WARN_ON(!area->pages))
> > +		return;
> > +
> > +	ipu3_dmamap_free_buffer(area->pages, map->size);
> > +	vunmap(map->vaddr);
> > +	map->vaddr = NULL;
> > +}
> > +EXPORT_SYMBOL_GPL(ipu3_dmamap_free);
> > +
> > +int ipu3_dmamap_map_sg(struct imgu_device *imgu, struct scatterlist
> *sglist,
> > +		       int nents, enum dma_data_direction dir,
> > +		       struct ipu3_css_map *map)
> > +{
> > +	unsigned long shift = iova_shift(&imgu->iova_domain);
> > +	struct scatterlist *sg;
> > +	struct iova *iova;
> > +	size_t size = 0;
> > +	size_t size_aligned;
> > +	int i;
> > +
> > +	for_each_sg(sglist, sg, nents, i) {
> > +		if (sg->offset)
> > +			return -EINVAL;
> > +
> > +		if (i != nents - 1 && !PAGE_ALIGNED(sg->length))
> > +			return -EINVAL;
> > +
> > +		size += sg->length;
> > +	}
> > +	size_aligned = PAGE_ALIGN(size);
> > +
> > +	dev_dbg(&imgu->pci_dev->dev, "dmamap: mapping sg %d
> entries, %zu pages\n",
> > +		nents, size_aligned >> shift);
> > +
> > +	iova = alloc_iova(&imgu->iova_domain, size_aligned >> shift,
> > +			  imgu->domain->geometry.aperture_end >> shift, 0);
> > +	if (!iova)
> > +		return -ENOMEM;
> > +
> > +	dev_dbg(&imgu->pci_dev->dev, "dmamap: iova low pfn %lu, high
> pfn %lu\n",
> > +		iova->pfn_lo, iova->pfn_hi);
> > +
> > +	if (iommu_map_sg(imgu->domain,
> > +			 iova_dma_addr(&imgu->iova_domain, iova),
> > +			 sglist, nents, dma_direction_to_prot(dir, true))
> > +			 < size)
> > +		goto out_fail;
> > +
> > +	memset(map, 0, sizeof(*map));
> > +	map->daddr = iova_dma_addr(&imgu->iova_domain, iova);
> > +	map->size = size_aligned;
> > +
> > +	return 0;
> > +
> > +out_fail:
> > +	__free_iova(&imgu->iova_domain, iova);
> > +
> > +	return -EFAULT;
> > +}
> > +EXPORT_SYMBOL_GPL(ipu3_dmamap_map_sg);
> > +
> > +int ipu3_dmamap_init(struct imgu_device *imgu) {
> > +	unsigned long order, base_pfn, end_pfn;
> > +	int ret;
> > +
> > +	imgu->domain = iommu_domain_alloc(imgu->mmu->bus);
> > +	if (!imgu->domain)
> > +		return -ENOMEM;
> > +
> > +	ret = iova_cache_get();
> > +	if (ret)
> > +		goto out_domain;
> > +
> > +	order = __ffs(imgu->domain->pgsize_bitmap);
> > +	base_pfn = max_t(unsigned long, 1,
> > +			 imgu->domain->geometry.aperture_start >> order);
> > +	end_pfn = imgu->domain->geometry.aperture_end >> order;
> > +
> > +	init_iova_domain(&imgu->iova_domain, 1UL << order, base_pfn,
> > +end_pfn);
> > +
> > +	ret = iommu_attach_device(imgu->domain, imgu->mmu);
> > +	if (ret)
> > +		goto out_iova_cache;
> > +
> > +	return 0;
> > +
> > +out_iova_cache:
> > +	iova_cache_put();
> > +	put_iova_domain(&imgu->iova_domain);
> > +out_domain:
> > +	iommu_domain_free(imgu->domain);
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(ipu3_dmamap_init);
> > +
> > +void ipu3_dmamap_exit(struct imgu_device *imgu) {
> > +	put_iova_domain(&imgu->iova_domain);
> > +	iova_cache_put();
> > +	iommu_detach_device(imgu->domain, imgu->mmu);
> > +	iommu_domain_free(imgu->domain);
> > +	imgu->domain = NULL;
> > +}
> > +EXPORT_SYMBOL_GPL(ipu3_dmamap_exit);
> > +
> > +MODULE_AUTHOR("Tomasz Figa <tfiga@chromium.org>");
> > +MODULE_AUTHOR("Yong Zhi <yong.zhi@intel.com>");
> MODULE_LICENSE("GPL
> > +v2");
> > +MODULE_DESCRIPTION("IPU3 DMA mapping support");
> > diff --git a/drivers/media/pci/intel/ipu3/ipu3-dmamap.h
> > b/drivers/media/pci/intel/ipu3/ipu3-dmamap.h
> > new file mode 100644
> > index 000000000000..9b442a40ee06
> > --- /dev/null
> > +++ b/drivers/media/pci/intel/ipu3/ipu3-dmamap.h
> > @@ -0,0 +1,33 @@
> > +/*
> > + * Copyright (c) 2017 Intel Corporation.
> > + * Copyright (C) 2017 Google, Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > +version
> > + * 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + */
> > +
> > +#ifndef __IPU3_DMAMAP_H
> > +#define __IPU3_DMAMAP_H
> > +
> > +struct imgu_device;
> > +
> > +void *ipu3_dmamap_alloc(struct imgu_device *imgu, struct ipu3_css_map
> *map,
> > +			size_t len);
> > +void ipu3_dmamap_free(struct imgu_device *imgu, struct ipu3_css_map
> > +*map);
> > +
> > +int ipu3_dmamap_map_sg(struct imgu_device *imgu, struct scatterlist
> *sglist,
> > +		       int nents, enum dma_data_direction dir,
> > +		       struct ipu3_css_map *map);
> > +void ipu3_dmamap_unmap(struct imgu_device *imgu, struct
> ipu3_css_map
> > +*map);
> > +
> > +int ipu3_dmamap_init(struct imgu_device *imgu); void
> > +ipu3_dmamap_exit(struct imgu_device *imgu);
> > +
> > +#endif
> >
> 
> --
> Kind regards,
> 
> Sakari Ailus
> e-mail: sakari.ailus@iki.fi