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Commit 707e9d34 authored by Liam Mark's avatar Liam Mark
Browse files

dma-mapping: add support for dma-coherent-hint-cached 



When clients configure their device as dma-coherent-hint-cached this will
result in the memory framework only trying to DMA map buffers as
IO-coherent if the framework is confident that the buffers are mapped as
cached in the CPU.

Clients should configure their device as dma-coherent-hint-cached instead
of dma-coherent when they need to DMA map both buffers that have cached
CPU mappings and other buffers which have uncached CPU mappings. By using
dma-coherent-hint-cached the framework will ensure that the client's
buffers with uncached CPU mappings don't get DMA mapped as IO-coherent.

Change-Id: I990184b54d4148bf952cc672ec267b51efd81473
Signed-off-by: default avatarLiam Mark <lmark@codeaurora.org>
parent 333b4ccb

drivers/iommu/msm_dma_iommu_mapping.c

+3 −2
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2015-2019, The Linux Foundation. All rights reserved.

 * Copyright (c) 2015-2020, The Linux Foundation. All rights reserved.

 */



#include <linux/dma-noncoherent.h>
@@ -251,7 +251,8 @@ static inline int __msm_dma_map_sg(struct device *dev, struct scatterlist *sg, 
				dma_sync_sg_for_device(dev, iommu_map->sgl,

					iommu_map->nents, iommu_map->dir);



			if (dev_is_dma_coherent(dev))

			if (dev_is_dma_coherent(dev) ||

			    (attrs & DMA_ATTR_FORCE_COHERENT))

				/*

				 * Ensure all outstanding changes for coherent

				 * buffers are applied to the cache before any

drivers/of/address.c

+25 −0
Original line number Diff line number Diff line
@@ -1015,3 +1015,28 @@ bool of_dma_is_coherent(struct device_node *np) 
	return false;

}

EXPORT_SYMBOL_GPL(of_dma_is_coherent);



#if defined(CONFIG_DMA_COHERENT_HINT_CACHED)

/**

 * of_dma_is_coherent_hint_cached - Check if device is coherent hint cached

 * @np: device node

 *

 * It returns true if "dma-coherent-hint-cached" property was found

 * for this device in DT.

 */

bool of_dma_is_coherent_hint_cached(struct device_node *np)

{

	struct device_node *node = of_node_get(np);



	while (node) {

		if (of_property_read_bool(node, "dma-coherent-hint-cached")) {

			of_node_put(node);

			return true;

		}

		node = of_get_next_parent(node);

	}

	of_node_put(node);

	return false;

}

EXPORT_SYMBOL(of_dma_is_coherent_hint_cached);

#endif /* CONFIG_DMA_COHERENT_HINT_CACHED */

drivers/of/device.c

+8 −1
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma) 
{

	u64 dma_addr, paddr, size = 0;

	int ret;

	bool coherent;

	bool coherent, coherent_hint_cached;

	unsigned long offset;

	const struct iommu_ops *iommu;

	u64 mask;
@@ -159,6 +159,13 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma) 
	dev_dbg(dev, "device is%sdma coherent\n",

		coherent ? " " : " not ");



	coherent_hint_cached = of_dma_is_coherent_hint_cached(np);

	dev_dbg(dev, "device is%sdma coherent_hint_cached\n",

		coherent_hint_cached ? " " : " not ");

	dma_set_coherent_hint_cached(dev, coherent_hint_cached);

	WARN(coherent && coherent_hint_cached,

	     "Should not set both dma-coherent and dma-coherent-hint-cached on the same device");



	iommu = of_iommu_configure(dev, np);

	if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER)

		return -EPROBE_DEFER;

drivers/staging/android/ion/heaps/msm_ion_dma_buf.c

+21 −1
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (C) 2011 Google, Inc.

 * Copyright (c) 2011-2019, The Linux Foundation. All rights reserved.

 * Copyright (c) 2011-2020, The Linux Foundation. All rights reserved.

 */



#include <linux/device.h>

#include <linux/dma-buf.h>

#include <linux/dma-noncoherent.h>

#include <linux/err.h>

#include <linux/export.h>

#include <linux/file.h>
@@ -163,6 +164,20 @@ static struct sg_table 
	    !hlos_accessible_buffer(buffer))

		map_attrs |= DMA_ATTR_SKIP_CPU_SYNC;



	if ((buffer->flags & ION_FLAG_CACHED) &&

	    hlos_accessible_buffer(buffer) &&

	    dev_is_dma_coherent_hint_cached(attachment->dev))

		map_attrs |= DMA_ATTR_FORCE_COHERENT;



	if (((dev_is_dma_coherent(attachment->dev) &&

	      !(map_attrs & DMA_ATTR_FORCE_NON_COHERENT)) ||

	     (map_attrs & DMA_ATTR_FORCE_COHERENT)) &&

	    !(buffer->flags & ION_FLAG_CACHED)) {

		pr_warn_ratelimited("dev:%s Cannot DMA map uncached buffer as IO-coherent attrs:0x%lx\n",

				    dev_name(attachment->dev), map_attrs);

		return ERR_PTR(-EINVAL);

	}



	mutex_lock(&buffer->lock);

	if (map_attrs & DMA_ATTR_SKIP_CPU_SYNC)

		trace_ion_dma_map_cmo_skip(attachment->dev,
@@ -233,6 +248,11 @@ static void msm_ion_unmap_dma_buf(struct dma_buf_attachment *attachment, 
	    !hlos_accessible_buffer(buffer))

		map_attrs |= DMA_ATTR_SKIP_CPU_SYNC;



	if ((buffer->flags & ION_FLAG_CACHED) &&

	    hlos_accessible_buffer(buffer) &&

	    dev_is_dma_coherent_hint_cached(attachment->dev))

		map_attrs |= DMA_ATTR_FORCE_COHERENT;



	mutex_lock(&buffer->lock);

	if (map_attrs & DMA_ATTR_SKIP_CPU_SYNC)

		trace_ion_dma_unmap_cmo_skip(attachment->dev,

include/linux/device.h

+7 −1
Original line number Diff line number Diff line
@@ -1245,7 +1245,9 @@ struct dev_links_info { 
 *		  sync_state() callback.

 * @dma_coherent: this particular device is dma coherent, even if the

 *		architecture supports non-coherent devices.

 *

 * @dma_coherent_hint_cached: Tell the framework to try and treat the device

 *			      as DMA coherent when working with CPU cached

 *			      buffers.

 * At the lowest level, every device in a Linux system is represented by an

 * instance of struct device. The device structure contains the information

 * that the device model core needs to model the system. Most subsystems,
@@ -1345,6 +1347,10 @@ struct device { 
    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)

	bool			dma_coherent:1;

#endif

#if defined(CONFIG_DMA_COHERENT_HINT_CACHED)

	bool			dma_coherent_hint_cached:1;

#endif



};



static inline struct device *kobj_to_dev(struct kobject *kobj)