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From: Christoph Hellwig <hch@lst.de>
To: iommu@lists.linux-foundation.org,
	Russell King <linux@armlinux.org.uk>,
	Brian Cain <bcain@codeaurora.org>
Cc: Dillon Min <dillon.minfei@gmail.com>,
	Vladimir Murzin <vladimir.murzin@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/7] dma-direct: add support for dma_coherent_default_memory
Date: Mon, 12 Jul 2021 08:16:58 +0200	[thread overview]
Message-ID: <20210712061704.4162464-2-hch@lst.de> (raw)
In-Reply-To: <20210712061704.4162464-1-hch@lst.de>

Add an option to allocate uncached memory for dma_alloc_coherent from
the global dma_coherent_default_memory.  This will allow to move
arm-nommu (and eventually other platforms) to use generic code for
allocating uncached memory from a pre-populated pool.

Note that this is a different pool from the one that platforms that
can remap at runtime use for GFP_ATOMIC allocations for now, although
there might be opportunities to eventually end up with a common codebase
for the two use cases.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <dillon.minfei@gmail.com>
---
 kernel/dma/Kconfig  |  4 ++++
 kernel/dma/direct.c | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 77b405508743..725cfd51762b 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -93,6 +93,10 @@ config DMA_COHERENT_POOL
 	select GENERIC_ALLOCATOR
 	bool
 
+config DMA_GLOBAL_POOL
+	select DMA_DECLARE_COHERENT
+	bool
+
 config DMA_REMAP
 	bool
 	depends on MMU
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index f737e3347059..d1d0258ed6d0 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -156,9 +156,14 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+	    !IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) &&
 	    !dev_is_dma_coherent(dev))
 		return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
 
+	if (IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) &&
+	    !dev_is_dma_coherent(dev))
+		return dma_alloc_from_global_coherent(dev, size, dma_handle);
+
 	/*
 	 * Remapping or decrypting memory may block. If either is required and
 	 * we can't block, allocate the memory from the atomic pools.
@@ -255,11 +260,19 @@ void dma_direct_free(struct device *dev, size_t size,
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+	    !IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) &&
 	    !dev_is_dma_coherent(dev)) {
 		arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
 		return;
 	}
 
+	if (IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) &&
+	    !dev_is_dma_coherent(dev)) {
+		if (!dma_release_from_global_coherent(page_order, cpu_addr))
+			WARN_ON_ONCE(1);
+		return;
+	}
+
 	/* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
 	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 	    dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size)))
@@ -462,6 +475,8 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
 
 	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
 		return ret;
+	if (dma_mmap_from_global_coherent(vma, cpu_addr, size, &ret))
+		return ret;
 
 	if (vma->vm_pgoff >= count || user_count > count - vma->vm_pgoff)
 		return -ENXIO;
-- 
2.30.2


  reply	other threads:[~2021-07-12  6:35 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-12  6:16 add support for the global coherent pool to the dma core Christoph Hellwig
2021-07-12  6:16 ` Christoph Hellwig [this message]
2021-07-12  6:16 ` [PATCH 2/7] ARM/nommu: use the generic dma-direct code for non-coherent devices Christoph Hellwig
2021-07-12  6:17 ` [PATCH 3/7] dma-mapping: allow using the global coherent pool for !ARM Christoph Hellwig
2021-07-12  6:17 ` [PATCH 4/7] dma-mapping: simplify dma_init_coherent_memory Christoph Hellwig
2021-07-12  6:17 ` [PATCH 5/7] dma-mapping: add a dma_init_global_coherent helper Christoph Hellwig
2021-07-12  6:17 ` [PATCH 6/7] dma-mapping: make the global coherent pool conditional Christoph Hellwig
2021-07-23 21:41   ` Atish Patra
2021-07-12  6:17 ` [PATCH 7/7] hexagon: use the generic global coherent pool Christoph Hellwig
2021-08-14  1:57   ` Brian Cain
2021-08-18 14:27     ` 'Christoph Hellwig'
2021-07-28 15:20 ` add support for the global coherent pool to the dma core Brian Cain
2021-08-12 13:09   ` 'Christoph Hellwig'
2021-08-14  7:03 ` Christoph Hellwig

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