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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2012 ARM Ltd.
* Author: Catalin Marinas <catalin.marinas@arm.com>
*/
#include <linux/gfp.h>
#include <linux/cache.h>
#include <linux/dma-map-ops.h>
#include <linux/iommu.h>
#include <xen/xen.h>
#include <asm/cacheflush.h>
#include <asm/xen/xen-ops.h>
void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
unsigned long start = (unsigned long)phys_to_virt(paddr);
dcache_clean_poc(start, start + size);
}
void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
unsigned long start = (unsigned long)phys_to_virt(paddr);
if (dir == DMA_TO_DEVICE)
return;
dcache_inval_poc(start, start + size);
}
void arch_dma_prep_coherent(struct page *page, size_t size)
{
unsigned long start = (unsigned long)page_address(page);
/*
* The architecture only requires a clean to the PoC here in order to
* meet the requirements of the DMA API. However, some vendors (i.e.
* Qualcomm) abuse the DMA API for transferring buffers from the
* non-secure to the secure world, resetting the system if a non-secure
* access shows up after the buffer has been transferred:
*
* https://lore.kernel.org/r/20221114110329.68413-1-manivannan.sadhasivam@linaro.org
*
* Using clean+invalidate appears to make this issue less likely, but
* the drivers themselves still need fixing as the CPU could issue a
* speculative read from the buffer via the linear mapping irrespective
* of the cache maintenance we use. Once the drivers are fixed, we can
* relax this to a clean operation.
*/
dcache_clean_inval_poc(start, start + size);
}
#ifdef CONFIG_IOMMU_DMA
void arch_teardown_dma_ops(struct device *dev)
{
dev->dma_ops = NULL;
}
#endif
void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent)
{
int cls = cache_line_size_of_cpu();
WARN_TAINT(!coherent && cls > ARCH_DMA_MINALIGN,
TAINT_CPU_OUT_OF_SPEC,
"%s %s: ARCH_DMA_MINALIGN smaller than CTR_EL0.CWG (%d < %d)",
dev_driver_string(dev), dev_name(dev),
ARCH_DMA_MINALIGN, cls);
dev->dma_coherent = coherent;
if (iommu)
iommu_setup_dma_ops(dev, dma_base, dma_base + size - 1);
xen_setup_dma_ops(dev);
}
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