linux_dsm_epyc7002/arch/arc/mm/dma.c
Christoph Hellwig f73c904534 arc: use the generic remapping allocator for coherent DMA allocations
Replace the code that sets up uncached PTEs with the generic vmap based
remapping code.  It also provides an atomic pool for allocations from
non-blocking context, which we not properly supported by the existing
arc code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Evgeniy Paltsev <paltsev@synopsys.com>
Tested-by: Evgeniy Paltsev <paltsev@synopsys.com>
2019-06-25 14:28:05 +02:00

116 lines
3.3 KiB
C

/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* 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.
*/
#include <linux/dma-noncoherent.h>
#include <asm/cache.h>
#include <asm/cacheflush.h>
/*
* ARCH specific callbacks for generic noncoherent DMA ops
* - hardware IOC not available (or "dma-coherent" not set for device in DT)
* - But still handle both coherent and non-coherent requests from caller
*
* For DMA coherent hardware (IOC) generic code suffices
*/
void arch_dma_prep_coherent(struct page *page, size_t size)
{
/*
* Evict any existing L1 and/or L2 lines for the backing page
* in case it was used earlier as a normal "cached" page.
* Yeah this bit us - STAR 9000898266
*
* Although core does call flush_cache_vmap(), it gets kvaddr hence
* can't be used to efficiently flush L1 and/or L2 which need paddr
* Currently flush_cache_vmap nukes the L1 cache completely which
* will be optimized as a separate commit
*/
dma_cache_wback_inv(page_to_phys(page), size);
}
/*
* Cache operations depending on function and direction argument, inspired by
* https://lkml.org/lkml/2018/5/18/979
* "dma_sync_*_for_cpu and direction=TO_DEVICE (was Re: [PATCH 02/20]
* dma-mapping: provide a generic dma-noncoherent implementation)"
*
* | map == for_device | unmap == for_cpu
* |----------------------------------------------------------------
* TO_DEV | writeback writeback | none none
* FROM_DEV | invalidate invalidate | invalidate* invalidate*
* BIDIR | writeback+inv writeback+inv | invalidate invalidate
*
* [*] needed for CPU speculative prefetches
*
* NOTE: we don't check the validity of direction argument as it is done in
* upper layer functions (in include/linux/dma-mapping.h)
*/
void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
switch (dir) {
case DMA_TO_DEVICE:
dma_cache_wback(paddr, size);
break;
case DMA_FROM_DEVICE:
dma_cache_inv(paddr, size);
break;
case DMA_BIDIRECTIONAL:
dma_cache_wback_inv(paddr, size);
break;
default:
break;
}
}
void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
switch (dir) {
case DMA_TO_DEVICE:
break;
/* FROM_DEVICE invalidate needed if speculative CPU prefetch only */
case DMA_FROM_DEVICE:
case DMA_BIDIRECTIONAL:
dma_cache_inv(paddr, size);
break;
default:
break;
}
}
/*
* Plug in direct dma map ops.
*/
void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent)
{
/*
* IOC hardware snoops all DMA traffic keeping the caches consistent
* with memory - eliding need for any explicit cache maintenance of
* DMA buffers.
*/
if (is_isa_arcv2() && ioc_enable && coherent)
dev->dma_coherent = true;
dev_info(dev, "use %sncoherent DMA ops\n",
dev->dma_coherent ? "" : "non");
}
static int __init atomic_pool_init(void)
{
return dma_atomic_pool_init(GFP_KERNEL, pgprot_noncached(PAGE_KERNEL));
}
postcore_initcall(atomic_pool_init);