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drm: Implement drm_need_swiotlb() in drm_cache.c

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The function is declared in drm_cache.h. I also removed the curly
braces from the for loop to adhere to kernel coding style.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210112081035.6882-3-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann 2021-01-12 09:10:31 +01:00
parent ff28a9f8d3
commit 3abc667063
2 changed files with 32 additions and 33 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

32
drivers/gpu/drm/drm_cache.c
View file

@ -30,6 +30,7 @@
#include <linux/export.h>
#include <linux/highmem.h>
#include <xen/xen.h>
#include <drm/drm_cache.h>
@ -176,3 +177,34 @@ drm_clflush_virt_range(void *addr, unsigned long length)
#endif
}
EXPORT_SYMBOL(drm_clflush_virt_range);
bool drm_need_swiotlb(int dma_bits)
{
struct resource *tmp;
resource_size_t max_iomem = 0;
/*
* Xen paravirtual hosts require swiotlb regardless of requested dma
* transfer size.
*
* NOTE: Really, what it requires is use of the dma_alloc_coherent
* allocator used in ttm_dma_populate() instead of
* ttm_populate_and_map_pages(), which bounce buffers so much in
* Xen it leads to swiotlb buffer exhaustion.
*/
if (xen_pv_domain())
return true;
/*
* Enforce dma_alloc_coherent when memory encryption is active as well
* for the same reasons as for Xen paravirtual hosts.
*/
if (mem_encrypt_active())
return true;
for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling)
max_iomem = max(max_iomem, tmp->end);
return max_iomem > ((u64)1 << dma_bits);
}
EXPORT_SYMBOL(drm_need_swiotlb);

33
drivers/gpu/drm/drm_memory.c
View file

@ -37,7 +37,6 @@
#include <linux/highmem.h>
#include <linux/pci.h>
#include <linux/vmalloc.h>
#include <xen/xen.h>
#include <drm/drm_agpsupport.h>
#include <drm/drm_cache.h>
@ -138,35 +137,3 @@ void drm_legacy_ioremapfree(struct drm_local_map *map, struct drm_device *dev)
iounmap(map->handle);
}
EXPORT_SYMBOL(drm_legacy_ioremapfree);
bool drm_need_swiotlb(int dma_bits)
{
struct resource *tmp;
resource_size_t max_iomem = 0;
/*
* Xen paravirtual hosts require swiotlb regardless of requested dma
* transfer size.
*
* NOTE: Really, what it requires is use of the dma_alloc_coherent
* allocator used in ttm_dma_populate() instead of
* ttm_populate_and_map_pages(), which bounce buffers so much in
* Xen it leads to swiotlb buffer exhaustion.
*/
if (xen_pv_domain())
return true;
/*
* Enforce dma_alloc_coherent when memory encryption is active as well
* for the same reasons as for Xen paravirtual hosts.
*/
if (mem_encrypt_active())
return true;
for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling) {
max_iomem = max(max_iomem, tmp->end);
}
return max_iomem > ((u64)1 << dma_bits);
}
EXPORT_SYMBOL(drm_need_swiotlb);