Am Dienstag, den 23.01.2018, 18:56 -0800 schrieb Gurchetan Singh:
The dma_cache_maint_page function is important for cache maintenance on ARM32 (this was determined via testing).
Since we desire direct control of the caches in drm_cache.c, let's make a copy of the function, rename it and use it.
I don't see why having a (potentially incoherent) copy of dma_cache_maint_page in DRM does any good. Why can't we just export the original function to make it usable within DRM?
Regards, Lucas
v2: Don't use DMA API, call functions directly (Daniel)
Signed-off-by: Gurchetan Singh gurchetansingh@chromium.org
drivers/gpu/drm/drm_cache.c | 61 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+)
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c index 89cdd32fe1f3..5124582451c6 100644 --- a/drivers/gpu/drm/drm_cache.c +++ b/drivers/gpu/drm/drm_cache.c @@ -69,6 +69,55 @@ static void drm_cache_flush_clflush(struct page *pages[], } #endif +#if defined(CONFIG_ARM) +static void drm_cache_maint_page(struct page *page, unsigned long offset,
size_t size, enum dma_data_direction dir,void (*op)(const void *, size_t, int))+{
- unsigned long pfn;
- size_t left = size;
- pfn = page_to_pfn(page) + offset / PAGE_SIZE;
- offset %= PAGE_SIZE;
- /*
- * A single sg entry may refer to multiple physically contiguous
- * pages. But we still need to process highmem pages individually.
- * If highmem is not configured then the bulk of this loop gets
- * optimized out.
- */
- do {
size_t len = left;void *vaddr;
page = pfn_to_page(pfn);
if (PageHighMem(page)) {if (len + offset > PAGE_SIZE)len = PAGE_SIZE - offset;
if (cache_is_vipt_nonaliasing()) {vaddr = kmap_atomic(page);op(vaddr + offset, len, dir);kunmap_atomic(vaddr);} else {vaddr = kmap_high_get(page);if (vaddr) {op(vaddr + offset, len, dir);kunmap_high(page);}}} else {vaddr = page_address(page) + offset;op(vaddr, len, dir);}offset = 0;pfn++;left -= len;- } while (left);
+} +#endif
/** * drm_flush_pages - Flush dcache lines of a set of pages. * @pages: List of pages to be flushed. @@ -104,6 +153,12 @@ drm_flush_pages(struct page *pages[], unsigned long num_pages)
(unsigned long)page_virtual + PAGE_SIZE); kunmap_atomic(page_virtual); }
+#elif defined(CONFIG_ARM)
- unsigned long i;
- for (i = 0; i < num_pages; i++)
drm_cache_maint_page(pages[i], 0, PAGE_SIZE, DMA_TO_DEVICE,dmac_map_area);#else
pr_err("Architecture has no drm_cache.c support\n"); WARN_ON_ONCE(1);
@@ -135,6 +190,12 @@ drm_flush_sg(struct sg_table *st)
if (wbinvd_on_all_cpus()) pr_err("Timed out waiting for cache flush\n");
+#elif defined(CONFIG_ARM)
- struct sg_page_iter sg_iter;
- for_each_sg_page(st->sgl, &sg_iter, st->nents, 0)
drm_cache_maint_page(sg_page_iter_page(&sg_iter), 0, PAGE_SIZE,DMA_TO_DEVICE, dmac_map_area);#else
pr_err("Architecture has no drm_cache.c support\n"); WARN_ON_ONCE(1);