linux-kernel - [PATCH 1/2] drm: add cache support for arm64

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Message-Id: <20190805211451.20176-1-robdclark@gmail.com>
Date:   Mon,  5 Aug 2019 14:14:33 -0700
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Christoph Hellwig <hch@....de>, Rob Clark <robdclark@...omium.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Allison Randal <allison@...utok.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] drm: add cache support for arm64

From: Rob Clark <robdclark@...omium.org>

This will let drm/msm stop abusing DMA API for cache ops, at least for
arm64.

Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 arch/arm64/mm/flush.c       |  2 ++
 drivers/gpu/drm/drm_cache.c | 20 +++++++++++++++++---
 include/drm/drm_cache.h     |  4 ++++
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index dc19300309d2..f0eb6320c979 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -93,3 +93,5 @@ void arch_invalidate_pmem(void *addr, size_t size)
 }
 EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
 #endif
+
+EXPORT_SYMBOL_GPL(__flush_dcache_area);
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index 3bd76e918b5d..90105c637797 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -69,6 +69,14 @@ static void drm_cache_flush_clflush(struct page *pages[],
 }
 #endif
 
+#if defined(__powerpc__)
+static void __flush_dcache_area(void *addr, size_t len)
+{
+	flush_dcache_range((unsigned long)addr,
+			   (unsigned long)addr + PAGE_SIZE);
+}
+#endif
+
 /**
  * drm_clflush_pages - Flush dcache lines of a set of pages.
  * @pages: List of pages to be flushed.
@@ -90,7 +98,7 @@ drm_clflush_pages(struct page *pages[], unsigned long num_pages)
 	if (wbinvd_on_all_cpus())
 		pr_err("Timed out waiting for cache flush\n");
 
-#elif defined(__powerpc__)
+#elif defined(__powerpc__) || defined(CONFIG_ARM64)
 	unsigned long i;
 	for (i = 0; i < num_pages; i++) {
 		struct page *page = pages[i];
@@ -100,8 +108,7 @@ drm_clflush_pages(struct page *pages[], unsigned long num_pages)
 			continue;
 
 		page_virtual = kmap_atomic(page);
-		flush_dcache_range((unsigned long)page_virtual,
-				   (unsigned long)page_virtual + PAGE_SIZE);
+		__flush_dcache_area(page_virtual, PAGE_SIZE);
 		kunmap_atomic(page_virtual);
 	}
 #else
@@ -135,6 +142,13 @@ drm_clflush_sg(struct sg_table *st)
 
 	if (wbinvd_on_all_cpus())
 		pr_err("Timed out waiting for cache flush\n");
+#elif defined(CONFIG_ARM64)
+	struct sg_page_iter sg_iter;
+
+	for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) {
+		struct page *p = sg_page_iter_page(&sg_iter);
+		drm_clflush_pages(&p, 1);
+	}
 #else
 	pr_err("Architecture has no drm_cache.c support\n");
 	WARN_ON_ONCE(1);
diff --git a/include/drm/drm_cache.h b/include/drm/drm_cache.h
index 987ff16b9420..f94e7bd3eca4 100644
--- a/include/drm/drm_cache.h
+++ b/include/drm/drm_cache.h
@@ -40,6 +40,10 @@ void drm_clflush_sg(struct sg_table *st);
 void drm_clflush_virt_range(void *addr, unsigned long length);
 bool drm_need_swiotlb(int dma_bits);
 
+#if defined(CONFIG_X86) || defined(__powerpc__) || defined(CONFIG_ARM64)
+#define HAS_DRM_CACHE 1
+#endif
+
 
 static inline bool drm_arch_can_wc_memory(void)
 {
-- 
2.21.0