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From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: barebox@lists.infradead.org
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>,
	Sam Ravnborg <sam@ravnborg.org>
Subject: [PATCH v2 12/12] ARM: mmu: Make sure DMA coherent memory is zeroed out
Date: Thu, 17 Jan 2019 16:38:27 -0800	[thread overview]
Message-ID: <20190118003827.17517-13-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <20190118003827.17517-1-andrew.smirnov@gmail.com>

In order to avoid passing random/junky values to DMA/HW as well as to
allow simplifying memory initialization in individual drivers, change
dma_alloc_coherent() to guarantee that memory it returns is properly
zeroed out.

Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 arch/arm/cpu/mmu-common.c | 3 ++-
 arch/arm/cpu/mmu-common.h | 1 +
 arch/arm/cpu/mmu.c        | 2 +-
 arch/arm/cpu/mmu_64.c     | 8 ++++++++
 4 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/arm/cpu/mmu-common.c b/arch/arm/cpu/mmu-common.c
index c5b24bff8..aeefbb2da 100644
--- a/arch/arm/cpu/mmu-common.c
+++ b/arch/arm/cpu/mmu-common.c
@@ -43,7 +43,8 @@ void *dma_alloc_map(size_t size, dma_addr_t *dma_handle, unsigned flags)
 	if (dma_handle)
 		*dma_handle = (dma_addr_t)ret;
 
-	dma_inv_range(ret, size);
+	memset(ret, 0, size);
+	dma_flush_range(ret, size);
 
 	arch_remap_range(ret, size, flags);
 
diff --git a/arch/arm/cpu/mmu-common.h b/arch/arm/cpu/mmu-common.h
index 679799c3c..0a33b138e 100644
--- a/arch/arm/cpu/mmu-common.h
+++ b/arch/arm/cpu/mmu-common.h
@@ -2,6 +2,7 @@
 #define __ARM_MMU_COMMON_H
 
 void dma_inv_range(void *ptr, size_t size);
+void dma_flush_range(void *ptr, size_t size);
 void *dma_alloc_map(size_t size, dma_addr_t *dma_handle, unsigned flags);
 void __mmu_init(bool mmu_on);
 
diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
index 9e261a0be..29816ad56 100644
--- a/arch/arm/cpu/mmu.c
+++ b/arch/arm/cpu/mmu.c
@@ -97,7 +97,7 @@ static u32 *find_pte(unsigned long adr)
 	return &table[(adr >> PAGE_SHIFT) & 0xff];
 }
 
-static void dma_flush_range(void *ptr, size_t size)
+void dma_flush_range(void *ptr, size_t size)
 {
 	unsigned long start = (unsigned long)ptr;
 	unsigned long end = start + size;
diff --git a/arch/arm/cpu/mmu_64.c b/arch/arm/cpu/mmu_64.c
index a3074b10d..b45a69661 100644
--- a/arch/arm/cpu/mmu_64.c
+++ b/arch/arm/cpu/mmu_64.c
@@ -233,6 +233,14 @@ void dma_inv_range(void *ptr, size_t size)
 	v8_inv_dcache_range(start, end);
 }
 
+void dma_flush_range(void *ptr, size_t size)
+{
+	unsigned long start = (unsigned long)ptr;
+	unsigned long end = start + size - 1;
+
+	v8_flush_dcache_range(start, end);
+}
+
 void dma_sync_single_for_device(dma_addr_t address, size_t size,
                                 enum dma_data_direction dir)
 {
-- 
2.20.1


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  parent reply	other threads:[~2019-01-18  0:39 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-18  0:38 [PATCH v2 00/12] ARM/ARM64 MMU code consolidation, zeroing of DMA coherent memory Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 01/12] ARM: mmu: Drop custom virt_to_phys/phys_to_virt Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 02/12] ARM: mmu: Simplify the use of dma_inv_range() Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 03/12] ARM: mmu: Share code for dma_(un)map_single() Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 04/12] ARM64: mmu: Use arch_remap_range() internally Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 05/12] ARM64: mmu: Merge create_sections() and map_region() together Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 06/12] ARM: mmu: Share code for dma_free_coherent() Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 07/12] ARM64: mmu: Invalidate memory before remapping as DMA coherent Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 08/12] ARM: mmu: Share code for dma_alloc_coherent() Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 09/12] ARM: mmu: Share code for dma_sync_single_for_cpu() Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 10/12] ARM: mmu: Share sanity checking code in mmu_init() Andrey Smirnov
2019-01-18  0:38 ` [PATCH v2 11/12] ARM: mmu: Share code for arm_mmu_not_initialized_error() Andrey Smirnov
2019-01-18  0:38 ` Andrey Smirnov [this message]
2019-01-21  7:34 ` [PATCH v2 00/12] ARM/ARM64 MMU code consolidation, zeroing of DMA coherent memory Sascha Hauer

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