aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/generic/pending-4.14/341-MIPS-mm-remove-no-op-dma_map_ops-where-possible.patch
blob: de2dd65b1795c7f74021fe5eac61363d51755ec5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
From: Felix Fietkau <nbd@nbd.name>
Date: Tue, 5 Dec 2017 12:46:01 +0100
Subject: [PATCH] MIPS: mm: remove no-op dma_map_ops where possible

If no post-DMA flush is required, and the platform does not provide
plat_unmap_dma_mem(), there is no need to include unmap or sync_for_cpu
ops.

With this patch they are compiled out to improve icache footprint
on devices that handle lots of DMA traffic (especially network routers).

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -221,6 +221,7 @@ config BMIPS_GENERIC
 	select BRCMSTB_L2_IRQ
 	select IRQ_MIPS_CPU
 	select DMA_NONCOHERENT
+	select DMA_UNMAP_POST_FLUSH
 	select SYS_SUPPORTS_32BIT_KERNEL
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select SYS_SUPPORTS_BIG_ENDIAN
@@ -346,6 +347,7 @@ config MACH_JAZZ
 	select CSRC_R4K
 	select DEFAULT_SGI_PARTITION if CPU_BIG_ENDIAN
 	select GENERIC_ISA_DMA
+	select DMA_UNMAP_POST_FLUSH
 	select HAVE_PCSPKR_PLATFORM
 	select IRQ_MIPS_CPU
 	select I8253
@@ -1128,6 +1130,9 @@ config DMA_NONCOHERENT
 	bool
 	select NEED_DMA_MAP_STATE
 
+config DMA_UNMAP_POST_FLUSH
+	bool
+
 config NEED_DMA_MAP_STATE
 	bool
 
@@ -1652,6 +1657,7 @@ config CPU_R10000
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_SUPPORTS_HUGEPAGES
+	select DMA_UNMAP_POST_FLUSH
 	help
 	  MIPS Technologies R10000-series processors.
 
@@ -1900,9 +1906,11 @@ config SYS_HAS_CPU_MIPS32_R3_5
 	bool
 
 config SYS_HAS_CPU_MIPS32_R5
+	select DMA_UNMAP_POST_FLUSH
 	bool
 
 config SYS_HAS_CPU_MIPS32_R6
+	select DMA_UNMAP_POST_FLUSH
 	bool
 
 config SYS_HAS_CPU_MIPS64_R1
@@ -1912,6 +1920,7 @@ config SYS_HAS_CPU_MIPS64_R2
 	bool
 
 config SYS_HAS_CPU_MIPS64_R6
+	select DMA_UNMAP_POST_FLUSH
 	bool
 
 config SYS_HAS_CPU_R3000
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -267,8 +267,9 @@ static inline void __dma_sync(struct pag
 	} while (left);
 }
 
-static void mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
-	size_t size, enum dma_data_direction direction, unsigned long attrs)
+static void __maybe_unused
+mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
+		    enum dma_data_direction direction, unsigned long attrs)
 {
 	if (cpu_needs_post_dma_flush(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		__dma_sync(dma_addr_to_page(dev, dma_addr),
@@ -308,9 +309,10 @@ static dma_addr_t mips_dma_map_page(stru
 	return plat_map_dma_mem_page(dev, page) + offset;
 }
 
-static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
-	int nhwentries, enum dma_data_direction direction,
-	unsigned long attrs)
+static void __maybe_unused
+mips_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
+		  int nhwentries, enum dma_data_direction direction,
+		  unsigned long attrs)
 {
 	int i;
 	struct scatterlist *sg;
@@ -325,8 +327,9 @@ static void mips_dma_unmap_sg(struct dev
 	}
 }
 
-static void mips_dma_sync_single_for_cpu(struct device *dev,
-	dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
+static void __maybe_unused
+mips_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
+			     size_t size, enum dma_data_direction direction)
 {
 	if (cpu_needs_post_dma_flush(dev))
 		__dma_sync(dma_addr_to_page(dev, dma_handle),
@@ -342,9 +345,9 @@ static void mips_dma_sync_single_for_dev
 			   dma_handle & ~PAGE_MASK, size, direction);
 }
 
-static void mips_dma_sync_sg_for_cpu(struct device *dev,
-	struct scatterlist *sglist, int nelems,
-	enum dma_data_direction direction)
+static void __maybe_unused
+mips_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sglist,
+			 int nelems, enum dma_data_direction direction)
 {
 	int i;
 	struct scatterlist *sg;
@@ -394,12 +397,14 @@ static const struct dma_map_ops mips_def
 	.free = mips_dma_free_coherent,
 	.mmap = mips_dma_mmap,
 	.map_page = mips_dma_map_page,
-	.unmap_page = mips_dma_unmap_page,
 	.map_sg = mips_dma_map_sg,
+#ifdef CONFIG_DMA_UNMAP_POST_FLUSH
+	.unmap_page = mips_dma_unmap_page,
 	.unmap_sg = mips_dma_unmap_sg,
 	.sync_single_for_cpu = mips_dma_sync_single_for_cpu,
-	.sync_single_for_device = mips_dma_sync_single_for_device,
 	.sync_sg_for_cpu = mips_dma_sync_sg_for_cpu,
+#endif
+	.sync_single_for_device = mips_dma_sync_single_for_device,
 	.sync_sg_for_device = mips_dma_sync_sg_for_device,
 	.dma_supported = mips_dma_supported
 };