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
@@ -214,6 +214,7 @@ 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
@@ -339,6 +340,7 @@ 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
@@ -1129,6 +1131,9 @@ config DMA_NONCOHERENT
bool
select NEED_DMA_MAP_STATE
+config DMA_UNMAP_POST_FLUSH
+ bool
+
config NEED_DMA_MAP_STATE
bool
@@ -1653,6 +1658,7 @@ 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.
@@ -1898,9 +1904,11 @@ 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
@@ -1910,6 +1918,7 @@ 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
@@ -290,8 +290,9 @@ 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))
__dma_sync(dma_addr_to_page(dev, dma_addr),
@@ -330,9 +331,10 @@ 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;
@@ -346,8 +348,9 @@ 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),
@@ -363,9 +366,9 @@ 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;
@@ -415,12 +418,14 @@ static struct dma_map_ops mips_default_d
.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
};
|
