target/linux/generic/patches-3.12/131-improve_noncoherent_dma_checks.patch

   1 From d593f8fc627f8cdaee9c14e4d22b0770a09baaf1 Mon Sep 17 00:00:00 2001
   2 From: Felix Fietkau <nbd@openwrt.org>
   3 Date: Thu, 15 Aug 2013 10:47:47 +0200
   4 Subject: [PATCH] MIPS: improve checks for noncoherent DMA
   5
   6 Only one MIPS development board actually supports enabling/disabling DMA
   7 coherency at runtime, so it's not a good idea to push the overhead of
   8 checking that configuration setting onto every other supported target as
   9 well.
  10
  11 Signed-off-by: Felix Fietkau <nbd@openwrt.org>
  12 ---
  13  arch/mips/Kconfig                                  | 6 +++++-
  14  arch/mips/include/asm/dma-coherence.h              | 7 +++++++
  15  arch/mips/include/asm/mach-generic/dma-coherence.h | 4 ----
  16  arch/mips/mm/dma-default.c                         | 2 ++
  17  4 files changed, 14 insertions(+), 5 deletions(-)
  18
  19 --- a/arch/mips/Kconfig
  20 +++ b/arch/mips/Kconfig
  21 @@ -299,7 +299,7 @@ config MIPS_MALTA
  22         select CEVT_R4K
  23         select CSRC_R4K
  24         select CSRC_GIC
  25 -       select DMA_NONCOHERENT
  26 +       select DMA_MAYBE_COHERENT
  27         select GENERIC_ISA_DMA
  28         select HAVE_PCSPKR_PLATFORM
  29         select IRQ_CPU
  30 @@ -912,6 +912,10 @@ config FW_CFE
  31  config ARCH_DMA_ADDR_T_64BIT
  32         def_bool (HIGHMEM && 64BIT_PHYS_ADDR) || 64BIT
  33
  34 +config DMA_MAYBE_COHERENT
  35 +       select DMA_NONCOHERENT
  36 +       bool
  37 +
  38  config DMA_COHERENT
  39         bool
  40
  41 --- a/arch/mips/include/asm/dma-coherence.h
  42 +++ b/arch/mips/include/asm/dma-coherence.h
  43 @@ -9,7 +9,16 @@
  44  #ifndef __ASM_DMA_COHERENCE_H
  45  #define __ASM_DMA_COHERENCE_H
  46
  47 +#ifdef CONFIG_DMA_MAYBE_COHERENT
  48  extern int coherentio;
  49  extern int hw_coherentio;
  50 +#else
  51 +#ifdef CONFIG_DMA_COHERENT
  52 +#define coherentio     1
  53 +#else
  54 +#define coherentio     0
  55 +#endif
  56 +#define hw_coherentio  0
  57 +#endif /* CONFIG_DMA_MAYBE_COHERENT */
  58
  59  #endif
  60 --- a/arch/mips/include/asm/mach-generic/dma-coherence.h
  61 +++ b/arch/mips/include/asm/mach-generic/dma-coherence.h
  62 @@ -49,11 +49,7 @@ static inline int plat_dma_supported(str
  63
  64  static inline int plat_device_is_coherent(struct device *dev)
  65  {
  66 -#ifdef CONFIG_DMA_COHERENT
  67 -       return 1;
  68 -#else
  69         return coherentio;
  70 -#endif
  71  }
  72
  73  #ifdef CONFIG_SWIOTLB
  74 --- a/arch/mips/mm/dma-default.c
  75 +++ b/arch/mips/mm/dma-default.c
  76 @@ -23,6 +23,7 @@
  77
  78  #include <dma-coherence.h>
  79
  80 +#ifdef CONFIG_DMA_MAYBE_COHERENT
  81  int coherentio = 0;    /* User defined DMA coherency from command line. */
  82  EXPORT_SYMBOL_GPL(coherentio);
  83  int hw_coherentio = 0; /* Actual hardware supported DMA coherency setting. */
  84 @@ -42,6 +43,7 @@ static int __init setnocoherentio(char *
  85         return 0;
  86  }
  87  early_param("nocoherentio", setnocoherentio);
  88 +#endif
  89
  90  static inline struct page *dma_addr_to_page(struct device *dev,
  91         dma_addr_t dma_addr)