arch/mn10300/mm/Kconfig.cache

   1 #
   2 # MN10300 CPU cache options
   3 #
   4
   5 choice
   6         prompt "CPU Caching mode"
   7         default MN10300_CACHE_WBACK
   8         help
   9           This option determines the caching mode for the kernel.
  10
  11           Write-Back caching mode involves the all reads and writes causing
  12           the affected cacheline to be read into the cache first before being
  13           operated upon. Memory is not then updated by a write until the cache
  14           is filled and a cacheline needs to be displaced from the cache to
  15           make room. Only at that point is it written back.
  16
  17           Write-Through caching only fetches cachelines from memory on a
  18           read. Writes always get written directly to memory. If the affected
  19           cacheline is also in cache, it will be updated too.
  20
  21           The final option is to turn of caching entirely.
  22
  23 config MN10300_CACHE_WBACK
  24         bool "Write-Back"
  25         help
  26           The dcache operates in delayed write-back mode.  It must be manually
  27           flushed if writes are made that subsequently need to be executed or
  28           to be DMA'd by a device.
  29
  30 config MN10300_CACHE_WTHRU
  31         bool "Write-Through"
  32         help
  33           The dcache operates in immediate write-through mode.  Writes are
  34           committed to RAM immediately in addition to being stored in the
  35           cache.  This means that the written data is immediately available for
  36           execution or DMA.
  37
  38           This is not available for use with an SMP kernel if cache flushing
  39           and invalidation by automatic purge register is not selected.
  40
  41 config MN10300_CACHE_DISABLED
  42         bool "Disabled"
  43         help
  44           The icache and dcache are disabled.
  45
  46 endchoice
  47
  48 config MN10300_CACHE_ENABLED
  49         def_bool y if !MN10300_CACHE_DISABLED
  50
  51
  52 choice
  53         prompt "CPU cache flush/invalidate method"
  54         default MN10300_CACHE_MANAGE_BY_TAG if !AM34_2
  55         default MN10300_CACHE_MANAGE_BY_REG if AM34_2
  56         depends on MN10300_CACHE_ENABLED
  57         help
  58           This determines the method by which CPU cache flushing and
  59           invalidation is performed.
  60
  61 config MN10300_CACHE_MANAGE_BY_TAG
  62         bool "Use the cache tag registers directly"
  63         depends on !(SMP && MN10300_CACHE_WTHRU)
  64
  65 config MN10300_CACHE_MANAGE_BY_REG
  66         bool "Flush areas by way of automatic purge registers (AM34 only)"
  67         depends on AM34_2
  68
  69 endchoice
  70
  71 config MN10300_CACHE_INV_BY_TAG
  72         def_bool y if MN10300_CACHE_MANAGE_BY_TAG && MN10300_CACHE_ENABLED
  73
  74 config MN10300_CACHE_INV_BY_REG
  75         def_bool y if MN10300_CACHE_MANAGE_BY_REG && MN10300_CACHE_ENABLED
  76
  77 config MN10300_CACHE_FLUSH_BY_TAG
  78         def_bool y if MN10300_CACHE_MANAGE_BY_TAG && MN10300_CACHE_WBACK
  79
  80 config MN10300_CACHE_FLUSH_BY_REG
  81         def_bool y if MN10300_CACHE_MANAGE_BY_REG && MN10300_CACHE_WBACK
  82
  83
  84 config MN10300_HAS_CACHE_SNOOP
  85         def_bool n
  86
  87 config MN10300_CACHE_SNOOP
  88         bool "Use CPU Cache Snooping"
  89         depends on MN10300_CACHE_ENABLED && MN10300_HAS_CACHE_SNOOP
  90         default y
  91
  92 config MN10300_CACHE_FLUSH_ICACHE
  93         def_bool y if MN10300_CACHE_WBACK && !MN10300_CACHE_SNOOP
  94         help
  95           Set if we need the dcache flushing before the icache is invalidated.
  96
  97 config MN10300_CACHE_INV_ICACHE
  98         def_bool y if MN10300_CACHE_WTHRU && !MN10300_CACHE_SNOOP
  99         help
 100           Set if we need the icache to be invalidated, even if the dcache is in
 101           write-through mode and doesn't need flushing.
 102
 103 #
 104 # The kernel debugger gets its own separate cache flushing functions
 105 #
 106 config MN10300_DEBUGGER_CACHE_FLUSH_BY_TAG
 107         def_bool y if KERNEL_DEBUGGER && \
 108                         MN10300_CACHE_WBACK && \
 109                         !MN10300_CACHE_SNOOP && \
 110                         MN10300_CACHE_MANAGE_BY_TAG
 111         help
 112           Set if the debugger needs to flush the dcache and invalidate the
 113           icache using the cache tag registers to make breakpoints work.
 114
 115 config MN10300_DEBUGGER_CACHE_FLUSH_BY_REG
 116         def_bool y if KERNEL_DEBUGGER && \
 117                         MN10300_CACHE_WBACK && \
 118                         !MN10300_CACHE_SNOOP && \
 119                         MN10300_CACHE_MANAGE_BY_REG
 120         help
 121           Set if the debugger needs to flush the dcache and invalidate the
 122           icache using automatic purge registers to make breakpoints work.
 123
 124 config MN10300_DEBUGGER_CACHE_INV_BY_TAG
 125         def_bool y if KERNEL_DEBUGGER && \
 126                         MN10300_CACHE_WTHRU && \
 127                         !MN10300_CACHE_SNOOP && \
 128                         MN10300_CACHE_MANAGE_BY_TAG
 129         help
 130           Set if the debugger needs to invalidate the icache using the cache
 131           tag registers to make breakpoints work.
 132
 133 config MN10300_DEBUGGER_CACHE_INV_BY_REG
 134         def_bool y if KERNEL_DEBUGGER && \
 135                         MN10300_CACHE_WTHRU && \
 136                         !MN10300_CACHE_SNOOP && \
 137                         MN10300_CACHE_MANAGE_BY_REG
 138         help
 139           Set if the debugger needs to invalidate the icache using automatic
 140           purge registers to make breakpoints work.
 141
 142 config MN10300_DEBUGGER_CACHE_NO_FLUSH
 143         def_bool y if KERNEL_DEBUGGER && \
 144                         (MN10300_CACHE_DISABLED || MN10300_CACHE_SNOOP)
 145         help
 146           Set if the debugger does not need to flush the dcache and/or
 147           invalidate the icache to make breakpoints work.