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How to configure the Linux kernel/arch/frv

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Howto configure the Linux kernel / arch / frv

For a description of the syntax of this configuration file,
see Documentation/kbuild/kconfig-language.txt.

  • Option: FRV
    • Kernel Versions: ...
    • (on/off)
    • default y

  • Option: UID16
    • Kernel Versions: ...
    • (on/off)
    • default y

    • Kernel Versions: ...
    • (on/off)
    • default y

    • Kernel Versions: ...
    • (on/off)

    • Kernel Versions: ...
    • (on/off)
    • default y

    • Kernel Versions: ...
    • (on/off)
    • default n

    • Kernel Versions: ...
    • (on/off)
    • default n

"Fujitsu FR-V Kernel Configuration"

Fujitsu FR-V system setupEdit

  • Option: MMU
    • Kernel Versions: ...
    • (on/off) MMU support
      This options switches on and off support for the FR-V MMU (effectively switching between vmlinux and uClinux). Not all FR-V CPUs support this. Currently only the FR451 has a sufficiently featured MMU.

    • Kernel Versions: ...
    • (on/off) Out-of-line the FRV atomic operations
    • default n
      Setting this option causes the FR-V atomic operations to be mostly implemented out-of-line.
      See Documentation/fujitsu/frv/atomic-ops.txt for more information.

  • Option: HIGHMEM
    • Kernel Versions: ...
    • (on/off) High memory support
    • depends on MMU
    • default y
      If you wish to use more than 256MB of memory with your MMU based system, you will need to select this option. The kernel can only see the memory between 0xC0000000 and 0xD0000000 directly... everything else must be kmapped.
      The arch is, however, capable of supporting up to 3GB of SDRAM.

  • Option: HIGHPTE
    • Kernel Versions: ...
    • (on/off) Allocate page tables in highmem
    • depends on HIGHMEM
    • default y
      The VM uses one page of memory for each page table. For systems with a lot of RAM, this can be wasteful of precious low memory. Setting this option will put user-space page tables in high memory.

"uClinux kernel load address"

    • depends on !MMU
    • default UCPAGE_OFFSET_C0000000
      This option sets the base address for the uClinux kernel. The kernel will rearrange the SDRAM layout to start at this address, and move itself to start there. It must be greater than 0, and it must be sufficiently less than 0xE0000000 that the SDRAM does not intersect the I/O region.
      The base address must also be aligned such that the SDRAM controller can decode it. For instance, a 512MB SDRAM bank must be 512MB aligned.

  • Option: UCPAGE_OFFSET_20000000
    • Kernel Versions: ... bool 0x20000000

  • Option: UCPAGE_OFFSET_40000000
    • Kernel Versions: ... bool 0x40000000

  • Option: UCPAGE_OFFSET_60000000
    • Kernel Versions: ... bool 0x60000000

  • Option: UCPAGE_OFFSET_80000000
    • Kernel Versions: ... bool 0x80000000

  • Option: UCPAGE_OFFSET_A0000000
    • Kernel Versions: ... bool 0xA0000000

  • Option: UCPAGE_OFFSET_C0000000
    • Kernel Versions: ... bool 0xC0000000 (Recommended)

    • Kernel Versions: ...
    • (on/off) Protect core kernel against userspace
    • depends on !MMU
    • default y
      Selecting this option causes the uClinux kernel to change the permittivity of DAMPR register covering the core kernel image to prevent userspace accessing the underlying memory directly.

"CPU Caching mode"

    • default FRV_DEFL_CACHE_WBACK
      This option determines the default caching mode for the kernel.
      Write-Back caching mode involves the all reads and writes causing the affected cacheline to be read into the cache first before being operated upon. Memory is not then updated by a write until the cache is filled and a cacheline needs to be displaced from the cache to make room. Only at that point is it written back.
      Write-Behind caching is similar to Write-Back caching, except that a write won't fetch a cacheline into the cache if there isn't already one there; it will write directly to memory instead.
      Write-Through caching only fetches cachelines from memory on a read. Writes always get written directly to memory. If the affected cacheline is also in cache, it will be updated too.
      The final option is to turn of caching entirely.
      Note that not all CPUs support Write-Behind caching. If the CPU on which the kernel is running doesn't, it'll fall back to Write-Back caching.

    • Kernel Versions: ...
    • (on/off) Write-Back

    • Kernel Versions: ...
    • (on/off) Write-Behind

    • Kernel Versions: ...
    • (on/off) Write-Through

    • Kernel Versions: ...
    • (on/off) Disabled

CPU core supportEdit

  • Option: CPU_FR401
    • Kernel Versions: ...
    • (on/off) Include FR401 core support
    • depends on !MMU
    • default y
      This enables support for the FR401, FR401A and FR403 CPUs

  • Option: CPU_FR405
    • Kernel Versions: ...
    • (on/off) Include FR405 core support
    • depends on !MMU
    • default y
      This enables support for the FR405 CPU

  • Option: CPU_FR451
    • Kernel Versions: ...
    • (on/off) Include FR451 core support
    • default y
      This enables support for the FR451 CPU

  • Option: CPU_FR451_COMPILE
    • Kernel Versions: ...
    • (on/off) Specifically compile for FR451 core
    • depends on CPU_FR451 && !CPU_FR401 && !CPU_FR405 && !CPU_FR551
    • default y
      This causes appropriate flags to be passed to the compiler to optimise for the FR451 CPU

  • Option: CPU_FR551
    • Kernel Versions: ...
    • (on/off) Include FR551 core support
    • depends on !MMU
    • default y
      This enables support for the FR555 CPU

  • Option: CPU_FR551_COMPILE
    • Kernel Versions: ...
    • (on/off) Specifically compile for FR551 core
    • depends on CPU_FR551 && !CPU_FR401 && !CPU_FR405 && !CPU_FR451
    • default y
      This causes appropriate flags to be passed to the compiler to optimise for the FR555 CPU

  • Option: FRV_L1_CACHE_SHIFT
    • Kernel Versions: ...
    • default "5" if CPU_FR401 || CPU_FR405 || CPU_FR451
    • default "6" if CPU_FR551

"System support"

    • default MB93091_VDK

  • Option: MB93091_VDK
    • Kernel Versions: ...
    • (on/off) MB93091 CPU board with or without motherboard

  • Option: MB93093_PDK
    • Kernel Versions: ...
    • (on/off) MB93093 PDK unit


"Motherboard support"

    • default MB93090_MB00

  • Option: MB93090_MB00
    • Kernel Versions: ...
    • (on/off) Use the MB93090-MB00 motherboard
      Select this option if the MB93091 CPU board is going to be used with a MB93090-MB00 VDK motherboard

  • Option: MB93091_NO_MB
    • Kernel Versions: ...
    • (on/off) Use standalone
      Select this option if the MB93091 CPU board is going to be used without a motherboard

"GP-Relative data support"

    • default GPREL_DATA_8
      This option controls what data, if any, should be placed in the GP relative data sections. Using this means that the compiler can generate accesses to the data using GR16-relative addressing which is faster than absolute instructions and saves space (2 instructions per access).
      However, the GPREL region is limited in size because the immediate value used in the load and store instructions is limited to a 12-bit signed number.
      So if the linker starts complaining that accesses to GPREL data are out of range, try changing this option from the default.
      Note that modules will always be compiled with this feature disabled as the module data will not be in range of the GP base address.

  • Option: GPREL_DATA_8
    • Kernel Versions: ...
    • (on/off) Put data objects of up to 8 bytes into GP-REL

  • Option: GPREL_DATA_4
    • Kernel Versions: ...
    • (on/off) Put data objects of up to 4 bytes into GP-REL

    • Kernel Versions: ...
    • (on/off) Don't use GP-REL

  • Option: PCI
    • Kernel Versions: ...
    • (on/off) Use PCI
    • depends on MB93090_MB00
    • default y
      Some FR-V systems (such as the MB93090-MB00 VDK) have PCI on board. If you have one of these boards and you wish to use the PCI facilities, say Y here.
      The PCI-HOWTO, available from <>, contains valuable information about which PCI hardware does work under Linux and which doesn't.

    • Kernel Versions: ...
    • (on/off) Reserve DMA coherent memory
    • depends on PCI && !MMU
    • default y
      Many PCI drivers require access to uncached memory for DMA device communications (such as is done with some Ethernet buffer rings). If a fully featured MMU is available, this can be done through page table settings, but if not, a region has to be set aside and marked with a special DAMPR register.
      Setting this option causes uClinux to set aside a portion of the available memory for use in this manner. The memory will then be unavailable for normal kernel use.

  • Option: PCMCIA
    • Kernel Versions: ...
    • (on/off/module) Use PCMCIA
      Say Y here if you want to attach PCMCIA- or PC-cards to your FR-V board. These are credit-card size devices such as network cards, modems or hard drives often used with laptops computers. There are actually two varieties of these cards: the older 16 bit PCMCIA cards and the newer 32 bit CardBus cards. If you want to use CardBus cards, you need to say Y here and also to "CardBus support" below.
      To use your PC-cards, you will need supporting software from David Hinds pcmcia-cs package (see the file <file:Documentation/Changes> for location). Please also read the PCMCIA-HOWTO, available from <>.
      To compile this driver as modules, choose M here: the modules will be called pcmcia_core and ds.
bool Math emulation support (EXPERIMENTAL)
At some point in the future, this will cause floating-point math
instructions to be emulated by the kernel on machines that lack a
floating-point math coprocessor. Thrill-seekers and chronically
sleep-deprived psychotic hacker types can say Y now, everyone else
should probably wait a while.

Power management optionsEdit

Executable formatsEdit

Linux Kernel Configuration

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