lkml.org 
[lkml]   [2020]   [Dec]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 1/2] arm64: mm: update the comments about ZONE_DMA
    Date
    Since patchset "arm64: Default to 32-bit wide ZONE_DMA", ZONE_DMA's
    size is fine-tuned. In the absence of addressing limited masters,
    ZONE_DMA will span the whole 32-bit address space, otherwise, in
    the case of the Raspberry Pi 4, it'll only span the 30-bit address
    space. Update the comments.

    Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
    ---
    arch/arm64/mm/init.c | 9 +++++----
    1 file changed, 5 insertions(+), 4 deletions(-)

    diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
    index 75addb36354a..7b9809e39927 100644
    --- a/arch/arm64/mm/init.c
    +++ b/arch/arm64/mm/init.c
    @@ -53,10 +53,11 @@ s64 memstart_addr __ro_after_init = -1;
    EXPORT_SYMBOL(memstart_addr);

    /*
    - * We create both ZONE_DMA and ZONE_DMA32. ZONE_DMA covers the first 1G of
    - * memory as some devices, namely the Raspberry Pi 4, have peripherals with
    - * this limited view of the memory. ZONE_DMA32 will cover the rest of the 32
    - * bit addressable memory area.
    + * We create both ZONE_DMA and ZONE_DMA32. ZONE_DMA's size is fine-tuned.
    + * In the absence of addressing limited masters, ZONE_DMA will span the
    + * whole 32-bit address space, otherwise, in the case of the Raspberry Pi 4,
    + * it'll only span the 30-bit address space. ZONE_DMA32 will cover the rest
    + * of the 32 bit addressable memory area.
    */
    phys_addr_t arm64_dma_phys_limit __ro_after_init;
    static phys_addr_t arm64_dma32_phys_limit __ro_after_init;
    --
    2.20.1
    \
     
     \ /
      Last update: 2020-12-26 04:30    [W:3.789 / U:0.208 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site