Eric Lee / smarc-fsl-linux-kernel

12 Oct, 2018

1 commit

  • 3f2aa244e   TC: Set DMA masks for devices ... Browse Code »

    Fix a TURBOchannel support regression with commit 205e1b7f51e4
    ("dma-mapping: warn when there is no coherent_dma_mask") that caused
    coherent DMA allocations to produce a warning such as:

    defxx: v1.11 2014/07/01 Lawrence V. Stefani and others
    tc1: DEFTA at MMIO addr = 0x1e900000, IRQ = 20, Hardware addr = 08-00-2b-a3-a3-29
    ------------[ cut here ]------------
    WARNING: CPU: 0 PID: 1 at ./include/linux/dma-mapping.h:516 dfx_dev_register+0x670/0x678
    Modules linked in:
    CPU: 0 PID: 1 Comm: swapper Not tainted 4.19.0-rc6 #2
    Stack : ffffffff8009ffc0 fffffffffffffec0 0000000000000000 ffffffff80647650
    0000000000000000 0000000000000000 ffffffff806f5f80 ffffffffffffffff
    0000000000000000 0000000000000000 0000000000000001 ffffffff8065d4e8
    98000000031b6300 ffffffff80563478 ffffffff805685b0 ffffffffffffffff
    0000000000000000 ffffffff805d6720 0000000000000204 ffffffff80388df8
    0000000000000000 0000000000000009 ffffffff8053efd0 ffffffff806657d0
    0000000000000000 ffffffff803177f8 0000000000000000 ffffffff806d0000
    9800000003078000 980000000307b9e0 000000001e900000 ffffffff80067940
    0000000000000000 ffffffff805d6720 0000000000000204 ffffffff80388df8
    ffffffff805176c0 ffffffff8004dc78 0000000000000000 ffffffff80067940
    ...
    Call Trace:
    [] show_stack+0xa0/0x130
    [] __warn+0x128/0x170
    ---[ end trace b1d1e094f67f3bb2 ]---

    This is because the TURBOchannel bus driver fails to set the coherent
    DMA mask for devices enumerated.

    Set the regular and coherent DMA masks for TURBOchannel devices then,
    observing that the bus protocol supports a 34-bit (16GiB) DMA address
    space, by interpreting the value presented in the address cycle across
    the 32 `ad' lines as a 32-bit word rather than byte address[1]. The
    architectural size of the TURBOchannel DMA address space exceeds the
    maximum amount of RAM any actual TURBOchannel system in existence may
    have, hence both masks are the same.

    This removes the warning shown above.

    References:

    [1] "TURBOchannel Hardware Specification", EK-369AA-OD-007B, Digital
    Equipment Corporation, January 1993, Section "DMA", pp. 1-15 -- 1-17

    Signed-off-by: Maciej W. Rozycki
    Signed-off-by: Paul Burton
    Patchwork: https://patchwork.linux-mips.org/patch/20835/
    Fixes: 205e1b7f51e4 ("dma-mapping: warn when there is no coherent_dma_mask")
    Cc: stable@vger.kernel.org # 4.16+
    Cc: Ralf Baechle

    Maciej W. Rozycki
     

10 Feb, 2007

1 commit

  • b454cc663   [TC] MIPS: TURBOchannel update to the driver model ... Browse Code »

    This is a set of changes to convert support for the TURBOchannel bus to the
    driver model. It implements the usual set of calls similar to what other bus
    drivers have: tc_register_driver(), tc_unregister_driver(), etc. All the
    platform-specific bits have been removed and headers from asm-mips/dec/ have
    been merged into linux/tc.h, which should be included by drivers.

    Signed-off-by: Maciej W. Rozycki
    Signed-off-by: Andrew Morton
    Signed-off-by: Ralf Baechle

    Maciej W. Rozycki