[v4,0/3] mmc: Add LiteSDCard mmc driver

Message

Gabriel L. Somlo Dec. 10, 2021, 2:54 p.m. UTC

Add support for the LiteX SD-Card device, LiteSDCard.

LiteSDCard is a simple SD-Card interface available as part of the LiteX
environment, used with various RISC-V and other FPGA based SoCs.

New in v4:

Doc/dt/bindings/mmc/litex,mmc.yaml:

  - fixed `dt_binding_check` errors uncovered by Rob's script

drivers/mmc/host/litex_mmc.c:

  - struct litex_mmc_host fields re-ordered so that `pahole` reports
    no holes in either 32- or 64-bit builds
  - litex_mmc_set_bus_width() now encapsulates check for
    host->is_bus_width_set
  - litex_mmc_request() - factor out dma data setup into separate
    helper function: litex_mmc_do_dma()

>New in v3:
>
>  MAINTAINERS:
>
>  - picked up acked-by Joel
>  - added listing for liteeth driver
>  - added Joel as additional co-maintainer (thanks!)
>
>  Doc/dt/bindings/mmc/litex,mmc.yaml:
>
>  - picked up r/b Geert Uytterhoeven <[e-mail]> in DT
>    bindings document (please let me know if that was premature, and
>    happy to take further review if needed :)
>  - add dedicated DT property for source clock frequency
>
>  drivers/mmc/host/litex_mmc.c:
>
>  - fixed function signature (no line split), and naming (litex_mmc_*)
>  - more informative MODULE_AUTHOR() entries
>    - also added matching "Copyright" entries in file header
>  - fixed description in Kconfig
>  - fixed DT documentation
>  - removed magic constants
>  - removed litex_map_status(), have sdcard_wait_done() return *real*
>    error codes directly instead.
>  - streamlined litex_mmc_reponse_len()
>  - call litex_mmc_set_bus_width() only once, and ensure it returns
>    correct error code(s)
>  - use readx_poll_timeout() -- more concise -- instead of
>    read_poll_timeout()
>  - use dev_err() in litex_mmc_send_cmd() (instead of pr_err())
>  - litex_mmc_setclk() will update host->clock before returning
>  - separate irq initialization into its own function,
>    litex_mmc_irq_init()
>  - document rationale for f_min, f_max
>  - use dmam_alloc_coherent(), which simplifies cleanup significantly
>  - large `if (data) { ... }` block in litex_mmc_request() left as-is,
>    there are too many variables shared with the rest of the parent
>    function body to easily separate (e.g., `len`, `transfer`, `direct`).
>    If this is indeed a blocker, I can take another shot at refactoring
>    it in a future revision!
>  - bump dma_set_mask_and_coherent() to 64-bits on suitable
>    architectures
>  - clock source picked up from dedicated DT clock reference property
>  - remove gpio card-detect logic (needs testing and a dt binding
>    example before being eligible for upstream inclusion)
>
>> New in v2:
>>   - reword info message in litex_set_clk()
>>   - streamline code in litex_map_status()
>>   - fix typos in Kconfig (thanks Randy Dunlap <[e-mail]>)
>>   - improvements suggested by Stafford Horne <[e-mail]>
>>     - allow COMPILE_TEST in Kconfig
>>     - use read_poll_timeout() when waiting for cmd/data/DMA
>>       xfer completion
>>   - include interrupt.h (thanks kernel test robot <[e-mail]>)

Gabriel Somlo (3):
  MAINTAINERS: co-maintain LiteX platform
  dt-bindings: mmc: Add bindings for LiteSDCard
  mmc: Add driver for LiteX's LiteSDCard interface

 .../devicetree/bindings/mmc/litex,mmc.yaml    |  72 ++
 MAINTAINERS                                   |   9 +-
 drivers/mmc/host/Kconfig                      |   9 +
 drivers/mmc/host/Makefile                     |   1 +
 drivers/mmc/host/litex_mmc.c                  | 654 ++++++++++++++++++
 5 files changed, 743 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mmc/litex,mmc.yaml
 create mode 100644 drivers/mmc/host/litex_mmc.c