[v6,0/3] mmc: Add LiteSDCard mmc driver

Message

Gabriel L. Somlo Jan. 6, 2022, 5:48 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 v6:

drivers/mmc/host/litex_mmc.c:
  - fix handling of deferred probe vs. platform_get_irq_optional()
  - don't #ifdef dma_set_mask_and_coherent(), since it automatically
    does the right thing on both 32- and 64-bit DMA capable arches
  - remove MMC_CAP2_FULL_PWR_CYCLE, add MMC_CAP2_NO_MMC to list of
    hardcoded capabilities during litex_mmc_probe()
  - hardcode mmc->ocr_avail to the full 2.7-3.6V range allowed by the
    SDCard spec (the LiteSDCard device doesn't accept software
    configuration)

>New in v5:
>
>MAINTAINERS:
>
>  - picked up a/b Mateusz
>
>Doc/dt/bindings/mmc/litex,mmc.yaml:
>
>  - picked up r/b Rob, Joel
>
>drivers/mmc/host/litex_mmc.c:
>
>  - shorten #define constant names (cosmetic, make them less unwieldy)
>  - picked up r/b Joel
>
>>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                  | 659 ++++++++++++++++++
 5 files changed, 748 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mmc/litex,mmc.yaml
 create mode 100644 drivers/mmc/host/litex_mmc.c