[v8,0/3] mmc: Add LiteSDCard mmc driver

Message

Gabriel L. Somlo Jan. 7, 2022, 11:34 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 v8:
commit blurbs:
  - cosmetic editing of descriptions
  - removed `Cc:` lines
drivers/mmc/host/litex_mmc.c:
  - fix file header comment (for real, this time)
  - add explicit `bits.h` include
  - remove `of_match_ptr()` wrapper from around .of_match_table argument
  - fix devm ordering issues: use `devm_request_irq()`, which precludes
    the need to call `free_irq()` on `probe()` error path or from `remove()`

>New in v7:
>
>drivers/mmc/host/Kconfig:
>  - added module name in LiteSDCard Kconfig entry
>
>drivers/mmc/host/litex_mmc.c:
>  - fixed comment formatting, ordering, and capitalization throughout
>    the entire file
>  - sorted header #include statements
>  - removed redundant parantheses in readx_poll_timeout() condition
>  - explicit handling of readx_poll_timeout() timeout scenarios
>  - dev_err() used in litex_mmc_sdcard_wait_done()
>  - use memcpy_fromio() to grab command response
>  - no need to apply 0xffff mask to a 32-bit value right-shifted by 16
>    (host->resp[3])
>  - use clamp() instead of min(max(...)...)
>  - reworked platform_get_irq_optional() error handling logic
>  - no need to explicitly zero host->irq, kzalloc() does that already
>  - added missing free_irq() in litex_mmc_probe() error path
>  - reordered calls inside litex_mmc_remove() (calling mmc_free_host()
>    before free_irq()
>
>>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                      |  10 +
 drivers/mmc/host/Makefile                     |   1 +
 drivers/mmc/host/litex_mmc.c                  | 666 ++++++++++++++++++
 5 files changed, 756 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mmc/litex,mmc.yaml
 create mode 100644 drivers/mmc/host/litex_mmc.c