[v7,0/3] mmc: Add LiteSDCard mmc driver

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 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 <geert@linux-m68k.org> 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 <rdunlap@infradead.org>)
>>>>>   - improvements suggested by Stafford Horne <shorne@gmail.com>
>>>>>     - allow COMPILE_TEST in Kconfig
>>>>>     - use read_poll_timeout() when waiting for cmd/data/DMA
>>>>>       xfer completion
>>>>>   - include interrupt.h (thanks kernel test robot <lkp@intel.com>)

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                  | 670 ++++++++++++++++++
 5 files changed, 760 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mmc/litex,mmc.yaml
 create mode 100644 drivers/mmc/host/litex_mmc.c