[v9,0/3] 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 v9:

drivers/mmc/host/Kconfig:
  - fix OF dependency
drivers/mmc/host/litex_mmc.c:
  - remove `linux/of.h` include, no longer needed since dropping
    `of_match_ptr()`
  - add `linux/mod_devicetable.h` include
  - use devm_action_or_reset() to devm-ify mmc_alloc_host(), and obviate
    the need to call mmc_free_host() explicitly during either probe()
    error path or during remove()

>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 <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                      |   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