[PATCH v10 0/3] mmc: Add LiteSDCard mmc driver

[Gabriel Somlo]

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 v10:
drivers/mmc/host/litex_mmc.c:
  - group `linux/mmc/*` includes by themselves
  - clean-up of `return` style (multiple locations throughout source)
  - create `mmc_free_host()` wrapper for use with
    `devm_add_action_or_reset()`
  - use GFP_KERNEL with `dmam_alloc_coherent()`

>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@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>)
>>>>>>>>   - improvements suggested by Stafford Horne <shorne@xxxxxxxxx>
>>>>>>>>     - 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@xxxxxxxxx>)

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                  | 655 ++++++++++++++++++
 5 files changed, 744 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mmc/litex,mmc.yaml
 create mode 100644 drivers/mmc/host/litex_mmc.c

-- 
2.31.1