Date:   Mon, 10 Jan 2022 17:56:20 -0500
From:   Gabriel Somlo <gsomlo@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     robh+dt@...nel.org, devicetree@...r.kernel.org,
        ulf.hansson@...aro.org, linux-mmc@...r.kernel.org,
        kgugala@...micro.com, mholenko@...micro.com, krakoczy@...micro.com,
        mdudek@...ernships.antmicro.com, paulus@...abs.org, joel@....id.au,
        shorne@...il.com, geert@...ux-m68k.org,
        david.abdurachmanov@...ive.com, florent@...oy-digital.fr,
        rdunlap@...radead.org, andy.shevchenko@...il.com, hdanton@...a.com
Subject: [PATCH v12 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 v12:
drivers/mmc/host/Kconfig:
  - add dependency on HAVE_CLK for litex_mmc driver
  - (re)add "If unsure, say N" to the litex_mmc driver help message
drivers/mmc/host/litex_mmc.c:
  - prints message using dev_info() before returning success from probe()

>New in v11:
>  - picked up r/b from Andy
>drivers/mmc/host/litex_mmc.c:
>  - defensive coding of litex_mmc_interrupt() return logic
>  - remove `dev` member of `struct litex_mmc_host`, only used during probe
>
>>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@...ux-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@...radead.org>)
>>>>>>>>>>   - improvements suggested by Stafford Horne <shorne@...il.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@...el.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                      |  11 +
 drivers/mmc/host/Makefile                     |   1 +
 drivers/mmc/host/litex_mmc.c                  | 663 ++++++++++++++++++
 5 files changed, 754 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

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