[PATCH v14 0/3] mmc: Add LiteSDCard mmc driver

From: Gabriel Somlo
Date: Thu Jan 13 2022 - 12:03:11 EST


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 v14:
Documentation/devicetree/bindings/mmc/litex,mmc.yaml:
- add missing `vmmc-supply = ...` property to example section

>New in v13:
>Documentation/devicetree/bindings/mmc/litex,mmc.yaml:
> - add `vmmc-supply` requirement
>drivers/mmc/host/Kconfig:
> - add dependency on REGULATOR, REGULATOR_FIXED_VOLTAGE
>drivers/mmc/host/litex_mmc.c:
> - use `mmc_regulator_get_supply()`, with fallback to hardcoded 3.3V
>
>>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@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 | 78 +++
MAINTAINERS | 9 +-
drivers/mmc/host/Kconfig | 13 +
drivers/mmc/host/Makefile | 1 +
drivers/mmc/host/litex_mmc.c | 661 ++++++++++++++++++
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

--
2.31.1