Re: [RFC PATCH v3.1 00/27] Add support UHS-II for GL9755

AKASHI Takahiro
2020-11-25T07:41:52Z

Gentle ping;

On Fri, Nov 06, 2020 at 11:26:59AM +0900, AKASHI Takahiro wrote:
> This is an interim snapshot of our next version, v4, for enabling
> UHS-II on MMC/SD.
>
> It is focused on 'sdhci' side to address Adrian's comments regarding
> "modularising" sdhci-uhs2.c.
> The whole aim of this version is to get early feedback from Adrian (and
> others) on this issue. Without any consensus about the code structure,

Any comments so far?

-Takahiro Akashi

> it would make little sense to go further ahead on sdhci side.
> (Actually, Adrian has made no comments other than "modularising" so far.)
>
> I heavily reworked/refactored sdhci-uhs2.c and re-organised the patch
> set to meet what I believe Adrian expects; no UHS-II related code in
> Legacy (UHS-I) code or sdhci.c.
>
> Nevertheless, almost of all changes I made are trivial and straightforward
> in this direction, and I believe that there is no logic changed since v3
> except sdhci_uhs2_irq(), as ops->irq hook, where we must deal with UHS-II
> command sequences in addition to UHS-II errors. So I added extra handlings.
>
> I admit that there is plenty of room for improvements (for example,
> handling host->flags), but again the focal point here is how sdhci-uhs2.c
> should be built as a module.
>
> Please review this series (particularly Patch#8-#26 and #27) from this
> viewpoint in the first place.
> (Ben is working on 'host' side but there is no change on 'host' side
> in this submission except a minor tweak.)
>
> Thanks,
> -Takahiro Akashi
>
> ------ original cover letter from v3 ------
> Summary
> =======
> These patches[1] support UHS-II and fix GL9755 UHS-II compatibility.
>
> About UHS-II, roughly deal with the following three parts:
> 1) A UHS-II detection and initialization:
> - Host setup to support UHS-II (Section 3.13.1 Host Controller Setup Sequence
> [2]).
> - Detect a UHS-II I/F (Section 3.13.2 Card Interface Detection Sequence[2]).
> - In step(9) of Section 3.13.2 in [2], UHS-II initialization is include Section
> 3.13.3 UHS-II Card Initialization and Section 3.13.4 UHS-II Setting Register
> Setup Sequence.
>
> 2) Send Legacy SD command through SD-TRAN
> - Encapsulated SD packets are defined in SD-TRAN in order to ensure Legacy SD
> compatibility and preserve Legacy SD infrastructures (Section 7.1.1 Packet
> Types and Format Overview[3]).
> - Host issue a UHS-II CCMD packet or a UHS-II DCMD (Section 3.13.5 UHS-II
> CCMD Packet issuing and Section 3.13.6 UHS-II DCMD Packet issuing[2]).
>
> 3) UHS-II Interrupt
> - Except for UHS-II error interrupts, most interrupts share the original
> interrupt registers.
>
> Patch structure
> ===============
> patch#1-#7: for core
> patch#8-#17: for sdhci
> patch#18-#21: for GL9755
>
> Tests
> =====
> Ran 'dd' command to evaluate the performance:
> (SanDisk UHS-II card on GL9755 controller)
> Read Write
> UHS-II disabled (UHS-I): 88.3MB/s 60.7MB/s
> UHS-II enabled : 206MB/s 80MB/s
>
> TODO
> ====
> - replace some define with BIT macro
>
> Reference
> =========
> [1] https://gitlab.com/ben.chuang/linux-uhs2-gl9755.git
> [2] SD Host Controller Simplified Specification 4.20
> [3] UHS-II Simplified Addendum 1.02
>
> Changes in v3 (Jul. 10, 2020)
> * rebased to v5.8-rc4
> * add copyright notice
> * reorganize the patch set and split some commits into smaller ones
> * separate uhs-2 headers from others
> * correct wrong spellings
> * fix most of checkpatch warnings/errors
> * remove all k[cz]alloc() from the code
> * guard sdhci-uhs2 specific code with
> 'if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2))'
> * make sdhci-uhs2.c as a module
> * trivial changes, including
> - rename back sdhci-core.c to sdhci.c
> - allow vendor code to disable uhs2 if v4_mode == 0
> in __sdhci_add_host()
> - merge uhs2_power_up() into mmc_power_up()
> - remove flag_uhs2 from mmc_attach_sd()
> - add function descriptions to EXPORT'ed functions
> - other minor code optimization
>
> Changes in v2 (Jan. 9, 2020)
> * rebased to v5.5-rc5
>
> AKASHI Takahiro (23):
> mmc: core: UHS-II support, modify power-up sequence
> mmc: core: UHS-II support, skip set_chip_select()
> mmc: core: UHS-II support, skip TMODE setup in some cases
> mmc: core: UHS-II support, generate UHS-II SD command packet
> mmc: core: UHS-II support, set APP_CMD bit if necessary
> mmc: sdhci: add a kernel configuration for enabling UHS-II support
> mmc: sdhci: add UHS-II related definitions in headers
> mmc: sdhci: add UHS-II module
> mmc: sdhci-uhs2: dump UHS-II registers
> mmc: sdhci-uhs2: add reset function
> mmc: sdhci-uhs2: add set_power() to support vdd2
> mmc: sdhci-uhs2: skip signal_voltage_switch()
> mmc: sdhci-uhs2: add set_timeout()
> mmc: sdhci-uhs2: add set_ios()
> mmc: sdhci-uhs2: add detect_init() to detect the interface
> mmc: sdhci-uhs2: add clock operations
> mmc: sdhci-uhs2: add set_reg() to initialise the interface
> mmc: sdhci-uhs2: add request() and others
> mmc: sdhci-uhs2: add irq() and others
> mmc: sdhci-uhs2: add add_host() and others to set up the driver
> mmc: core: add post-mmc_attach_sd hook
> mmc: sdhci-pci: add UHS-II support framework
> mmc: sdhci-pci-gli: enable UHS-II mode for GL9755
>
> Ben Chuang (4):
> mmc: add UHS-II related definitions in public headers
> mmc: core: UHS-II support, try to select UHS-II interface
> mmc: sdhci-uhs2: add pre-detect_init hook
> mmc: sdhci-uhs2: add post-mmc_attach_sd hook
>
> drivers/mmc/core/Makefile | 2 +-
> drivers/mmc/core/block.c | 7 +-
> drivers/mmc/core/bus.c | 5 +-
> drivers/mmc/core/core.c | 118 +-
> drivers/mmc/core/regulator.c | 14 +
> drivers/mmc/core/sd.c | 32 +
> drivers/mmc/core/sd_ops.c | 12 +
> drivers/mmc/core/uhs2.c | 883 +++++++++++++++
> drivers/mmc/core/uhs2.h | 21 +
> drivers/mmc/host/Kconfig | 10 +
> drivers/mmc/host/Makefile | 1 +
> drivers/mmc/host/sdhci-pci-core.c | 16 +-
> drivers/mmc/host/sdhci-pci-gli.c | 318 +++++-
> drivers/mmc/host/sdhci-pci.h | 3 +
> drivers/mmc/host/sdhci-uhs2.c | 1697 +++++++++++++++++++++++++++++
> drivers/mmc/host/sdhci-uhs2.h | 224 ++++
> drivers/mmc/host/sdhci.c | 333 +++---
> drivers/mmc/host/sdhci.h | 117 +-
> include/linux/mmc/card.h | 1 +
> include/linux/mmc/core.h | 6 +
> include/linux/mmc/host.h | 31 +
> include/linux/mmc/uhs2.h | 268 +++++
> 22 files changed, 3961 insertions(+), 158 deletions(-)
> create mode 100644 drivers/mmc/core/uhs2.c
> create mode 100644 drivers/mmc/core/uhs2.h
> create mode 100644 drivers/mmc/host/sdhci-uhs2.c
> create mode 100644 drivers/mmc/host/sdhci-uhs2.h
> create mode 100644 include/linux/mmc/uhs2.h
>
> --
> 2.28.0
>