Re: [PATCH v5 0/2] MTK Smart Device Gen1 NAND Driver

[Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>]

On Tue, 14 Jun 2016 11:50:49 -0400
Jorge Ramirez-Ortiz <jorge.ramirez-ortiz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:

>   Fixes/Changes on v5 relative to: 
>   --------------------------------
> 
>   tree		: https://github.com/bbrezillon/linux-0day
>   branch	: nand/next
>   commit	:
>  		'commit "mtd: nand: sunxi: fix return value check..."'
> 		 Author: Wei Yongjun <yongjun_wei-zrsr2BFq86L20UzCJQGyNP8+0UxHXcjY@public.gmane.org>
> 		 Date: Mon Jun 13 14:27:18 2016 +0000
> 
>   Patch v5
>   --------
>   mtd: mediatek: device tree bindings for MTK Smart Device Gen1 NAND
>        - remove unused property
>   
>   mtd: mediatek: driver for MTK Smart Device Gen1 NAND
>        - clean up macros and clarify semantics.
>        - replace codec requests with operations.
>        - replace semaphore with mutex on ecc accesses.
>        - addtional comments to some functions.
>        - explicit error for 16bits buswidth (not supported).
>        - resolve endian issues.
>        - determine active ecc codec by register inspection. 
> 
>   Patch v4
>   --------
>   mtd: mediatek: device tree docs for MTK Smart Device Gen1 NAND
>        - nand-on-flash-bbt, nand-ecc-mode, nand-ecc-step-size and
>          nand-ecc-strength are now optional parameters
>        - spare-per-sector removed from DT settings.
>        - extend documentation.
> 
>   mtd: mediatek: driver for MTK Smart Device Gen1 NAND
>        - rename functions (semantic issues).
>        - add lock to ECC engine.
>        - rework ECC interface (single enable/disable function).
>        - rework bad block mark (now stored in OOB).
>        - fix stat reporting.
>        - rework FDM calculation.
>        - handle optional DT settings (strength, mode, ecc step size).
>        - spare per sector clamped to valid register values (hw spec).
> 		
>   Patch v3
>   --------
>   mtd: mediatek: device tree docs for MTK Smart Device Gen1 NAND
> 	- rename nandc (nand controller)
> 
>   mtd: mediatek: driver for MTK Smart Device Gen1 NAND
>  	- rename source and header files
> 	- register definitions move to source files
> 	- ecc interface dropped
> 	- blank lines between functions (checkpatch.pl doesn't catch them)
> 	- ecc_check function renamed ecc_get_stats
> 	- ecc->dev assigned during probe()
> 	- generic ecc control function replaced by individual functions
> 	- required ecc parameters passed in ecc specific structures
> 	- fix memory corruption (size 0 array)
> 	- clarify nand offset/ptr function helpers (naming corrected)
> 	- move ecc config call to select_chip()
> 	- comment on hw issue workaround during read_byte
> 	- implement write_buf
> 	- remove switch_oob
> 	- fix suspend/resume operation
> 	- make nand-ecc-mode mandatory in device tree 
> 
>   RFC v2
>   ------
>  
>   mtd: mediatek: device tree docs for MTK Smart Device Gen1 NAND
> 	- split nand flash interface and ecc engine
> 
>   mtd: mediatek: driver for MTK Smart Device Gen1 NAND
> 	- split host and ecc in two separate drivers.
> 	- expose ecc layout through mtd_ooblayout_ops.
> 	- fix wait loops.
> 	- use device tree to describe ecc strength and ecc size.
> 	- use device tree to describe CS.
> 	- replace cmdfunc with cmd_ctrl.
> 	- fix read byte interface.
> 
>   dont enable controller in mt2701.dtsi
> 	- requires additional device tree changes. This will be done in
> 	  the near future.
> 
> Overview:
> =========
> 
> The following patch-set adds support for Mediatek's Smart Device
> Gen1 NAND controller.
> 
> * Controller expected layout:
> -----------------------------
> 
> The controller expects the OOB information relevant to each sector
> within the page to follow immediately the data field.
> 
> For example for a 4KiB page with 1KiB sectors and 224B of OOB information,
> the controller would expect the following layout.
> 
> -----------------------------------------------------
> | 1KiB | 56B | 1KiB | 56B | 1KiB | 56B | 1KiB | 56B |
> -----------------------------------------------------
> 
> This implies that the following actions are required:
> 
> - raw writes:
>   to match the controller expected layout, the driver uses the CPU and
>   a private bounce buffer to reassemble the page before the actual
>   writes.
>   
> - non raw writes:
>   ecc is hardware generated and data DMA'd in a single transfer.
> 
> Bad Block mark
> ==============
> The bad block mark is stored in the OOB region (one byte)
> 
> Controller limitations:
> =======================
> 
>  * dma chaning not supported:
> 	To guarantee that the pages corresponding to the buffers are contiguous
> 	in memory the driver enables NAND_USE_BOUNCE_BUFFER.
>  * spare per sector: 16B to 128B
>  * sector sizes: 512B or 1024B
>  * programable page sizes: 512B, 2KB, 4KB, 8K, 16K 
> 
> Tests:
> ======
> 
> * UBIFS support has been validated on 512MiB device (iozone, dd)
> * All drivers/mtd/tests/* pass clean.
> * Speed tests:
>   eraseblock write speed:	7563 KiB/s
>   eraseblock read speed:	10904 KiB/s
>   page write speed:		7497 KiB/s
>   page read speed:		10864 KiB/s
>   2 page write speed:		7527 KiB/s
>   2 page read speed:		10881 KiB/s
>   erase speed:			103157 KiB/s
>   2x multi-block erase speed:	357445 KiB/s
>   4x multi-block erase speed:	362944 KiB/s
>   8x multi-block erase speed:	363805 KiB/s
>   16x multi-block erase speed:	364237 KiB/s
>   32x multi-block erase speed:	364670 KiB/s
>   64x multi-block erase speed:	365104 KiB/s

Applied after fixing a few coding style issues.

Thanks,

Boris

> 
> Jorge Ramirez-Ortiz (2):
>   mtd: mediatek: device tree bindings for MTK Smart Device Gen1 NAND
>   mtd: mediatek: driver for MTK Smart Device Gen1 NAND
> 
>  Documentation/devicetree/bindings/mtd/mtk-nand.txt |  160 +++
>  drivers/mtd/nand/Kconfig                           |    7 +
>  drivers/mtd/nand/Makefile                          |    1 +
>  drivers/mtd/nand/mtk_ecc.c                         |  528 +++++++
>  drivers/mtd/nand/mtk_ecc.h                         |   50 +
>  drivers/mtd/nand/mtk_nand.c                        | 1509 ++++++++++++++++++++
>  6 files changed, 2255 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mtd/mtk-nand.txt
>  create mode 100644 drivers/mtd/nand/mtk_ecc.c
>  create mode 100644 drivers/mtd/nand/mtk_ecc.h
>  create mode 100644 drivers/mtd/nand/mtk_nand.c
>