b120612206
GPMI driver timings derivation looks very empirical and does not use the known timings that the core wants to use with the NAND chip, by using local defined constants that have no special meaning from the outside world. Simplify the way all of this is computed and use the NAND core's SDR timings. Integrity of the reads/writes has been checked with nandbiterrs, speed improvements with flash_speed on a Freescale i.MX6 DualLite/Solo SABRE Automotive Board. Measures are below, variations of less than 150kiB/s between tests are common and then not significant. Speeds using mode 5 are the same, while speeds using mode 0 are quite improved (+40/50% from non-optimal computation). Forcing timings mode 0: ======================= Before this patch: ------------------ eraseblock write speed is 2298 KiB/s eraseblock read speed is 3636 KiB/s page write speed is 2136 KiB/s page read speed is 3316 KiB/s 2 page write speed is 2199 KiB/s 2 page read speed is 3468 KiB/s After this patch: ----------------- eraseblock write speed is 3232 KiB/s eraseblock read speed is 5663 KiB/s page write speed is 2915 KiB/s page read speed is 4904 KiB/s 2 page write speed is 3084 KiB/s 2 page read speed is 5267 KiB/s Forcing timings mode 5: ======================= Before this patch: ------------------ eraseblock write speed is 4338 KiB/s eraseblock read speed is 14883 KiB/s page write speed is 3786 KiB/s page read speed is 12800 KiB/s 2 page write speed is 4076 KiB/s 2 page read speed is 14065 KiB/s After this patch: ----------------- eraseblock write speed is 4309 KiB/s eraseblock read speed is 14712 KiB/s page write speed is 3764 KiB/s page read speed is 12673 KiB/s 2 page write speed is 4076 KiB/s 2 page read speed is 14065 KiB/s Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com> |
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README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.