• Stefan Agner's avatar
    mtd: nand: vf610_nfc: Freescale NFC for VF610, MPC5125 and others · 456930d8
    Stefan Agner authored
    This driver supports Freescale NFC (NAND flash controller) found on
    Vybrid (VF610), MPC5125, MCF54418 and Kinetis K70. The driver has
    been tested using 8-bit and 16-bit NAND interface on the ARM based
    Vybrid SoC VF500 and VF610 platform.
    parameter page reading.
    
    Limitations:
    - Untested on MPC5125 and M54418.
    - DMA and pipelining not used.
    - 2K pages or less.
    - No chip select, one NAND chip per controller.
    - No hardware ECC.
    
    Some paths have been hand-optimized and evaluated by measurements
    made using mtd_speedtest.ko on a 100MB MTD partition.
    
    Colibri VF50
            eb write     %   eb read     %   page write      %   page read     %
    rel/opt     5175           11537                4560             11039
    opt         5164 -0.21     11420 -1.01          4737 +3.88       10918 -1.10
    none        5113 -1.20     11352 -1.60          4490 -1.54       10865 -1.58
    
    Colibri VF61
            eb write     %   eb read     %   page write      %   page read     %
    rel/opt     5766           13096                5459             12846
    opt         5883 +2.03     13064 -0.24          5561 +1.87       12802 -0.34
    none        5701 -1.13     12980 -0.89          5488 +0.53       12735 -0.86
    
    rel = using readl_relaxed/writel_relaxed in optimized paths
    opt = hand-optimized by combining multiple accesses into one read/write
    
    The measurements have not been statistically verfied, hence use them
    with care. The author came to the conclusion that using the relaxed
    variants of readl/writel are not worth the additional code.
    Signed-off-by: default avatarBill Pringlemeir <bpringlemeir@nbsps.com>
    Tested-by: default avatarAlbert ARIBAUD <albert.aribaud@3adev.fr>
    Signed-off-by: default avatarStefan Agner <stefan@agner.ch>
    Reviewed-by: default avatarAlexey Klimov <klimov.linux@gmail.com>
    Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
    456930d8
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