Hi, LiuShuo a écrit : > 于 2011年08月23日 18:02, Matthieu CASTET 写道: >> LiuShuo a écrit : >>> 于 2011年08月19日 00:25, Scott Wood 写道: >>>> On 08/17/2011 09:33 PM, b35...@freescale.com wrote: >>>>> From: Liu Shuo<b35...@freescale.com> >>>>> >>>>> Freescale FCM controller has a 2K size limitation of buffer RAM. In order >>>>> to support the Nand flash chip whose page size is larger than 2K bytes, >>>>> we divide a page into multi-2K pages for MTD layer driver. In that case, >>>>> we force to set the page size to 2K bytes. We convert the page address of >>>>> MTD layer driver to a real page address in flash chips and a column index >>>>> in fsl_elbc driver. We can issue any column address by UA instruction of >>>>> elbc controller. >>>>> >>>>> NOTE: Due to there is a limitation of 'Number of Partial Program Cycles in >>>>> the Same Page (NOP)', the flash chip which is supported by this workaround >>>>> have to meet below conditions. >>>>> 1. page size is not greater than 4KB >>>>> 2. 1) if main area and spare area have independent NOPs: >>>>> main area NOP :>=3 >>>>> spare area NOP :>=2? >>>> How often are the NOPs split like this? >>>> >>>>> 2) if main area and spare area have a common NOP: >>>>> NOP :>=4 >>>> This depends on how the flash is used. If you treat it as a NOP1 flash >>>> (e.g. run ubifs rather than jffs2), then you need NOP2 for a 4K chip and >>>> NOP4 for an 8K chip. OTOH, if you would be making full use of NOP4 on a >>>> real 2K chip, you'll need NOP8 for a 4K chip. >>>> >>>> The NOP restrictions should be documented in the code itself, not just >>>> in the git changelog. Maybe print it to the console when this hack is >>>> used, along with the NOP value read from the ID. >>> We can't read the NOP from the ID on any chip. Some chips don't >>> give this infomation.(e.g. Micron MT29F4G08BAC) >> Doesn't the micron chip provide it with onfi info ? > Sorry, there is something wrong with my expression. > We can get the NOP info from datasheet, but can't get it by READID > command in code. > ok I was thinking the micron chip was a 4K nand. But it is an old 2K. Why do you want NOP from it ?
Also can you reply my question about the sequence you use when trying to read 4k with one command. Thanks Matthieu _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
