Messages in this thread | | | Date | Mon, 4 Mar 2013 16:57:51 +0800 | From | Huang Shijie <> | Subject | Re: [PATCH V3 1/3] mtd: add new fields to nand_flash_dev{} |
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于 2013年03月04日 16:37, Artem Bityutskiy 写道: > On Mon, 2013-03-04 at 16:08 +0800, Huang Shijie wrote: >> 于 2013年03月04日 15:50, Artem Bityutskiy 写道: >>> On Mon, 2013-03-04 at 13:57 +0800, Huang Shijie wrote: >>>> The current code uses the @id to store the device id(byte 1). >>>> But if we use the 8 bytes id data as the keyword, and expand the @id >>>> field to 8byte array, >>>> the device id is the second byte now. All the added zeros are for the >>> I do not think you need to store the full array of ID's. Device ID's for >>> all the 4 of above chips are different, which is enough to distinguish >>> between them. >>> >>> The only thing you need to add is the OOB size field to 'struct >>> nand_flash_dev'. >>> >> If i only add the oob size field. There will be two items with the same >> Device ID in nand_flash_ids table, >> one has oob_size, one does not have. such as: >> >> {"NAND 8GIB 3,3V 8-bit", 0xDE, 0, 8192, 0, LP_OPTIONS}, > OK, I guess for this one: > > {"NAND 8GIB 3,3V 8-bit", 0xDE, 0, 8192, 0, LP_OPTIONS, 0}, > > nand_decode_ext_id() will calculate the OOB size. > >> {"NAND 8GIB 3,3V 8-bit", 0xDE, 0, 8192, 0, LP_OPTIONS, 640}, //OOB >> size is 640. > And for this one 'nand_decode_ext_id()' will calculate it too, but > _afterwards_ we change OOB size to 640. > > Does this sound sane? > I think not.
The problem is : we can not know which nand_flash_dev item we should use when the same Device ID occurs. When we meet a nand whose Device ID is 0xDE, the current code will select the first one: {"NAND 8GIB 3,3V 8-bit", 0xDE, 0, 8192, 0, LP_OPTIONS, 0}
Could you tell me how can we choose the seconde one? The second same device-id item is {"NAND 8GIB 3,3V 8-bit", 0xDE, 0, 8192, 0, LP_OPTIONS, 640}
thanks Huang Shijie
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