Messages in this thread |  | | Date | Mon, 16 Feb 2015 13:57:12 -0300 | From | Ezequiel Garcia <> | Subject | Re: [PATCH v3 1/2] mtd: nand: pxa3xx: Fix PIO FIFO draining |
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On 02/16/2015 01:41 PM, Maxime Ripard wrote: > On Mon, Feb 16, 2015 at 05:27:53PM +0100, Thomas Petazzoni wrote: >> Dear Maxime Ripard, >> >> On Mon, 16 Feb 2015 13:51:11 +0100, Maxime Ripard wrote: >> >>> + while (index < (len * 4)) { >>> + u32 timeout; >>> + >>> + __raw_readsl(info->mmio_base + NDDB, data + index, 8); >> >> Are you guaranteed that 'len' is a multiple of 32 bytes? > > I don't know if you're guaranteed of anything, but the controller > supports only 512, 2k, 4k and 8k pages, which are all mutiples of 32 > bytes. >
'len' here comes from:
do_bytes = min(info->data_size, info->chunk_size);
and
DIV_ROUND_UP(do_bytes, 4)
Where chunk_size is the size we want to read/write in each command step (keep in mind that with extended commands we issue multiple commands, and read/write data in chunks for each page).
And data_size is initialized at mtd->writesize (i.e. the size of a page).
Given all the flash pages I'm aware of are multiples of 32-bytes, and given a chunk is either a quarter or half a page... I'd say it's guaranteed to be 32-byte multiple, but perhaps it's a good idea to enforce it. - -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v2
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