| Message ID | 877h2590zp.fsf@free.fr |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 2011-12-09 at 17:13 +0100, Robert Jarzmik wrote: > Artem Bityutskiy <dedekind1@gmail.com> writes: > > > On Fri, 2011-12-02 at 20:00 +0100, Robert Jarzmik wrote: > >> This patch takes into account checkpatch, sparse and ECC > >> comments. > >> > >> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr> > > > > Pushed to l2-mtd-2.6.git, thanks. But I still see this warning when > > I compile on x86_64: > > > > drivers/mtd/devices/docg3.c:1050:12: warning: ‘doc_get_erase_count’ defined > > but not used [-Wunused-function] > > Hi Artem, > > I have found no clean and good way to handle the erase count. As a fallback, > please accept the following patch which removes the unused function. It's kind > of a "looser" approach, but that's the best I can do by now. What do you mean by "handle" ? Is the problem that docg3 maintains per-eraseblock erase-counters and you do not know how to use them? May be it is better to just embrace this function with "#ifdef 0" and add a comment that we can do this but do not have a good use for this? Artem.
Artem Bityutskiy <dedekind1@gmail.com> writes: > On Fri, 2011-12-09 at 17:13 +0100, Robert Jarzmik wrote: > What do you mean by "handle" ? Is the problem that docg3 maintains > per-eraseblock erase-counters and you do not know how to use them? Yes, exactly, docg3 maintains that counter for each block. I thought that upper layers (UBI,...) could use both the erase counter and the ECC number of flipped bits to select which block to erase next. After a quick glance, I don't think they can do it. > May be it is better to just embrace this function with "#ifdef 0" and add a > comment that we can do this but do not have a good use for this? Ah yes, I didn't think about that possibility. It's looks better, I'll submit another patch with a comment and the #if 0. Cheers.
On 12/12/2011 02:03 PM, Robert Jarzmik wrote: > Artem Bityutskiy <dedekind1@gmail.com> writes: > >> On Fri, 2011-12-09 at 17:13 +0100, Robert Jarzmik wrote: >> What do you mean by "handle" ? Is the problem that docg3 maintains >> per-eraseblock erase-counters and you do not know how to use them? > Yes, exactly, docg3 maintains that counter for each block. > > I thought that upper layers (UBI,...) could use both the erase counter and the > ECC number of flipped bits to select which block to erase next. After a quick > glance, I don't think they can do it. The erase counters are surely used by the TrueFFS library. The diskonchip and TrueFFS were both developed by M-Sys. But since it's a unique feature of this device, it would probably be impractical for ubi or mtd to use them. I'm impressed that you discovered them, though. I had no clue that they existed on the diskonchip P3. They are probably on the G4 too. >> May be it is better to just embrace this function with "#ifdef 0" and add a >> comment that we can do this but do not have a good use for this? > Ah yes, I didn't think about that possibility. It's looks better, I'll submit > another patch with a comment and the #if 0. Yeah, leave it in, commented out. But don't submit a patch that produces a compiler warning! Thanks, Mike
diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c index 2a32072..f05c5bc 100644 --- a/drivers/mtd/devices/docg3.c +++ b/drivers/mtd/devices/docg3.c @@ -1038,48 +1038,6 @@ static int doc_block_isbad(struct mtd_info *mtd, loff_t from) } /** - * doc_get_erase_count - Get block erase count - * @docg3: the device - * @from: the offset in which the block is. - * - * Get the number of times a block was erased. The number is the maximum of - * erase times between first and second plane (which should be equal normally). - * - * Returns The number of erases, or -EINVAL or -EIO on error. - */ -static int doc_get_erase_count(struct docg3 *docg3, loff_t from) -{ - u8 buf[DOC_LAYOUT_WEAR_SIZE]; - int ret, plane1_erase_count, plane2_erase_count; - int block0, block1, page, ofs; - - doc_dbg("doc_get_erase_count(from=%lld, buf=%p)\n", from, buf); - if (from % DOC_LAYOUT_PAGE_SIZE) - return -EINVAL; - calc_block_sector(from, &block0, &block1, &page, &ofs, docg3->reliable); - if (block1 > docg3->max_block) - return -EINVAL; - - ret = doc_reset_seq(docg3); - if (!ret) - ret = doc_read_page_prepare(docg3, block0, block1, page, - ofs + DOC_LAYOUT_WEAR_OFFSET); - if (!ret) - ret = doc_read_page_getbytes(docg3, DOC_LAYOUT_WEAR_SIZE, - buf, 1); - doc_read_page_finish(docg3); - - if (ret || (buf[0] != DOC_ERASE_MARK) || (buf[2] != DOC_ERASE_MARK)) - return -EIO; - plane1_erase_count = (u8)(~buf[1]) | ((u8)(~buf[4]) << 8) - | ((u8)(~buf[5]) << 16); - plane2_erase_count = (u8)(~buf[3]) | ((u8)(~buf[6]) << 8) - | ((u8)(~buf[7]) << 16); - - return max(plane1_erase_count, plane2_erase_count); -} - -/** * doc_get_op_status - get erase/write operation status * @docg3: the device *