From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from down.free-electrons.com ([37.187.137.238] helo=mail.free-electrons.com) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aGBml-0001qf-Iu for linux-mtd@lists.infradead.org; Mon, 04 Jan 2016 20:31:24 +0000 Date: Mon, 4 Jan 2016 21:31:02 +0100 From: Boris Brezillon To: Brian Norris Cc: , , Heiko Schocher , Frans Klaver Subject: Re: [PATCH for-4.4] mtd: nand: assign reasonable default name for NAND drivers Message-ID: <20160104213102.4e3757d3@bbrezillon> In-Reply-To: <1451934663-68925-1-git-send-email-computersforpeace@gmail.com> References: <1451934663-68925-1-git-send-email-computersforpeace@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Brian, On Mon, 4 Jan 2016 11:11:03 -0800 Brian Norris wrote: > Commits such as commit 853f1c58c4b2 ("mtd: nand: omap2: show parent > device structure in sysfs") attempt to rely on the core MTD code to set > the MTD name based on the parent device. However, nand_base tries to set > a different default name according to the flash name (e.g., extracted > from the ONFI parameter page), which means NAND drivers will never make > use of the MTD defaults. This is not the intention of commit > 853f1c58c4b2. > > This results in problems when trying to use the cmdline partition > parser, since the MTD name is different than expected. Let's fix this by > providing a default NAND name, where possible. > > Note that this is not really a great default name in the long run, since > this means that if there are multiple MTDs attached to the same > controller device, they will have the same name. But that is an existing > issue and requires future work on a better controller vs. flash chip > abstraction to fix properly. Yep, and IMHO, the chip numbering currently in use in most NAND controller drivers is not the best solution either. We should somehow find a way to describe the mtd id using something like: mtd-id: @ nand-controller-id: - Anyway, let's discuss that after the nand-chip <-> nand-controller separation rework. > > Reported-by: Heiko Schocher > Signed-off-by: Brian Norris > Cc: Heiko Schocher > Cc: Frans Klaver > --- > This patch is needed in additon to commit 472b444eef93 ("mtd: fix cmdlinepart > parser, early naming for auto-filled MTD") to fix Heiko's reported problem. At > this point, I'm not sure if this should be targeted toward late 4.4 or for 4.5. > It's a 4.4 regresssion, but a very small one. And I'm not sure if this will > have wide enough impact that it should be given a longer time to be reviewed > and tested. We can always send it to -stable later, if it's really needed. > > drivers/mtd/nand/nand_base.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index ece544efccc3..9f169566fba4 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -3826,6 +3826,9 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd, > if (!type) > type = nand_flash_ids; > > + if (!mtd->name && mtd->dev.parent) > + mtd->name = dev_name(mtd->dev.parent); > + Just nitpicking, but I think this would be better placed in nand_set_defaults() or in nand_scan_ident() before nand_get_flash_type() call. Anyway, Reviewed-by: Boris Brezillon > for (; type->name != NULL; type++) { > if (is_full_id_nand(type)) { > if (find_full_id_nand(mtd, chip, type, id_data, &busw)) Best Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com