Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751310AbdFASnp (ORCPT ); Thu, 1 Jun 2017 14:43:45 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:36813 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751078AbdFASnn (ORCPT ); Thu, 1 Jun 2017 14:43:43 -0400 Date: Thu, 1 Jun 2017 11:43:40 -0700 From: Brian Norris To: Boris Brezillon Cc: Chris Packham , dwmw2@infradead.org, andrew@lunn.ch, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, Marek Vasut , Richard Weinberger , Cyrille Pitchen Subject: Re: [PATCH 3/4] mtd: mchp23k256: add partitioning support Message-ID: <20170601184340.GA102137@google.com> References: <20170517053908.26138-1-chris.packham@alliedtelesis.co.nz> <20170517053908.26138-4-chris.packham@alliedtelesis.co.nz> <20170517172911.5f926712@bbrezillon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170517172911.5f926712@bbrezillon> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1944 Lines: 51 On Wed, May 17, 2017 at 05:29:11PM +0200, Boris Brezillon wrote: > Hi Chris, > > On Wed, 17 May 2017 17:39:07 +1200 > Chris Packham wrote: > > > Setting the of_node for the mtd device allows the generic mtd code to > > setup the partitions. Additionally we must specify a non-zero erasesize > > for the partitions to be writeable. > > > > Signed-off-by: Chris Packham > > --- > > drivers/mtd/devices/mchp23k256.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/drivers/mtd/devices/mchp23k256.c b/drivers/mtd/devices/mchp23k256.c > > index 2542f5b8b63f..02c6b9dcbd3e 100644 > > --- a/drivers/mtd/devices/mchp23k256.c > > +++ b/drivers/mtd/devices/mchp23k256.c > > @@ -143,6 +143,7 @@ static int mchp23k256_probe(struct spi_device *spi) > > > > data = dev_get_platdata(&spi->dev); > > > > + mtd_set_of_node(&flash->mtd, spi->dev.of_node); > > flash->mtd.dev.parent = &spi->dev; > > flash->mtd.type = MTD_RAM; > > flash->mtd.flags = MTD_CAP_RAM; > > @@ -151,6 +152,10 @@ static int mchp23k256_probe(struct spi_device *spi) > > flash->mtd._read = mchp23k256_read; > > flash->mtd._write = mchp23k256_write; > > > > + flash->mtd.erasesize = PAGE_SIZE; > > + while (flash->mtd.size & (flash->mtd.erasesize - 1)) > > + flash->mtd.erasesize >>= 1; > > + > > Can we fix allocate_partition() to properly handle the > master->erasesize == 0 case instead of doing that? Is everything actually ready for the eraseblock size to be 0? That would seem surprising to many applications, I would think. Can you, for instance, even use UBI on such a device? BTW, I feel like this check is a little more natural to do with 'mtd->flags & MTD_NO_ERASE', rather than checking the (apparently meaningless) erasesize. (I realize there's a later version of these patches, but I figured I'd put my comments where the suggestion was brought up.) Brian