From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pa0-x22d.google.com ([2607:f8b0:400e:c03::22d]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1a2RUE-0001Qi-M5 for linux-mtd@lists.infradead.org; Fri, 27 Nov 2015 22:27:27 +0000 Received: by padhx2 with SMTP id hx2so124267519pad.1 for ; Fri, 27 Nov 2015 14:27:05 -0800 (PST) Date: Fri, 27 Nov 2015 14:27:01 -0800 From: Brian Norris To: Felix Fietkau Cc: linux-mtd@lists.infradead.org, Ezequiel Garcia Subject: Re: [PATCH] Revert "mtd: spi-nor: disable protection for Winbond flash at startup" Message-ID: <20151127222701.GA19615@localhost> References: <1448555221-24257-1-git-send-email-nbd@openwrt.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1448555221-24257-1-git-send-email-nbd@openwrt.org> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Felix, On Thu, Nov 26, 2015 at 05:27:01PM +0100, Felix Fietkau wrote: > This reverts commit c6fc2171b249e73745c497b578b417a2946f1b2f. > > This commit is breaking read access on at least s25fl064k, but also > possibly other Spansion flash chips. This makes no sense. This patch is about Winbond flash, but you're referencing Spansion flash in the commit subject. I suspect you have either some more explaining, or some better investigation to do, because I don't understand how the commit in question could be the problem for you. > Any mtd read seems to succeed, but simply returns a zero-filled buffer. If this is the symptom you're looking at, I doubt you have the right fix. Wild guess: something similar to this patch: http://patchwork.ozlabs.org/patch/547367/ "mtd: spi-nor: wait until lock/unlock operations are ready" Brian > Signed-off-by: Felix Fietkau > --- > drivers/mtd/spi-nor/spi-nor.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c > index 4988390..8b8842e 100644 > --- a/drivers/mtd/spi-nor/spi-nor.c > +++ b/drivers/mtd/spi-nor/spi-nor.c > @@ -1194,14 +1194,13 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode) > mutex_init(&nor->lock); > > /* > - * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up > - * with the software protection bits set > + * Atmel, SST and Intel/Numonyx serial nor tend to power > + * up with the software protection bits set > */ > > if (JEDEC_MFR(info) == SNOR_MFR_ATMEL || > JEDEC_MFR(info) == SNOR_MFR_INTEL || > - JEDEC_MFR(info) == SNOR_MFR_SST || > - JEDEC_MFR(info) == SNOR_MFR_WINBOND) { > + JEDEC_MFR(info) == SNOR_MFR_SST) { > write_enable(nor); > write_sr(nor, 0); > } > -- > 2.2.2 >