From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@free-electrons.com (Boris Brezillon) Date: Tue, 26 Apr 2016 19:30:02 +0200 Subject: [PATCH v2] gpmi-nand: Handle ECC Errors in erased pages In-Reply-To: <1461587712-16403-1-git-send-email-mpa@pengutronix.de> References: <1461587712-16403-1-git-send-email-mpa@pengutronix.de> Message-ID: <20160426193002.187aefc2@bbrezillon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 25 Apr 2016 14:35:12 +0200 Markus Pargmann wrote: > ECC is only calculated for written pages. As erased pages are not > actively written the ECC is always invalid. For this purpose the > Hardware BCH unit is able to check for erased pages and does not raise > an ECC error in this case. This behaviour can be influenced using the > BCH_MODE register which sets the number of allowed bitflips in an erased > page. Unfortunately the unit is not capable of fixing the bitflips in > memory. > > To avoid complete software checks for erased pages, we can simply check > buffers with uncorrectable ECC errors because we know that any erased > page with errors is uncorrectable by the BCH unit. > > This patch adds the generic nand_check_erased_ecc_chunk() to gpmi-nand > to correct erased pages. To have the valid data in the buffer before > using them, this patch moves the read_page_swap_end() call before the > ECC status checking for-loop. > > Signed-off-by: Markus Pargmann > [Squashed patches by Stefan and Boris to check ECC area] > Cc: Stefan Christ > Cc: Boris Brezillon > > Signed-off-by: Markus Pargmann > --- Applied, thanks. Boris -- Boris Brezillon, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com