Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752936AbdI0PIR (ORCPT ); Wed, 27 Sep 2017 11:08:17 -0400 Received: from mail.free-electrons.com ([62.4.15.54]:40087 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752445AbdI0PIO (ORCPT ); Wed, 27 Sep 2017 11:08:14 -0400 Date: Wed, 27 Sep 2017 17:08:11 +0200 From: Boris Brezillon To: Romain Izard Cc: Michael Turquette , Stephen Boyd , Lee Jones , Wenyou Yang , Josh Wu , Richard Weinberger , David Woodhouse , Brian Norris , Marek Vasut , Cyrille Pitchen , Thierry Reding , Richard Genoud , Greg Kroah-Hartman , Jiri Slaby , Alan Stern , Ludovic Desroches , Nicolas Ferre , Alexandre Belloni , linux-pwm@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-serial@vger.kernel.org, linux-clk@vger.kernel.org Subject: Re: [PATCH v3 4/8] mtd: nand: atmel: Avoid ECC errors when leaving backup mode Message-ID: <20170927170811.57830c1f@bbrezillon> In-Reply-To: <20170927083555.16580-5-romain.izard.pro@gmail.com> References: <20170927083555.16580-1-romain.izard.pro@gmail.com> <20170927083555.16580-5-romain.izard.pro@gmail.com> X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2634 Lines: 63 On Wed, 27 Sep 2017 10:35:51 +0200 Romain Izard wrote: > During backup mode, the contents of all registers will be cleared as the > SoC will be completely powered down. For a product that boots on NAND > Flash memory, the bootloader will obviously use the related controller > to read the Flash and correct any detected error in the memory, before > handling back control to the kernel's resuming entry point. > > But it does not clean the NAND controller registers after use and on its > side the kernel driver expects the error locator to be powered down and > in a clean state. Add a resume hook for the PMECC error locator, and > reset its registers. > > Signed-off-by: Romain Izard > --- > Change in v3: > * keep the PMECC disabled when not in use, and use atmel_pmecc_resume to > reset the controller after the bootloader has left it enabled. > > drivers/mtd/nand/atmel/nand-controller.c | 3 +++ > drivers/mtd/nand/atmel/pmecc.c | 22 ++++++++++++++-------- > drivers/mtd/nand/atmel/pmecc.h | 1 + > 3 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/drivers/mtd/nand/atmel/nand-controller.c b/drivers/mtd/nand/atmel/nand-controller.c > index f25eca79f4e5..86c2199380c2 100644 > --- a/drivers/mtd/nand/atmel/nand-controller.c > +++ b/drivers/mtd/nand/atmel/nand-controller.c > @@ -2530,6 +2530,9 @@ static __maybe_unused int atmel_nand_controller_resume(struct device *dev) > struct atmel_nand_controller *nc = dev_get_drvdata(dev); > struct atmel_nand *nand; > > + if (nand->pmecc) > + atmel_pmecc_resume(nand->pmecc); > + nand is used uninitialized here, and atmel_pmecc_resume() should be passed a atmel_pmecc object not a atmel_pmecc_user. if (nc->pmecc) atmel_pmecc_resume(nc->pmecc); > list_for_each_entry(nand, &nc->chips, node) { > int i; > > diff --git a/drivers/mtd/nand/atmel/pmecc.c b/drivers/mtd/nand/atmel/pmecc.c > index 146af8218314..ff09c0f25dd4 100644 > --- a/drivers/mtd/nand/atmel/pmecc.c > +++ b/drivers/mtd/nand/atmel/pmecc.c > @@ -765,6 +765,12 @@ void atmel_pmecc_get_generated_eccbytes(struct atmel_pmecc_user *user, > } > EXPORT_SYMBOL_GPL(atmel_pmecc_get_generated_eccbytes); > > +void atmel_pmecc_reset(struct atmel_pmecc *pmecc) > +{ > + writel(PMECC_CTRL_RST, pmecc->regs.base + ATMEL_PMECC_CTRL); > + writel(PMECC_CTRL_DISABLE, pmecc->regs.base + ATMEL_PMECC_CTRL); > +} It's not used outside of this file, so it should have a static specifier. Anyway, I wonder why you don't expose atmel_pmecc_reset() directly instead of creating this atmel_pmecc_resume() wrapper.