From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v3 4/6] mtd: rawnand: add NVIDIA Tegra NAND Flash controller driver Date: Sat, 9 Jun 2018 07:52:56 +0200 Message-ID: <20180609075256.725354d6@bbrezillon> References: <20180531221637.6017-1-stefan@agner.ch> <20180531221637.6017-5-stefan@agner.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Stefan Agner Cc: Dmitry Osipenko , dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com, robh+dt@kernel.org, mark.rutland@arm.com, thierry.reding@gmail.com, dev@lynxeye.de, miquel.raynal@bootlin.com, richard@nod.at, marcel@ziswiler.com, krzk@kernel.org, benjamin.lindqvist@endian.se, jonathanh@nvidia.com, pdeschrijver@nvidia.com, pgaikwad@nvidia.com, mirza.krak@gmail.com, linux-mtd@lists.infradead.org, linux-tegra@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org On Fri, 08 Jun 2018 23:51:01 +0200 Stefan Agner wrote: > > > > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl) > > { > > int err; > > > > disable_irq(ctrl->irq); > > > > err = reset_control_reset(ctrl->rst); > > if (err) { > > dev_err(ctrl->dev, "Failed to reset HW: %d\n", err); > > msleep(HW_TIMEOUT); > > } > > > > writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD); > > writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK); > > writel_relaxed(INT_MASK, ctrl->regs + ISR); > > If we do a controller reset, there is much more state than that which > needs to be restored. A lot of it is not readily available currently > (timing, ECC settings...) This is actually a good test to detect what is not properly initialized by the driver. Timings should be configured correctly through ->setup_data_interface(). ECC engine should be disabled by default and only enabled when ->{read,write}_page() is called. > > That seems a lot of work for a code path I do not intend to ever use :-) > Not so sure it's a lot of work. If ECC and timing settings are the only thing you need to initialize then it should work just fine. Try with a controller reset and you'll know if you miss something ;-).