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Fri, 12 Jun 2020 01:23:31 -0700 (PDT) Received: from pi3 ([194.230.155.184]) by smtp.googlemail.com with ESMTPSA id g22sm2797843edj.63.2020.06.12.01.23.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Jun 2020 01:23:29 -0700 (PDT) Date: Fri, 12 Jun 2020 10:23:27 +0200 From: Krzysztof Kozlowski To: Oleksij Rempel Subject: Re: [PATCH] i2c: imx: Fix external abort on early interrupt Message-ID: <20200612082327.GA25893@pi3> References: <1591796802-23504-1-git-send-email-krzk@kernel.org> <20200612055114.alhm2uakoze6epvf@pengutronix.de> <20200612073815.GA25803@pi3> <20200612080240.73xkiu2esgg6nbp3@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200612080240.73xkiu2esgg6nbp3@pengutronix.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200612_012332_718613_8EE2C353 X-CRM114-Status: GOOD ( 22.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fugang Duan , Fabio Estevam , Sascha Hauer , linux-kernel@vger.kernel.org, Gao Pan , Oleksij Rempel , Wolfram Sang , NXP Linux Team , Pengutronix Kernel Team , stable@vger.kernel.org, Shawn Guo , linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jun 12, 2020 at 10:02:40AM +0200, Oleksij Rempel wrote: > On Fri, Jun 12, 2020 at 09:38:15AM +0200, Krzysztof Kozlowski wrote: > > On Fri, Jun 12, 2020 at 07:51:14AM +0200, Oleksij Rempel wrote: > > > Hi Krzysztof, > > > > > > thank you for your patch. > > > > > > On Wed, Jun 10, 2020 at 03:46:42PM +0200, Krzysztof Kozlowski wrote: > > > > If interrupt comes early (could be triggered with CONFIG_DEBUG_SHIRQ), > > > > the i2c_imx_isr() will access registers before the I2C hardware is > > > > initialized. This leads to external abort on non-linefetch on Toradex > > > > Colibri VF50 module (with Vybrid VF5xx): > > > > > > > > Unhandled fault: external abort on non-linefetch (0x1008) at 0x8882d003 > > > > Internal error: : 1008 [#1] ARM > > > > Modules linked in: > > > > CPU: 0 PID: 1 Comm: swapper Not tainted 5.7.0 #607 > > > > Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree) > > > > (i2c_imx_isr) from [<8017009c>] (free_irq+0x25c/0x3b0) > > > > (free_irq) from [<805844ec>] (release_nodes+0x178/0x284) > > > > (release_nodes) from [<80580030>] (really_probe+0x10c/0x348) > > > > (really_probe) from [<80580380>] (driver_probe_device+0x60/0x170) > > > > (driver_probe_device) from [<80580630>] (device_driver_attach+0x58/0x60) > > > > (device_driver_attach) from [<805806bc>] (__driver_attach+0x84/0xc0) > > > > (__driver_attach) from [<8057e228>] (bus_for_each_dev+0x68/0xb4) > > > > (bus_for_each_dev) from [<8057f3ec>] (bus_add_driver+0x144/0x1ec) > > > > (bus_add_driver) from [<80581320>] (driver_register+0x78/0x110) > > > > (driver_register) from [<8010213c>] (do_one_initcall+0xa8/0x2f4) > > > > (do_one_initcall) from [<80c0100c>] (kernel_init_freeable+0x178/0x1dc) > > > > (kernel_init_freeable) from [<80807048>] (kernel_init+0x8/0x110) > > > > (kernel_init) from [<80100114>] (ret_from_fork+0x14/0x20) > > > > > > > > Additionally, the i2c_imx_isr() could wake up the wait queue > > > > (imx_i2c_struct->queue) before its initialization happens. > > > > > > > > Fixes: 1c4b6c3bcf30 ("i2c: imx: implement bus recovery") > > > > Cc: > > > > Signed-off-by: Krzysztof Kozlowski > > > > > > > > > I assume register access is aborted, because the IP core clock is not > > > enabled. In this case we have bigger problem then just probe. > > > > If by IP core clock you mean the clock which driver is getting, then > > answer is no. This clock is enabled. > > > > > Since this driver support runtime power management, the clock will be > > > disabled as soon as transfer is done. It means, on shared interrupt, we > > > will get in trouble even if there is no active transfer. > > > > The driver's runtime PM plays only with this one clock, so it seems > > you meant i2c_imx->clk. It is not this problem. > > > > > > > > So, probably the only way to fix it, is to check in i2c_imx_isr() if the > > > HW is expected to be active and register access should be save. > > > > Checking in every interrupt whether the interrupt should be serviced > > based on some SW flag because HW might be disabled? That looks unusual, > > like a hack. > > > > No, the interrupt should be registered when the driver and some other > > pieces of HW are ready to service it. > > OK. > please make sure, irq is probed before calling > i2c_add_numbered_adapter(). This will trigger deferred probing of > slave devices. Since the irq handler will be added later, tx completion > of some requests will be lost or fail. Right. I'll move the devm_request_irq(). Best regards, Krzysztof _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel