From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dinh Nguyen Subject: Re: [PATCH V2] net: stmmac: socfpga: Remove re-registration of reset controller Date: Tue, 19 Apr 2016 21:04:14 -0500 Message-ID: <5716E39E.3010905@opensource.altera.com> References: <1461110753-7641-1-git-send-email-marex@denx.de> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Cc: , , Matthew Gerlach , "David S . Miller" To: Marek Vasut , Return-path: Received: from mail-bl2on0093.outbound.protection.outlook.com ([65.55.169.93]:55017 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751723AbcDTChR (ORCPT ); Tue, 19 Apr 2016 22:37:17 -0400 In-Reply-To: <1461110753-7641-1-git-send-email-marex@denx.de> Sender: netdev-owner@vger.kernel.org List-ID: On 04/19/2016 07:05 PM, Marek Vasut wrote: > Both socfpga_dwmac_parse_data() in dwmac-socfpga.c and stmmac_dvr_probe() > in stmmac_main.c functions call devm_reset_control_get() to register an > reset controller for the stmmac. This results in an attempt to register > two reset controllers for the same non-shared reset line. > > The first attempt to register the reset controller works fine. The second > attempt fails with warning from the reset controller core, see below. > The warning is produced because the reset line is non-shared and thus > it is allowed to have only up-to one reset controller associated with > that reset line, not two or more. > > The solution is not great. Since the hardware needs to toggle the reset > before calling stmmac_dvr_probe() to perform mandatory preconfiguration, > this patch splits socfpga_dwmac_init_probe() from socfpga_dwmac_init(). > > The socfpga_dwmac_init_probe() temporarily registers the reset controller, > performs the pre-configuration and unregisters the reset controller again. > This function is only called from the socfpga_dwmac_probe(). > > The original socfpga_dwmac_init() is tweaked to use reset controller > pointer from the stmmac_priv (private data of the stmmac core) instead > of the local instance, which was used before. > > Finally, plat_dat->exit and socfpga_dwmac_exit() is no longer necessary, > since the functionality is already performed by the stmmac core. > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 1 at drivers/reset/core.c:187 __of_reset_control_get+0x218/0x270 > Modules linked in: > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.6.0-rc4-next-20160419-00015-gabb2477-dirty #4 > Hardware name: Altera SOCFPGA > [] (unwind_backtrace) from [] (show_stack+0x10/0x14) > [] (show_stack) from [] (dump_stack+0x94/0xa8) > [] (dump_stack) from [] (__warn+0xec/0x104) > [] (__warn) from [] (warn_slowpath_null+0x20/0x28) > [] (warn_slowpath_null) from [] (__of_reset_control_get+0x218/0x270) > [] (__of_reset_control_get) from [] (__devm_reset_control_get+0x54/0x90) > [] (__devm_reset_control_get) from [] (stmmac_dvr_probe+0x1b4/0x8e8) > [] (stmmac_dvr_probe) from [] (socfpga_dwmac_probe+0x1b8/0x28c) > [] (socfpga_dwmac_probe) from [] (platform_drv_probe+0x4c/0xb0) > [] (platform_drv_probe) from [] (driver_probe_device+0x224/0x2bc) > [] (driver_probe_device) from [] (__driver_attach+0xac/0xb0) > [] (__driver_attach) from [] (bus_for_each_dev+0x6c/0xa0) > [] (bus_for_each_dev) from [] (bus_add_driver+0x1a4/0x21c) > [] (bus_add_driver) from [] (driver_register+0x78/0xf8) > [] (driver_register) from [] (do_one_initcall+0x40/0x170) > [] (do_one_initcall) from [] (kernel_init_freeable+0x1dc/0x27c) > [] (kernel_init_freeable) from [] (kernel_init+0x8/0x114) > [] (kernel_init) from [] (ret_from_fork+0x14/0x3c) > ---[ end trace 059d2fbe87608fa9 ]--- > Odd, I hadn't seen this error before. I would have noticed it, but I haven't ran linux-next for a few days. I see that this error was introduced on linux-next/next-20160414. The error was not there prior to that. While I agree that the extra call to get the reset control is not needed, I wonder what commit between next-20160413 and next-20160414 exposed this error. I'll try to dig this some more. Dinh