Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758523AbcDADbS (ORCPT ); Thu, 31 Mar 2016 23:31:18 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:53279 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756307AbcDADbR (ORCPT ); Thu, 31 Mar 2016 23:31:17 -0400 Subject: Re: [PATCH 2/2] gpiolib: Defer gpio device setup until after gpiolib initialization To: Greg Ungerer References: <1459437090-10029-1-git-send-email-linux@roeck-us.net> <1459437090-10029-2-git-send-email-linux@roeck-us.net> <56FDC0D7.5040101@westnet.com.au> <20160401005301.GA17066@roeck-us.net> <56FDCFDF.2090107@westnet.com.au> Cc: Linus Walleij , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Alexandre Courbot , Greg Ungerer From: Guenter Roeck Message-ID: <56FDEB84.7090006@roeck-us.net> Date: Thu, 31 Mar 2016 20:31:16 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <56FDCFDF.2090107@westnet.com.au> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9350 Lines: 255 On 03/31/2016 06:33 PM, Greg Ungerer wrote: > On 01/04/16 10:53, Guenter Roeck wrote: >> On Fri, Apr 01, 2016 at 10:29:11AM +1000, Greg Ungerer wrote: >>> Hi Guenter, >>> >>> On 01/04/16 01:11, Guenter Roeck wrote: >>>> Since commit ff2b13592299 ("gpio: make the gpiochip a real device"), >>>> attempts to add a gpio chip prior to gpiolib initialization cause >>>> the system to crash. This happens because gpio_bus_type has not been >>>> registered yet. Defer creating gpio devices until after gpiolib has >>>> been initialized to fix the problem. >>>> >>>> Cc: Greg Ungerer >>>> Cc: Alexandre Courbot >>>> Fixes: ff2b13592299 ("gpio: make the gpiochip a real device") >>>> Signed-off-by: Guenter Roeck >>> >>> Thanks for putting these patches together. >>> I can now boot all my boards again with them applied :-) >>> >>> But, I am seeing an issue on one of my targets during boot: >>> >>> ... >>> Mount-cache hash table entries: 2048 (order: 0, 8192 bytes) >>> Mountpoint-cache hash table entries: 2048 (order: 0, 8192 bytes) >>> clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns >>> ------------[ cut here ]------------ >>> WARNING: CPU: 0 PID: 1 at fs/sysfs/dir.c:31 0x000da0e6 >>> sysfs: cannot create duplicate filename '/bus/gpio' >>> Modules linked in: >>> CPU: 0 PID: 1 Comm: swapper Not tainted 4.6.0-rc1-dirty #1 >>> Stack from 0383de38: >>> 0383de38 0021f692 00027eb0 03841000 002134f2 038261b0 0382f688 00111c1e >>> 00027efe 0021ccc4 0000001f 000da0e6 00000009 00000000 0383de74 0021cc91 >>> 0383de90 0383df8c 000da0e6 0021ccc4 0000001f 0021cc91 03841000 002134f2 >>> 038261b0 0382f688 00000000 000da1f0 038261b0 002134f2 0382f688 0382f688 >>> 00111d86 0382f688 00000000 0382f688 0382f688 0382f680 0024fe84 0002118e >>> 0383df8c 0382f688 00112094 0382f688 00000000 0013f5dc 0382f680 00000001 >>> Call Trace: >>> ... >>> ---[ end trace 013025e2024d8831 ]--- >>> ------------[ cut here ]------------ >>> WARNING: CPU: 0 PID: 1 at lib/kobject.c:240 0x00111fc0 >>> kobject_add_internal failed for gpio with -EEXIST, don't try to register things with the same name in the same directory. >>> Modules linked in: >>> CPU: 0 PID: 1 Comm: swapper Tainted: G W 4.6.0-rc1-dirty #1 >>> Stack from 0383de68: >>> 0383de68 0021f692 00027eb0 ffffffef 0382f688 00000000 0382f688 00111a26 >>> 00027efe 0021f817 000000f0 00111fc0 00000009 00000000 0383dea4 0021f8cd >>> 0383dec0 0383df8c 00111fc0 0021f817 000000f0 0021f8cd 002069e9 002134f2 >>> 0382f688 0382f680 0024fe84 0002118e 0383df8c 0382f688 00112094 0382f688 >>> 00000000 0013f5dc 0382f680 00000001 0000001f 002600de 00265950 0002118e >>> 0383df8c 002600f2 0024fe84 00000001 002600de 00265950 0002118e 00021274 >>> Call Trace: >>> ... >>> ---[ end trace 013025e2024d8832 ]--- >>> gpiolib: could not register GPIO bus type >>> NET: Registered protocol family 16 >> >> Probably coldfire ? >> >> arch/m68k/coldfire/gpio.c: > > Yes, that is the one. > > >> static struct bus_type mcfgpio_subsys = { >> .name = "gpio", >> .dev_name = "gpio", >> }; >> >> No idea what to do about that. Can that bus be renamed ? > > Yeah, it could. But is it even necessary at all now? > > I am thinking I could remove the subsys_system_register(&mcfgpio_subsys, NULL) > call from that coldfire/gpio.c. Doing that certainly cleans up the > boot. There was nothing much under the old coldfire /sys/gpio other than > the standard devices/drivers/etc. And the new gpio api ofcourse has all > that as well. > Sure, if that works for you. Guenter > Regards > Greg > > >>> The boot otherwise continues and is successful. >>> >> Thanks for testing! >> >> Guenter >> >>> Regards >>> Greg >>> >>> >>>> --- >>>> drivers/gpio/gpiolib.c | 98 ++++++++++++++++++++++++++++++++++---------------- >>>> 1 file changed, 67 insertions(+), 31 deletions(-) >>>> >>>> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c >>>> index f1531070814d..8bb24dc8dc3d 100644 >>>> --- a/drivers/gpio/gpiolib.c >>>> +++ b/drivers/gpio/gpiolib.c >>>> @@ -68,6 +68,7 @@ LIST_HEAD(gpio_devices); >>>> static void gpiochip_free_hogs(struct gpio_chip *chip); >>>> static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip); >>>> >>>> +static bool gpiolib_initialized; >>>> >>>> static inline void desc_set_label(struct gpio_desc *d, const char *label) >>>> { >>>> @@ -445,6 +446,58 @@ static void gpiodevice_release(struct device *dev) >>>> kfree(gdev); >>>> } >>>> >>>> +static int gpiochip_setup_dev(struct gpio_device *gdev) >>>> +{ >>>> + int status; >>>> + >>>> + cdev_init(&gdev->chrdev, &gpio_fileops); >>>> + gdev->chrdev.owner = THIS_MODULE; >>>> + gdev->chrdev.kobj.parent = &gdev->dev.kobj; >>>> + gdev->dev.devt = MKDEV(MAJOR(gpio_devt), gdev->id); >>>> + status = cdev_add(&gdev->chrdev, gdev->dev.devt, 1); >>>> + if (status < 0) >>>> + chip_warn(gdev->chip, "failed to add char device %d:%d\n", >>>> + MAJOR(gpio_devt), gdev->id); >>>> + else >>>> + chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", >>>> + MAJOR(gpio_devt), gdev->id); >>>> + status = device_add(&gdev->dev); >>>> + if (status) >>>> + goto err_remove_chardev; >>>> + >>>> + status = gpiochip_sysfs_register(gdev); >>>> + if (status) >>>> + goto err_remove_device; >>>> + >>>> + /* From this point, the .release() function cleans up gpio_device */ >>>> + gdev->dev.release = gpiodevice_release; >>>> + get_device(&gdev->dev); >>>> + pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n", >>>> + __func__, gdev->base, gdev->base + gdev->ngpio - 1, >>>> + dev_name(&gdev->dev), gdev->chip->label ? : "generic"); >>>> + >>>> + return 0; >>>> + >>>> +err_remove_device: >>>> + device_del(&gdev->dev); >>>> +err_remove_chardev: >>>> + cdev_del(&gdev->chrdev); >>>> + return status; >>>> +} >>>> + >>>> +static void gpiochip_setup_devs(void) >>>> +{ >>>> + struct gpio_device *gdev; >>>> + int err; >>>> + >>>> + list_for_each_entry(gdev, &gpio_devices, list) { >>>> + err = gpiochip_setup_dev(gdev); >>>> + if (err) >>>> + pr_err("%s: Failed to initialize gpio device (%d)\n", >>>> + dev_name(&gdev->dev), err); >>>> + } >>>> +} >>>> + >>>> /** >>>> * gpiochip_add_data() - register a gpio_chip >>>> * @chip: the chip to register, with chip->base initialized >>>> @@ -459,6 +512,9 @@ static void gpiodevice_release(struct device *dev) >>>> * the gpio framework's arch_initcall(). Otherwise sysfs initialization >>>> * for GPIOs will fail rudely. >>>> * >>>> + * gpiochip_add_data() must only be called after gpiolib initialization, >>>> + * ie after core_initcall(). >>>> + * >>>> * If chip->base is negative, this requests dynamic assignment of >>>> * a range of valid GPIOs. >>>> */ >>>> @@ -515,7 +571,7 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data) >>>> if (chip->ngpio == 0) { >>>> chip_err(chip, "tried to insert a GPIO chip with zero lines\n"); >>>> status = -EINVAL; >>>> - goto err_free_gdev; >>>> + goto err_free_descs; >>>> } >>>> >>>> if (chip->label) >>>> @@ -597,39 +653,16 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data) >>>> * we get a device node entry in sysfs under >>>> * /sys/bus/gpio/devices/gpiochipN/dev that can be used for >>>> * coldplug of device nodes and other udev business. >>>> + * We can do this only if gpiolib has been initialized. >>>> + * Otherwise, defer until later. >>>> */ >>>> - cdev_init(&gdev->chrdev, &gpio_fileops); >>>> - gdev->chrdev.owner = THIS_MODULE; >>>> - gdev->chrdev.kobj.parent = &gdev->dev.kobj; >>>> - gdev->dev.devt = MKDEV(MAJOR(gpio_devt), gdev->id); >>>> - status = cdev_add(&gdev->chrdev, gdev->dev.devt, 1); >>>> - if (status < 0) >>>> - chip_warn(chip, "failed to add char device %d:%d\n", >>>> - MAJOR(gpio_devt), gdev->id); >>>> - else >>>> - chip_dbg(chip, "added GPIO chardev (%d:%d)\n", >>>> - MAJOR(gpio_devt), gdev->id); >>>> - status = device_add(&gdev->dev); >>>> - if (status) >>>> - goto err_remove_chardev; >>>> - >>>> - status = gpiochip_sysfs_register(gdev); >>>> - if (status) >>>> - goto err_remove_device; >>>> - >>>> - /* From this point, the .release() function cleans up gpio_device */ >>>> - gdev->dev.release = gpiodevice_release; >>>> - get_device(&gdev->dev); >>>> - pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n", >>>> - __func__, gdev->base, gdev->base + gdev->ngpio - 1, >>>> - dev_name(&gdev->dev), chip->label ? : "generic"); >>>> - >>>> + if (gpiolib_initialized) { >>>> + status = gpiochip_setup_dev(gdev); >>>> + if (status) >>>> + goto err_remove_chip; >>>> + } >>>> return 0; >>>> >>>> -err_remove_device: >>>> - device_del(&gdev->dev); >>>> -err_remove_chardev: >>>> - cdev_del(&gdev->chrdev); >>>> err_remove_chip: >>>> acpi_gpiochip_remove(chip); >>>> gpiochip_free_hogs(chip); >>>> @@ -2834,6 +2867,9 @@ static int __init gpiolib_dev_init(void) >>>> if (ret < 0) { >>>> pr_err("gpiolib: failed to allocate char dev region\n"); >>>> bus_unregister(&gpio_bus_type); >>>> + } else { >>>> + gpiolib_initialized = true; >>>> + gpiochip_setup_devs(); >>>> } >>>> return ret; >>>> } >>>> >>> >> > >