diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0040-Add-dev-gpiomem-device-for-rootless-user-GPIO-access.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0040-Add-dev-gpiomem-device-for-rootless-user-GPIO-access.patch | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0040-Add-dev-gpiomem-device-for-rootless-user-GPIO-access.patch b/target/linux/brcm2708/patches-4.4/0040-Add-dev-gpiomem-device-for-rootless-user-GPIO-access.patch new file mode 100644 index 0000000000..cf964e1b8f --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0040-Add-dev-gpiomem-device-for-rootless-user-GPIO-access.patch @@ -0,0 +1,306 @@ +From 6ddd3a6f0a8a3e4506b4fe4e1b410d9d945c5df2 Mon Sep 17 00:00:00 2001 +From: Luke Wren <luke@raspberrypi.org> +Date: Fri, 21 Aug 2015 23:14:48 +0100 +Subject: [PATCH 040/127] Add /dev/gpiomem device for rootless user GPIO access + +Signed-off-by: Luke Wren <luke@raspberrypi.org> + +bcm2835-gpiomem: Fix for ARCH_BCM2835 builds + +Build on ARCH_BCM2835, and fail to probe if no IO resource. + +See: https://github.com/raspberrypi/linux/issues/1154 +--- + drivers/char/broadcom/Kconfig | 9 ++ + drivers/char/broadcom/Makefile | 3 + + drivers/char/broadcom/bcm2835-gpiomem.c | 260 ++++++++++++++++++++++++++++++++ + 3 files changed, 272 insertions(+) + create mode 100644 drivers/char/broadcom/bcm2835-gpiomem.c + +--- a/drivers/char/broadcom/Kconfig ++++ b/drivers/char/broadcom/Kconfig +@@ -32,3 +32,12 @@ config BCM_VC_SM + help + Support for the VC shared memory on the Broadcom reference + design. Uses the VCHIQ stack. ++ ++config BCM2835_DEVGPIOMEM ++ tristate "/dev/gpiomem rootless GPIO access via mmap() on the BCM2835" ++ default m ++ help ++ Provides users with root-free access to the GPIO registers ++ on the 2835. Calling mmap(/dev/gpiomem) will map the GPIO ++ register page to the user's pointer. ++ +--- a/drivers/char/broadcom/Makefile ++++ b/drivers/char/broadcom/Makefile +@@ -1,3 +1,6 @@ + obj-$(CONFIG_BCM_VC_CMA) += vc_cma/ + obj-$(CONFIG_BCM2708_VCMEM) += vc_mem.o + obj-$(CONFIG_BCM_VC_SM) += vc_sm/ ++ ++obj-$(CONFIG_BCM2835_DEVGPIOMEM)+= bcm2835-gpiomem.o ++ +--- /dev/null ++++ b/drivers/char/broadcom/bcm2835-gpiomem.c +@@ -0,0 +1,260 @@ ++/** ++ * GPIO memory device driver ++ * ++ * Creates a chardev /dev/gpiomem which will provide user access to ++ * the BCM2835's GPIO registers when it is mmap()'d. ++ * No longer need root for user GPIO access, but without relaxing permissions ++ * on /dev/mem. ++ * ++ * Written by Luke Wren <luke@raspberrypi.org> ++ * Copyright (c) 2015, Raspberry Pi (Trading) Ltd. ++ * ++ * Redistribution and use in source and binary forms, with or without ++ * modification, are permitted provided that the following conditions ++ * are met: ++ * 1. Redistributions of source code must retain the above copyright ++ * notice, this list of conditions, and the following disclaimer, ++ * without modification. ++ * 2. Redistributions in binary form must reproduce the above copyright ++ * notice, this list of conditions and the following disclaimer in the ++ * documentation and/or other materials provided with the distribution. ++ * 3. The names of the above-listed copyright holders may not be used ++ * to endorse or promote products derived from this software without ++ * specific prior written permission. ++ * ++ * ALTERNATIVELY, this software may be distributed under the terms of the ++ * GNU General Public License ("GPL") version 2, as published by the Free ++ * Software Foundation. ++ * ++ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS ++ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, ++ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR ++ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR ++ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, ++ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, ++ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR ++ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ++ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING ++ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS ++ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ++ */ ++ ++#include <linux/kernel.h> ++#include <linux/module.h> ++#include <linux/of.h> ++#include <linux/platform_device.h> ++#include <linux/mm.h> ++#include <linux/slab.h> ++#include <linux/cdev.h> ++#include <linux/pagemap.h> ++#include <linux/io.h> ++ ++#define DEVICE_NAME "bcm2835-gpiomem" ++#define DRIVER_NAME "gpiomem-bcm2835" ++#define DEVICE_MINOR 0 ++ ++struct bcm2835_gpiomem_instance { ++ unsigned long gpio_regs_phys; ++ struct device *dev; ++}; ++ ++static struct cdev bcm2835_gpiomem_cdev; ++static dev_t bcm2835_gpiomem_devid; ++static struct class *bcm2835_gpiomem_class; ++static struct device *bcm2835_gpiomem_dev; ++static struct bcm2835_gpiomem_instance *inst; ++ ++ ++/**************************************************************************** ++* ++* GPIO mem chardev file ops ++* ++***************************************************************************/ ++ ++static int bcm2835_gpiomem_open(struct inode *inode, struct file *file) ++{ ++ int dev = iminor(inode); ++ int ret = 0; ++ ++ dev_info(inst->dev, "gpiomem device opened."); ++ ++ if (dev != DEVICE_MINOR) { ++ dev_err(inst->dev, "Unknown minor device: %d", dev); ++ ret = -ENXIO; ++ } ++ return ret; ++} ++ ++static int bcm2835_gpiomem_release(struct inode *inode, struct file *file) ++{ ++ int dev = iminor(inode); ++ int ret = 0; ++ ++ if (dev != DEVICE_MINOR) { ++ dev_err(inst->dev, "Unknown minor device %d", dev); ++ ret = -ENXIO; ++ } ++ return ret; ++} ++ ++static const struct vm_operations_struct bcm2835_gpiomem_vm_ops = { ++#ifdef CONFIG_HAVE_IOREMAP_PROT ++ .access = generic_access_phys ++#endif ++}; ++ ++static int bcm2835_gpiomem_mmap(struct file *file, struct vm_area_struct *vma) ++{ ++ /* Ignore what the user says - they're getting the GPIO regs ++ whether they like it or not! */ ++ unsigned long gpio_page = inst->gpio_regs_phys >> PAGE_SHIFT; ++ ++ vma->vm_page_prot = phys_mem_access_prot(file, gpio_page, ++ PAGE_SIZE, ++ vma->vm_page_prot); ++ vma->vm_ops = &bcm2835_gpiomem_vm_ops; ++ if (remap_pfn_range(vma, vma->vm_start, ++ gpio_page, ++ PAGE_SIZE, ++ vma->vm_page_prot)) { ++ return -EAGAIN; ++ } ++ return 0; ++} ++ ++static const struct file_operations ++bcm2835_gpiomem_fops = { ++ .owner = THIS_MODULE, ++ .open = bcm2835_gpiomem_open, ++ .release = bcm2835_gpiomem_release, ++ .mmap = bcm2835_gpiomem_mmap, ++}; ++ ++ ++ /**************************************************************************** ++* ++* Probe and remove functions ++* ++***************************************************************************/ ++ ++ ++static int bcm2835_gpiomem_probe(struct platform_device *pdev) ++{ ++ int err; ++ void *ptr_err; ++ struct device *dev = &pdev->dev; ++ struct resource *ioresource; ++ ++ /* Allocate buffers and instance data */ ++ ++ inst = kzalloc(sizeof(struct bcm2835_gpiomem_instance), GFP_KERNEL); ++ ++ if (!inst) { ++ err = -ENOMEM; ++ goto failed_inst_alloc; ++ } ++ ++ inst->dev = dev; ++ ++ ioresource = platform_get_resource(pdev, IORESOURCE_MEM, 0); ++ if (ioresource) { ++ inst->gpio_regs_phys = ioresource->start; ++ } else { ++ dev_err(inst->dev, "failed to get IO resource"); ++ err = -ENOENT; ++ goto failed_get_resource; ++ } ++ ++ /* Create character device entries */ ++ ++ err = alloc_chrdev_region(&bcm2835_gpiomem_devid, ++ DEVICE_MINOR, 1, DEVICE_NAME); ++ if (err != 0) { ++ dev_err(inst->dev, "unable to allocate device number"); ++ goto failed_alloc_chrdev; ++ } ++ cdev_init(&bcm2835_gpiomem_cdev, &bcm2835_gpiomem_fops); ++ bcm2835_gpiomem_cdev.owner = THIS_MODULE; ++ err = cdev_add(&bcm2835_gpiomem_cdev, bcm2835_gpiomem_devid, 1); ++ if (err != 0) { ++ dev_err(inst->dev, "unable to register device"); ++ goto failed_cdev_add; ++ } ++ ++ /* Create sysfs entries */ ++ ++ bcm2835_gpiomem_class = class_create(THIS_MODULE, DEVICE_NAME); ++ ptr_err = bcm2835_gpiomem_class; ++ if (IS_ERR(ptr_err)) ++ goto failed_class_create; ++ ++ bcm2835_gpiomem_dev = device_create(bcm2835_gpiomem_class, NULL, ++ bcm2835_gpiomem_devid, NULL, ++ "gpiomem"); ++ ptr_err = bcm2835_gpiomem_dev; ++ if (IS_ERR(ptr_err)) ++ goto failed_device_create; ++ ++ dev_info(inst->dev, "Initialised: Registers at 0x%08lx", ++ inst->gpio_regs_phys); ++ ++ return 0; ++ ++failed_device_create: ++ class_destroy(bcm2835_gpiomem_class); ++failed_class_create: ++ cdev_del(&bcm2835_gpiomem_cdev); ++ err = PTR_ERR(ptr_err); ++failed_cdev_add: ++ unregister_chrdev_region(bcm2835_gpiomem_devid, 1); ++failed_alloc_chrdev: ++failed_get_resource: ++ kfree(inst); ++failed_inst_alloc: ++ dev_err(inst->dev, "could not load bcm2835_gpiomem"); ++ return err; ++} ++ ++static int bcm2835_gpiomem_remove(struct platform_device *pdev) ++{ ++ struct device *dev = inst->dev; ++ ++ kfree(inst); ++ device_destroy(bcm2835_gpiomem_class, bcm2835_gpiomem_devid); ++ class_destroy(bcm2835_gpiomem_class); ++ cdev_del(&bcm2835_gpiomem_cdev); ++ unregister_chrdev_region(bcm2835_gpiomem_devid, 1); ++ ++ dev_info(dev, "GPIO mem driver removed - OK"); ++ return 0; ++} ++ ++ /**************************************************************************** ++* ++* Register the driver with device tree ++* ++***************************************************************************/ ++ ++static const struct of_device_id bcm2835_gpiomem_of_match[] = { ++ {.compatible = "brcm,bcm2835-gpiomem",}, ++ { /* sentinel */ }, ++}; ++ ++MODULE_DEVICE_TABLE(of, bcm2835_gpiomem_of_match); ++ ++static struct platform_driver bcm2835_gpiomem_driver = { ++ .probe = bcm2835_gpiomem_probe, ++ .remove = bcm2835_gpiomem_remove, ++ .driver = { ++ .name = DRIVER_NAME, ++ .owner = THIS_MODULE, ++ .of_match_table = bcm2835_gpiomem_of_match, ++ }, ++}; ++ ++module_platform_driver(bcm2835_gpiomem_driver); ++ ++MODULE_ALIAS("platform:gpiomem-bcm2835"); ++MODULE_LICENSE("GPL"); ++MODULE_DESCRIPTION("gpiomem driver for accessing GPIO from userspace"); ++MODULE_AUTHOR("Luke Wren <luke@raspberrypi.org>"); |