--- /dev/null
+From cff179ff275e8f7849384ad2876c9a3237eeac79 Mon Sep 17 00:00:00 2001
+From: Luke Wren <luke@raspberrypi.org>
+Date: Fri, 21 Aug 2015 23:14:48 +0100
+Subject: [PATCH] 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 | 258 ++++++++++++++++++++++++
+ 3 files changed, 270 insertions(+)
+ create mode 100644 drivers/char/broadcom/bcm2835-gpiomem.c
+
+--- a/drivers/char/broadcom/Kconfig
++++ b/drivers/char/broadcom/Kconfig
+@@ -26,3 +26,12 @@ 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
+@@ -1,2 +1,5 @@
+ 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 +1,258 @@
++/**
++ * 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;
++
++ 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>");
projects / openwrt / staging / chunkeey.git / blobdiff