From beafc54c4e2fba24e1ca45cdb7f79d9aa83e3db1 Mon Sep 17 00:00:00 2001 From: "Hans J. Koch" Date: Thu, 7 Dec 2006 10:58:29 +0100 Subject: [PATCH 1/3] UIO: Add the User IO core code This interface allows the ability to write the majority of a driver in userspace with only a very small shell of a driver in the kernel itself. It uses a char device and sysfs to interact with a userspace process to process interrupts and control memory accesses. See the docbook documentation for more details on how to use this interface. From: Hans J. Koch Cc: Thomas Gleixner Cc: Benedikt Spranger Signed-off-by: Greg Kroah-Hartman --- drivers/Kconfig | 1 + drivers/Makefile | 1 + drivers/uio/Kconfig | 16 + drivers/uio/Makefile | 1 + drivers/uio/uio.c | 701 +++++++++++++++++++++++++++++++++++++ include/linux/uio_driver.h | 91 +++++ 6 files changed, 811 insertions(+) create mode 100644 drivers/uio/Kconfig create mode 100644 drivers/uio/Makefile create mode 100644 drivers/uio/uio.c create mode 100644 include/linux/uio_driver.h diff --git a/drivers/Kconfig b/drivers/Kconfig index 7916f4b86d23..ae01d86070bb 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -84,4 +84,5 @@ source "drivers/auxdisplay/Kconfig" source "drivers/kvm/Kconfig" +source "drivers/uio/Kconfig" endmenu diff --git a/drivers/Makefile b/drivers/Makefile index 6d9d7fab77f5..c34c8efff609 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -40,6 +40,7 @@ obj-$(CONFIG_ATA) += ata/ obj-$(CONFIG_FUSION) += message/ obj-$(CONFIG_FIREWIRE) += firewire/ obj-$(CONFIG_IEEE1394) += ieee1394/ +obj-$(CONFIG_UIO) += uio/ obj-y += cdrom/ obj-y += auxdisplay/ obj-$(CONFIG_MTD) += mtd/ diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig new file mode 100644 index 000000000000..6b1a62d45e46 --- /dev/null +++ b/drivers/uio/Kconfig @@ -0,0 +1,16 @@ +menu "Userspace I/O" + depends on !S390 + +config UIO + tristate "Userspace I/O drivers" + default n + help + Enable this to allow the userspace driver core code to be + built. This code allows userspace programs easy access to + kernel interrupts and memory locations, allowing some drivers + to be written in userspace. Note that a small kernel driver + is also required for interrupt handling to work properly. + + If you don't know what to do here, say N. + +endmenu diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile new file mode 100644 index 000000000000..9b7c83063e15 --- /dev/null +++ b/drivers/uio/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_UIO) += uio.o diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c new file mode 100644 index 000000000000..865f32b63b5c --- /dev/null +++ b/drivers/uio/uio.c @@ -0,0 +1,701 @@ +/* + * drivers/uio/uio.c + * + * Copyright(C) 2005, Benedikt Spranger + * Copyright(C) 2005, Thomas Gleixner + * Copyright(C) 2006, Hans J. Koch + * Copyright(C) 2006, Greg Kroah-Hartman + * + * Userspace IO + * + * Base Functions + * + * Licensed under the GPLv2 only. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define UIO_MAX_DEVICES 255 + +struct uio_device { + struct module *owner; + struct device *dev; + int minor; + atomic_t event; + struct fasync_struct *async_queue; + wait_queue_head_t wait; + int vma_count; + struct uio_info *info; + struct kset map_attr_kset; +}; + +static int uio_major; +static DEFINE_IDR(uio_idr); +static struct file_operations uio_fops; + +/* UIO class infrastructure */ +static struct uio_class { + struct kref kref; + struct class *class; +} *uio_class; + +/* + * attributes + */ + +static struct attribute attr_addr = { + .name = "addr", + .mode = S_IRUGO, +}; + +static struct attribute attr_size = { + .name = "size", + .mode = S_IRUGO, +}; + +static struct attribute* map_attrs[] = { + &attr_addr, &attr_size, NULL +}; + +static ssize_t map_attr_show(struct kobject *kobj, struct attribute *attr, + char *buf) +{ + struct uio_mem *mem = container_of(kobj, struct uio_mem, kobj); + + if (strncmp(attr->name,"addr",4) == 0) + return sprintf(buf, "0x%lx\n", mem->addr); + + if (strncmp(attr->name,"size",4) == 0) + return sprintf(buf, "0x%lx\n", mem->size); + + return -ENODEV; +} + +static void map_attr_release(struct kobject *kobj) +{ + /* TODO ??? */ +} + +static struct sysfs_ops map_attr_ops = { + .show = map_attr_show, +}; + +static struct kobj_type map_attr_type = { + .release = map_attr_release, + .sysfs_ops = &map_attr_ops, + .default_attrs = map_attrs, +}; + +static ssize_t show_name(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct uio_device *idev = dev_get_drvdata(dev); + if (idev) + return sprintf(buf, "%s\n", idev->info->name); + else + return -ENODEV; +} +static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); + +static ssize_t show_version(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct uio_device *idev = dev_get_drvdata(dev); + if (idev) + return sprintf(buf, "%s\n", idev->info->version); + else + return -ENODEV; +} +static DEVICE_ATTR(version, S_IRUGO, show_version, NULL); + +static ssize_t show_event(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct uio_device *idev = dev_get_drvdata(dev); + if (idev) + return sprintf(buf, "%u\n", + (unsigned int)atomic_read(&idev->event)); + else + return -ENODEV; +} +static DEVICE_ATTR(event, S_IRUGO, show_event, NULL); + +static struct attribute *uio_attrs[] = { + &dev_attr_name.attr, + &dev_attr_version.attr, + &dev_attr_event.attr, + NULL, +}; + +static struct attribute_group uio_attr_grp = { + .attrs = uio_attrs, +}; + +/* + * device functions + */ +static int uio_dev_add_attributes(struct uio_device *idev) +{ + int ret; + int mi; + int map_found = 0; + struct uio_mem *mem; + + ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp); + if (ret) + goto err_group; + + for (mi = 0; mi < MAX_UIO_MAPS; mi++) { + mem = &idev->info->mem[mi]; + if (mem->size == 0) + break; + if (!map_found) { + map_found = 1; + kobject_set_name(&idev->map_attr_kset.kobj,"maps"); + idev->map_attr_kset.ktype = &map_attr_type; + idev->map_attr_kset.kobj.parent = &idev->dev->kobj; + ret = kset_register(&idev->map_attr_kset); + if (ret) + goto err_remove_group; + } + kobject_init(&mem->kobj); + kobject_set_name(&mem->kobj,"map%d",mi); + mem->kobj.parent = &idev->map_attr_kset.kobj; + mem->kobj.kset = &idev->map_attr_kset; + ret = kobject_add(&mem->kobj); + if (ret) + goto err_remove_maps; + } + + return 0; + +err_remove_maps: + for (mi--; mi>=0; mi--) { + mem = &idev->info->mem[mi]; + kobject_unregister(&mem->kobj); + } + kset_unregister(&idev->map_attr_kset); /* Needed ? */ +err_remove_group: + sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp); +err_group: + dev_err(idev->dev, "error creating sysfs files (%d)\n", ret); + return ret; +} + +static void uio_dev_del_attributes(struct uio_device *idev) +{ + int mi; + struct uio_mem *mem; + for (mi = 0; mi < MAX_UIO_MAPS; mi++) { + mem = &idev->info->mem[mi]; + if (mem->size == 0) + break; + kobject_unregister(&mem->kobj); + } + kset_unregister(&idev->map_attr_kset); + sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp); +} + +static int uio_get_minor(struct uio_device *idev) +{ + static DEFINE_MUTEX(minor_lock); + int retval = -ENOMEM; + int id; + + mutex_lock(&minor_lock); + if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0) + goto exit; + + retval = idr_get_new(&uio_idr, idev, &id); + if (retval < 0) { + if (retval == -EAGAIN) + retval = -ENOMEM; + goto exit; + } + idev->minor = id & MAX_ID_MASK; +exit: + mutex_unlock(&minor_lock); + return retval; +} + +static void uio_free_minor(struct uio_device *idev) +{ + idr_remove(&uio_idr, idev->minor); +} + +/** + * uio_event_notify - trigger an interrupt event + * @info: UIO device capabilities + */ +void uio_event_notify(struct uio_info *info) +{ + struct uio_device *idev = info->uio_dev; + + atomic_inc(&idev->event); + wake_up_interruptible(&idev->wait); + kill_fasync(&idev->async_queue, SIGIO, POLL_IN); +} +EXPORT_SYMBOL_GPL(uio_event_notify); + +/** + * uio_interrupt - hardware interrupt handler + * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer + * @dev_id: Pointer to the devices uio_device structure + */ +static irqreturn_t uio_interrupt(int irq, void *dev_id) +{ + struct uio_device *idev = (struct uio_device *)dev_id; + irqreturn_t ret = idev->info->handler(irq, idev->info); + + if (ret == IRQ_HANDLED) + uio_event_notify(idev->info); + + return ret; +} + +struct uio_listener { + struct uio_device *dev; + s32 event_count; +}; + +static int uio_open(struct inode *inode, struct file *filep) +{ + struct uio_device *idev; + struct uio_listener *listener; + int ret = 0; + + idev = idr_find(&uio_idr, iminor(inode)); + if (!idev) + return -ENODEV; + + listener = kmalloc(sizeof(*listener), GFP_KERNEL); + if (!listener) + return -ENOMEM; + + listener->dev = idev; + listener->event_count = atomic_read(&idev->event); + filep->private_data = listener; + + if (idev->info->open) { + if (!try_module_get(idev->owner)) + return -ENODEV; + ret = idev->info->open(idev->info, inode); + module_put(idev->owner); + } + + if (ret) + kfree(listener); + + return ret; +} + +static int uio_fasync(int fd, struct file *filep, int on) +{ + struct uio_listener *listener = filep->private_data; + struct uio_device *idev = listener->dev; + + return fasync_helper(fd, filep, on, &idev->async_queue); +} + +static int uio_release(struct inode *inode, struct file *filep) +{ + int ret = 0; + struct uio_listener *listener = filep->private_data; + struct uio_device *idev = listener->dev; + + if (idev->info->release) { + if (!try_module_get(idev->owner)) + return -ENODEV; + ret = idev->info->release(idev->info, inode); + module_put(idev->owner); + } + if (filep->f_flags & FASYNC) + ret = uio_fasync(-1, filep, 0); + kfree(listener); + return ret; +} + +static unsigned int uio_poll(struct file *filep, poll_table *wait) +{ + struct uio_listener *listener = filep->private_data; + struct uio_device *idev = listener->dev; + + if (idev->info->irq == UIO_IRQ_NONE) + return -EIO; + + poll_wait(filep, &idev->wait, wait); + if (listener->event_count != atomic_read(&idev->event)) + return POLLIN | POLLRDNORM; + return 0; +} + +static ssize_t uio_read(struct file *filep, char __user *buf, + size_t count, loff_t *ppos) +{ + struct uio_listener *listener = filep->private_data; + struct uio_device *idev = listener->dev; + DECLARE_WAITQUEUE(wait, current); + ssize_t retval; + s32 event_count; + + if (idev->info->irq == UIO_IRQ_NONE) + return -EIO; + + if (count != sizeof(s32)) + return -EINVAL; + + add_wait_queue(&idev->wait, &wait); + + do { + set_current_state(TASK_INTERRUPTIBLE); + + event_count = atomic_read(&idev->event); + if (event_count != listener->event_count) { + if (copy_to_user(buf, &event_count, count)) + retval = -EFAULT; + else { + listener->event_count = event_count; + retval = count; + } + break; + } + + if (filep->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + break; + } + + if (signal_pending(current)) { + retval = -ERESTARTSYS; + break; + } + schedule(); + } while (1); + + __set_current_state(TASK_RUNNING); + remove_wait_queue(&idev->wait, &wait); + + return retval; +} + +static int uio_find_mem_index(struct vm_area_struct *vma) +{ + int mi; + struct uio_device *idev = vma->vm_private_data; + + for (mi = 0; mi < MAX_UIO_MAPS; mi++) { + if (idev->info->mem[mi].size == 0) + return -1; + if (vma->vm_pgoff == mi) + return mi; + } + return -1; +} + +static void uio_vma_open(struct vm_area_struct *vma) +{ + struct uio_device *idev = vma->vm_private_data; + idev->vma_count++; +} + +static void uio_vma_close(struct vm_area_struct *vma) +{ + struct uio_device *idev = vma->vm_private_data; + idev->vma_count--; +} + +static struct page *uio_vma_nopage(struct vm_area_struct *vma, + unsigned long address, int *type) +{ + struct uio_device *idev = vma->vm_private_data; + struct page* page = NOPAGE_SIGBUS; + + int mi = uio_find_mem_index(vma); + if (mi < 0) + return page; + + if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL) + page = virt_to_page(idev->info->mem[mi].addr); + else + page = vmalloc_to_page((void*)idev->info->mem[mi].addr); + get_page(page); + if (type) + *type = VM_FAULT_MINOR; + return page; +} + +static struct vm_operations_struct uio_vm_ops = { + .open = uio_vma_open, + .close = uio_vma_close, + .nopage = uio_vma_nopage, +}; + +static int uio_mmap_physical(struct vm_area_struct *vma) +{ + struct uio_device *idev = vma->vm_private_data; + int mi = uio_find_mem_index(vma); + if (mi < 0) + return -EINVAL; + + vma->vm_flags |= VM_IO | VM_RESERVED; + + return remap_pfn_range(vma, + vma->vm_start, + idev->info->mem[mi].addr >> PAGE_SHIFT, + vma->vm_end - vma->vm_start, + vma->vm_page_prot); +} + +static int uio_mmap_logical(struct vm_area_struct *vma) +{ + vma->vm_flags |= VM_RESERVED; + vma->vm_ops = &uio_vm_ops; + uio_vma_open(vma); + return 0; +} + +static int uio_mmap(struct file *filep, struct vm_area_struct *vma) +{ + struct uio_listener *listener = filep->private_data; + struct uio_device *idev = listener->dev; + int mi; + unsigned long requested_pages, actual_pages; + int ret = 0; + + if (vma->vm_end < vma->vm_start) + return -EINVAL; + + vma->vm_private_data = idev; + + mi = uio_find_mem_index(vma); + if (mi < 0) + return -EINVAL; + + requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; + actual_pages = (idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT; + if (requested_pages > actual_pages) + return -EINVAL; + + if (idev->info->mmap) { + if (!try_module_get(idev->owner)) + return -ENODEV; + ret = idev->info->mmap(idev->info, vma); + module_put(idev->owner); + return ret; + } + + switch (idev->info->mem[mi].memtype) { + case UIO_MEM_PHYS: + return uio_mmap_physical(vma); + case UIO_MEM_LOGICAL: + case UIO_MEM_VIRTUAL: + return uio_mmap_logical(vma); + default: + return -EINVAL; + } +} + +static struct file_operations uio_fops = { + .owner = THIS_MODULE, + .open = uio_open, + .release = uio_release, + .read = uio_read, + .mmap = uio_mmap, + .poll = uio_poll, + .fasync = uio_fasync, +}; + +static int uio_major_init(void) +{ + uio_major = register_chrdev(0, "uio", &uio_fops); + if (uio_major < 0) + return uio_major; + return 0; +} + +static void uio_major_cleanup(void) +{ + unregister_chrdev(uio_major, "uio"); +} + +static int init_uio_class(void) +{ + int ret = 0; + + if (uio_class != NULL) { + kref_get(&uio_class->kref); + goto exit; + } + + /* This is the first time in here, set everything up properly */ + ret = uio_major_init(); + if (ret) + goto exit; + + uio_class = kzalloc(sizeof(*uio_class), GFP_KERNEL); + if (!uio_class) { + ret = -ENOMEM; + goto err_kzalloc; + } + + kref_init(&uio_class->kref); + uio_class->class = class_create(THIS_MODULE, "uio"); + if (IS_ERR(uio_class->class)) { + ret = IS_ERR(uio_class->class); + printk(KERN_ERR "class_create failed for uio\n"); + goto err_class_create; + } + return 0; + +err_class_create: + kfree(uio_class); + uio_class = NULL; +err_kzalloc: + uio_major_cleanup(); +exit: + return ret; +} + +static void release_uio_class(struct kref *kref) +{ + /* Ok, we cheat as we know we only have one uio_class */ + class_destroy(uio_class->class); + kfree(uio_class); + uio_major_cleanup(); + uio_class = NULL; +} + +static void uio_class_destroy(void) +{ + if (uio_class) + kref_put(&uio_class->kref, release_uio_class); +} + +/** + * uio_register_device - register a new userspace IO device + * @owner: module that creates the new device + * @parent: parent device + * @info: UIO device capabilities + * + * returns zero on success or a negative error code. + */ +int __uio_register_device(struct module *owner, + struct device *parent, + struct uio_info *info) +{ + struct uio_device *idev; + int ret = 0; + + if (!parent || !info || !info->name || !info->version) + return -EINVAL; + + info->uio_dev = NULL; + + ret = init_uio_class(); + if (ret) + return ret; + + idev = kzalloc(sizeof(*idev), GFP_KERNEL); + if (!idev) { + ret = -ENOMEM; + goto err_kzalloc; + } + + idev->owner = owner; + idev->info = info; + init_waitqueue_head(&idev->wait); + atomic_set(&idev->event, 0); + + ret = uio_get_minor(idev); + if (ret) + goto err_get_minor; + + idev->dev = device_create(uio_class->class, parent, + MKDEV(uio_major, idev->minor), + "uio%d", idev->minor); + if (IS_ERR(idev->dev)) { + printk(KERN_ERR "UIO: device register failed\n"); + ret = PTR_ERR(idev->dev); + goto err_device_create; + } + dev_set_drvdata(idev->dev, idev); + + ret = uio_dev_add_attributes(idev); + if (ret) + goto err_uio_dev_add_attributes; + + info->uio_dev = idev; + + if (idev->info->irq >= 0) { + ret = request_irq(idev->info->irq, uio_interrupt, + idev->info->irq_flags, idev->info->name, idev); + if (ret) + goto err_request_irq; + } + + return 0; + +err_request_irq: + uio_dev_del_attributes(idev); +err_uio_dev_add_attributes: + device_destroy(uio_class->class, MKDEV(uio_major, idev->minor)); +err_device_create: + uio_free_minor(idev); +err_get_minor: + kfree(idev); +err_kzalloc: + uio_class_destroy(); + return ret; +} +EXPORT_SYMBOL_GPL(__uio_register_device); + +/** + * uio_unregister_device - unregister a industrial IO device + * @info: UIO device capabilities + * + */ +void uio_unregister_device(struct uio_info *info) +{ + struct uio_device *idev; + + if (!info || !info->uio_dev) + return; + + idev = info->uio_dev; + + uio_free_minor(idev); + + if (info->irq >= 0) + free_irq(info->irq, idev); + + uio_dev_del_attributes(idev); + + dev_set_drvdata(idev->dev, NULL); + device_destroy(uio_class->class, MKDEV(uio_major, idev->minor)); + kfree(idev); + uio_class_destroy(); + + return; +} +EXPORT_SYMBOL_GPL(uio_unregister_device); + +static int __init uio_init(void) +{ + return 0; +} + +static void __exit uio_exit(void) +{ +} + +module_init(uio_init) +module_exit(uio_exit) +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h new file mode 100644 index 000000000000..44c28e94df50 --- /dev/null +++ b/include/linux/uio_driver.h @@ -0,0 +1,91 @@ +/* + * include/linux/uio_driver.h + * + * Copyright(C) 2005, Benedikt Spranger + * Copyright(C) 2005, Thomas Gleixner + * Copyright(C) 2006, Hans J. Koch + * Copyright(C) 2006, Greg Kroah-Hartman + * + * Userspace IO driver. + * + * Licensed under the GPLv2 only. + */ + +#ifndef _UIO_DRIVER_H_ +#define _UIO_DRIVER_H_ + +#include +#include +#include + +/** + * struct uio_mem - description of a UIO memory region + * @kobj: kobject for this mapping + * @addr: address of the device's memory + * @size: size of IO + * @memtype: type of memory addr points to + * @internal_addr: ioremap-ped version of addr, for driver internal use + */ +struct uio_mem { + struct kobject kobj; + unsigned long addr; + unsigned long size; + int memtype; + void __iomem *internal_addr; +}; + +#define MAX_UIO_MAPS 5 + +struct uio_device; + +/** + * struct uio_info - UIO device capabilities + * @uio_dev: the UIO device this info belongs to + * @name: device name + * @version: device driver version + * @mem: list of mappable memory regions, size==0 for end of list + * @irq: interrupt number or UIO_IRQ_CUSTOM + * @irq_flags: flags for request_irq() + * @priv: optional private data + * @handler: the device's irq handler + * @mmap: mmap operation for this uio device + * @open: open operation for this uio device + * @release: release operation for this uio device + */ +struct uio_info { + struct uio_device *uio_dev; + char *name; + char *version; + struct uio_mem mem[MAX_UIO_MAPS]; + long irq; + unsigned long irq_flags; + void *priv; + irqreturn_t (*handler)(int irq, struct uio_info *dev_info); + int (*mmap)(struct uio_info *info, struct vm_area_struct *vma); + int (*open)(struct uio_info *info, struct inode *inode); + int (*release)(struct uio_info *info, struct inode *inode); +}; + +extern int __must_check + __uio_register_device(struct module *owner, + struct device *parent, + struct uio_info *info); +static inline int __must_check + uio_register_device(struct device *parent, struct uio_info *info) +{ + return __uio_register_device(THIS_MODULE, parent, info); +} +extern void uio_unregister_device(struct uio_info *info); +extern void uio_event_notify(struct uio_info *info); + +/* defines for uio_device->irq */ +#define UIO_IRQ_CUSTOM -1 +#define UIO_IRQ_NONE -2 + +/* defines for uio_device->memtype */ +#define UIO_MEM_NONE 0 +#define UIO_MEM_PHYS 1 +#define UIO_MEM_LOGICAL 2 +#define UIO_MEM_VIRTUAL 3 + +#endif /* _LINUX_UIO_DRIVER_H_ */ From e3e0a28b5b067d16b8e2e5ddaedecda5bd0c3ec2 Mon Sep 17 00:00:00 2001 From: "Hans J. Koch" Date: Mon, 11 Dec 2006 16:59:59 +0100 Subject: [PATCH 2/3] UIO: Documentation Documentation for the UIO interface From: Hans J. Koch Signed-off-by: Greg Kroah-Hartman --- Documentation/DocBook/kernel-api.tmpl | 4 + Documentation/DocBook/uio-howto.tmpl | 611 ++++++++++++++++++++++++++ 2 files changed, 615 insertions(+) create mode 100644 Documentation/DocBook/uio-howto.tmpl diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index fd2ef4d29b6d..a0af560ed740 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl @@ -408,6 +408,10 @@ X!Edrivers/pnp/system.c !Edrivers/pnp/manager.c !Edrivers/pnp/support.c + Userspace IO devices +!Edrivers/uio/uio.c +!Iinclude/linux/uio_driver.h + diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl new file mode 100644 index 000000000000..e3bb29a8d8dd --- /dev/null +++ b/Documentation/DocBook/uio-howto.tmpl @@ -0,0 +1,611 @@ + + + + + +The Userspace I/O HOWTO + + + Hans-Jürgen + Koch + Linux developer, Linutronix + + + Linutronix + + +
+ hjk@linutronix.de +
+ + + +2006-12-11 + + + This HOWTO describes concept and usage of Linux kernel's + Userspace I/O system. + + + + + 0.3 + 2007-04-29 + hjk + Added section about userspace drivers. + + + 0.2 + 2007-02-13 + hjk + Update after multiple mappings were added. + + + 0.1 + 2006-12-11 + hjk + First draft. + + + + + + +About this document + + + +Copyright and License + + Copyright (c) 2006 by Hans-Jürgen Koch. + +This documentation is Free Software licensed under the terms of the +GPL version 2. + + + + + +Translations + +If you know of any translations for this document, or you are +interested in translating it, please email me +hjk@linutronix.de. + + + + +Preface + + For many types of devices, creating a Linux kernel driver is + overkill. All that is really needed is some way to handle an + interrupt and provide access to the memory space of the + device. The logic of controlling the device does not + necessarily have to be within the kernel, as the device does + not need to take advantage of any of other resources that the + kernel provides. One such common class of devices that are + like this are for industrial I/O cards. + + + To address this situation, the userspace I/O system (UIO) was + designed. For typical industrial I/O cards, only a very small + kernel module is needed. The main part of the driver will run in + user space. This simplifies development and reduces the risk of + serious bugs within a kernel module. + + + + +Acknowledgments + I'd like to thank Thomas Gleixner and Benedikt Spranger of + Linutronix, who have not only written most of the UIO code, but also + helped greatly writing this HOWTO by giving me all kinds of background + information. + + + +Feedback + Find something wrong with this document? (Or perhaps something + right?) I would love to hear from you. Please email me at + hjk@linutronix.de. + + + + + +About UIO + +If you use UIO for your card's driver, here's what you get: + + + + only one small kernel module to write and maintain. + + + develop the main part of your driver in user space, + with all the tools and libraries you're used to. + + + bugs in your driver won't crash the kernel. + + + updates of your driver can take place without recompiling + the kernel. + + + if you need to keep some parts of your driver closed source, + you can do so without violating the GPL license on the kernel. + + + + +How UIO works + + Each UIO device is accessed through a device file and several + sysfs attribute files. The device file will be called + /dev/uio0 for the first device, and + /dev/uio1, /dev/uio2 + and so on for subsequent devices. + + + /dev/uioX is used to access the + address space of the card. Just use + mmap() to access registers or RAM + locations of your card. + + + + Interrupts are handled by reading from + /dev/uioX. A blocking + read() from + /dev/uioX will return as soon as an + interrupt occurs. You can also use + select() on + /dev/uioX to wait for an interrupt. The + integer value read from /dev/uioX + represents the total interrupt count. You can use this number + to figure out if you missed some interrupts. + + + + To handle interrupts properly, your custom kernel module can + provide its own interrupt handler. It will automatically be + called by the built-in handler. + + + + For cards that don't generate interrupts but need to be + polled, there is the possibility to set up a timer that + triggers the interrupt handler at configurable time intervals. + See drivers/uio/uio_dummy.c for an + example of this technique. + + + + Each driver provides attributes that are used to read or write + variables. These attributes are accessible through sysfs + files. A custom kernel driver module can add its own + attributes to the device owned by the uio driver, but not added + to the UIO device itself at this time. This might change in the + future if it would be found to be useful. + + + + The following standard attributes are provided by the UIO + framework: + + + + + name: The name of your device. It is + recommended to use the name of your kernel module for this. + + + + + version: A version string defined by your + driver. This allows the user space part of your driver to deal + with different versions of the kernel module. + + + + + event: The total number of interrupts + handled by the driver since the last time the device node was + read. + + + + + These attributes appear under the + /sys/class/uio/uioX directory. Please + note that this directory might be a symlink, and not a real + directory. Any userspace code that accesses it must be able + to handle this. + + + Each UIO device can make one or more memory regions available for + memory mapping. This is necessary because some industrial I/O cards + require access to more than one PCI memory region in a driver. + + + Each mapping has its own directory in sysfs, the first mapping + appears as /sys/class/uio/uioX/maps/map0/. + Subsequent mappings create directories map1/, + map2/, and so on. These directories will only + appear if the size of the mapping is not 0. + + + Each mapX/ directory contains two read-only files + that show start address and size of the memory: + + + + + addr: The address of memory that can be mapped. + + + + + size: The size, in bytes, of the memory + pointed to by addr. + + + + + + From userspace, the different mappings are distinguished by adjusting + the offset parameter of the + mmap() call. To map the memory of mapping N, you + have to use N times the page size as your offset: + + +offset = N * getpagesize(); + + + + + + + +Using uio_dummy + + Well, there is no real use for uio_dummy. Its only purpose is + to test most parts of the UIO system (everything except + hardware interrupts), and to serve as an example for the + kernel module that you will have to write yourself. + + + +What uio_dummy does + + The kernel module uio_dummy.ko creates a + device that uses a timer to generate periodic interrupts. The + interrupt handler does nothing but increment a counter. The + driver adds two custom attributes, count + and freq, that appear under + /sys/devices/platform/uio_dummy/. + + + + The attribute count can be read and + written. The associated file + /sys/devices/platform/uio_dummy/count + appears as a normal text file and contains the total number of + timer interrupts. If you look at it (e.g. using + cat), you'll notice it is slowly counting + up. + + + + The attribute freq can be read and written. + The content of + /sys/devices/platform/uio_dummy/freq + represents the number of system timer ticks between two timer + interrupts. The default value of freq is + the value of the kernel variable HZ, which + gives you an interval of one second. Lower values will + increase the frequency. Try the following: + + +cd /sys/devices/platform/uio_dummy/ +echo 100 > freq + + + Use cat count to see how the interrupt + frequency changes. + + + + + + +Writing your own kernel module + + Please have a look at uio_dummy.c as an + example. The following paragraphs explain the different + sections of this file. + + + +struct uio_info + + This structure tells the framework the details of your driver, + Some of the members are required, others are optional. + + + + +char *name: Required. The name of your driver as +it will appear in sysfs. I recommend using the name of your module for this. + + + +char *version: Required. This string appears in +/sys/class/uio/uioX/version. + + + +struct uio_mem mem[ MAX_UIO_MAPS ]: Required if you +have memory that can be mapped with mmap(). For each +mapping you need to fill one of the uio_mem structures. +See the description below for details. + + + +long irq: Required. If your hardware generates an +interrupt, it's your modules task to determine the irq number during +initialization. If you don't have a hardware generated interrupt but +want to trigger the interrupt handler in some other way, set +irq to UIO_IRQ_CUSTOM. The +uio_dummy module does this as it triggers the event mechanism in a timer +routine. If you had no interrupt at all, you could set +irq to UIO_IRQ_NONE, though this +rarely makes sense. + + + +unsigned long irq_flags: Required if you've set +irq to a hardware interrupt number. The flags given +here will be used in the call to request_irq(). + + + +int (*mmap)(struct uio_info *info, struct vm_area_struct +*vma): Optional. If you need a special +mmap() function, you can set it here. If this +pointer is not NULL, your mmap() will be called +instead of the built-in one. + + + +int (*open)(struct uio_info *info, struct inode *inode) +: Optional. You might want to have your own +open(), e.g. to enable interrupts only when your +device is actually used. + + + +int (*release)(struct uio_info *info, struct inode *inode) +: Optional. If you define your own +open(), you will probably also want a custom +release() function. + + + + +Usually, your device will have one or more memory regions that can be mapped +to user space. For each region, you have to set up a +struct uio_mem in the mem[] array. +Here's a description of the fields of struct uio_mem: + + + + +int memtype: Required if the mapping is used. Set this to +UIO_MEM_PHYS if you you have physical memory on your +card to be mapped. Use UIO_MEM_LOGICAL for logical +memory (e.g. allocated with kmalloc()). There's also +UIO_MEM_VIRTUAL for virtual memory. + + + +unsigned long addr: Required if the mapping is used. +Fill in the address of your memory block. This address is the one that +appears in sysfs. + + + +unsigned long size: Fill in the size of the +memory block that addr points to. If size +is zero, the mapping is considered unused. Note that you +must initialize size with zero for +all unused mappings. + + + +void *internal_addr: If you have to access this memory +region from within your kernel module, you will want to map it internally by +using something like ioremap(). Addresses +returned by this function cannot be mapped to user space, so you must not +store it in addr. Use internal_addr +instead to remember such an address. + + + + +Please do not touch the kobj element of +struct uio_mem! It is used by the UIO framework +to set up sysfs files for this mapping. Simply leave it alone. + + + + +Adding an interrupt handler + + What you need to do in your interrupt handler depends on your + hardware and on how you want to handle it. You should try to + keep the amount of code in your kernel interrupt handler low. + If your hardware requires no action that you + have to perform after each interrupt, + then your handler can be empty. If, on the other + hand, your hardware needs some action to + be performed after each interrupt, then you + must do it in your kernel module. Note + that you cannot rely on the userspace part of your driver. Your + userspace program can terminate at any time, possibly leaving + your hardware in a state where proper interrupt handling is + still required. + + + + There might also be applications where you want to read data + from your hardware at each interrupt and buffer it in a piece + of kernel memory you've allocated for that purpose. With this + technique you could avoid loss of data if your userspace + program misses an interrupt. + + + + A note on shared interrupts: Your driver should support + interrupt sharing whenever this is possible. It is possible if + and only if your driver can detect whether your hardware has + triggered the interrupt or not. This is usually done by looking + at an interrupt status register. If your driver sees that the + IRQ bit is actually set, it will perform its actions, and the + handler returns IRQ_HANDLED. If the driver detects that it was + not your hardware that caused the interrupt, it will do nothing + and return IRQ_NONE, allowing the kernel to call the next + possible interrupt handler. + + + + If you decide not to support shared interrupts, your card + won't work in computers with no free interrupts. As this + frequently happens on the PC platform, you can save yourself a + lot of trouble by supporting interrupt sharing. + + + + + + + +Writing a driver in userspace + + Once you have a working kernel module for your hardware, you can + write the userspace part of your driver. You don't need any special + libraries, your driver can be written in any reasonable language, + you can use floating point numbers and so on. In short, you can + use all the tools and libraries you'd normally use for writing a + userspace application. + + + +Getting information about your UIO device + + Information about all UIO devices is available in sysfs. The + first thing you should do in your driver is check + name and version to + make sure your talking to the right device and that its kernel + driver has the version you expect. + + + You should also make sure that the memory mapping you need + exists and has the size you expect. + + + There is a tool called lsuio that lists + UIO devices and their attributes. It is available here: + + + + http://www.osadl.org/projects/downloads/UIO/user/ + + + With lsuio you can quickly check if your + kernel module is loaded and which attributes it exports. + Have a look at the manpage for details. + + + The source code of lsuio can serve as an + example for getting information about an UIO device. + The file uio_helper.c contains a lot of + functions you could use in your userspace driver code. + + + + +mmap() device memory + + After you made sure you've got the right device with the + memory mappings you need, all you have to do is to call + mmap() to map the device's memory + to userspace. + + + The parameter offset of the + mmap() call has a special meaning + for UIO devices: It is used to select which mapping of + your device you want to map. To map the memory of + mapping N, you have to use N times the page size as + your offset: + + + offset = N * getpagesize(); + + + N starts from zero, so if you've got only one memory + range to map, set offset = 0. + A drawback of this technique is that memory is always + mapped beginning with its start address. + + + + +Waiting for interrupts + + After you successfully mapped your devices memory, you + can access it like an ordinary array. Usually, you will + perform some initialization. After that, your hardware + starts working and will generate an interrupt as soon + as it's finished, has some data available, or needs your + attention because an error occured. + + + /dev/uioX is a read-only file. A + read() will always block until an + interrupt occurs. There is only one legal value for the + count parameter of + read(), and that is the size of a + signed 32 bit integer (4). Any other value for + count causes read() + to fail. The signed 32 bit integer read is the interrupt + count of your device. If the value is one more than the value + you read the last time, everything is OK. If the difference + is greater than one, you missed interrupts. + + + You can also use select() on + /dev/uioX. + + + + + + +Further information + + + + OSADL homepage. + + + + Linutronix homepage. + + + + + From bc4c4f45acbe1f1528d654b0b1793f25c175bf8f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Hans-J=C3=BCrgen=20Koch?= Date: Fri, 2 Mar 2007 13:03:12 +0100 Subject: [PATCH 3/3] UIO: Hilscher CIF card driver MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit this is a patch that adds support for Hilscher CIF DeviceNet and Profibus cards. I tested it on a Kontron CPX board, and Thomas reviewed it. You can find the user space part here: http://www.osadl.org/projects/downloads/UIO/user/cif-0.1.0.tar.gz Notes: cif_api.c is the main file you want to look at. It contains the functions to open, close, mmap and so on. cif_dps.c adds functions specific to Profibus cards, and cif_dn.c contains functions for DeviceNet cards. cif.c is a universal playground, it's just a small test program. The user space part of this UIO driver is still work in progress, and not everything is tested yet. At the moment, the thread in cif_api.c contains some code that artificially makes the card generate interrupts, this was added for testing and will be removed later. But the driver already contains all the functions needed for useful operation, so it gives a good idea of how such a thing looks like. For comparison, here's what you get from the manufacturer (www.hilscher.com) when you ask for a Linux 2.6 driver: http://www.tglx.de/private/hjk/cif-orig-2.6.tar.bz2 WARNING: Don't look at the code for too long, you might become sick :-) Signed-off-by: Hans-Jürgen Koch Signed-off-by: Greg Kroah-Hartman --- drivers/uio/Kconfig | 13 ++++ drivers/uio/Makefile | 3 +- drivers/uio/uio_cif.c | 156 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 171 insertions(+), 1 deletion(-) create mode 100644 drivers/uio/uio_cif.c diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig index 6b1a62d45e46..b778ed71f636 100644 --- a/drivers/uio/Kconfig +++ b/drivers/uio/Kconfig @@ -13,4 +13,17 @@ config UIO If you don't know what to do here, say N. +config UIO_CIF + tristate "generic Hilscher CIF Card driver" + depends on UIO && PCI + default n + help + Driver for Hilscher CIF DeviceNet and Profibus cards. This + driver requires a userspace component that handles all of the + heavy lifting and can be found at: + http://www.osadl.org/projects/downloads/UIO/user/cif-* + + To compile this driver as a module, choose M here: the module + will be called uio_cif. + endmenu diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile index 9b7c83063e15..7fecfb459da5 100644 --- a/drivers/uio/Makefile +++ b/drivers/uio/Makefile @@ -1 +1,2 @@ -obj-$(CONFIG_UIO) += uio.o +obj-$(CONFIG_UIO) += uio.o +obj-$(CONFIG_UIO_CIF) += uio_cif.o diff --git a/drivers/uio/uio_cif.c b/drivers/uio/uio_cif.c new file mode 100644 index 000000000000..838bae460831 --- /dev/null +++ b/drivers/uio/uio_cif.c @@ -0,0 +1,156 @@ +/* + * UIO Hilscher CIF card driver + * + * (C) 2007 Hans J. Koch + * Original code (C) 2005 Benedikt Spranger + * + * Licensed under GPL version 2 only. + * + */ + +#include +#include +#include +#include + +#include + +#ifndef PCI_DEVICE_ID_PLX_9030 +#define PCI_DEVICE_ID_PLX_9030 0x9030 +#endif + +#define PLX9030_INTCSR 0x4C +#define INTSCR_INT1_ENABLE 0x01 +#define INTSCR_INT1_STATUS 0x04 +#define INT1_ENABLED_AND_ACTIVE (INTSCR_INT1_ENABLE | INTSCR_INT1_STATUS) + +#define PCI_SUBVENDOR_ID_PEP 0x1518 +#define CIF_SUBDEVICE_PROFIBUS 0x430 +#define CIF_SUBDEVICE_DEVICENET 0x432 + + +static irqreturn_t hilscher_handler(int irq, struct uio_info *dev_info) +{ + void __iomem *plx_intscr = dev_info->mem[0].internal_addr + + PLX9030_INTCSR; + + if ((ioread8(plx_intscr) & INT1_ENABLED_AND_ACTIVE) + != INT1_ENABLED_AND_ACTIVE) + return IRQ_NONE; + + /* Disable interrupt */ + iowrite8(ioread8(plx_intscr) & ~INTSCR_INT1_ENABLE, plx_intscr); + return IRQ_HANDLED; +} + +static int __devinit hilscher_pci_probe(struct pci_dev *dev, + const struct pci_device_id *id) +{ + struct uio_info *info; + + info = kzalloc(sizeof(struct uio_info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + if (pci_enable_device(dev)) + goto out_free; + + if (pci_request_regions(dev, "hilscher")) + goto out_disable; + + info->mem[0].addr = pci_resource_start(dev, 0); + if (!info->mem[0].addr) + goto out_release; + info->mem[0].internal_addr = ioremap(pci_resource_start(dev, 0), + pci_resource_len(dev, 0)); + if (!info->mem[0].internal_addr) + goto out_release; + + info->mem[0].size = pci_resource_len(dev, 0); + info->mem[0].memtype = UIO_MEM_PHYS; + info->mem[1].addr = pci_resource_start(dev, 2); + info->mem[1].size = pci_resource_len(dev, 2); + info->mem[1].memtype = UIO_MEM_PHYS; + switch (id->subdevice) { + case CIF_SUBDEVICE_PROFIBUS: + info->name = "CIF_Profibus"; + break; + case CIF_SUBDEVICE_DEVICENET: + info->name = "CIF_Devicenet"; + break; + default: + info->name = "CIF_???"; + } + info->version = "0.0.1"; + info->irq = dev->irq; + info->irq_flags = IRQF_DISABLED | IRQF_SHARED; + info->handler = hilscher_handler; + + if (uio_register_device(&dev->dev, info)) + goto out_unmap; + + pci_set_drvdata(dev, info); + + return 0; +out_unmap: + iounmap(info->mem[0].internal_addr); +out_release: + pci_release_regions(dev); +out_disable: + pci_disable_device(dev); +out_free: + kfree (info); + return -ENODEV; +} + +static void hilscher_pci_remove(struct pci_dev *dev) +{ + struct uio_info *info = pci_get_drvdata(dev); + + uio_unregister_device(info); + pci_release_regions(dev); + pci_disable_device(dev); + pci_set_drvdata(dev, NULL); + iounmap(info->mem[0].internal_addr); + + kfree (info); +} + +static struct pci_device_id hilscher_pci_ids[] = { + { + .vendor = PCI_VENDOR_ID_PLX, + .device = PCI_DEVICE_ID_PLX_9030, + .subvendor = PCI_SUBVENDOR_ID_PEP, + .subdevice = CIF_SUBDEVICE_PROFIBUS, + }, + { + .vendor = PCI_VENDOR_ID_PLX, + .device = PCI_DEVICE_ID_PLX_9030, + .subvendor = PCI_SUBVENDOR_ID_PEP, + .subdevice = CIF_SUBDEVICE_DEVICENET, + }, + { 0, } +}; + +static struct pci_driver hilscher_pci_driver = { + .name = "hilscher", + .id_table = hilscher_pci_ids, + .probe = hilscher_pci_probe, + .remove = hilscher_pci_remove, +}; + +static int __init hilscher_init_module(void) +{ + return pci_register_driver(&hilscher_pci_driver); +} + +static void __exit hilscher_exit_module(void) +{ + pci_unregister_driver(&hilscher_pci_driver); +} + +module_init(hilscher_init_module); +module_exit(hilscher_exit_module); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Hans J. Koch, Benedikt Spranger");