/* -*- C -*- * main.c -- the bare sculld char module * * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet * Copyright (C) 2001 O'Reilly & Associates * * The source code in this file can be freely used, adapted, * and redistributed in source or binary form, so long as an * acknowledgment appears in derived source files. The citation * should list that the code comes from the book "Linux Device * Drivers" by Alessandro Rubini and Jonathan Corbet, published * by O'Reilly & Associates. No warranty is attached; * we cannot take responsibility for errors or fitness for use. * * $Id: _main.c.in,v 1.21 2004/10/14 20:11:39 corbet Exp $ */ #include #include #include #include #include /* printk() */ #include /* kmalloc() */ #include /* everything... */ #include /* error codes */ #include /* size_t */ #include #include /* O_ACCMODE */ #include #include #include "sculld.h" /* local definitions */ int sculld_major = SCULLD_MAJOR; int sculld_devs = SCULLD_DEVS; /* number of bare sculld devices */ int sculld_qset = SCULLD_QSET; int sculld_order = SCULLD_ORDER; module_param(sculld_major, int, 0); module_param(sculld_devs, int, 0); module_param(sculld_qset, int, 0); module_param(sculld_order, int, 0); MODULE_AUTHOR("Alessandro Rubini"); MODULE_LICENSE("Dual BSD/GPL"); struct sculld_dev *sculld_devices; /* allocated in sculld_init */ int sculld_trim(struct sculld_dev *dev); void sculld_cleanup(void); /* Device model stuff */ static struct ldd_driver sculld_driver = { .version = "$Revision: 1.21 $", .module = THIS_MODULE, .driver = { .name = "sculld", }, }; #ifdef SCULLD_USE_PROC /* don't waste space if unused */ /* * The proc filesystem: function to read and entry */ void sculld_proc_offset(char *buf, char **start, off_t *offset, int *len) { if (*offset == 0) return; if (*offset >= *len) { /* Not there yet */ *offset -= *len; *len = 0; } else { /* We're into the interesting stuff now */ *start = buf + *offset; *offset = 0; } } /* FIXME: Do we need this here?? It be ugly */ int sculld_read_procmem(char *buf, char **start, off_t offset, int count, int *eof, void *data) { int i, j, order, qset, len = 0; int limit = count - 80; /* Don't print more than this */ struct sculld_dev *d; *start = buf; for(i = 0; i < sculld_devs; i++) { d = &sculld_devices[i]; if (down_interruptible (&d->sem)) return -ERESTARTSYS; qset = d->qset; /* retrieve the features of each device */ order = d->order; len += sprintf(buf+len,"\nDevice %i: qset %i, order %i, sz %li\n", i, qset, order, (long)(d->size)); for (; d; d = d->next) { /* scan the list */ len += sprintf(buf+len," item at %p, qset at %p\n",d,d->data); sculld_proc_offset (buf, start, &offset, &len); if (len > limit) goto out; if (d->data && !d->next) /* dump only the last item - save space */ for (j = 0; j < qset; j++) { if (d->data[j]) len += sprintf(buf+len," % 4i:%8p\n",j,d->data[j]); sculld_proc_offset (buf, start, &offset, &len); if (len > limit) goto out; } } out: up (&sculld_devices[i].sem); if (len > limit) break; } *eof = 1; return len; } #endif /* SCULLD_USE_PROC */ /* * Open and close */ int sculld_open (struct inode *inode, struct file *filp) { struct sculld_dev *dev; /* device information */ /* Find the device */ dev = container_of(inode->i_cdev, struct sculld_dev, cdev); /* now trim to 0 the length of the device if open was write-only */ if ( (filp->f_flags & O_ACCMODE) == O_WRONLY) { if (down_interruptible (&dev->sem)) return -ERESTARTSYS; sculld_trim(dev); /* ignore errors */ up (&dev->sem); } /* and use filp->private_data to point to the device data */ filp->private_data = dev; return 0; /* success */ } int sculld_release (struct inode *inode, struct file *filp) { return 0; } /* * Follow the list */ struct sculld_dev *sculld_follow(struct sculld_dev *dev, int n) { while (n--) { if (!dev->next) { dev->next = kmalloc(sizeof(struct sculld_dev), GFP_KERNEL); memset(dev->next, 0, sizeof(struct sculld_dev)); } dev = dev->next; continue; } return dev; } /* * Data management: read and write */ ssize_t sculld_read (struct file *filp, char __user *buf, size_t count, loff_t *f_pos) { struct sculld_dev *dev = filp->private_data; /* the first listitem */ struct sculld_dev *dptr; int quantum = PAGE_SIZE << dev->order; int qset = dev->qset; int itemsize = quantum * qset; /* how many bytes in the listitem */ int item, s_pos, q_pos, rest; ssize_t retval = 0; if (down_interruptible (&dev->sem)) return -ERESTARTSYS; if (*f_pos > dev->size) goto nothing; if (*f_pos + count > dev->size) count = dev->size - *f_pos; /* find listitem, qset index, and offset in the quantum */ item = ((long) *f_pos) / itemsize; rest = ((long) *f_pos) % itemsize; s_pos = rest / quantum; q_pos = rest % quantum; /* follow the list up to the right position (defined elsewhere) */ dptr = sculld_follow(dev, item); if (!dptr->data) goto nothing; /* don't fill holes */ if (!dptr->data[s_pos]) goto nothing; if (count > quantum - q_pos) count = quantum - q_pos; /* read only up to the end of this quantum */ if (copy_to_user (buf, dptr->data[s_pos]+q_pos, count)) { retval = -EFAULT; goto nothing; } up (&dev->sem); *f_pos += count; return count; nothing: up (&dev->sem); return retval; } ssize_t sculld_write (struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) { struct sculld_dev *dev = filp->private_data; struct sculld_dev *dptr; int quantum = PAGE_SIZE << dev->order; int qset = dev->qset; int itemsize = quantum * qset; int item, s_pos, q_pos, rest; ssize_t retval = -ENOMEM; /* our most likely error */ if (down_interruptible (&dev->sem)) return -ERESTARTSYS; /* find listitem, qset index and offset in the quantum */ item = ((long) *f_pos) / itemsize; rest = ((long) *f_pos) % itemsize; s_pos = rest / quantum; q_pos = rest % quantum; /* follow the list up to the right position */ dptr = sculld_follow(dev, item); if (!dptr->data) { dptr->data = kmalloc(qset * sizeof(void *), GFP_KERNEL); if (!dptr->data) goto nomem; memset(dptr->data, 0, qset * sizeof(char *)); } /* Here's the allocation of a single quantum */ if (!dptr->data[s_pos]) { dptr->data[s_pos] = (void *)__get_free_pages(GFP_KERNEL, dptr->order); if (!dptr->data[s_pos]) goto nomem; memset(dptr->data[s_pos], 0, PAGE_SIZE << dptr->order); } if (count > quantum - q_pos) count = quantum - q_pos; /* write only up to the end of this quantum */ if (copy_from_user (dptr->data[s_pos]+q_pos, buf, count)) { retval = -EFAULT; goto nomem; } *f_pos += count; /* update the size */ if (dev->size < *f_pos) dev->size = *f_pos; up (&dev->sem); return count; nomem: up (&dev->sem); return retval; } /* * The ioctl() implementation */ int sculld_ioctl (struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) { int err = 0, ret = 0, tmp; /* don't even decode wrong cmds: better returning ENOTTY than EFAULT */ if (_IOC_TYPE(cmd) != SCULLD_IOC_MAGIC) return -ENOTTY; if (_IOC_NR(cmd) > SCULLD_IOC_MAXNR) return -ENOTTY; /* * the type is a bitmask, and VERIFY_WRITE catches R/W * transfers. Note that the type is user-oriented, while * verify_area is kernel-oriented, so the concept of "read" and * "write" is reversed */ if (_IOC_DIR(cmd) & _IOC_READ) err = !access_ok(VERIFY_WRITE, (void __user *)arg, _IOC_SIZE(cmd)); else if (_IOC_DIR(cmd) & _IOC_WRITE) err = !access_ok(VERIFY_READ, (void __user *)arg, _IOC_SIZE(cmd)); if (err) return -EFAULT; switch(cmd) { case SCULLD_IOCRESET: sculld_qset = SCULLD_QSET; sculld_order = SCULLD_ORDER; break; case SCULLD_IOCSORDER: /* Set: arg points to the value */ ret = __get_user(sculld_order, (int __user *) arg); break; case SCULLD_IOCTORDER: /* Tell: arg is the value */ sculld_order = arg; break; case SCULLD_IOCGORDER: /* Get: arg is pointer to result */ ret = __put_user (sculld_order, (int __user *) arg); break; case SCULLD_IOCQORDER: /* Query: return it (it's positive) */ return sculld_order; case SCULLD_IOCXORDER: /* eXchange: use arg as pointer */ tmp = sculld_order; ret = __get_user(sculld_order, (int __user *) arg); if (ret == 0) ret = __put_user(tmp, (int __user *) arg); break; case SCULLD_IOCHORDER: /* sHift: like Tell + Query */ tmp = sculld_order; sculld_order = arg; return tmp; case SCULLD_IOCSQSET: ret = __get_user(sculld_qset, (int __user *) arg); break; case SCULLD_IOCTQSET: sculld_qset = arg; break; case SCULLD_IOCGQSET: ret = __put_user(sculld_qset, (int __user *)arg); break; case SCULLD_IOCQQSET: return sculld_qset; case SCULLD_IOCXQSET: tmp = sculld_qset; ret = __get_user(sculld_qset, (int __user *)arg); if (ret == 0) ret = __put_user(tmp, (int __user *)arg); break; case SCULLD_IOCHQSET: tmp = sculld_qset; sculld_qset = arg; return tmp; default: /* redundant, as cmd was checked against MAXNR */ return -ENOTTY; } return ret; } /* * The "extended" operations */ loff_t sculld_llseek (struct file *filp, loff_t off, int whence) { struct sculld_dev *dev = filp->private_data; long newpos; switch(whence) { case 0: /* SEEK_SET */ newpos = off; break; case 1: /* SEEK_CUR */ newpos = filp->f_pos + off; break; case 2: /* SEEK_END */ newpos = dev->size + off; break; default: /* can't happen */ return -EINVAL; } if (newpos<0) return -EINVAL; filp->f_pos = newpos; return newpos; } /* * A simple asynchronous I/O implementation. */ struct async_work { struct kiocb *iocb; int result; struct work_struct work; }; /* * "Complete" an asynchronous operation. */ static void sculld_do_deferred_op(void *p) { struct async_work *stuff = (struct async_work *) p; aio_complete(stuff->iocb, stuff->result, 0); kfree(stuff); } static int sculld_defer_op(int write, struct kiocb *iocb, char __user *buf, size_t count, loff_t pos) { struct async_work *stuff; int result; /* Copy now while we can access the buffer */ if (write) result = sculld_write(iocb->ki_filp, buf, count, &pos); else result = sculld_read(iocb->ki_filp, buf, count, &pos); /* If this is a synchronous IOCB, we return our status now. */ if (is_sync_kiocb(iocb)) return result; /* Otherwise defer the completion for a few milliseconds. */ stuff = kmalloc (sizeof (*stuff), GFP_KERNEL); if (stuff == NULL) return result; /* No memory, just complete now */ stuff->iocb = iocb; stuff->result = result; INIT_WORK(&stuff->work, sculld_do_deferred_op, stuff); schedule_delayed_work(&stuff->work, HZ/100); return -EIOCBQUEUED; } static ssize_t sculld_aio_read(struct kiocb *iocb, char __user *buf, size_t count, loff_t pos) { return sculld_defer_op(0, iocb, buf, count, pos); } static ssize_t sculld_aio_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t pos) { return sculld_defer_op(1, iocb, (char __user *) buf, count, pos); } /* * Mmap *is* available, but confined in a different file */ extern int sculld_mmap(struct file *filp, struct vm_area_struct *vma); /* * The fops */ struct file_operations sculld_fops = { .owner = THIS_MODULE, .llseek = sculld_llseek, .read = sculld_read, .write = sculld_write, .ioctl = sculld_ioctl, .mmap = sculld_mmap, .open = sculld_open, .release = sculld_release, .aio_read = sculld_aio_read, .aio_write = sculld_aio_write, }; int sculld_trim(struct sculld_dev *dev) { struct sculld_dev *next, *dptr; int qset = dev->qset; /* "dev" is not-null */ int i; if (dev->vmas) /* don't trim: there are active mappings */ return -EBUSY; for (dptr = dev; dptr; dptr = next) { /* all the list items */ if (dptr->data) { /* This code frees a whole quantum-set */ for (i = 0; i < qset; i++) if (dptr->data[i]) free_pages((unsigned long)(dptr->data[i]), dptr->order); kfree(dptr->data); dptr->data=NULL; } next=dptr->next; if (dptr != dev) kfree(dptr); /* all of them but the first */ } dev->size = 0; dev->qset = sculld_qset; dev->order = sculld_order; dev->next = NULL; return 0; } static void sculld_setup_cdev(struct sculld_dev *dev, int index) { int err, devno = MKDEV(sculld_major, index); cdev_init(&dev->cdev, &sculld_fops); dev->cdev.owner = THIS_MODULE; dev->cdev.ops = &sculld_fops; err = cdev_add (&dev->cdev, devno, 1); /* Fail gracefully if need be */ if (err) printk(KERN_NOTICE "Error %d adding scull%d", err, index); } static ssize_t sculld_show_dev(struct device *ddev, char *buf) { struct sculld_dev *dev = ddev->driver_data; return print_dev_t(buf, dev->cdev.dev); } static DEVICE_ATTR(dev, S_IRUGO, sculld_show_dev, NULL); static void sculld_register_dev(struct sculld_dev *dev, int index) { sprintf(dev->devname, "sculld%d", index); dev->ldev.name = dev->devname; dev->ldev.driver = &sculld_driver; dev->ldev.dev.driver_data = dev; register_ldd_device(&dev->ldev); device_create_file(&dev->ldev.dev, &dev_attr_dev); } /* * Finally, the module stuff */ int sculld_init(void) { int result, i; dev_t dev = MKDEV(sculld_major, 0); /* * Register your major, and accept a dynamic number. */ if (sculld_major) result = register_chrdev_region(dev, sculld_devs, "sculld"); else { result = alloc_chrdev_region(&dev, 0, sculld_devs, "sculld"); sculld_major = MAJOR(dev); } if (result < 0) return result; /* * Register with the driver core. */ register_ldd_driver(&sculld_driver); /* * allocate the devices -- we can't have them static, as the number * can be specified at load time */ sculld_devices = kmalloc(sculld_devs*sizeof (struct sculld_dev), GFP_KERNEL); if (!sculld_devices) { result = -ENOMEM; goto fail_malloc; } memset(sculld_devices, 0, sculld_devs*sizeof (struct sculld_dev)); for (i = 0; i < sculld_devs; i++) { sculld_devices[i].order = sculld_order; sculld_devices[i].qset = sculld_qset; sema_init (&sculld_devices[i].sem, 1); sculld_setup_cdev(sculld_devices + i, i); sculld_register_dev(sculld_devices + i, i); } #ifdef SCULLD_USE_PROC /* only when available */ create_proc_read_entry("sculldmem", 0, NULL, sculld_read_procmem, NULL); #endif return 0; /* succeed */ fail_malloc: unregister_chrdev_region(dev, sculld_devs); return result; } void sculld_cleanup(void) { int i; #ifdef SCULLD_USE_PROC remove_proc_entry("sculldmem", NULL); #endif for (i = 0; i < sculld_devs; i++) { unregister_ldd_device(&sculld_devices[i].ldev); cdev_del(&sculld_devices[i].cdev); sculld_trim(sculld_devices + i); } kfree(sculld_devices); unregister_ldd_driver(&sculld_driver); unregister_chrdev_region(MKDEV (sculld_major, 0), sculld_devs); } module_init(sculld_init); module_exit(sculld_cleanup);