patch-2.1.73 linux/drivers/sgi/char/shmiq.c

• Lines: 461
• Date: Wed Dec 10 10:31:11 1997
• Orig file: v2.1.72/linux/drivers/sgi/char/shmiq.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.72/linux/drivers/sgi/char/shmiq.c linux/drivers/sgi/char/shmiq.c
@@ -0,0 +1,460 @@
+/*
+ * shmiq.c: shared memory input queue driver
+ * written 1997 Miguel de Icaza (miguel@nuclecu.unam.mx)
+ *
+ * We implement /dev/shmiq, /dev/qcntlN here
+ * this is different from IRIX that has shmiq as a misc
+ * streams device and the and qcntl devices as a major device.
+ *
+ * minor number 0 implements /dev/shmiq,
+ * any other number implements /dev/qcntl${minor-1}
+ *
+ * /dev/shmiq is used by the X server for two things:
+ * 
+ *    1. for I_LINK()ing trough ioctl the file handle of a
+ *       STREAMS device.
+ *
+ *    2. To send STREAMS-commands to the devices with the
+ *       QIO ioctl interface.
+ *
+ * I have not yet figured how to make multiple X servers share
+ * /dev/shmiq for having different servers running.  So, for now
+ * I keep a kernel-global array of inodes that are pushed into
+ * /dev/shmiq.
+ *
+ * /dev/qcntlN is used by the X server for two things:
+ *
+ *    1. Issuing the QIOCATTACH for mapping the shared input
+ *       queue into the address space of the X server (yeah, yeah,
+ *       I did not invent this interface).
+ *
+ *    2. used by select.  I bet it is used for checking for events on
+ *       the queue.
+ *
+ * Now the problem is that there does not seem anything that
+ * establishes a connection between /dev/shmiq and the qcntlN file.  I
+ * need an strace from an X server that runs on a machine with more
+ * than one keyboard.  And this is a problem since the file handles
+ * are pushed in /dev/shmiq, while the events should be dispatched to
+ * the /dev/qcntlN device. 
+ *
+ * Until then, I just allow for 1 qcntl device.
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/interrupt.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+#include <linux/major.h>
+
+#include <asm/smp_lock.h>
+#include <asm/shmiq.h>
+#include <asm/mman.h>
+#include <asm/uaccess.h>
+#include <asm/poll.h>
+#include "graphics.h"
+
+/* we are not really getting any more than a few files in the shmiq */
+#define MAX_SHMIQ_DEVS 10
+
+/*
+ * One per X server running, not going to get very big.
+ * Even if we have this we now assume just 1 /dev/qcntl can be
+ * active, I need to find how this works on multi-headed machines.
+ */
+#define MAX_SHMI_QUEUES 4
+
+static struct {
+	int                 used;
+	struct file         *filp;
+	struct shmiqsetcpos cpos;
+} shmiq_pushed_devices [MAX_SHMIQ_DEVS];
+
+/* /dev/qcntlN attached memory regions, location and size of the event queue */
+static struct {
+	int    opened;		/* if this device has been opened */
+	void   *shmiq_vaddr;	/* mapping in kernel-land */
+	int    tail;		/* our copy of the shmiq->tail */
+	int    events;
+	int    mapped;
+	
+	struct wait_queue    *proc_list;
+	struct fasync_struct *fasync;
+} shmiqs [MAX_SHMI_QUEUES];
+
+void
+shmiq_push_event (struct shmqevent *e)
+{
+	struct sharedMemoryInputQueue *s;
+	int    device = 0;	/* FIXME: here is the assumption /dev/shmiq == /dev/qcntl0 */
+	int    tail_next;
+
+	if (!shmiqs [device].mapped)
+		return;
+	s = shmiqs [device].shmiq_vaddr;
+
+	s->flags = 0;
+	if (s->tail != shmiqs [device].tail){
+		s->flags |= SHMIQ_CORRUPTED;
+		return;
+	}
+	tail_next = (s->tail + 1) % (shmiqs [device].events);
+	
+	if (tail_next == s->head){
+		s->flags |= SHMIQ_OVERFLOW;
+		return;
+	}
+	
+	e->un.time = jiffies;
+	s->events [s->tail] = *e;
+	printk ("KERNEL: dev=%d which=%d type=%d flags=%d\n",
+		e->data.device, e->data.which, e->data.type, e->data.flags);
+	s->tail = tail_next;
+	shmiqs [device].tail = tail_next;
+	if (shmiqs [device].fasync)
+		kill_fasync (shmiqs [device].fasync, SIGIO);
+	wake_up_interruptible (&shmiqs [device].proc_list);
+}
+
+static int
+shmiq_manage_file (struct file *filp)
+{
+	int i;
+
+	if (!filp->f_op || !filp->f_op->ioctl)
+		return -ENOSR;
+
+	for (i = 0; i < MAX_SHMIQ_DEVS; i++){
+		if (shmiq_pushed_devices [i].used)
+			continue;
+		if ((*filp->f_op->ioctl)(filp->f_dentry->d_inode, filp, SHMIQ_ON, i) != 0)
+			return -ENOSR;
+		shmiq_pushed_devices [i].used = 1;
+		shmiq_pushed_devices [i].filp = filp;
+		shmiq_pushed_devices [i].cpos.x = 0;
+		shmiq_pushed_devices [i].cpos.y = 0;
+		return i;
+	}
+	return -ENOSR;
+}
+
+static int
+shmiq_forget_file (unsigned long fdes)
+{
+	struct file *filp;
+
+	if (fdes > MAX_SHMIQ_DEVS)
+		return -EINVAL;
+	
+	if (!shmiq_pushed_devices [fdes].used)
+		return -EINVAL;
+
+	filp = shmiq_pushed_devices [fdes].filp;
+	if (filp){
+		(*filp->f_op->ioctl)(filp->f_dentry->d_inode, filp, SHMIQ_OFF, 0);
+		shmiq_pushed_devices [fdes].filp = 0;
+		fput (filp);
+	}
+	shmiq_pushed_devices [fdes].used = 0;
+
+	return 0;
+}
+
+static int
+shmiq_sioc (int device, int cmd, struct strioctl *s)
+{
+	switch (cmd){
+	case QIOCGETINDX:
+		/*
+		 * Ok, we just return the index they are providing us
+		 */
+		printk ("QIOCGETINDX: returning %d\n", *(int *)s->ic_dp);
+		return 0;
+
+	case QIOCIISTR: {
+		struct muxioctl *mux = (struct muxioctl *) s->ic_dp;
+		
+		printk ("Double indirect ioctl: [%d, %x\n", mux->index, mux->realcmd);
+		return -EINVAL;
+	}
+
+	case QIOCSETCPOS: {
+		if (copy_from_user (&shmiq_pushed_devices [device].cpos, s->ic_dp,
+				    sizeof (struct shmiqsetcpos)))
+			return -EFAULT;
+		return 0;
+	}
+	}
+	printk ("Unknown I_STR request for shmiq device: 0x%x\n", cmd);
+	return -EINVAL;
+}
+
+static int
+shmiq_ioctl (struct inode *inode, struct file *f, unsigned int cmd, unsigned long arg)
+{
+	struct file *file;
+	struct strioctl sioc;
+	int v;
+
+	switch (cmd){
+		/*
+		 * They are giving us the file descriptor for one
+		 * of their streams devices
+		 */
+
+	case I_LINK:
+		file = fget (arg);
+		if (!file)
+			goto bad_file;
+
+		v = shmiq_manage_file (file);
+		return v;
+
+		/*
+		 * Remove a device from our list of managed
+		 * stream devices
+		 */
+	case I_UNLINK:
+		v = shmiq_forget_file (arg);
+		return v;
+		
+	case I_STR:
+		v = get_sioc (&sioc, arg);
+		if (v)
+			return v;
+		
+		/* FIXME: This forces device = 0 */
+		return shmiq_sioc (0, sioc.ic_cmd, &sioc);
+	}
+
+	return -EINVAL;
+bad_file:
+	unlock_kernel ();
+	return -EBADF;
+}
+
+extern sys_munmap(unsigned long addr, size_t len);
+
+static int
+qcntl_ioctl (struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg, int minor)
+{
+	struct shmiqreq req;
+	struct vm_area_struct *vma;
+	int v;
+	
+	switch (cmd){
+		/*
+		 * The address space is already mapped as a /dev/zero
+		 * mapping.  FIXME: check that /dev/zero is what the user
+		 * had mapped before :-)
+		 */
+	case QIOCATTACH: {
+		unsigned long vaddr;
+		int s;
+		
+		v = verify_area (VERIFY_READ, (void *) arg, sizeof (struct shmiqreq));
+		if (v)
+			return v;
+		if (copy_from_user (&req, (void *) arg, sizeof (req)))
+			return -EFAULT;
+		/* Do not allow to attach to another region if it has been already attached */
+		if (shmiqs [minor].mapped){
+			printk ("SHMIQ:The thingie is already mapped\n");
+			return -EINVAL;
+		}
+
+		vaddr = (unsigned long) req.user_vaddr;
+		vma = find_vma (current->mm, vaddr);
+		if (!vma){
+			printk ("SHMIQ: could not find %lx the vma\n", vaddr);
+			return -EINVAL;
+		}
+		s = req.arg * sizeof (struct shmqevent) + sizeof (struct sharedMemoryInputQueue);
+		v = sys_munmap (vaddr, s);
+		do_mmap (filp, vaddr, s, PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 0);
+		shmiqs [minor].events = req.arg;
+		shmiqs [minor].mapped = 1;
+		return 0;
+	}
+	}
+	return -EINVAL;
+}
+
+unsigned long
+shmiq_nopage (struct vm_area_struct *vma, unsigned long address, int write_access)
+{
+	/* Do not allow for mremap to expand us */
+	return 0;
+}
+
+static struct vm_operations_struct qcntl_mmap = {
+	NULL,			/* no special mmap-open */
+	NULL,			/* no special mmap-close */
+	NULL,			/* no special mmap-unmap */
+	NULL,			/* no special mmap-protect */
+	NULL,			/* no special mmap-sync */
+	NULL,			/* no special mmap-advise */
+	shmiq_nopage,		/* our magic no-page fault handler */
+	NULL,			/* no special mmap-wppage */
+	NULL,			/* no special mmap-swapout */
+	NULL			/* no special mmap-swapin */
+};
+
+static int
+shmiq_qcntl_mmap (struct file *file, struct vm_area_struct *vma)
+{
+	int           minor = MINOR (file->f_dentry->d_inode->i_rdev), error;
+	unsigned int  size;
+	unsigned long mem, start;
+	
+	/* mmap is only supported on the qcntl devices */
+	if (minor-- == 0)
+		return -EINVAL;
+
+	if (vma->vm_offset != 0)
+		return -EINVAL;
+
+	size  = vma->vm_end - vma->vm_start;
+	start = vma->vm_start; 
+	mem = (unsigned long) shmiqs [minor].shmiq_vaddr =  vmalloc_uncached (size);
+	if (!mem)
+		return -EINVAL;
+
+	/* Prevent the swapper from considering these pages for swap and touching them */
+	vma->vm_flags    |= (VM_SHM  | VM_LOCKED | VM_IO);
+	vma->vm_ops = &qcntl_mmap;
+	
+	/* Uncache the pages */
+	vma->vm_page_prot = PAGE_USERIO;
+
+	error = vmap_page_range (vma->vm_start, size, mem);
+
+	shmiqs [minor].tail = 0;
+	/* Init the shared memory input queue */
+	memset (shmiqs [minor].shmiq_vaddr, 0, size);
+	
+	return error;
+}
+		  
+static int
+shmiq_qcntl_ioctl (struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	int minor = MINOR (inode->i_rdev);
+
+	lock_kernel ();
+
+	if (minor-- == 0)
+		return shmiq_ioctl (inode, filp, cmd, arg);
+
+	return qcntl_ioctl (inode, filp, cmd, arg, minor);
+}
+
+static unsigned int
+shmiq_qcntl_poll (struct file *filp, poll_table *wait)
+{
+	struct sharedMemoryInputQueue *s;
+	int minor = MINOR (filp->f_dentry->d_inode->i_rdev);
+
+	if (minor-- == 0)
+		return 0;
+
+	if (!shmiqs [minor].mapped)
+		return 0;
+	
+	poll_wait (&shmiqs [minor].proc_list, wait);
+	s = shmiqs [minor].shmiq_vaddr;
+	if (s->head != s->tail)
+		return POLLIN | POLLRDNORM;
+	return 0;
+}
+
+static int
+shmiq_qcntl_open (struct inode *inode, struct file *filp)
+{
+	int minor = MINOR (inode->i_rdev);
+
+	if (minor == 0)
+		return 0;
+
+	minor--;
+	if (minor > MAX_SHMI_QUEUES)
+		return -EINVAL;
+	if (shmiqs [minor].opened)
+		return -EBUSY;
+
+	lock_kernel ();
+	shmiqs [minor].opened      = 1;
+	shmiqs [minor].shmiq_vaddr = 0;
+	unlock_kernel ();
+	return 0;
+}
+
+static int
+shmiq_qcntl_fasync (struct file *file, int on)
+{
+	int retval;
+	int minor = MINOR (file->f_dentry->d_inode->i_rdev);
+
+	retval = fasync_helper (file, on, &shmiqs [minor].fasync);
+	if (retval < 0)
+		return retval;
+	return 0;
+}
+
+static int
+shmiq_qcntl_close (struct inode *inode, struct file *filp)
+{
+	int minor = MINOR (inode->i_rdev);
+	int j;
+	
+	if (minor-- == 0){
+		for (j = 0; j < MAX_SHMIQ_DEVS; j++)
+			shmiq_forget_file (j);
+	}
+
+	if (minor > MAX_SHMI_QUEUES)
+		return -EINVAL;
+	if (shmiqs [minor].opened == 0)
+		return -EINVAL;
+
+	lock_kernel ();
+	shmiq_qcntl_fasync (filp, 0);
+	shmiqs [minor].opened      = 0;
+	shmiqs [minor].mapped      = 0;
+	shmiqs [minor].events      = 0;
+	shmiqs [minor].fasync      = 0;
+	vfree (shmiqs [minor].shmiq_vaddr);
+	shmiqs [minor].shmiq_vaddr = 0;
+	unlock_kernel ();
+	return 0;
+}
+
+
+static struct
+file_operations shmiq_fops =
+{
+        NULL,                   /* seek */
+        NULL,                   /* read */
+        NULL,                   /* write */
+        NULL,                   /* readdir */
+        shmiq_qcntl_poll,       /* poll */
+        shmiq_qcntl_ioctl,      /* ioctl */
+        shmiq_qcntl_mmap,       /* mmap */
+        shmiq_qcntl_open,       /* open */
+        shmiq_qcntl_close,      /* close */
+        NULL,                   /* fsync */
+        shmiq_qcntl_fasync,     /* fasync */
+        NULL,                   /* check_media_change */
+        NULL,                   /* revalidate */
+};
+
+void
+shmiq_init (void)
+{
+	printk ("SHMIQ setup\n");
+	register_chrdev (SHMIQ_MAJOR, "shmiq", &shmiq_fops);
+}