added bufconfig ioctl

diff --git a/comedi/comedi_fops.c b/comedi/comedi_fops.c
index 5a047e087727274e6d25aeef5a48cef887b098e2..e2ba5ce0d4205fc8eec3399c2ca40de4a2089585 100644 (file)
--- a/comedi/comedi_fops.c
+++ b/comedi/comedi_fops.c
@@ -48,6 +48,7 @@
 comedi_device *comedi_devices;
 
 static int do_devconfig_ioctl(comedi_device *dev,comedi_devconfig *arg,kdev_t minor);
+static int do_bufconfig_ioctl(comedi_device *dev,void *arg);
 static int do_devinfo_ioctl(comedi_device *dev,comedi_devinfo *arg);
 static int do_subdinfo_ioctl(comedi_device *dev,comedi_subdinfo *arg,void *file);
 static int do_chaninfo_ioctl(comedi_device *dev,comedi_chaninfo *arg);
@@ -62,6 +63,7 @@ static int do_cmdtest_ioctl(comedi_device *dev,void *arg,void *file);
 static int do_insnlist_ioctl(comedi_device *dev,void *arg,void *file);
 
 static void do_become_nonbusy(comedi_device *dev,comedi_subdevice *s);
+int resize_buf(comedi_device *dev,comedi_subdevice *s, unsigned int size);
 
 static int comedi_ioctl(struct inode * inode,struct file * file,unsigned int cmd,unsigned long arg)
 {
@@ -72,6 +74,8 @@ static int comedi_ioctl(struct inode * inode,struct file * file,unsigned int cmd
        {
        case COMEDI_DEVCONFIG:
                return do_devconfig_ioctl(dev,(void *)arg,minor);
+       case COMEDI_BUFCONFIG:
+               return do_bufconfig_ioctl(dev,(void*)arg);
        case COMEDI_DEVINFO:
                return do_devinfo_ioctl(dev,(void *)arg);
        case COMEDI_SUBDINFO:
@@ -121,7 +125,7 @@ static int do_devconfig_ioctl(comedi_device *dev,comedi_devconfig *arg,kdev_t mi
        
        if(!suser())
                return -EPERM;
-       
+
        if(arg==NULL){
                return comedi_device_detach(dev);
        }
@@ -130,15 +134,122 @@ static int do_devconfig_ioctl(comedi_device *dev,comedi_devconfig *arg,kdev_t mi
                return -EFAULT;
        
        it.board_name[COMEDI_NAMELEN-1]=0;
-       
+
        return comedi_device_attach(dev,&it);
 }
 
+/*
+       COMEDI_BUFCONFIG
+       buffer configuration ioctl
+
+       arg:
+               pointer to bufconfig structure
+
+       reads:
+               bufconfig at arg
+
+       writes:
+               modified bufconfig at arg
+
+*/
+static int do_bufconfig_ioctl(comedi_device *dev,void *arg)
+{
+       comedi_bufconfig bc;
+       comedi_subdevice *rsd=NULL, *wsd=NULL;
+       int read_ret = 0, write_ret = 0;
+
+       if(!suser())
+               return -EPERM;
+
+       // perform sanity checks
+       if(!dev->attached)
+               return -EINVAL;
+
+       if(copy_from_user(&bc,arg,sizeof(comedi_bufconfig)))
+               return -EFAULT;
+
+       // Should check to see if buffer is memory mapped and avoid
+       // changing buffer if it is.  (Have to wait until a mapped flag
+       // gets added to subdevice struct.)
+
+       if(bc.read_size){
+               rsd = &dev->subdevices[dev->read_subdev];
+
+               if(rsd->busy)
+                       return -EBUSY;
+
+               if(!rsd->prealloc_buf)
+                       return -EINVAL;
+       }
+
+       if(bc.write_size && dev->read_subdev != dev->write_subdev){
+               wsd = &dev->subdevices[dev->write_subdev];
+
+               if(wsd->busy)
+                       return -EBUSY;
+
+               if(!wsd->prealloc_buf)
+                       return -EINVAL;
+       }
+
+       // resize buffers
+       if(rsd){
+               read_ret = resize_buf(dev,rsd,bc.read_size);
+               bc.read_size = rsd->prealloc_bufsz;
+               DPRINTK("dev %i read buffer resized to %i bytes\n", dev->minor, bc.read_size);
+       }
+
+       if(wsd){
+               write_ret = resize_buf(dev,wsd,bc.write_size);
+               bc.write_size = wsd->prealloc_bufsz;
+               DPRINTK("dev %i write buffer resized to %i bytes\n", dev->minor, bc.write_size);
+       }
+       else bc.write_size = 0;
+
+
+       if(copy_to_user(arg,&bc,sizeof(comedi_bufconfig)))
+               return -EFAULT;
+
+       if(read_ret < 0 || write_ret < 0)
+               return -ENOMEM;
+
+       return 0;
+}
+
+/* utility function that resizes the prealloc_buf for
+ * a subdevice
+ */
+int resize_buf(comedi_device *dev, comedi_subdevice *s, unsigned int size)
+{
+       void *old_buf;
+
+       // make sure buffer is an integral number of pages (we round up)
+       size = ((size + PAGE_SIZE - 1) / PAGE_SIZE) * PAGE_SIZE;
+
+       // if no change is required, do nothing
+       if(s->prealloc_buf && s->prealloc_bufsz){
+               if(s->prealloc_bufsz == size)
+                       return 0;
+       }
+
+       old_buf = s->prealloc_buf;
+       s->prealloc_buf = rvmalloc(size);
+       // restore old buffer on error
+       if(s->prealloc_buf == 0){
+               s->prealloc_buf = old_buf;
+               return -ENOMEM;
+       }
+
+       rvfree(old_buf, s->prealloc_bufsz);
+       s->prealloc_bufsz = size;
+
+       return 0;
+}
 
 /*
        COMEDI_DEVINFO
        device info ioctl
-       
+
        arg:
                pointer to devinfo structure