staging: comedi: amplc_dio200: add min register region size in board

Store the length of the main register region in new member `mainsize` of
`struct dio200_board` and initialize it in each element of
`dio200_boards[]`.  For all currently supported boards this is
initialized to `DIO200_IO_SIZE` (0x20), but will be different for newer
boards to be supported in the future.

For ISA boards, this is the actual region length requested, but for PCI
boards it's the minimum expected region length.  Verify that the PCI BAR
region length is sufficient in `dio200_attach_pci()`.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/amplc_dio200.c

@@ -309,6 +309,7 @@ struct dio200_board {
 	enum dio200_model model;
 	enum dio200_layout_idx layout;
 	unsigned char mainbar;
+	unsigned int mainsize;
 };
 
 static const struct dio200_board dio200_boards[] = {
@@ -318,30 +319,35 @@ static const struct dio200_board dio200_boards[] = {
 	 .bustype = isa_bustype,
 	 .model = pc212e_model,
 	 .layout = pc212_layout,
+	 .mainsize = DIO200_IO_SIZE,
 	 },
 	{
 	 .name = "pc214e",
 	 .bustype = isa_bustype,
 	 .model = pc214e_model,
 	 .layout = pc214_layout,
+	 .mainsize = DIO200_IO_SIZE,
 	 },
 	{
 	 .name = "pc215e",
 	 .bustype = isa_bustype,
 	 .model = pc215e_model,
 	 .layout = pc215_layout,
+	 .mainsize = DIO200_IO_SIZE,
 	 },
 	{
 	 .name = "pc218e",
 	 .bustype = isa_bustype,
 	 .model = pc218e_model,
 	 .layout = pc218_layout,
+	 .mainsize = DIO200_IO_SIZE,
 	 },
 	{
 	 .name = "pc272e",
 	 .bustype = isa_bustype,
 	 .model = pc272e_model,
 	 .layout = pc272_layout,
+	 .mainsize = DIO200_IO_SIZE,
 	 },
 #endif
 #if DO_PCI
@@ -352,6 +358,7 @@ static const struct dio200_board dio200_boards[] = {
 	 .model = pci215_model,
 	 .layout = pc215_layout,
 	 .mainbar = 2,
+	 .mainsize = DIO200_IO_SIZE,
 	 },
 	{
 	 .name = "pci272",
@@ -360,6 +367,7 @@ static const struct dio200_board dio200_boards[] = {
 	 .model = pci272_model,
 	 .layout = pc272_layout,
 	 .mainbar = 2,
+	 .mainsize = DIO200_IO_SIZE,
 	 },
 #endif
 };
@@ -1550,7 +1558,7 @@ static int dio200_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 
 		iobase = it->options[0];
 		irq = it->options[1];
-		ret = dio200_request_region(dev, iobase, DIO200_IO_SIZE);
+		ret = dio200_request_region(dev, iobase, thisboard->mainsize);
 		if (ret < 0)
 			return ret;
 		devpriv->io.u.iobase = iobase;
@@ -1578,7 +1586,7 @@ static int __devinit dio200_attach_pci(struct comedi_device *dev,
 {
 	const struct dio200_board *thisboard;
 	struct dio200_private *devpriv;
-	resource_size_t base;
+	resource_size_t base, len;
 	unsigned int bar;
 	int ret;
 
@@ -1607,8 +1615,12 @@ static int __devinit dio200_attach_pci(struct comedi_device *dev,
 	}
 	bar = thisboard->mainbar;
 	base = pci_resource_start(pci_dev, bar);
+	len = pci_resource_len(pci_dev, bar);
+	if (len < thisboard->mainsize) {
+		dev_err(dev->class_dev, "error! PCI region size too small!\n");
+		return -EINVAL;
+	}
 	if ((pci_resource_flags(pci_dev, bar) & IORESOURCE_MEM) != 0) {
-		resource_size_t len = pci_resource_len(pci_dev, bar);
 		devpriv->io.u.membase = ioremap_nocache(base, len);
 		if (!devpriv->io.u.membase) {
 			dev_err(dev->class_dev,
@@ -1655,7 +1667,8 @@ static void dio200_detach(struct comedi_device *dev)
 	}
 	if (is_isa_board(thisboard)) {
 		if (devpriv->io.regtype == io_regtype)
-			release_region(devpriv->io.u.iobase, DIO200_IO_SIZE);
+			release_region(devpriv->io.u.iobase,
+				       thisboard->mainsize);
 	} else if (is_pci_board(thisboard)) {
 		struct pci_dev *pcidev = comedi_to_pci_dev(dev);
 		if (pcidev) {