comedi: fl512: Add sanity checks for I/O base address

The "fl512" driver uses an admin-supplied configuration option
(`it->options[0]`) to configure the I/O port base address of an FL512
board.  It currently allows any base address to be configured and uses a
16-byte register region.

I cannot find any information about this board, but assume it needs to
be aligned to a 16-byte boundary.  I have no idea about the allowed
range, so allow anything in a 32-bit range and add a "FIXME" comment
(although most ancient ISA cards only support 10-bit address decoding).
Add a sanity check to ensure the device is not configured at an
unsupported base address.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://patch.msgid.link/20260130170416.49994-25-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/comedi/drivers/dt282x.c b/drivers/comedi/drivers/dt282x.c
index 4ae80e6c72662bc22152d8d0caf5a0c86a015816..29832e1f062de886fd4fc93c7b364ddde82e7937 100644 (file)
--- a/drivers/comedi/drivers/dt282x.c
+++ b/drivers/comedi/drivers/dt282x.c
@@ -1064,7 +1064,12 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        struct comedi_subdevice *s;
        int ret;
 
-       ret = comedi_request_region(dev, it->options[0], 0x10);
+       /*
+        * Although it has only 16 bytes (8 16-bit registers), it needs to
+        * start on a 32-byte boundary in range 0x200 to 0x3E0.
+        */
+       ret = comedi_check_request_region(dev, it->options[0], 0x10,
+                                         0x200, 0x3ff, 32);
        if (ret)
                return ret;