comedi: das1800: Add sanity checks for I/O base address

The "das1800" driver uses an admin-supplied configuration option
(`it->options[0]`) to configure the I/O port base address of a board
compatible with the DAS1800 series.  It currently allows any base
address to be configured but the hardware only supports base addresses
(configured by an on-board DIP switch) in the range 0 to 0x3f0 on
16-byte boundaries.  Some boards have an additional span of up to 0x10
registers at offset 0x400 from the main 0x10 byte region.

Add a sanity check to ensure the device is not configured at an
unsupported base address.  If the main base address is correctly aligned
and within range, then the additional region at offset 0x400 from the
configured base address will naturally be within range and correctly
aligned.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://patch.msgid.link/20260130170416.49994-16-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/comedi/drivers/das1800.c b/drivers/comedi/drivers/das1800.c
index 7117c67aee7e13e240f5f22abf9c96559ac6cc51..7d7ea99a81aaebdf065658a17eb79b850d61ab56 100644 (file)
--- a/drivers/comedi/drivers/das1800.c
+++ b/drivers/comedi/drivers/das1800.c
@@ -1172,7 +1172,8 @@ static int das1800_attach(struct comedi_device *dev,
        if (!devpriv)
                return -ENOMEM;
 
-       ret = comedi_request_region(dev, it->options[0], DAS1800_SIZE);
+       ret = comedi_check_request_region(dev, it->options[0], DAS1800_SIZE,
+                                         0, 0x3ff, 16);
        if (ret)
                return ret;