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comedi: 8255: Add some I/O base address sanity checks

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The "8255" driver allows a COMEDI device to be constructed from one or
more 8255 chips, each at an I/O port base address specified by the
admin-supplied configuration options (`it->options[]`).  Currently, the
driver allows any I/O base addresses to be specified as long as the I/O
regions can be reserved, and it converts the specified `int` option
values holding the base address to `unsigned long`.

It doesn't make sense to allow base addresses that are not aligned to
4-byte boundaries because the hardware register addresses would not be
decoded properly, so add a check for valid alignment.

Convert the option values that specify the base addresses from `int` to
`unsigned int` instead of `unsigned long` so they end up the same on
32-bit and 64-bit systems.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://patch.msgid.link/20260130170416.49994-3-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2026-01-30 16:47:27 +00:00 committed by Greg Kroah-Hartman
parent 241cb8dee0
commit cb51837eee
1 changed files with 6 additions and 4 deletions
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10
drivers/comedi/drivers/8255.c
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@ -47,7 +47,7 @@ static int dev_8255_attach(struct comedi_device *dev,
struct comedi_devconfig *it)
{
struct comedi_subdevice *s;
unsigned long iobase;
unsigned int iobase;
int ret;
int i;
@ -70,13 +70,15 @@ static int dev_8255_attach(struct comedi_device *dev,
iobase = it->options[i];
/*
* __comedi_request_region() does not set dev->iobase.
* __comedi_check_request_region() does not set dev->iobase.
*
* For 8255 devices that are manually attached using
* comedi_config, the 'iobase' is the actual I/O port
* base address of the chip.
* base address of the chip. It should be aligned on
* a 4-byte boundary.
*/
ret = __comedi_request_region(dev, iobase, I8255_SIZE);
ret = __comedi_check_request_region(dev, iobase, I8255_SIZE,
0, UINT_MAX, 4);
if (ret)
return ret;
ret = subdev_8255_io_init(dev, s, iobase);