Commit 5ff1c08c authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
Browse files

staging: comedi: ni_65xx: Use 16-bit 0 for interrupt data 



The ni_65xx driver has an "interrupt" subdevice that supports Comedi
asynchronous commands, placing a value in the Comedi buffer for each
interrupt.  The subdevice uses Comedi's 16-bit sample format but the
interrupt handler is calling `comedi_buf_write_samples()` with the
address of a 32-bit integer `&s->state`.  On bigendian machines, this
will copy 2 bytes from the wrong end of the 32-bit integer.  This isn't
really a problem since `s->state` will always be 0 for this subdevice,
but clean it up by using a 16-bit variable initialized to 0 to pass the
value.

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210223143055.257402-14-abbotti@mev.co.uk


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 33444638

drivers/staging/comedi/drivers/ni_65xx.c

+2 −1
Original line number Diff line number Diff line
@@ -472,6 +472,7 @@ static irqreturn_t ni_65xx_interrupt(int irq, void *d) 
	struct comedi_device *dev = d;

	struct comedi_subdevice *s = dev->read_subdev;

	unsigned int status;

	unsigned short val = 0;



	status = readb(dev->mmio + NI_65XX_STATUS_REG);

	if ((status & NI_65XX_STATUS_INT) == 0)
@@ -482,7 +483,7 @@ static irqreturn_t ni_65xx_interrupt(int irq, void *d) 
	writeb(NI_65XX_CLR_EDGE_INT | NI_65XX_CLR_OVERFLOW_INT,

	       dev->mmio + NI_65XX_CLR_REG);



	comedi_buf_write_samples(s, &s->state, 1);

	comedi_buf_write_samples(s, &val, 1);

	comedi_handle_events(dev, s);



	return IRQ_HANDLED;