staging: comedi: pcmmio: introduce pcmmio_dio_write()

The paged registers in the asic need to be spinlock protected to
ensure that the page is not changed while writing to the registers.

Introduce a helper function to make sure the spinlock is used.

Use the new helper in pcmmio_reset(). This is one of the places where
the spinlock is not used.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/pcmmio.c b/drivers/staging/comedi/drivers/pcmmio.c
index 3f1fb9b..873fcf3 100644 (file)
--- a/drivers/staging/comedi/drivers/pcmmio.c
+++ b/drivers/staging/comedi/drivers/pcmmio.c
@@ -260,6 +260,28 @@ struct pcmmio_private {
        unsigned int ao_readback[8];
 };
 
+static void pcmmio_dio_write(struct comedi_device *dev, unsigned int val,
+                            int page, int port)
+{
+       struct pcmmio_private *devpriv = dev->private;
+       unsigned long iobase = dev->iobase;
+       unsigned long flags;
+
+       spin_lock_irqsave(&devpriv->pagelock, flags);
+       if (page == 0) {
+               /* Port registers are valid for any page */
+               outb(val & 0xff, iobase + PCMMIO_PORT_REG(port + 0));
+               outb((val >> 8) & 0xff, iobase + PCMMIO_PORT_REG(port + 1));
+               outb((val >> 16) & 0xff, iobase + PCMMIO_PORT_REG(port + 2));
+       } else {
+               outb(PCMMIO_PAGE(page), iobase + PCMMIO_PAGE_LOCK_REG);
+               outb(val & 0xff, iobase + PCMMIO_PAGE_REG(0));
+               outb((val >> 8) & 0xff, iobase + PCMMIO_PAGE_REG(1));
+               outb((val >> 16) & 0xff, iobase + PCMMIO_PAGE_REG(2));
+       }
+       spin_unlock_irqrestore(&devpriv->pagelock, flags);
+}
+
 /* DIO devices are slightly special.  Although it is possible to
  * implement the insn_read/insn_write interface, it is much more
  * useful to applications if you implement the insn_bits interface.
@@ -355,25 +377,14 @@ static void switch_page(struct comedi_device *dev, int page)
 
 static void pcmmio_reset(struct comedi_device *dev)
 {
-       int port, page;
-
-       switch_page(dev, 0);    /* switch back to page 0 */
-
-       /* first, clear all the DIO port bits */
-       for (port = 0; port < PORTS_PER_ASIC; ++port)
-               outb(0, dev->iobase + PCMMIO_PORT_REG(port));
-
-       /* Next, clear all the paged registers for each page */
-       for (page = 1; page < NUM_PAGES; ++page) {
-               int reg;
-               /* now clear all the paged registers */
-               switch_page(dev, page);
-               for (reg = 0; reg < NUM_PAGED_REGS; ++reg)
-                       outb(0, dev->iobase + PCMMIO_PAGE_REG(reg));
-       }
-
-       /* switch back to default page 0 */
-       switch_page(dev, 0);
+       /* Clear all the DIO port bits */
+       pcmmio_dio_write(dev, 0, 0, 0);
+       pcmmio_dio_write(dev, 0, 0, 3);
+
+       /* Clear all the paged registers */
+       pcmmio_dio_write(dev, 0, PCMMIO_PAGE_POL, 0);
+       pcmmio_dio_write(dev, 0, PCMMIO_PAGE_ENAB, 0);
+       pcmmio_dio_write(dev, 0, PCMMIO_PAGE_INT_ID, 0);
 }
 
 static void pcmmio_stop_intr(struct comedi_device *dev,