Staging: comedi: pcl816: Check channel list in AI command test

Check the channel list is valid in step 5 of the AI command test.
Split function check_and_setup_channel_list() in two.  Also, remove
unnecessary chanlist_len tests in step 3 of the AI command test as the
comedi core has already checked it.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/comedi/drivers/pcl816.c b/drivers/staging/comedi/drivers/pcl816.c
index 5c88ddc1fc0574ffc431fac058e02658d5bf7936..9820759ec54f9da66f6c0ecb9d3cf5d0dfc32766 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl816.c
+++ b/drivers/staging/comedi/drivers/pcl816.c
@@ -214,9 +214,12 @@ struct pcl816_private {
 /*
 ==============================================================================
 */
-static int check_and_setup_channel_list(struct comedi_device *dev,
-                                       struct comedi_subdevice *s,
-                                       unsigned int *chanlist, int chanlen);
+static int check_channel_list(struct comedi_device *dev,
+                             struct comedi_subdevice *s,
+                             unsigned int *chanlist, unsigned int chanlen);
+static void setup_channel_list(struct comedi_device *dev,
+                              struct comedi_subdevice *s,
+                              unsigned int *chanlist, unsigned int seglen);
 static int pcl816_ai_cancel(struct comedi_device *dev,
                            struct comedi_subdevice *s);
 static void start_pacer(struct comedi_device *dev, int mode,
@@ -566,14 +569,6 @@ static int pcl816_ai_cmdtest(struct comedi_device *dev,
                }
        }
 
-       if (!cmd->chanlist_len) {
-               cmd->chanlist_len = 1;
-               err++;
-       }
-       if (cmd->chanlist_len > this_board->n_aichan) {
-               cmd->chanlist_len = this_board->n_aichan;
-               err++;
-       }
        if (cmd->scan_end_arg != cmd->chanlist_len) {
                cmd->scan_end_arg = cmd->chanlist_len;
                err++;
@@ -611,6 +606,14 @@ static int pcl816_ai_cmdtest(struct comedi_device *dev,
                return 4;
        }
 
+       /* step 5: complain about special chanlist considerations */
+
+       if (cmd->chanlist) {
+               if (!check_channel_list(dev, s, cmd->chanlist,
+                                       cmd->chanlist_len))
+                       return 5;       /*  incorrect channels list */
+       }
+
        return 0;
 }
 
@@ -618,6 +621,7 @@ static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 {
        unsigned int divisor1 = 0, divisor2 = 0, dma_flags, bytes, dmairq;
        struct comedi_cmd *cmd = &s->async->cmd;
+       unsigned int seglen;
 
        if (cmd->start_src != TRIG_NOW)
                return -EINVAL;
@@ -650,9 +654,10 @@ static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 
        start_pacer(dev, -1, 0, 0);     /*  stop pacer */
 
-       if (!check_and_setup_channel_list(dev, s, cmd->chanlist,
-                                         cmd->chanlist_len))
+       seglen = check_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len);
+       if (seglen < 1)
                return -EINVAL;
+       setup_channel_list(dev, s, cmd->chanlist, seglen);
        udelay(1);
 
        devpriv->ai_n_chan = cmd->chanlist_len;
@@ -880,12 +885,12 @@ start_pacer(struct comedi_device *dev, int mode, unsigned int divisor1,
 /*
 ==============================================================================
  Check if channel list from user is builded correctly
- If it's ok, then program scan/gain logic
+ If it's ok, then return non-zero length of repeated segment of channel list
 */
 static int
-check_and_setup_channel_list(struct comedi_device *dev,
-                            struct comedi_subdevice *s, unsigned int *chanlist,
-                            int chanlen)
+check_channel_list(struct comedi_device *dev,
+                  struct comedi_subdevice *s, unsigned int *chanlist,
+                  unsigned int chanlen)
 {
        unsigned int chansegment[16];
        unsigned int i, nowmustbechan, seglen, segpos;
@@ -939,6 +944,20 @@ check_and_setup_channel_list(struct comedi_device *dev,
                seglen = 1;
        }
 
+       return seglen;  /*  we can serve this with MUX logic */
+}
+
+/*
+==============================================================================
+ Program scan/gain logic with channel list.
+*/
+static void
+setup_channel_list(struct comedi_device *dev,
+                  struct comedi_subdevice *s, unsigned int *chanlist,
+                  unsigned int seglen)
+{
+       unsigned int i;
+
        devpriv->ai_act_chanlist_len = seglen;
        devpriv->ai_act_chanlist_pos = 0;
 
@@ -951,8 +970,6 @@ check_and_setup_channel_list(struct comedi_device *dev,
        udelay(1);
 
        outb(devpriv->ai_act_chanlist[0] | (devpriv->ai_act_chanlist[seglen - 1] << 4), dev->iobase + PCL816_MUX);      /* select channel interval to scan */
-
-       return 1;               /*  we can serve this with MUX logic */
 }
 
 #ifdef unused