staging: comedi: das1800: don't pass struct comedi_cmd by value

Various functions in das1800.c take a `struct comedi_cmd` parameter by
value.  Change them to pass the parameter by reference instead.

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

diff --git a/drivers/staging/comedi/drivers/das1800.c b/drivers/staging/comedi/drivers/das1800.c
index 5aca8fbdc246ee047291d3c0d563a3ae35b0cab7..711d4e243b88cacefd196c2040ac0749349cc514 100644 (file)
--- a/drivers/staging/comedi/drivers/das1800.c
+++ b/drivers/staging/comedi/drivers/das1800.c
@@ -958,14 +958,14 @@ static int das1800_ai_do_cmdtest(struct comedi_device *dev,
 }
 
 /* returns appropriate bits for control register a, depending on command */
-static int control_a_bits(struct comedi_cmd cmd)
+static int control_a_bits(const struct comedi_cmd *cmd)
 {
        int control_a;
 
        control_a = FFEN;       /* enable fifo */
-       if (cmd.stop_src == TRIG_EXT)
+       if (cmd->stop_src == TRIG_EXT)
                control_a |= ATEN;
-       switch (cmd.start_src) {
+       switch (cmd->start_src) {
        case TRIG_EXT:
                control_a |= TGEN | CGSL;
                break;
@@ -980,7 +980,7 @@ static int control_a_bits(struct comedi_cmd cmd)
 }
 
 /* returns appropriate bits for control register c, depending on command */
-static int control_c_bits(struct comedi_cmd cmd)
+static int control_c_bits(const struct comedi_cmd *cmd)
 {
        int control_c;
        int aref;
@@ -988,18 +988,18 @@ static int control_c_bits(struct comedi_cmd cmd)
        /* set clock source to internal or external, select analog reference,
         * select unipolar / bipolar
         */
-       aref = CR_AREF(cmd.chanlist[0]);
+       aref = CR_AREF(cmd->chanlist[0]);
        control_c = UQEN;       /* enable upper qram addresses */
        if (aref != AREF_DIFF)
                control_c |= SD;
        if (aref == AREF_COMMON)
                control_c |= CMEN;
        /* if a unipolar range was selected */
-       if (CR_RANGE(cmd.chanlist[0]) & UNIPOLAR)
+       if (CR_RANGE(cmd->chanlist[0]) & UNIPOLAR)
                control_c |= UB;
-       switch (cmd.scan_begin_src) {
+       switch (cmd->scan_begin_src) {
        case TRIG_FOLLOW:       /*  not in burst mode */
-               switch (cmd.convert_src) {
+               switch (cmd->convert_src) {
                case TRIG_TIMER:
                        /* trig on cascaded counters */
                        control_c |= IPCLK;
@@ -1047,29 +1047,33 @@ static int das1800_set_frequency(struct comedi_device *dev)
 }
 
 /* sets up counters */
-static int setup_counters(struct comedi_device *dev, struct comedi_cmd cmd)
+static int setup_counters(struct comedi_device *dev,
+                         const struct comedi_cmd *cmd)
 {
+       unsigned int period;
+
        /*  setup cascaded counters for conversion/scan frequency */
-       switch (cmd.scan_begin_src) {
+       switch (cmd->scan_begin_src) {
        case TRIG_FOLLOW:       /*  not in burst mode */
-               if (cmd.convert_src == TRIG_TIMER) {
+               if (cmd->convert_src == TRIG_TIMER) {
                        /* set conversion frequency */
+                       period = cmd->convert_arg;
                        i8253_cascade_ns_to_timer_2div(TIMER_BASE,
-                                                      &(devpriv->divisor1),
-                                                      &(devpriv->divisor2),
-                                                      &(cmd.convert_arg),
-                                                      cmd.
-                                                      flags & TRIG_ROUND_MASK);
+                                                      &devpriv->divisor1,
+                                                      &devpriv->divisor2,
+                                                      &period,
+                                                      cmd->flags &
+                                                       TRIG_ROUND_MASK);
                        if (das1800_set_frequency(dev) < 0)
                                return -1;
                }
                break;
        case TRIG_TIMER:        /*  in burst mode */
                /* set scan frequency */
-               i8253_cascade_ns_to_timer_2div(TIMER_BASE, &(devpriv->divisor1),
-                                              &(devpriv->divisor2),
-                                              &(cmd.scan_begin_arg),
-                                              cmd.flags & TRIG_ROUND_MASK);
+               period = cmd->scan_begin_arg;
+               i8253_cascade_ns_to_timer_2div(TIMER_BASE, &devpriv->divisor1,
+                                              &devpriv->divisor2, &period,
+                                              cmd->flags & TRIG_ROUND_MASK);
                if (das1800_set_frequency(dev) < 0)
                        return -1;
                break;
@@ -1078,7 +1082,7 @@ static int setup_counters(struct comedi_device *dev, struct comedi_cmd cmd)
        }
 
        /*  setup counter 0 for 'about triggering' */
-       if (cmd.stop_src == TRIG_EXT) {
+       if (cmd->stop_src == TRIG_EXT) {
                /*  load counter 0 in mode 0 */
                i8254_load(dev->iobase + DAS1800_COUNTER, 0, 0, 1, 0);
        }
@@ -1087,7 +1091,7 @@ static int setup_counters(struct comedi_device *dev, struct comedi_cmd cmd)
 }
 
 /* utility function that suggests a dma transfer size based on the conversion period 'ns' */
-static unsigned int suggest_transfer_size(struct comedi_cmd *cmd)
+static unsigned int suggest_transfer_size(const struct comedi_cmd *cmd)
 {
        unsigned int size = DMA_BUF_SIZE;
        static const int sample_size = 2;       /*  size in bytes of one sample from board */
@@ -1125,7 +1129,7 @@ static unsigned int suggest_transfer_size(struct comedi_cmd *cmd)
 }
 
 /* sets up dma */
-static void setup_dma(struct comedi_device *dev, struct comedi_cmd cmd)
+static void setup_dma(struct comedi_device *dev, const struct comedi_cmd *cmd)
 {
        unsigned long lock_flags;
        const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;
@@ -1134,7 +1138,7 @@ static void setup_dma(struct comedi_device *dev, struct comedi_cmd cmd)
                return;
 
        /* determine a reasonable dma transfer size */
-       devpriv->dma_transfer_size = suggest_transfer_size(&cmd);
+       devpriv->dma_transfer_size = suggest_transfer_size(cmd);
        lock_flags = claim_dma_lock();
        disable_dma(devpriv->dma0);
        /* clear flip-flop to make sure 2-byte registers for
@@ -1163,14 +1167,15 @@ static void setup_dma(struct comedi_device *dev, struct comedi_cmd cmd)
 }
 
 /* programs channel/gain list into card */
-static void program_chanlist(struct comedi_device *dev, struct comedi_cmd cmd)
+static void program_chanlist(struct comedi_device *dev,
+                            const struct comedi_cmd *cmd)
 {
        int i, n, chan_range;
        unsigned long irq_flags;
        const int range_mask = 0x3;     /* masks unipolar/bipolar bit off range */
        const int range_bitshift = 8;
 
-       n = cmd.chanlist_len;
+       n = cmd->chanlist_len;
        /*  spinlock protects indirect addressing */
        spin_lock_irqsave(&dev->spinlock, irq_flags);
        outb(QRAM, dev->iobase + DAS1800_SELECT);       /* select QRAM for baseAddress + 0x0 */
@@ -1178,9 +1183,9 @@ static void program_chanlist(struct comedi_device *dev, struct comedi_cmd cmd)
        /* make channel / gain list */
        for (i = 0; i < n; i++) {
                chan_range =
-                   CR_CHAN(cmd.
-                           chanlist[i]) | ((CR_RANGE(cmd.chanlist[i]) &
-                                            range_mask) << range_bitshift);
+                   CR_CHAN(cmd->chanlist[i]) |
+                   ((CR_RANGE(cmd->chanlist[i]) & range_mask) <<
+                    range_bitshift);
                outw(chan_range, dev->iobase + DAS1800_QRAM);
        }
        outb(n - 1, dev->iobase + DAS1800_QRAM_ADDRESS);        /*finish write to QRAM */
@@ -1196,7 +1201,7 @@ static int das1800_ai_do_cmd(struct comedi_device *dev,
        int ret;
        int control_a, control_c;
        struct comedi_async *async = s->async;
-       struct comedi_cmd cmd = async->cmd;
+       const struct comedi_cmd *cmd = &async->cmd;
 
        if (!dev->irq) {
                comedi_error(dev,
@@ -1206,12 +1211,12 @@ static int das1800_ai_do_cmd(struct comedi_device *dev,
 
        /* disable dma on TRIG_WAKE_EOS, or TRIG_RT
         * (because dma in handler is unsafe at hard real-time priority) */
-       if (cmd.flags & (TRIG_WAKE_EOS | TRIG_RT))
+       if (cmd->flags & (TRIG_WAKE_EOS | TRIG_RT))
                devpriv->irq_dma_bits &= ~DMA_ENABLED;
        else
                devpriv->irq_dma_bits |= devpriv->dma_bits;
        /*  interrupt on end of conversion for TRIG_WAKE_EOS */
-       if (cmd.flags & TRIG_WAKE_EOS) {
+       if (cmd->flags & TRIG_WAKE_EOS) {
                /*  interrupt fifo not empty */
                devpriv->irq_dma_bits &= ~FIMD;
        } else {
@@ -1219,8 +1224,8 @@ static int das1800_ai_do_cmd(struct comedi_device *dev,
                devpriv->irq_dma_bits |= FIMD;
        }
        /*  determine how many conversions we need */
-       if (cmd.stop_src == TRIG_COUNT)
-               devpriv->count = cmd.stop_arg * cmd.chanlist_len;
+       if (cmd->stop_src == TRIG_COUNT)
+               devpriv->count = cmd->stop_arg * cmd->chanlist_len;
 
        das1800_cancel(dev, s);
 
@@ -1240,9 +1245,9 @@ static int das1800_ai_do_cmd(struct comedi_device *dev,
        /*  set conversion rate and length for burst mode */
        if (control_c & BMDE) {
                /*  program conversion period with number of microseconds minus 1 */
-               outb(cmd.convert_arg / 1000 - 1,
+               outb(cmd->convert_arg / 1000 - 1,
                     dev->iobase + DAS1800_BURST_RATE);
-               outb(cmd.chanlist_len - 1, dev->iobase + DAS1800_BURST_LENGTH);
+               outb(cmd->chanlist_len - 1, dev->iobase + DAS1800_BURST_LENGTH);
        }
        outb(devpriv->irq_dma_bits, dev->iobase + DAS1800_CONTROL_B);   /*  enable irq/dma */
        outb(control_a, dev->iobase + DAS1800_CONTROL_A);       /* enable fifo and triggering */