staging: comedi: amplc_pci230: use comedi_async 'scans_done' to detect AI EOA

Remove the private data member 'ai_scan_count' and use the comedi_async 'scans_done'
member to detect the analog input end-of-acquisition.

Use the comedi_nsamples_left() helper to work out the number of 'wake' samples in
pci230_ai_update_fifo_trigger_level() and the number of 'todo' samples actually
added to the async buffer in pci230_handle_ai().

Remove the unnecessary COMEDI_CB_OVERFLOW event for the hardware FIFO overflow
error. The COMEDI_CB_ERROR event will terminate the command.

comedi_buf_write_samples() can fail if the async buffer does not have room for
the sample. The it will set the COMEDI_CB_OVERFLOW event and return 0. Detect
this and quit trying to read and add more samples. The event will terminate the
command.

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/amplc_pci230.c b/drivers/staging/comedi/drivers/amplc_pci230.c
index 5f4b67505932b751a56f98a0c4bc1519fcc0de96..fb0b70fdce7da3b3c0f00dea4cdd53713fefa723 100644 (file)
--- a/drivers/staging/comedi/drivers/amplc_pci230.c
+++ b/drivers/staging/comedi/drivers/amplc_pci230.c
@@ -490,7 +490,6 @@ struct pci230_private {
        spinlock_t ai_stop_spinlock;    /* Spin lock for stopping AI command */
        spinlock_t ao_stop_spinlock;    /* Spin lock for stopping AO command */
        unsigned long daqio;            /* PCI230's DAQ I/O space */
-       unsigned int ai_scan_count;     /* Number of AI scans remaining */
        int intr_cpuid;                 /* ID of CPU running ISR */
        unsigned short hwver;           /* Hardware version (for '+' models) */
        unsigned short adccon;          /* ADCCON register value */
@@ -1720,19 +1719,15 @@ static void pci230_ai_update_fifo_trigger_level(struct comedi_device *dev,
 {
        struct pci230_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
-       unsigned int scanlen = cmd->scan_end_arg;
        unsigned int wake;
        unsigned short triglev;
        unsigned short adccon;
 
        if (cmd->flags & CMDF_WAKE_EOS)
-               wake = scanlen - s->async->cur_chan;
-       else if (cmd->stop_src != TRIG_COUNT ||
-                devpriv->ai_scan_count >= PCI230_ADC_FIFOLEVEL_HALFFULL ||
-                scanlen >= PCI230_ADC_FIFOLEVEL_HALFFULL)
-               wake = PCI230_ADC_FIFOLEVEL_HALFFULL;
+               wake = cmd->scan_end_arg - s->async->cur_chan;
        else
-               wake = devpriv->ai_scan_count * scanlen - s->async->cur_chan;
+               wake = comedi_nsamples_left(s, PCI230_ADC_FIFOLEVEL_HALFFULL);
+
        if (wake >= PCI230_ADC_FIFOLEVEL_HALFFULL) {
                triglev = PCI230_ADC_INT_FIFO_HALF;
        } else if (wake > 1 && devpriv->hwver > 0) {
@@ -2025,8 +2020,6 @@ static void pci230_handle_ai(struct comedi_device *dev,
        struct pci230_private *devpriv = dev->private;
        struct comedi_async *async = s->async;
        struct comedi_cmd *cmd = &async->cmd;
-       unsigned int scanlen = cmd->scan_end_arg;
-       unsigned int events = 0;
        unsigned int status_fifo;
        unsigned int i;
        unsigned int todo;
@@ -2034,20 +2027,10 @@ static void pci230_handle_ai(struct comedi_device *dev,
        unsigned short val;
 
        /* Determine number of samples to read. */
-       if (cmd->stop_src != TRIG_COUNT) {
-               todo = PCI230_ADC_FIFOLEVEL_HALFFULL;
-       } else if (devpriv->ai_scan_count == 0) {
-               todo = 0;
-       } else if (devpriv->ai_scan_count > PCI230_ADC_FIFOLEVEL_HALFFULL ||
-                  scanlen > PCI230_ADC_FIFOLEVEL_HALFFULL) {
-               todo = PCI230_ADC_FIFOLEVEL_HALFFULL;
-       } else {
-               todo = devpriv->ai_scan_count * scanlen - async->cur_chan;
-               if (todo > PCI230_ADC_FIFOLEVEL_HALFFULL)
-                       todo = PCI230_ADC_FIFOLEVEL_HALFFULL;
-       }
+       todo = comedi_nsamples_left(s, PCI230_ADC_FIFOLEVEL_HALFFULL);
        if (todo == 0)
                return;
+
        fifoamount = 0;
        for (i = 0; i < todo; i++) {
                if (fifoamount == 0) {
@@ -2059,7 +2042,7 @@ static void pci230_handle_ai(struct comedi_device *dev,
                                 * unnoticed by the caller.
                                 */
                                dev_err(dev->class_dev, "AI FIFO overrun\n");
-                               events |= COMEDI_CB_OVERFLOW | COMEDI_CB_ERROR;
+                               async->events |= COMEDI_CB_ERROR;
                                break;
                        } else if (status_fifo & PCI230_ADC_FIFO_EMPTY) {
                                /* FIFO empty. */
@@ -2080,21 +2063,21 @@ static void pci230_handle_ai(struct comedi_device *dev,
                }
 
                val = pci230_ai_read(dev);
-               comedi_buf_write_samples(s, &val, 1);
+               if (!comedi_buf_write_samples(s, &val, 1))
+                       break;
 
                fifoamount--;
-               if (async->cur_chan == 0)
-                       devpriv->ai_scan_count--;
-       }
-       if (cmd->stop_src == TRIG_COUNT && devpriv->ai_scan_count == 0) {
-               /* End of acquisition. */
-               events |= COMEDI_CB_EOA;
+
+               if (cmd->stop_src == TRIG_COUNT &&
+                   async->scans_done >= cmd->stop_arg) {
+                       async->events |= COMEDI_CB_EOA;
+                       break;
+               }
        }
-       async->events |= events;
-       if (!(async->events & COMEDI_CB_CANCEL_MASK)) {
-               /* update FIFO interrupt trigger level */
+
+       /* update FIFO interrupt trigger level if still running */
+       if (!(async->events & COMEDI_CB_CANCEL_MASK))
                pci230_ai_update_fifo_trigger_level(dev, s);
-       }
 }
 
 static int pci230_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
@@ -2130,8 +2113,6 @@ static int pci230_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
        if (!pci230_claim_shared(dev, res_mask, OWNER_AICMD))
                return -EBUSY;
 
-       devpriv->ai_scan_count = cmd->stop_arg;
-
        /*
         * Steps:
         * - Set channel scan list.