protected indirect addressing with comedi_spin_lock_irqsave()

diff --git a/comedi/drivers/das1800.c b/comedi/drivers/das1800.c
index f607193a54e95d51fbc2097016d0ed726aa8e2eb..37a8b0f5dd2c0400590cd7161346899f29a5bc87 100644 (file)
--- a/comedi/drivers/das1800.c
+++ b/comedi/drivers/das1800.c
@@ -71,11 +71,8 @@ Only the DAS-1801ST has been tested by me.
 Unipolar and bipolar ranges cannot be mixed in the channel/gain list.
 Documentation on register-level programing of the das-1800 series boards
        is available for download from Keitley's web site http://www.keithley.com
-
-WARNING:
-It is not safe to run this driver at real-time priority with dma enabled.
-       It's allright if you are just using irq with no dma.  If you enable
-       dual dma you shouldn't need real-time priority anyways.
+For safety reasons, the driver disables dma transfers if you enable
+       real-time support in comedi.
 
 TODO:
        Add support for analog out on 'ao' cards.
@@ -385,8 +382,9 @@ typedef struct{
        short *dma_current_buf; /* pointer to dma buffer currently being used */
        unsigned int dma_buf_size;      /* size in bytes of dma buffers */
        int iobase2;    /* secondary io address used for analog out on 'ao' boards */
-       short ao_update_bits; /* remembers the last write to the 'update' dac
-*/ }das1800_private;
+       short ao_update_bits; /* remembers the last write to the 'update' dac */
+       spinlock_t      spinlock;       /* used to protect indirect addressing */
+}das1800_private;
 
 #define devpriv ((das1800_private *)dev->private)
 
@@ -480,10 +478,18 @@ static int das1800_attach(comedi_device *dev, comedi_devconfig *it)
        unsigned long flags;
        int iobase = it->options[0];
        int irq = it->options[1];
-       int dma0 = it->options[2];
-       int dma1 = it->options[3];
+       int dma0, dma1;
        int iobase2;
 
+// disable unsafe isa dma if we are using real time kernel
+#ifdef CONFIG_COMEDI_RT
+       dma0 = 0;
+       dma1 = 0;
+#else
+       dma0 = it->options[2];
+       dma1 = it->options[3];
+#endif
+
        /* allocate and initialize dev->private */
        if(alloc_private(dev, sizeof(das1800_private)) < 0)
                return -ENOMEM;
@@ -877,7 +883,8 @@ static int das1800_cancel(comedi_device *dev, comedi_subdevice *s)
 
 static void das1800_interrupt(int irq, void *d, struct pt_regs *regs)
 {
-       int status, select;
+       int status;
+       unsigned long irq_flags;
        comedi_device *dev = d;
        comedi_subdevice *s = dev->subdevices + 0;      /* analog input subdevice */
 
@@ -887,10 +894,8 @@ static void das1800_interrupt(int irq, void *d, struct pt_regs *regs)
        {
                return;
        }
-       // save contents of data select register so they can be restored later
-       select = inb(dev->iobase + DAS1800_SELECT) & 0xf;
-       // select adc for base address + 0
-       if(select != ADC) outb(ADC, dev->iobase + DAS1800_SELECT);
+       comedi_spin_lock_irqsave(&devpriv->spinlock, irq_flags);
+       outb(ADC, dev->iobase + DAS1800_SELECT);
        if(devpriv->dma0)       /* if dma is enabled and generated the interrupt */
        {
                // dma buffer full or about-triggering (stop_src == TRIG_EXT)
@@ -903,9 +908,8 @@ static void das1800_interrupt(int irq, void *d, struct pt_regs *regs)
        {
                das1800_handle_fifo_not_empty(dev, s);
        }
+       comedi_spin_unlock_irqrestore(&devpriv->spinlock, irq_flags);
        comedi_bufcheck(dev, s);
-       // restore data select register
-       if(select != ADC) outb(select, dev->iobase + DAS1800_SELECT);
        /* if the card's fifo has overflowed */
        if(status & OVF)
        {
@@ -1284,6 +1288,7 @@ static int das1800_ai_do_cmd(comedi_device *dev, comedi_subdevice *s)
        int conv_flags;
        int control_a;
        int lock_flags;
+       unsigned long irq_flags;
 
        if(!dev->irq)
        {
@@ -1294,6 +1299,7 @@ static int das1800_ai_do_cmd(comedi_device *dev, comedi_subdevice *s)
        disable_das1800(dev);
 
        n = s->async->cmd.chanlist_len;
+       comedi_spin_lock_irqsave(&devpriv->spinlock, irq_flags);
        outb(QRAM, dev->iobase + DAS1800_SELECT); /* select QRAM for baseAddress + 0x0 */
        outb(n - 1, dev->iobase + DAS1800_QRAM_ADDRESS);        /*set QRAM address start */
        for(i = 0; i < n; i++)  /* make channel / gain list */
@@ -1303,7 +1309,7 @@ static int das1800_ai_do_cmd(comedi_device *dev, comedi_subdevice *s)
                outw(chan_range, dev->iobase + DAS1800_QRAM);
        }
        outb(n - 1, dev->iobase + DAS1800_QRAM_ADDRESS);        /*finish write to QRAM */
-       outb(ADC, dev->iobase + DAS1800_SELECT);        /* select ADC for baseAddress + 0x0 */
+       comedi_spin_unlock_irqrestore(&devpriv->spinlock, irq_flags);
 
        /* enable auto channel scan, send interrupts on end of conversion,
         * set clock source to internal or external, select analog reference,
@@ -1456,6 +1462,7 @@ static int das1800_ai_rinsn(comedi_device *dev, comedi_subdevice *s, comedi_insn
        int timeout = 1000;
        short dpnt;
        int conv_flags = 0;
+       unsigned long irq_flags;
 
        /* set up analog reference and unipolar / bipolar mode */
        aref = CR_AREF(insn->chanspec);
@@ -1478,6 +1485,7 @@ static int das1800_ai_rinsn(comedi_device *dev, comedi_subdevice *s, comedi_insn
        /* mask of unipolar/bipolar bit from range */
        range = CR_RANGE(insn->chanspec) & 0x3;
        chan_range = chan | (range << 8);
+       comedi_spin_lock_irqsave(&devpriv->spinlock, irq_flags);
        outb(QRAM, dev->iobase + DAS1800_SELECT);       /* select QRAM for baseAddress + 0x0 */
        outb(0x0, dev->iobase + DAS1800_QRAM_ADDRESS);  /* set QRAM address start */
        outw(chan_range, dev->iobase + DAS1800_QRAM);
@@ -1506,6 +1514,7 @@ static int das1800_ai_rinsn(comedi_device *dev, comedi_subdevice *s, comedi_insn
                        dpnt += 1 << (thisboard->resolution - 1);
                data[n] = dpnt;
        }
+       comedi_spin_unlock_irqrestore(&devpriv->spinlock, irq_flags);
 
        return n;
 }
@@ -1517,7 +1526,7 @@ static int das1800_ao_winsn(comedi_device *dev, comedi_subdevice *s, comedi_insn
 //     int range = CR_RANGE(insn->chanspec);
        int update_chan = thisboard->ao_n_chan - 1;
        short output;
-
+       unsigned long irq_flags;
 
        //  card expects two's complement data
        output = data[0] - (1 << (thisboard->resolution - 1));
@@ -1525,6 +1534,7 @@ static int das1800_ao_winsn(comedi_device *dev, comedi_subdevice *s, comedi_insn
        if(chan == update_chan)
                devpriv->ao_update_bits = output;
        // write to channel
+       comedi_spin_lock_irqsave(&devpriv->spinlock, irq_flags);
        outb(DAC(chan), dev->iobase + DAS1800_SELECT); /* select dac channel for baseAddress + 0x0 */
        outw(output, dev->iobase + DAS1800_DAC);
        // now we need to write to 'update' channel to update all dac channels
@@ -1533,6 +1543,7 @@ static int das1800_ao_winsn(comedi_device *dev, comedi_subdevice *s, comedi_insn
                outb(DAC(update_chan), dev->iobase + DAS1800_SELECT); /* select 'update' channel for baseAddress + 0x0 */
                outw(devpriv->ao_update_bits, dev->iobase + DAS1800_DAC);
        }
+       comedi_spin_unlock_irqrestore(&devpriv->spinlock, irq_flags);
 
        return 1;
 }