staging: comedi: ni_labpc: introduce struct labpc_dma_desc

For aesthetics, introduce a struct to hold the DMA descriptor data.

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/ni_labpc.h b/drivers/staging/comedi/drivers/ni_labpc.h
index ac2c01f..7ba7f2f 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_labpc.h
+++ b/drivers/staging/comedi/drivers/ni_labpc.h
@@ -34,6 +34,13 @@ struct labpc_boardinfo {
        unsigned is_labpc1200:1;        /* has extra regs compared to pc+ */
 };
 
+struct labpc_dma_desc {
+       unsigned int chan;      /* DMA channel */
+       u16 *virt_addr;         /* virtual address of DMA buffer */
+       phys_addr_t hw_addr;    /* hardware (bus) address of DMA buffer */
+       unsigned int size;      /* size of DMA transfer (in bytes) */
+};
+
 struct labpc_private {
        /*  number of data points left to be taken */
        unsigned long long count;
@@ -61,11 +68,9 @@ struct labpc_private {
         * conversions
         */
        unsigned int divisor_b1;
-       unsigned int dma_chan;  /*  dma channel to use */
-       u16 *dma_buffer;        /*  buffer ai will dma into */
-       phys_addr_t dma_addr;
-       /* transfer size in bytes for current transfer */
-       unsigned int dma_transfer_size;
+
+       struct labpc_dma_desc dma_desc;
+
        /* we are using dma/fifo-half-full/etc. */
        enum transfer_type current_transfer;
        /*

diff --git a/drivers/staging/comedi/drivers/ni_labpc_isadma.c b/drivers/staging/comedi/drivers/ni_labpc_isadma.c
index 6d38605..b7217a7 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_labpc_isadma.c
+++ b/drivers/staging/comedi/drivers/ni_labpc_isadma.c
@@ -60,22 +60,23 @@ static unsigned int labpc_suggest_transfer_size(const struct comedi_cmd *cmd)
 void labpc_setup_dma(struct comedi_device *dev, struct comedi_subdevice *s)
 {
        struct labpc_private *devpriv = dev->private;
+       struct labpc_dma_desc *dma = &devpriv->dma_desc;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned long irq_flags;
 
        irq_flags = claim_dma_lock();
-       disable_dma(devpriv->dma_chan);
+       disable_dma(dma->chan);
        /* clear flip-flop to make sure 2-byte registers for
         * count and address get set correctly */
-       clear_dma_ff(devpriv->dma_chan);
-       set_dma_addr(devpriv->dma_chan, devpriv->dma_addr);
+       clear_dma_ff(dma->chan);
+       set_dma_addr(dma->chan, dma->hw_addr);
        /* set appropriate size of transfer */
-       devpriv->dma_transfer_size = labpc_suggest_transfer_size(cmd);
+       dma->size = labpc_suggest_transfer_size(cmd);
        if (cmd->stop_src == TRIG_COUNT &&
-           devpriv->count * sample_size < devpriv->dma_transfer_size)
-               devpriv->dma_transfer_size = devpriv->count * sample_size;
-       set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size);
-       enable_dma(devpriv->dma_chan);
+           devpriv->count * sample_size < dma->size)
+               dma->size = devpriv->count * sample_size;
+       set_dma_count(dma->chan, dma->size);
+       enable_dma(dma->chan);
        release_dma_lock(irq_flags);
        /* set CMD3 bits for caller to enable DMA and interrupt */
        devpriv->cmd3 |= (CMD3_DMAEN | CMD3_DMATCINTEN);
@@ -85,6 +86,7 @@ EXPORT_SYMBOL_GPL(labpc_setup_dma);
 void labpc_drain_dma(struct comedi_device *dev)
 {
        struct labpc_private *devpriv = dev->private;
+       struct labpc_dma_desc *dma = &devpriv->dma_desc;
        struct comedi_subdevice *s = dev->read_subdev;
        struct comedi_async *async = s->async;
        struct comedi_cmd *cmd = &async->cmd;
@@ -95,18 +97,18 @@ void labpc_drain_dma(struct comedi_device *dev)
        status = devpriv->stat1;
 
        flags = claim_dma_lock();
-       disable_dma(devpriv->dma_chan);
+       disable_dma(dma->chan);
        /* clear flip-flop to make sure 2-byte registers for
         * count and address get set correctly */
-       clear_dma_ff(devpriv->dma_chan);
+       clear_dma_ff(dma->chan);
 
        /* figure out how many points to read */
-       max_points = devpriv->dma_transfer_size / sample_size;
+       max_points = dma->size / sample_size;
        /* residue is the number of points left to be done on the dma
         * transfer.  It should always be zero at this point unless
         * the stop_src is set to external triggering.
         */
-       residue = get_dma_residue(devpriv->dma_chan) / sample_size;
+       residue = get_dma_residue(dma->chan) / sample_size;
        num_points = max_points - residue;
        if (cmd->stop_src == TRIG_COUNT && devpriv->count < num_points)
                num_points = devpriv->count;
@@ -114,21 +116,21 @@ void labpc_drain_dma(struct comedi_device *dev)
        /* figure out how many points will be stored next time */
        leftover = 0;
        if (cmd->stop_src != TRIG_COUNT) {
-               leftover = devpriv->dma_transfer_size / sample_size;
+               leftover = dma->size / sample_size;
        } else if (devpriv->count > num_points) {
                leftover = devpriv->count - num_points;
                if (leftover > max_points)
                        leftover = max_points;
        }
 
-       comedi_buf_write_samples(s, devpriv->dma_buffer, num_points);
+       comedi_buf_write_samples(s, dma->virt_addr, num_points);
 
        if (cmd->stop_src == TRIG_COUNT)
                devpriv->count -= num_points;
 
        /* set address and count for next transfer */
-       set_dma_addr(devpriv->dma_chan, devpriv->dma_addr);
-       set_dma_count(devpriv->dma_chan, leftover * sample_size);
+       set_dma_addr(dma->chan, dma->hw_addr);
+       set_dma_count(dma->chan, leftover * sample_size);
        release_dma_lock(flags);
 }
 EXPORT_SYMBOL_GPL(labpc_drain_dma);
@@ -136,10 +138,11 @@ EXPORT_SYMBOL_GPL(labpc_drain_dma);
 static void handle_isa_dma(struct comedi_device *dev)
 {
        struct labpc_private *devpriv = dev->private;
+       struct labpc_dma_desc *dma = &devpriv->dma_desc;
 
        labpc_drain_dma(dev);
 
-       enable_dma(devpriv->dma_chan);
+       enable_dma(dma->chan);
 
        /* clear dma tc interrupt */
        devpriv->write_byte(dev, 0x1, DMATC_CLEAR_REG);
@@ -163,6 +166,7 @@ EXPORT_SYMBOL_GPL(labpc_handle_dma_status);
 int labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan)
 {
        struct labpc_private *devpriv = dev->private;
+       struct labpc_dma_desc *dma = &devpriv->dma_desc;
        void *dma_buffer;
        unsigned long dma_flags;
        int ret;
@@ -180,13 +184,13 @@ int labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan)
                return ret;
        }
 
-       devpriv->dma_buffer = dma_buffer;
-       devpriv->dma_chan = dma_chan;
-       devpriv->dma_addr = virt_to_bus(devpriv->dma_buffer);
+       dma->virt_addr = dma_buffer;
+       dma->chan = dma_chan;
+       dma->hw_addr = virt_to_bus(dma->virt_addr);
 
        dma_flags = claim_dma_lock();
-       disable_dma(devpriv->dma_chan);
-       set_dma_mode(devpriv->dma_chan, DMA_MODE_READ);
+       disable_dma(dma->chan);
+       set_dma_mode(dma->chan, DMA_MODE_READ);
        release_dma_lock(dma_flags);
 
        return 0;
@@ -196,13 +200,11 @@ EXPORT_SYMBOL_GPL(labpc_init_dma_chan);
 void labpc_free_dma_chan(struct comedi_device *dev)
 {
        struct labpc_private *devpriv = dev->private;
+       struct labpc_dma_desc *dma = &devpriv->dma_desc;
 
-       kfree(devpriv->dma_buffer);
-       devpriv->dma_buffer = NULL;
-       if (devpriv->dma_chan) {
-               free_dma(devpriv->dma_chan);
-               devpriv->dma_chan = 0;
-       }
+       kfree(dma->virt_addr);
+       if (dma->chan)
+               free_dma(dma->chan);
 }
 EXPORT_SYMBOL_GPL(labpc_free_dma_chan);
 

diff --git a/drivers/staging/comedi/drivers/ni_labpc_isadma.h b/drivers/staging/comedi/drivers/ni_labpc_isadma.h
index 771af4b..2582f22 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_labpc_isadma.h
+++ b/drivers/staging/comedi/drivers/ni_labpc_isadma.h
@@ -13,7 +13,7 @@ static inline bool labpc_have_dma_chan(struct comedi_device *dev)
 {
        struct labpc_private *devpriv = dev->private;
 
-       return (bool)devpriv->dma_chan;
+       return (bool)devpriv->dma_desc.chan;
 }
 
 int labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan);