staging: comedi: mite: tidy up mite dma channel request/release

For aesthetics, make the actual "request" function static and change
mite_request_channel_in_range() into a wrapper that calls the internal
function. Change the inline function that requests any free channel
into an export that also calls the internal function.

Move the functions to a more logical spot in the code and add docbook
comments for the exported functions.

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>

2 files changed, 91 insertions, 67 deletions

diff --git a/drivers/staging/comedi/drivers/mite.c b/drivers/staging/comedi/drivers/mite.c
index 308ceb602e64..b1231eddb592 100644
--- a/drivers/staging/comedi/drivers/mite.c
+++ b/drivers/staging/comedi/drivers/mite.c
@@ -228,59 +228,6 @@ static unsigned int mite_fifo_size(struct mite *mite, unsigned int channel)
         return empty_count + full_count;
 }
 
-struct mite_channel *mite_request_channel_in_range(struct mite *mite,
-                                                   struct mite_ring *ring,
-                                                   unsigned int min_channel,
-                                                   unsigned int max_channel)
-{
-        struct mite_channel *mite_chan = NULL;
-        unsigned long flags;
-        int i;
-
-        /*
-         * spin lock so mite_release_channel can be called safely
-         * from interrupts
-         */
-        spin_lock_irqsave(&mite->lock, flags);
-        for (i = min_channel; i <= max_channel; ++i) {
-                mite_chan = &mite->channels[i];
-                if (!mite_chan->ring) {
-                        mite_chan->ring = ring;
-                        break;
-                }
-                mite_chan = NULL;
-        }
-        spin_unlock_irqrestore(&mite->lock, flags);
-        return mite_chan;
-}
-EXPORT_SYMBOL_GPL(mite_request_channel_in_range);
-
-void mite_release_channel(struct mite_channel *mite_chan)
-{
-        struct mite *mite = mite_chan->mite;
-        unsigned long flags;
-
-        /* spin lock to prevent races with mite_request_channel */
-        spin_lock_irqsave(&mite->lock, flags);
-        if (mite_chan->ring) {
-                mite_dma_disarm(mite_chan);
-                mite_dma_reset(mite_chan);
-                /*
-                 * disable all channel's interrupts (do it after disarm/reset so
-                 * MITE_CHCR reg isn't changed while dma is still active!)
-                 */
-                writel(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE |
-                       CHCR_CLR_SAR_IE | CHCR_CLR_DONE_IE |
-                       CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |
-                       CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE,
-                       mite->mmio + MITE_CHCR(mite_chan->channel));
-                mite_chan->ring = NULL;
-                mmiowb();
-        }
-        spin_unlock_irqrestore(&mite->lock, flags);
-}
-EXPORT_SYMBOL_GPL(mite_release_channel);
-
 void mite_dma_arm(struct mite_channel *mite_chan)
 {
         struct mite *mite = mite_chan->mite;
@@ -585,6 +532,90 @@ int mite_done(struct mite_channel *mite_chan)
 }
 EXPORT_SYMBOL_GPL(mite_done);
 
+static struct mite_channel *__mite_request_channel(struct mite *mite,
+                                                   struct mite_ring *ring,
+                                                   unsigned int min_channel,
+                                                   unsigned int max_channel)
+{
+        struct mite_channel *mite_chan = NULL;
+        unsigned long flags;
+        int i;
+
+        /*
+         * spin lock so mite_release_channel can be called safely
+         * from interrupts
+         */
+        spin_lock_irqsave(&mite->lock, flags);
+        for (i = min_channel; i <= max_channel; ++i) {
+                mite_chan = &mite->channels[i];
+                if (!mite_chan->ring) {
+                        mite_chan->ring = ring;
+                        break;
+                }
+                mite_chan = NULL;
+        }
+        spin_unlock_irqrestore(&mite->lock, flags);
+        return mite_chan;
+}
+
+/**
+ * mite_request_channel_in_range() - Request a MITE dma channel.
+ * @mite: MITE device.
+ * @ring: MITE dma ring.
+ * @min_channel: minimum channel index to use.
+ * @max_channel: maximum channel index to use.
+ */
+struct mite_channel *mite_request_channel_in_range(struct mite *mite,
+                                                   struct mite_ring *ring,
+                                                   unsigned int min_channel,
+                                                   unsigned int max_channel)
+{
+        return __mite_request_channel(mite, ring, min_channel, max_channel);
+}
+EXPORT_SYMBOL_GPL(mite_request_channel_in_range);
+
+/**
+ * mite_request_channel() - Request a MITE dma channel.
+ * @mite: MITE device.
+ * @ring: MITE dma ring.
+ */
+struct mite_channel *mite_request_channel(struct mite *mite,
+                                          struct mite_ring *ring)
+{
+        return __mite_request_channel(mite, ring, 0, mite->num_channels - 1);
+}
+EXPORT_SYMBOL_GPL(mite_request_channel);
+
+/**
+ * mite_release_channel() - Release a MITE dma channel.
+ * @mite_chan: MITE dma channel.
+ */
+void mite_release_channel(struct mite_channel *mite_chan)
+{
+        struct mite *mite = mite_chan->mite;
+        unsigned long flags;
+
+        /* spin lock to prevent races with mite_request_channel */
+        spin_lock_irqsave(&mite->lock, flags);
+        if (mite_chan->ring) {
+                mite_dma_disarm(mite_chan);
+                mite_dma_reset(mite_chan);
+                /*
+                 * disable all channel's interrupts (do it after disarm/reset so
+                 * MITE_CHCR reg isn't changed while dma is still active!)
+                 */
+                writel(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE |
+                       CHCR_CLR_SAR_IE | CHCR_CLR_DONE_IE |
+                       CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |
+                       CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE,
+                       mite->mmio + MITE_CHCR(mite_chan->channel));
+                mite_chan->ring = NULL;
+                mmiowb();
+        }
+        spin_unlock_irqrestore(&mite->lock, flags);
+}
+EXPORT_SYMBOL_GPL(mite_release_channel);
+
 /**
  * mite_init_ring_descriptors() - Initialize a MITE dma ring descriptors.
  * @ring: MITE dma ring.
diff --git a/drivers/staging/comedi/drivers/mite.h b/drivers/staging/comedi/drivers/mite.h
index b5b11d419a38..eedef66c0bb1 100644
--- a/drivers/staging/comedi/drivers/mite.h
+++ b/drivers/staging/comedi/drivers/mite.h
@@ -60,20 +60,6 @@ struct mite {
         spinlock_t lock;
 };
 
-struct mite_channel *mite_request_channel_in_range(struct mite *,
-                                                   struct mite_ring *,
-                                                   unsigned int min_channel,
-                                                   unsigned int max_channel);
-
-static inline struct mite_channel *mite_request_channel(struct mite *mite,
-                                                        struct mite_ring *ring)
-{
-        return mite_request_channel_in_range(mite, ring, 0,
-                                             mite->num_channels - 1);
-}
-
-void mite_release_channel(struct mite_channel *mite_chan);
-
 void mite_dma_arm(struct mite_channel *mite_chan);
 void mite_dma_disarm(struct mite_channel *mite_chan);
 void mite_sync_dma(struct mite_channel *mite_chan, struct comedi_subdevice *s);
@@ -85,6 +71,13 @@ int mite_done(struct mite_channel *mite_chan);
 void mite_prep_dma(struct mite_channel *mite_chan,
                    unsigned int num_device_bits, unsigned int num_memory_bits);
 
+struct mite_channel *mite_request_channel_in_range(struct mite *,
+                                                   struct mite_ring *,
+                                                   unsigned int min_channel,
+                                                   unsigned int max_channel);
+struct mite_channel *mite_request_channel(struct mite *, struct mite_ring *);
+void mite_release_channel(struct mite_channel *);
+
 int mite_init_ring_descriptors(struct mite_ring *, struct comedi_subdevice *,
                                unsigned int nbytes);
 int mite_buf_change(struct mite_ring *, struct comedi_subdevice *);