staging: comedi: mite: move mite_prep_dma()

For aesthetics, move this functions to a more logical spot in the
code and add a docbook comment for the exported function.

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/mite.c b/drivers/staging/comedi/drivers/mite.c
index b1231ed..82f4fda 100644 (file)
--- a/drivers/staging/comedi/drivers/mite.c
+++ b/drivers/staging/comedi/drivers/mite.c
@@ -247,91 +247,6 @@ void mite_dma_arm(struct mite_channel *mite_chan)
 }
 EXPORT_SYMBOL_GPL(mite_dma_arm);
 
-void mite_prep_dma(struct mite_channel *mite_chan,
-                  unsigned int num_device_bits, unsigned int num_memory_bits)
-{
-       struct mite *mite = mite_chan->mite;
-       unsigned int chcr, mcr, dcr, lkcr;
-
-       mite_dma_reset(mite_chan);
-
-       /* short link chaining mode */
-       chcr = CHCR_SET_DMA_IE | CHCR_LINKSHORT | CHCR_SET_DONE_IE |
-           CHCR_BURSTEN;
-       /*
-        * Link Complete Interrupt: interrupt every time a link
-        * in MITE_RING is completed. This can generate a lot of
-        * extra interrupts, but right now we update the values
-        * of buf_int_ptr and buf_int_count at each interrupt. A
-        * better method is to poll the MITE before each user
-        * "read()" to calculate the number of bytes available.
-        */
-       chcr |= CHCR_SET_LC_IE;
-       if (num_memory_bits == 32 && num_device_bits == 16) {
-               /*
-                * Doing a combined 32 and 16 bit byteswap gets the 16 bit
-                * samples into the fifo in the right order. Tested doing 32 bit
-                * memory to 16 bit device transfers to the analog out of a
-                * pxi-6281, which has mite version = 1, type = 4. This also
-                * works for dma reads from the counters on e-series boards.
-                */
-               chcr |= CHCR_BYTE_SWAP_DEVICE | CHCR_BYTE_SWAP_MEMORY;
-       }
-       if (mite_chan->dir == COMEDI_INPUT)
-               chcr |= CHCR_DEV_TO_MEM;
-
-       writel(chcr, mite->mmio + MITE_CHCR(mite_chan->channel));
-
-       /* to/from memory */
-       mcr = mite_retry_limit(64) | CR_ASEQUP;
-       switch (num_memory_bits) {
-       case 8:
-               mcr |= CR_PSIZE8;
-               break;
-       case 16:
-               mcr |= CR_PSIZE16;
-               break;
-       case 32:
-               mcr |= CR_PSIZE32;
-               break;
-       default:
-               pr_warn("bug! invalid mem bit width for dma transfer\n");
-               break;
-       }
-       writel(mcr, mite->mmio + MITE_MCR(mite_chan->channel));
-
-       /* from/to device */
-       dcr = mite_retry_limit(64) | CR_ASEQUP;
-       dcr |= CR_PORTIO | CR_AMDEVICE | mite_drq_reqs(mite_chan->channel);
-       switch (num_device_bits) {
-       case 8:
-               dcr |= CR_PSIZE8;
-               break;
-       case 16:
-               dcr |= CR_PSIZE16;
-               break;
-       case 32:
-               dcr |= CR_PSIZE32;
-               break;
-       default:
-               pr_warn("bug! invalid dev bit width for dma transfer\n");
-               break;
-       }
-       writel(dcr, mite->mmio + MITE_DCR(mite_chan->channel));
-
-       /* reset the DAR */
-       writel(0, mite->mmio + MITE_DAR(mite_chan->channel));
-
-       /* the link is 32bits */
-       lkcr = mite_retry_limit(64) | CR_ASEQUP | CR_PSIZE32;
-       writel(lkcr, mite->mmio + MITE_LKCR(mite_chan->channel));
-
-       /* starting address for link chaining */
-       writel(mite_chan->ring->dma_addr,
-              mite->mmio + MITE_LKAR(mite_chan->channel));
-}
-EXPORT_SYMBOL_GPL(mite_prep_dma);
-
 static u32 mite_device_bytes_transferred(struct mite_channel *mite_chan)
 {
        struct mite *mite = mite_chan->mite;
@@ -532,6 +447,97 @@ int mite_done(struct mite_channel *mite_chan)
 }
 EXPORT_SYMBOL_GPL(mite_done);
 
+/**
+ * mite_prep_dma() - Prepare a MITE dma channel for transfers.
+ * @mite_chan: MITE dma channel.
+ * @num_device_bits: device transfer size (8, 16, or 32-bits).
+ * @num_memory_bits: memory transfer size (8, 16, or 32-bits).
+ */
+void mite_prep_dma(struct mite_channel *mite_chan,
+                  unsigned int num_device_bits, unsigned int num_memory_bits)
+{
+       struct mite *mite = mite_chan->mite;
+       unsigned int chcr, mcr, dcr, lkcr;
+
+       mite_dma_reset(mite_chan);
+
+       /* short link chaining mode */
+       chcr = CHCR_SET_DMA_IE | CHCR_LINKSHORT | CHCR_SET_DONE_IE |
+           CHCR_BURSTEN;
+       /*
+        * Link Complete Interrupt: interrupt every time a link
+        * in MITE_RING is completed. This can generate a lot of
+        * extra interrupts, but right now we update the values
+        * of buf_int_ptr and buf_int_count at each interrupt. A
+        * better method is to poll the MITE before each user
+        * "read()" to calculate the number of bytes available.
+        */
+       chcr |= CHCR_SET_LC_IE;
+       if (num_memory_bits == 32 && num_device_bits == 16) {
+               /*
+                * Doing a combined 32 and 16 bit byteswap gets the 16 bit
+                * samples into the fifo in the right order. Tested doing 32 bit
+                * memory to 16 bit device transfers to the analog out of a
+                * pxi-6281, which has mite version = 1, type = 4. This also
+                * works for dma reads from the counters on e-series boards.
+                */
+               chcr |= CHCR_BYTE_SWAP_DEVICE | CHCR_BYTE_SWAP_MEMORY;
+       }
+       if (mite_chan->dir == COMEDI_INPUT)
+               chcr |= CHCR_DEV_TO_MEM;
+
+       writel(chcr, mite->mmio + MITE_CHCR(mite_chan->channel));
+
+       /* to/from memory */
+       mcr = mite_retry_limit(64) | CR_ASEQUP;
+       switch (num_memory_bits) {
+       case 8:
+               mcr |= CR_PSIZE8;
+               break;
+       case 16:
+               mcr |= CR_PSIZE16;
+               break;
+       case 32:
+               mcr |= CR_PSIZE32;
+               break;
+       default:
+               pr_warn("bug! invalid mem bit width for dma transfer\n");
+               break;
+       }
+       writel(mcr, mite->mmio + MITE_MCR(mite_chan->channel));
+
+       /* from/to device */
+       dcr = mite_retry_limit(64) | CR_ASEQUP;
+       dcr |= CR_PORTIO | CR_AMDEVICE | mite_drq_reqs(mite_chan->channel);
+       switch (num_device_bits) {
+       case 8:
+               dcr |= CR_PSIZE8;
+               break;
+       case 16:
+               dcr |= CR_PSIZE16;
+               break;
+       case 32:
+               dcr |= CR_PSIZE32;
+               break;
+       default:
+               pr_warn("bug! invalid dev bit width for dma transfer\n");
+               break;
+       }
+       writel(dcr, mite->mmio + MITE_DCR(mite_chan->channel));
+
+       /* reset the DAR */
+       writel(0, mite->mmio + MITE_DAR(mite_chan->channel));
+
+       /* the link is 32bits */
+       lkcr = mite_retry_limit(64) | CR_ASEQUP | CR_PSIZE32;
+       writel(lkcr, mite->mmio + MITE_LKCR(mite_chan->channel));
+
+       /* starting address for link chaining */
+       writel(mite_chan->ring->dma_addr,
+              mite->mmio + MITE_LKAR(mite_chan->channel));
+}
+EXPORT_SYMBOL_GPL(mite_prep_dma);
+
 static struct mite_channel *__mite_request_channel(struct mite *mite,
                                                   struct mite_ring *ring,
                                                   unsigned int min_channel,

diff --git a/drivers/staging/comedi/drivers/mite.h b/drivers/staging/comedi/drivers/mite.h
index eedef66..4017ddb 100644 (file)
--- a/drivers/staging/comedi/drivers/mite.h
+++ b/drivers/staging/comedi/drivers/mite.h
@@ -68,7 +68,7 @@ void mite_ack_linkc(struct mite_channel *, struct comedi_subdevice *,
                    bool sync);
 int mite_done(struct mite_channel *mite_chan);
 
-void mite_prep_dma(struct mite_channel *mite_chan,
+void mite_prep_dma(struct mite_channel *,
                   unsigned int num_device_bits, unsigned int num_memory_bits);
 
 struct mite_channel *mite_request_channel_in_range(struct mite *,