1 files changed, 156 insertions, 172 deletions

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index cea08bed9cf9..286c3ac6bdcc 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -35,9 +35,10 @@
 #include <linux/dmapool.h>
 #include <linux/of_platform.h>
 
-#include <asm/fsldma.h>
 #include "fsldma.h"
 
+static const char msg_ld_oom[] = "No free memory for link descriptor\n";
+
 static void dma_init(struct fsldma_chan *chan)
 {
         /* Reset the channel */
@@ -499,7 +500,7 @@ fsl_dma_prep_interrupt(struct dma_chan *dchan, unsigned long flags)
 
         new = fsl_dma_alloc_descriptor(chan);
         if (!new) {
-                dev_err(chan->dev, "No free memory for link descriptor\n");
+                dev_err(chan->dev, msg_ld_oom);
                 return NULL;
         }
 
@@ -536,8 +537,7 @@ static struct dma_async_tx_descriptor *fsl_dma_prep_memcpy(
                 /* Allocate the link descriptor from DMA pool */
                 new = fsl_dma_alloc_descriptor(chan);
                 if (!new) {
-                        dev_err(chan->dev,
-                                        "No free memory for link descriptor\n");
+                        dev_err(chan->dev, msg_ld_oom);
                         goto fail;
                 }
 #ifdef FSL_DMA_LD_DEBUG
@@ -583,223 +583,205 @@ fail:
         return NULL;
 }
 
-/**
- * fsl_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
- * @chan: DMA channel
- * @sgl: scatterlist to transfer to/from
- * @sg_len: number of entries in @scatterlist
- * @direction: DMA direction
- * @flags: DMAEngine flags
- *
- * Prepare a set of descriptors for a DMA_SLAVE transaction. Following the
- * DMA_SLAVE API, this gets the device-specific information from the
- * chan->private variable.
- */
-static struct dma_async_tx_descriptor *fsl_dma_prep_slave_sg(
-        struct dma_chan *dchan, struct scatterlist *sgl, unsigned int sg_len,
-        enum dma_data_direction direction, unsigned long flags)
+static struct dma_async_tx_descriptor *fsl_dma_prep_sg(struct dma_chan *dchan,
+        struct scatterlist *dst_sg, unsigned int dst_nents,
+        struct scatterlist *src_sg, unsigned int src_nents,
+        unsigned long flags)
 {
-        struct fsldma_chan *chan;
         struct fsl_desc_sw *first = NULL, *prev = NULL, *new = NULL;
-        struct fsl_dma_slave *slave;
-        size_t copy;
-
-        int i;
-        struct scatterlist *sg;
-        size_t sg_used;
-        size_t hw_used;
-        struct fsl_dma_hw_addr *hw;
-        dma_addr_t dma_dst, dma_src;
+        struct fsldma_chan *chan = to_fsl_chan(dchan);
+        size_t dst_avail, src_avail;
+        dma_addr_t dst, src;
+        size_t len;
 
-        if (!dchan)
+        /* basic sanity checks */
+        if (dst_nents == 0 || src_nents == 0)
                 return NULL;
 
-        if (!dchan->private)
+        if (dst_sg == NULL || src_sg == NULL)
                 return NULL;
 
-        chan = to_fsl_chan(dchan);
-        slave = dchan->private;
+        /*
+         * TODO: should we check that both scatterlists have the same
+         * TODO: number of bytes in total? Is that really an error?
+         */
 
-        if (list_empty(&slave->addresses))
-                return NULL;
+        /* get prepared for the loop */
+        dst_avail = sg_dma_len(dst_sg);
+        src_avail = sg_dma_len(src_sg);
 
-        hw = list_first_entry(&slave->addresses, struct fsl_dma_hw_addr, entry);
-        hw_used = 0;
+        /* run until we are out of scatterlist entries */
+        while (true) {
 
-        /*
-         * Build the hardware transaction to copy from the scatterlist to
-         * the hardware, or from the hardware to the scatterlist
-         *
-         * If you are copying from the hardware to the scatterlist and it
-         * takes two hardware entries to fill an entire page, then both
-         * hardware entries will be coalesced into the same page
-         *
-         * If you are copying from the scatterlist to the hardware and a
-         * single page can fill two hardware entries, then the data will
-         * be read out of the page into the first hardware entry, and so on
-         */
-        for_each_sg(sgl, sg, sg_len, i) {
-                sg_used = 0;
-
-                /* Loop until the entire scatterlist entry is used */
-                while (sg_used < sg_dma_len(sg)) {
-
-                        /*
-                         * If we've used up the current hardware address/length
-                         * pair, we need to load a new one
-                         *
-                         * This is done in a while loop so that descriptors with
-                         * length == 0 will be skipped
-                         */
-                        while (hw_used >= hw->length) {
-
-                                /*
-                                 * If the current hardware entry is the last
-                                 * entry in the list, we're finished
-                                 */
-                                if (list_is_last(&hw->entry, &slave->addresses))
-                                        goto finished;
-
-                                /* Get the next hardware address/length pair */
-                                hw = list_entry(hw->entry.next,
-                                                struct fsl_dma_hw_addr, entry);
-                                hw_used = 0;
-                        }
-
-                        /* Allocate the link descriptor from DMA pool */
-                        new = fsl_dma_alloc_descriptor(chan);
-                        if (!new) {
-                                dev_err(chan->dev, "No free memory for "
-                                                       "link descriptor\n");
-                                goto fail;
-                        }
+                /* create the largest transaction possible */
+                len = min_t(size_t, src_avail, dst_avail);
+                len = min_t(size_t, len, FSL_DMA_BCR_MAX_CNT);
+                if (len == 0)
+                        goto fetch;
+
+                dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) - dst_avail;
+                src = sg_dma_address(src_sg) + sg_dma_len(src_sg) - src_avail;
+
+                /* allocate and populate the descriptor */
+                new = fsl_dma_alloc_descriptor(chan);
+                if (!new) {
+                        dev_err(chan->dev, msg_ld_oom);
+                        goto fail;
+                }
 #ifdef FSL_DMA_LD_DEBUG
-                        dev_dbg(chan->dev, "new link desc alloc %p\n", new);
+                dev_dbg(chan->dev, "new link desc alloc %p\n", new);
 #endif
 
-                        /*
-                         * Calculate the maximum number of bytes to transfer,
-                         * making sure it is less than the DMA controller limit
-                         */
-                        copy = min_t(size_t, sg_dma_len(sg) - sg_used,
-                                             hw->length - hw_used);
-                        copy = min_t(size_t, copy, FSL_DMA_BCR_MAX_CNT);
-
-                        /*
-                         * DMA_FROM_DEVICE
-                         * from the hardware to the scatterlist
-                         *
-                         * DMA_TO_DEVICE
-                         * from the scatterlist to the hardware
-                         */
-                        if (direction == DMA_FROM_DEVICE) {
-                                dma_src = hw->address + hw_used;
-                                dma_dst = sg_dma_address(sg) + sg_used;
-                        } else {
-                                dma_src = sg_dma_address(sg) + sg_used;
-                                dma_dst = hw->address + hw_used;
-                        }
-
-                        /* Fill in the descriptor */
-                        set_desc_cnt(chan, &new->hw, copy);
-                        set_desc_src(chan, &new->hw, dma_src);
-                        set_desc_dst(chan, &new->hw, dma_dst);
-
-                        /*
-                         * If this is not the first descriptor, chain the
-                         * current descriptor after the previous descriptor
-                         */
-                        if (!first) {
-                                first = new;
-                        } else {
-                                set_desc_next(chan, &prev->hw,
-                                              new->async_tx.phys);
-                        }
-
-                        new->async_tx.cookie = 0;
-                        async_tx_ack(&new->async_tx);
-
-                        prev = new;
-                        sg_used += copy;
-                        hw_used += copy;
-
-                        /* Insert the link descriptor into the LD ring */
-                        list_add_tail(&new->node, &first->tx_list);
-                }
-        }
+                set_desc_cnt(chan, &new->hw, len);
+                set_desc_src(chan, &new->hw, src);
+                set_desc_dst(chan, &new->hw, dst);
 
-finished:
+                if (!first)
+                        first = new;
+                else
+                        set_desc_next(chan, &prev->hw, new->async_tx.phys);
 
-        /* All of the hardware address/length pairs had length == 0 */
-        if (!first || !new)
-                return NULL;
+                new->async_tx.cookie = 0;
+                async_tx_ack(&new->async_tx);
+                prev = new;
 
-        new->async_tx.flags = flags;
-        new->async_tx.cookie = -EBUSY;
+                /* Insert the link descriptor to the LD ring */
+                list_add_tail(&new->node, &first->tx_list);
 
-        /* Set End-of-link to the last link descriptor of new list */
-        set_ld_eol(chan, new);
+                /* update metadata */
+                dst_avail -= len;
+                src_avail -= len;
+
+fetch:
+                /* fetch the next dst scatterlist entry */
+                if (dst_avail == 0) {
+
+                        /* no more entries: we're done */
+                        if (dst_nents == 0)
+                                break;
+
+                        /* fetch the next entry: if there are no more: done */
+                        dst_sg = sg_next(dst_sg);
+                        if (dst_sg == NULL)
+                                break;
+
+                        dst_nents--;
+                        dst_avail = sg_dma_len(dst_sg);
+                }
 
-        /* Enable extra controller features */
-        if (chan->set_src_loop_size)
-                chan->set_src_loop_size(chan, slave->src_loop_size);
+                /* fetch the next src scatterlist entry */
+                if (src_avail == 0) {
 
-        if (chan->set_dst_loop_size)
-                chan->set_dst_loop_size(chan, slave->dst_loop_size);
+                        /* no more entries: we're done */
+                        if (src_nents == 0)
+                                break;
 
-        if (chan->toggle_ext_start)
-                chan->toggle_ext_start(chan, slave->external_start);
+                        /* fetch the next entry: if there are no more: done */
+                        src_sg = sg_next(src_sg);
+                        if (src_sg == NULL)
+                                break;
 
-        if (chan->toggle_ext_pause)
-                chan->toggle_ext_pause(chan, slave->external_pause);
+                        src_nents--;
+                        src_avail = sg_dma_len(src_sg);
+                }
+        }
 
-        if (chan->set_request_count)
-                chan->set_request_count(chan, slave->request_count);
+        new->async_tx.flags = flags; /* client is in control of this ack */
+        new->async_tx.cookie = -EBUSY;
+
+        /* Set End-of-link to the last link descriptor of new list */
+        set_ld_eol(chan, new);
 
         return &first->async_tx;
 
 fail:
-        /* If first was not set, then we failed to allocate the very first
-         * descriptor, and we're done */
         if (!first)
                 return NULL;
 
+        fsldma_free_desc_list_reverse(chan, &first->tx_list);
+        return NULL;
+}
+
+/**
+ * fsl_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
+ * @chan: DMA channel
+ * @sgl: scatterlist to transfer to/from
+ * @sg_len: number of entries in @scatterlist
+ * @direction: DMA direction
+ * @flags: DMAEngine flags
+ *
+ * Prepare a set of descriptors for a DMA_SLAVE transaction. Following the
+ * DMA_SLAVE API, this gets the device-specific information from the
+ * chan->private variable.
+ */
+static struct dma_async_tx_descriptor *fsl_dma_prep_slave_sg(
+        struct dma_chan *dchan, struct scatterlist *sgl, unsigned int sg_len,
+        enum dma_data_direction direction, unsigned long flags)
+{
         /*
-         * First is set, so all of the descriptors we allocated have been added
-         * to first->tx_list, INCLUDING "first" itself. Therefore we
-         * must traverse the list backwards freeing each descriptor in turn
+         * This operation is not supported on the Freescale DMA controller
          *
-         * We're re-using variables for the loop, oh well
+         * However, we need to provide the function pointer to allow the
+         * device_control() method to work.
          */
-        fsldma_free_desc_list_reverse(chan, &first->tx_list);
         return NULL;
 }
 
 static int fsl_dma_device_control(struct dma_chan *dchan,
                                   enum dma_ctrl_cmd cmd, unsigned long arg)
 {
+        struct dma_slave_config *config;
         struct fsldma_chan *chan;
         unsigned long flags;
-
-        /* Only supports DMA_TERMINATE_ALL */
-        if (cmd != DMA_TERMINATE_ALL)
-                return -ENXIO;
+        int size;
 
         if (!dchan)
                 return -EINVAL;
 
         chan = to_fsl_chan(dchan);
 
-        /* Halt the DMA engine */
-        dma_halt(chan);
+        switch (cmd) {
+        case DMA_TERMINATE_ALL:
+                /* Halt the DMA engine */
+                dma_halt(chan);
 
-        spin_lock_irqsave(&chan->desc_lock, flags);
+                spin_lock_irqsave(&chan->desc_lock, flags);
 
-        /* Remove and free all of the descriptors in the LD queue */
-        fsldma_free_desc_list(chan, &chan->ld_pending);
-        fsldma_free_desc_list(chan, &chan->ld_running);
+                /* Remove and free all of the descriptors in the LD queue */
+                fsldma_free_desc_list(chan, &chan->ld_pending);
+                fsldma_free_desc_list(chan, &chan->ld_running);
 
-        spin_unlock_irqrestore(&chan->desc_lock, flags);
+                spin_unlock_irqrestore(&chan->desc_lock, flags);
+                return 0;
+
+        case DMA_SLAVE_CONFIG:
+                config = (struct dma_slave_config *)arg;
+
+                /* make sure the channel supports setting burst size */
+                if (!chan->set_request_count)
+                        return -ENXIO;
+
+                /* we set the controller burst size depending on direction */
+                if (config->direction == DMA_TO_DEVICE)
+                        size = config->dst_addr_width * config->dst_maxburst;
+                else
+                        size = config->src_addr_width * config->src_maxburst;
+
+                chan->set_request_count(chan, size);
+                return 0;
+
+        case FSLDMA_EXTERNAL_START:
+
+                /* make sure the channel supports external start */
+                if (!chan->toggle_ext_start)
+                        return -ENXIO;
+
+                chan->toggle_ext_start(chan, arg);
+                return 0;
+
+        default:
+                return -ENXIO;
+        }
 
         return 0;
 }
@@ -1327,11 +1309,13 @@ static int __devinit fsldma_of_probe(struct platform_device *op,
 
         dma_cap_set(DMA_MEMCPY, fdev->common.cap_mask);
         dma_cap_set(DMA_INTERRUPT, fdev->common.cap_mask);
+        dma_cap_set(DMA_SG, fdev->common.cap_mask);
         dma_cap_set(DMA_SLAVE, fdev->common.cap_mask);
         fdev->common.device_alloc_chan_resources = fsl_dma_alloc_chan_resources;
         fdev->common.device_free_chan_resources = fsl_dma_free_chan_resources;
         fdev->common.device_prep_dma_interrupt = fsl_dma_prep_interrupt;
         fdev->common.device_prep_dma_memcpy = fsl_dma_prep_memcpy;
+        fdev->common.device_prep_dma_sg = fsl_dma_prep_sg;
         fdev->common.device_tx_status = fsl_tx_status;
         fdev->common.device_issue_pending = fsl_dma_memcpy_issue_pending;
         fdev->common.device_prep_slave_sg = fsl_dma_prep_slave_sg;