ioat2,3: convert to a true ring buffer

Replace the current linked list munged into a ring with a native ring
buffer implementation.  The benefit of this approach is reduced overhead
as many parameters can be derived from ring position with simple pointer
comparisons and descriptor allocation/freeing becomes just a
manipulation of head/tail pointers.

It requires a contiguous allocation for the software descriptor
information.

Since this arrangement is significantly different from the ioat1 chain,
move ioat2,3 support into its own file and header.  Common routines are
exported from driver/dma/ioat/dma.[ch].

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 45 insertions, 5 deletions

diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
index 5b31db73ad8e..84065dfa4d40 100644
--- a/drivers/dma/ioat/dma.h
+++ b/drivers/dma/ioat/dma.h
@@ -62,6 +62,7 @@
  * @idx: per channel data
  * @dca: direct cache access context
  * @intr_quirk: interrupt setup quirk (for ioat_v1 devices)
+ * @enumerate_channels: hw version specific channel enumeration
  */
 
 struct ioatdma_device {
@@ -76,6 +77,7 @@ struct ioatdma_device {
         struct ioat_chan_common *idx[4];
         struct dca_provider *dca;
         void (*intr_quirk)(struct ioatdma_device *device);
+        int (*enumerate_channels)(struct ioatdma_device *device);
 };
 
 struct ioat_chan_common {
@@ -106,6 +108,7 @@ struct ioat_chan_common {
         struct tasklet_struct cleanup_task;
 };
 
+
 /**
  * struct ioat_dma_chan - internal representation of a DMA channel
  */
@@ -119,7 +122,6 @@ struct ioat_dma_chan {
         struct list_head used_desc;
 
         int pending;
-        u16 dmacount;
         u16 desccount;
 };
 
@@ -135,6 +137,33 @@ static inline struct ioat_dma_chan *to_ioat_chan(struct dma_chan *c)
         return container_of(chan, struct ioat_dma_chan, base);
 }
 
+/**
+ * ioat_is_complete - poll the status of an ioat transaction
+ * @c: channel handle
+ * @cookie: transaction identifier
+ * @done: if set, updated with last completed transaction
+ * @used: if set, updated with last used transaction
+ */
+static inline enum dma_status
+ioat_is_complete(struct dma_chan *c, dma_cookie_t cookie,
+                 dma_cookie_t *done, dma_cookie_t *used)
+{
+        struct ioat_chan_common *chan = to_chan_common(c);
+        dma_cookie_t last_used;
+        dma_cookie_t last_complete;
+
+        last_used = c->cookie;
+        last_complete = chan->completed_cookie;
+        chan->watchdog_tcp_cookie = cookie;
+
+        if (done)
+                *done = last_complete;
+        if (used)
+                *used = last_used;
+
+        return dma_async_is_complete(cookie, last_complete, last_used);
+}
+
 /* wrapper around hardware descriptor format + additional software fields */
 
 /**
@@ -162,11 +191,22 @@ static inline void ioat_set_tcp_copy_break(unsigned long copybreak)
         #endif
 }
 
+static inline struct ioat_chan_common *
+ioat_chan_by_index(struct ioatdma_device *device, int index)
+{
+        return device->idx[index];
+}
+
+int ioat_probe(struct ioatdma_device *device);
+int ioat_register(struct ioatdma_device *device);
 int ioat1_dma_probe(struct ioatdma_device *dev, int dca);
-int ioat2_dma_probe(struct ioatdma_device *dev, int dca);
-int ioat3_dma_probe(struct ioatdma_device *dev, int dca);
 void ioat_dma_remove(struct ioatdma_device *device);
 struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase);
-struct dca_provider *ioat2_dca_init(struct pci_dev *pdev, void __iomem *iobase);
-struct dca_provider *ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase);
+unsigned long ioat_get_current_completion(struct ioat_chan_common *chan);
+void ioat_init_channel(struct ioatdma_device *device,
+                       struct ioat_chan_common *chan, int idx,
+                       work_func_t work_fn, void (*tasklet)(unsigned long),
+                       unsigned long tasklet_data);
+void ioat_dma_unmap(struct ioat_chan_common *chan, enum dma_ctrl_flags flags,
+                    size_t len, struct ioat_dma_descriptor *hw);
 #endif /* IOATDMA_H */