dmaengine: refactor dmaengine around dma_async_tx_descriptor

The current dmaengine interface defines mutliple routines per operation,
i.e. dma_async_memcpy_buf_to_buf, dma_async_memcpy_buf_to_page etc.  Adding
more operation types (xor, crc, etc) to this model would result in an
unmanageable number of method permutations.

	Are we really going to add a set of hooks for each DMA engine
	whizbang feature?
		- Jeff Garzik

The descriptor creation process is refactored using the new common
dma_async_tx_descriptor structure.  Instead of per driver
do_<operation>_<dest>_to_<src> methods, drivers integrate
dma_async_tx_descriptor into their private software descriptor and then
define a 'prep' routine per operation.  The prep routine allocates a
descriptor and ensures that the tx_set_src, tx_set_dest, tx_submit routines
are valid.  Descriptor creation and submission becomes:

struct dma_device *dev;
struct dma_chan *chan;
struct dma_async_tx_descriptor *tx;

tx = dev->device_prep_dma_<operation>(chan, len, int_flag)
tx->tx_set_src(dma_addr_t, tx, index /* for multi-source ops */)
tx->tx_set_dest(dma_addr_t, tx, index)
tx->tx_submit(tx)

In addition to the refactoring, dma_async_tx_descriptor also lays the
groundwork for definining cross-channel-operation dependencies, and a
callback facility for asynchronous notification of operation completion.

Changelog:
* drop dma mapping methods, suggested by Chris Leech
* fix ioat_dma_dependency_added, also caught by Andrew Morton
* fix dma_sync_wait, change from Andrew Morton
* uninline large functions, change from Andrew Morton
* add tx->callback = NULL to dmaengine calls to interoperate with async_tx
  calls
* hookup ioat_tx_submit
* convert channel capabilities to a 'cpumask_t like' bitmap
* removed DMA_TX_ARRAY_INIT, no longer needed
* checkpatch.pl fixes
* make set_src, set_dest, and tx_submit descriptor specific methods
* fixup git-ioat merge
* move group_list and phys to dma_async_tx_descriptor

Cc: Jeff Garzik <jeff@garzik.org>
Cc: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>

1 files changed, 149 insertions, 88 deletions

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index c94d8f1d62e5..3de1cf71031a 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -21,13 +21,12 @@
 #ifndef DMAENGINE_H
 #define DMAENGINE_H
 
-#ifdef CONFIG_DMA_ENGINE
-
 #include <linux/device.h>
 #include <linux/uio.h>
 #include <linux/kref.h>
 #include <linux/completion.h>
 #include <linux/rcupdate.h>
+#include <linux/dma-mapping.h>
 
 /**
  * enum dma_event - resource PNP/power managment events
@@ -65,6 +64,31 @@ enum dma_status {
 };
 
 /**
+ * enum dma_transaction_type - DMA transaction types/indexes
+ */
+enum dma_transaction_type {
+        DMA_MEMCPY,
+        DMA_XOR,
+        DMA_PQ_XOR,
+        DMA_DUAL_XOR,
+        DMA_PQ_UPDATE,
+        DMA_ZERO_SUM,
+        DMA_PQ_ZERO_SUM,
+        DMA_MEMSET,
+        DMA_MEMCPY_CRC32C,
+        DMA_INTERRUPT,
+};
+
+/* last transaction type for creation of the capabilities mask */
+#define DMA_TX_TYPE_END (DMA_INTERRUPT + 1)
+
+/**
+ * dma_cap_mask_t - capabilities bitmap modeled after cpumask_t.
+ * See linux/cpumask.h
+ */
+typedef struct { DECLARE_BITMAP(bits, DMA_TX_TYPE_END); } dma_cap_mask_t;
+
+/**
  * struct dma_chan_percpu - the per-CPU part of struct dma_chan
  * @refcount: local_t used for open-coded "bigref" counting
  * @memcpy_count: transaction counter
@@ -157,48 +181,106 @@ struct dma_client {
         struct list_head        global_node;
 };
 
+typedef void (*dma_async_tx_callback)(void *dma_async_param);
+/**
+ * struct dma_async_tx_descriptor - async transaction descriptor
+ * ---dma generic offload fields---
+ * @cookie: tracking cookie for this transaction, set to -EBUSY if
+ *      this tx is sitting on a dependency list
+ * @ack: the descriptor can not be reused until the client acknowledges
+ *      receipt, i.e. has has a chance to establish any dependency chains
+ * @phys: physical address of the descriptor
+ * @tx_list: driver common field for operations that require multiple
+ *      descriptors
+ * @chan: target channel for this operation
+ * @tx_submit: set the prepared descriptor(s) to be executed by the engine
+ * @tx_set_dest: set a destination address in a hardware descriptor
+ * @tx_set_src: set a source address in a hardware descriptor
+ * @callback: routine to call after this operation is complete
+ * @callback_param: general parameter to pass to the callback routine
+ * ---async_tx api specific fields---
+ * @depend_list: at completion this list of transactions are submitted
+ * @depend_node: allow this transaction to be executed after another
+ *      transaction has completed, possibly on another channel
+ * @parent: pointer to the next level up in the dependency chain
+ * @lock: protect the dependency list
+ */
+struct dma_async_tx_descriptor {
+        dma_cookie_t cookie;
+        int ack;
+        dma_addr_t phys;
+        struct list_head tx_list;
+        struct dma_chan *chan;
+        dma_cookie_t (*tx_submit)(struct dma_async_tx_descriptor *tx);
+        void (*tx_set_dest)(dma_addr_t addr,
+                struct dma_async_tx_descriptor *tx, int index);
+        void (*tx_set_src)(dma_addr_t addr,
+                struct dma_async_tx_descriptor *tx, int index);
+        dma_async_tx_callback callback;
+        void *callback_param;
+        struct list_head depend_list;
+        struct list_head depend_node;
+        struct dma_async_tx_descriptor *parent;
+        spinlock_t lock;
+};
+
 /**
  * struct dma_device - info on the entity supplying DMA services
  * @chancnt: how many DMA channels are supported
  * @channels: the list of struct dma_chan
  * @global_node: list_head for global dma_device_list
+ * @cap_mask: one or more dma_capability flags
+ * @max_xor: maximum number of xor sources, 0 if no capability
  * @refcount: reference count
  * @done: IO completion struct
  * @dev_id: unique device ID
+ * @dev: struct device reference for dma mapping api
  * @device_alloc_chan_resources: allocate resources and return the
  *      number of allocated descriptors
  * @device_free_chan_resources: release DMA channel's resources
- * @device_memcpy_buf_to_buf: memcpy buf pointer to buf pointer
- * @device_memcpy_buf_to_pg: memcpy buf pointer to struct page
- * @device_memcpy_pg_to_pg: memcpy struct page/offset to struct page/offset
- * @device_memcpy_complete: poll the status of an IOAT DMA transaction
- * @device_memcpy_issue_pending: push appended descriptors to hardware
+ * @device_prep_dma_memcpy: prepares a memcpy operation
+ * @device_prep_dma_xor: prepares a xor operation
+ * @device_prep_dma_zero_sum: prepares a zero_sum operation
+ * @device_prep_dma_memset: prepares a memset operation
+ * @device_prep_dma_interrupt: prepares an end of chain interrupt operation
+ * @device_dependency_added: async_tx notifies the channel about new deps
+ * @device_issue_pending: push pending transactions to hardware
  */
 struct dma_device {
 
         unsigned int chancnt;
         struct list_head channels;
         struct list_head global_node;
+        dma_cap_mask_t  cap_mask;
+        int max_xor;
 
         struct kref refcount;
         struct completion done;
 
         int dev_id;
+        struct device *dev;
 
         int (*device_alloc_chan_resources)(struct dma_chan *chan);
         void (*device_free_chan_resources)(struct dma_chan *chan);
-        dma_cookie_t (*device_memcpy_buf_to_buf)(struct dma_chan *chan,
-                        void *dest, void *src, size_t len);
-        dma_cookie_t (*device_memcpy_buf_to_pg)(struct dma_chan *chan,
-                        struct page *page, unsigned int offset, void *kdata,
-                        size_t len);
-        dma_cookie_t (*device_memcpy_pg_to_pg)(struct dma_chan *chan,
-                        struct page *dest_pg, unsigned int dest_off,
-                        struct page *src_pg, unsigned int src_off, size_t len);
-        enum dma_status (*device_memcpy_complete)(struct dma_chan *chan,
+
+        struct dma_async_tx_descriptor *(*device_prep_dma_memcpy)(
+                struct dma_chan *chan, size_t len, int int_en);
+        struct dma_async_tx_descriptor *(*device_prep_dma_xor)(
+                struct dma_chan *chan, unsigned int src_cnt, size_t len,
+                int int_en);
+        struct dma_async_tx_descriptor *(*device_prep_dma_zero_sum)(
+                struct dma_chan *chan, unsigned int src_cnt, size_t len,
+                u32 *result, int int_en);
+        struct dma_async_tx_descriptor *(*device_prep_dma_memset)(
+                struct dma_chan *chan, int value, size_t len, int int_en);
+        struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(
+                struct dma_chan *chan);
+
+        void (*device_dependency_added)(struct dma_chan *chan);
+        enum dma_status (*device_is_tx_complete)(struct dma_chan *chan,
                         dma_cookie_t cookie, dma_cookie_t *last,
                         dma_cookie_t *used);
-        void (*device_memcpy_issue_pending)(struct dma_chan *chan);
+        void (*device_issue_pending)(struct dma_chan *chan);
 };
 
 /* --- public DMA engine API --- */
@@ -207,96 +289,72 @@ struct dma_client *dma_async_client_register(dma_event_callback event_callback);
 void dma_async_client_unregister(struct dma_client *client);
 void dma_async_client_chan_request(struct dma_client *client,
                 unsigned int number);
+dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
+        void *dest, void *src, size_t len);
+dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,
+        struct page *page, unsigned int offset, void *kdata, size_t len);
+dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan,
+        struct page *dest_pg, unsigned int dest_off, struct page *src_pg,
+        unsigned int src_off, size_t len);
+void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
+        struct dma_chan *chan);
 
-/**
- * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
- * @chan: DMA channel to offload copy to
- * @dest: destination address (virtual)
- * @src: source address (virtual)
- * @len: length
- *
- * Both @dest and @src must be mappable to a bus address according to the
- * DMA mapping API rules for streaming mappings.
- * Both @dest and @src must stay memory resident (kernel memory or locked
- * user space pages).
- */
-static inline dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
-        void *dest, void *src, size_t len)
-{
-        int cpu = get_cpu();
-        per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
-        per_cpu_ptr(chan->local, cpu)->memcpy_count++;
-        put_cpu();
 
-        return chan->device->device_memcpy_buf_to_buf(chan, dest, src, len);
+static inline void
+async_tx_ack(struct dma_async_tx_descriptor *tx)
+{
+        tx->ack = 1;
 }
 
-/**
- * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
- * @chan: DMA channel to offload copy to
- * @page: destination page
- * @offset: offset in page to copy to
- * @kdata: source address (virtual)
- * @len: length
- *
- * Both @page/@offset and @kdata must be mappable to a bus address according
- * to the DMA mapping API rules for streaming mappings.
- * Both @page/@offset and @kdata must stay memory resident (kernel memory or
- * locked user space pages)
- */
-static inline dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,
-        struct page *page, unsigned int offset, void *kdata, size_t len)
+#define first_dma_cap(mask) __first_dma_cap(&(mask))
+static inline int __first_dma_cap(const dma_cap_mask_t *srcp)
 {
-        int cpu = get_cpu();
-        per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
-        per_cpu_ptr(chan->local, cpu)->memcpy_count++;
-        put_cpu();
+        return min_t(int, DMA_TX_TYPE_END,
+                find_first_bit(srcp->bits, DMA_TX_TYPE_END));
+}
 
-        return chan->device->device_memcpy_buf_to_pg(chan, page, offset,
-                                                     kdata, len);
+#define next_dma_cap(n, mask) __next_dma_cap((n), &(mask))
+static inline int __next_dma_cap(int n, const dma_cap_mask_t *srcp)
+{
+        return min_t(int, DMA_TX_TYPE_END,
+                find_next_bit(srcp->bits, DMA_TX_TYPE_END, n+1));
 }
 
-/**
- * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
- * @chan: DMA channel to offload copy to
- * @dest_pg: destination page
- * @dest_off: offset in page to copy to
- * @src_pg: source page
- * @src_off: offset in page to copy from
- * @len: length
- *
- * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
- * address according to the DMA mapping API rules for streaming mappings.
- * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
- * (kernel memory or locked user space pages).
- */
-static inline dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan,
-        struct page *dest_pg, unsigned int dest_off, struct page *src_pg,
-        unsigned int src_off, size_t len)
+#define dma_cap_set(tx, mask) __dma_cap_set((tx), &(mask))
+static inline void
+__dma_cap_set(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
 {
-        int cpu = get_cpu();
-        per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
-        per_cpu_ptr(chan->local, cpu)->memcpy_count++;
-        put_cpu();
+        set_bit(tx_type, dstp->bits);
+}
 
-        return chan->device->device_memcpy_pg_to_pg(chan, dest_pg, dest_off,
-                                                    src_pg, src_off, len);
+#define dma_has_cap(tx, mask) __dma_has_cap((tx), &(mask))
+static inline int
+__dma_has_cap(enum dma_transaction_type tx_type, dma_cap_mask_t *srcp)
+{
+        return test_bit(tx_type, srcp->bits);
 }
 
+#define for_each_dma_cap_mask(cap, mask) \
+        for ((cap) = first_dma_cap(mask);       \
+                (cap) < DMA_TX_TYPE_END;        \
+                (cap) = next_dma_cap((cap), (mask)))
+
 /**
- * dma_async_memcpy_issue_pending - flush pending copies to HW
+ * dma_async_issue_pending - flush pending transactions to HW
  * @chan: target DMA channel
  *
  * This allows drivers to push copies to HW in batches,
  * reducing MMIO writes where possible.
  */
-static inline void dma_async_memcpy_issue_pending(struct dma_chan *chan)
+static inline void dma_async_issue_pending(struct dma_chan *chan)
 {
-        return chan->device->device_memcpy_issue_pending(chan);
+        return chan->device->device_issue_pending(chan);
 }
 
+#define dma_async_memcpy_issue_pending(chan) dma_async_issue_pending(chan)
+
 /**
- * dma_async_memcpy_complete - poll for transaction completion
+ * dma_async_is_tx_complete - poll for transaction completion
  * @chan: DMA channel
  * @cookie: transaction identifier to check status of
  * @last: returns last completed cookie, can be NULL
@@ -306,12 +364,15 @@ static inline void dma_async_memcpy_issue_pending(struct dma_chan *chan)
  * internal state and can be used with dma_async_is_complete() to check
  * the status of multiple cookies without re-checking hardware state.
  */
-static inline enum dma_status dma_async_memcpy_complete(struct dma_chan *chan,
+static inline enum dma_status dma_async_is_tx_complete(struct dma_chan *chan,
         dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
 {
-        return chan->device->device_memcpy_complete(chan, cookie, last, used);
+        return chan->device->device_is_tx_complete(chan, cookie, last, used);
 }
 
+#define dma_async_memcpy_complete(chan, cookie, last, used)\
+        dma_async_is_tx_complete(chan, cookie, last, used)
+
 /**
  * dma_async_is_complete - test a cookie against chan state
  * @cookie: transaction identifier to test status of
@@ -334,6 +395,7 @@ static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
         return DMA_IN_PROGRESS;
 }
 
+enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);
 
 /* --- DMA device --- */
 
@@ -362,5 +424,4 @@ dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
         struct dma_pinned_list *pinned_list, struct page *page,
         unsigned int offset, size_t len);
 
-#endif /* CONFIG_DMA_ENGINE */
 #endif /* DMAENGINE_H */