[PATCH 1/5] common: bouncebuf: Permit passing custom alignment check function

[Marek Vasut]

Add extended version of the bounce_buffer_start(), which permits passing in
a custom alignment checker function for the buffer. This is useful e.g. on
systems with various DMA restrictions and where the checker function might
be more complex than a simple CPU cache alignment check.

Signed-off-by: Marek Vasut <marek.vasut+renesas at gmail.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
Cc: Masahiro Yamada <yamada.masahiro at socionext.com>
Cc: Peng Fan <peng.fan at nxp.com>
Cc: Simon Glass <sjg at chromium.org>
Cc: Tom Rini <trini at konsulko.com>
---
 common/bouncebuf.c  | 20 +++++++++++++++-----
 include/bouncebuf.h | 15 +++++++++++++++
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/common/bouncebuf.c b/common/bouncebuf.c
index 614eb36c78..0ace152b98 100644
--- a/common/bouncebuf.c
+++ b/common/bouncebuf.c
@@ -31,17 +31,19 @@ static int addr_aligned(struct bounce_buffer *state)
 	return 1;
 }
 
-int bounce_buffer_start(struct bounce_buffer *state, void *data,
-			size_t len, unsigned int flags)
+int bounce_buffer_start_extalign(struct bounce_buffer *state, void *data,
+				 size_t len, unsigned int flags,
+				 size_t alignment,
+				 int (*addr_is_aligned)(struct bounce_buffer *state))
 {
 	state->user_buffer = data;
 	state->bounce_buffer = data;
 	state->len = len;
-	state->len_aligned = roundup(len, ARCH_DMA_MINALIGN);
+	state->len_aligned = roundup(len, alignment);
 	state->flags = flags;
 
-	if (!addr_aligned(state)) {
-		state->bounce_buffer = memalign(ARCH_DMA_MINALIGN,
+	if (!addr_is_aligned(state)) {
+		state->bounce_buffer = memalign(alignment,
 						state->len_aligned);
 		if (!state->bounce_buffer)
 			return -ENOMEM;
@@ -62,6 +64,14 @@ int bounce_buffer_start(struct bounce_buffer *state, void *data,
 	return 0;
 }
 
+int bounce_buffer_start(struct bounce_buffer *state, void *data,
+			size_t len, unsigned int flags)
+{
+	return bounce_buffer_start_extalign(state, data, len, flags,
+					    ARCH_DMA_MINALIGN,
+					    addr_aligned);
+}
+
 int bounce_buffer_stop(struct bounce_buffer *state)
 {
 	if (state->flags & GEN_BB_WRITE) {
diff --git a/include/bouncebuf.h b/include/bouncebuf.h
index fd9b0f3b28..7427bd12e2 100644
--- a/include/bouncebuf.h
+++ b/include/bouncebuf.h
@@ -62,6 +62,21 @@ struct bounce_buffer {
  */
 int bounce_buffer_start(struct bounce_buffer *state, void *data,
 			size_t len, unsigned int flags);
+
+/**
+ * bounce_buffer_start() -- Start the bounce buffer session with external align check function
+ * state:	stores state passed between bounce_buffer_{start,stop}
+ * data:	pointer to buffer to be aligned
+ * len:		length of the buffer
+ * flags:	flags describing the transaction, see above.
+ * alignment:	alignment of the newly allocated bounce buffer
+ * addr_is_aligned: function for checking the alignment instead of the default one
+ */
+int bounce_buffer_start_extalign(struct bounce_buffer *state, void *data,
+				 size_t len, unsigned int flags,
+				 size_t alignment,
+				 int (*addr_is_aligned)(struct bounce_buffer *state));
+
 /**
  * bounce_buffer_stop() -- Finish the bounce buffer session
  * state:	stores state passed between bounce_buffer_{start,stop}
-- 
2.25.0