Re: [PATCH v2 11/13] gpu: ipu-ic: Add complete image conversion support with tiling

This patch implements complete image conversion support to ipu-ic,
with tiling to support scaling to and from images up to 4096x4096.
Image rotation is also supported.

The internal API is subsystem agnostic (no V4L2 dependency except
for the use of V4L2 fourcc pixel formats).

Callers prepare for image conversion by calling
ipu_image_convert_prepare(), which initializes the parameters of
the conversion. The caller passes in the ipu_ic task to use for
the conversion, the input and output image formats, a rotation mode,
and a completion callback and completion context pointer:

struct image_converter_ctx *
ipu_image_convert_prepare(struct ipu_ic *ic,
                          struct ipu_image *in, struct ipu_image *out,
                          enum ipu_rotate_mode rot_mode,
                          image_converter_cb_t complete,
                          void *complete_context);

The caller is given a new conversion context that must be passed to
the further APIs:

struct image_converter_run *
ipu_image_convert_run(struct image_converter_ctx *ctx,
                      dma_addr_t in_phys, dma_addr_t out_phys);

This queues a new image conversion request to a run queue, and
starts the conversion immediately if the run queue is empty. Only
the physaddr's of the input and output image buffers are needed,
since the conversion context was created previously with
ipu_image_convert_prepare(). Returns a new run object pointer. When
the conversion completes, the run pointer is returned to the
completion callback.

void image_convert_abort(struct image_converter_ctx *ctx);

This will abort any active or pending conversions for this context.
Any currently active or pending runs belonging to this context are
returned via the completion callback with an error status.

void ipu_image_convert_unprepare(struct image_converter_ctx *ctx);

Unprepares the conversion context. Any active or pending runs will
be aborted by calling image_convert_abort().

Signed-off-by: Steve Longerbeam <redacted>
---
 drivers/gpu/ipu-v3/ipu-ic.c | 1691 ++++++++++++++++++++++++++++++++++++++++++-
 include/video/imx-ipu-v3.h  |   57 +-
 2 files changed, 1736 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/ipu-v3/ipu-ic.c b/drivers/gpu/ipu-v3/ipu-ic.c
index 1a37afc..5471b72 100644
--- a/drivers/gpu/ipu-v3/ipu-ic.c
+++ b/drivers/gpu/ipu-v3/ipu-ic.c

@@ -17,6 +17,8 @@
 #include <linux/bitrev.h>
 #include <linux/io.h>
 #include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/dma-mapping.h>
 #include "ipu-prv.h"
 
 /* IC Register Offsets */

@@ -82,6 +84,40 @@
 #define IC_IDMAC_3_PP_WIDTH_MASK        (0x3ff << 20)
 #define IC_IDMAC_3_PP_WIDTH_OFFSET      20
 
+/*
+ * The IC Resizer has a restriction that the output frame from the
+ * resizer must be 1024 or less in both width (pixels) and height
+ * (lines).
+ *
+ * The image conversion support attempts to split up a conversion when
+ * the desired output (converted) frame resolution exceeds the IC resizer
+ * limit of 1024 in either dimension.
+ *
+ * If either dimension of the output frame exceeds the limit, the
+ * dimension is split into 1, 2, or 4 equal stripes,