From 1770efc97981dbf756a18f5eb7615c4bafab665b Mon Sep 17 00:00:00 2001
From: John Cox <jc@kynesim.co.uk>
Date: Mon, 2 Oct 2023 15:12:52 +0100
Subject: [PATCH] media/rpivid: Allow use of iommu in rpivid

In order to use iommu on hevc set dma mask_and_coherent in probe.
I am assured dma_set_mask_and_coherent is benign on Pi4 (which has
no iommu) and it seems to be so in practice.
Also adds a bit of debug to make internal buffer allocation failure
easier to spot in future

Signed-off-by: John Cox <jc@kynesim.co.uk>
---
 drivers/staging/media/rpivid/rpivid.c      |  7 +++++++
 drivers/staging/media/rpivid/rpivid_h265.c | 12 ++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

--- a/drivers/staging/media/rpivid/rpivid.c
+++ b/drivers/staging/media/rpivid/rpivid.c
@@ -360,6 +360,13 @@ static int rpivid_probe(struct platform_
 	snprintf(vfd->name, sizeof(vfd->name), "%s", rpivid_video_device.name);
 	video_set_drvdata(vfd, dev);
 
+	ret = dma_set_mask_and_coherent(dev->dev, DMA_BIT_MASK(36));
+	if (ret) {
+		v4l2_err(&dev->v4l2_dev,
+			 "Failed dma_set_mask_and_coherent\n");
+		goto err_v4l2;
+	}
+
 	dev->m2m_dev = v4l2_m2m_init(&rpivid_m2m_ops);
 	if (IS_ERR(dev->m2m_dev)) {
 		v4l2_err(&dev->v4l2_dev,
--- a/drivers/staging/media/rpivid/rpivid_h265.c
+++ b/drivers/staging/media/rpivid/rpivid_h265.c
@@ -2495,11 +2495,19 @@ static int rpivid_h265_start(struct rpiv
 	for (i = 0; i != ARRAY_SIZE(ctx->pu_bufs); ++i) {
 		// Don't actually need a kernel mapping here
 		if (gptr_alloc(dev, ctx->pu_bufs + i, pu_alloc,
-			       DMA_ATTR_NO_KERNEL_MAPPING))
+			       DMA_ATTR_NO_KERNEL_MAPPING)) {
+			v4l2_err(&dev->v4l2_dev,
+				 "Failed to alloc %#zx PU%d buffer\n",
+				 pu_alloc, i);
 			goto fail;
+		}
 		if (gptr_alloc(dev, ctx->coeff_bufs + i, coeff_alloc,
-			       DMA_ATTR_NO_KERNEL_MAPPING))
+			       DMA_ATTR_NO_KERNEL_MAPPING)) {
+			v4l2_err(&dev->v4l2_dev,
+				 "Failed to alloc %#zx Coeff%d buffer\n",
+				 pu_alloc, i);
 			goto fail;
+		}
 	}
 	aux_q_init(ctx);
 
