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From:   Dmitry Osipenko <dmitry.osipenko@collabora.com>
To:     Maxime Ripard <mripard@kernel.org>,
        Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Samuel Holland <samuel@sholland.org>,
        Nicolas Dufresne <nicolas.dufresne@collabora.com>
Cc:     linux-media@vger.kernel.org, linux-staging@lists.linux.dev,
        linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
        kernel@collabora.com
Subject: [PATCH v1] media: cedrus: Propagate error code from cedrus_h265_skip_bits()
Date:   Wed, 14 Sep 2022 18:01:05 +0300
Message-Id: <20220914150105.209484-1-dmitry.osipenko@collabora.com>
MIME-Version: 1.0
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Precedence: bulk

The cedrus_h265_skip_bits() may get into infinite loop if decoding
parameters are incorrect. In this case we detect the loop and print
a error message, continuing the decoding that is fated to fail.

Will be cleaner to abort the decoding early. Propagate the error code
to cedrus_device_run() and reset hardware on the cedrus_h265_skip_bits()
failure.

Suggested-by: Jernej Škrabec <jernej.skrabec@gmail.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/staging/media/sunxi/cedrus/cedrus_dec.c  |  2 ++
 drivers/staging/media/sunxi/cedrus/cedrus_h265.c | 15 ++++++++++++---
 drivers/staging/media/sunxi/cedrus/cedrus_hw.c   |  7 ++++++-
 drivers/staging/media/sunxi/cedrus/cedrus_hw.h   |  2 ++
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
index e7f7602a5ab4..ae5df3dc01c0 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
@@ -112,6 +112,8 @@ void cedrus_device_run(void *priv)
 
 		dev->dec_ops[ctx->current_codec]->trigger(ctx);
 	} else {
+		cedrus_hw_reset(dev);
+
 		v4l2_m2m_buf_done_and_job_finish(ctx->dev->m2m_dev,
 						 ctx->fh.m2m_ctx,
 						 VB2_BUF_STATE_ERROR);
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
index 4952fc17f3e6..f409f59452d8 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
@@ -224,9 +224,10 @@ static void cedrus_h265_pred_weight_write(struct cedrus_dev *dev,
 	}
 }
 
-static void cedrus_h265_skip_bits(struct cedrus_dev *dev, int num)
+static int cedrus_h265_skip_bits(struct cedrus_dev *dev, int num)
 {
 	int count = 0;
+	int err;
 
 	while (count < num) {
 		int tmp = min(num - count, 32);
@@ -235,11 +236,16 @@ static void cedrus_h265_skip_bits(struct cedrus_dev *dev, int num)
 			     VE_DEC_H265_TRIGGER_FLUSH_BITS |
 			     VE_DEC_H265_TRIGGER_TYPE_N_BITS(tmp));
 
-		if (cedrus_wait_for(dev, VE_DEC_H265_STATUS, VE_DEC_H265_STATUS_VLD_BUSY))
+		err = cedrus_wait_for(dev, VE_DEC_H265_STATUS, VE_DEC_H265_STATUS_VLD_BUSY);
+		if (err) {
 			dev_err_ratelimited(dev->dev, "timed out waiting to skip bits\n");
+			return err;
+		}
 
 		count += tmp;
 	}
+
+	return 0;
 }
 
 static void cedrus_h265_write_scaling_list(struct cedrus_ctx *ctx,
@@ -408,6 +414,7 @@ static int cedrus_h265_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
 	u32 pic_order_cnt[2];
 	u8 *padding;
 	int count;
+	int err;
 	u32 reg;
 
 	sps = run->h265.sps;
@@ -534,7 +541,9 @@ static int cedrus_h265_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
 	/* Include the one bit. */
 	count++;
 
-	cedrus_h265_skip_bits(dev, slice_params->data_byte_offset * 8 - count);
+	err = cedrus_h265_skip_bits(dev, slice_params->data_byte_offset * 8 - count);
+	if (err)
+		return err;
 
 	/* Bitstream parameters. */
 
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
index a6470a89851e..e9ceca332062 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
@@ -168,11 +168,16 @@ void cedrus_watchdog(struct work_struct *work)
 					 VB2_BUF_STATE_ERROR);
 }
 
+void cedrus_hw_reset(struct cedrus_dev *dev)
+{
+	reset_control_reset(dev->rstc);
+}
+
 int cedrus_hw_suspend(struct device *device)
 {
 	struct cedrus_dev *dev = dev_get_drvdata(device);
 
-	reset_control_assert(dev->rstc);
+	cedrus_hw_reset(dev);
 
 	clk_disable_unprepare(dev->ram_clk);
 	clk_disable_unprepare(dev->mod_clk);
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
index 7c92f00e36da..919c4475f0d7 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
@@ -30,4 +30,6 @@ void cedrus_hw_remove(struct cedrus_dev *dev);
 
 void cedrus_watchdog(struct work_struct *work);
 
+void cedrus_hw_reset(struct cedrus_dev *dev);
+
 #endif
-- 
2.37.3