Re: [PATCH v8 4/8] media: platform: Add Cedrus VPU decoder driver

This introduces the Cedrus VPU driver that supports the VPU found in
Allwinner SoCs, also known as Video Engine. It is implemented through
a v4l2 m2m decoder device and a media device (used for media requests).
So far, it only supports MPEG2 decoding.

Since this VPU is stateless, synchronization with media requests is
required in order to ensure consistency between frame headers that
contain metadata about the frame to process and the raw slice data that
is used to generate the frame.

This driver was made possible thanks to the long-standing effort
carried out by the linux-sunxi community in the interest of reverse
engineering, documenting and implementing support for Allwinner VPU.

Signed-off-by: Paul Kocialkowski <redacted>
---
 MAINTAINERS                                   |   7 +
 drivers/staging/media/Kconfig                 |   2 +
 drivers/staging/media/Makefile                |   1 +
 drivers/staging/media/sunxi/Kconfig           |  15 +
 drivers/staging/media/sunxi/Makefile          |   1 +
 drivers/staging/media/sunxi/cedrus/Kconfig    |  14 +
 drivers/staging/media/sunxi/cedrus/Makefile   |   3 +
 drivers/staging/media/sunxi/cedrus/cedrus.c   | 420 +++++++++++++
 drivers/staging/media/sunxi/cedrus/cedrus.h   | 167 +++++
 .../staging/media/sunxi/cedrus/cedrus_dec.c   | 116 ++++
 .../staging/media/sunxi/cedrus/cedrus_dec.h   |  28 +
 .../staging/media/sunxi/cedrus/cedrus_hw.c    | 322 ++++++++++
 .../staging/media/sunxi/cedrus/cedrus_hw.h    |  30 +
 .../staging/media/sunxi/cedrus/cedrus_mpeg2.c | 235 +++++++
 .../staging/media/sunxi/cedrus/cedrus_regs.h  | 233 +++++++
 .../staging/media/sunxi/cedrus/cedrus_video.c | 574 ++++++++++++++++++
 .../staging/media/sunxi/cedrus/cedrus_video.h |  32 +
 17 files changed, 2200 insertions(+)
 create mode 100644 drivers/staging/media/sunxi/Kconfig
 create mode 100644 drivers/staging/media/sunxi/Makefile
 create mode 100644 drivers/staging/media/sunxi/cedrus/Kconfig
 create mode 100644 drivers/staging/media/sunxi/cedrus/Makefile
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus.c
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus.h
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus_dec.c
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus_dec.h
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus_hw.c
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus_hw.h
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus_regs.h
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus_video.c
 create mode 100644 drivers/staging/media/sunxi/cedrus/cedrus_video.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 435e6c08c694..08065d53c69d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS

@@ -656,6 +656,13 @@ L:	linux-crypto@vger.kernel.org
 S:	Maintained
 F:	drivers/crypto/sunxi-ss/
 
+ALLWINNER VPU DRIVER
+M:	Maxime Ripard <maxime.ripard@bootlin.com>
+M:	Paul Kocialkowski <paul.kocialkowski@bootlin.com>
+L:	linux-media@vger.kernel.org
+S:	Maintained
+F:	drivers/staging/media/sunxi/cedrus/
+
 ALPHA PORT
 M:	Richard Henderson <rth@twiddle.net>
 M:	Ivan Kokshaysky <ink@jurassic.park.msu.ru>

diff --git a/drivers/staging/media/Kconfig b/drivers/staging/media/Kconfig
index db5cf67047ad..b3620a8f2d9f 100644
--- a/drivers/staging/media/Kconfig
+++ b/drivers/staging/media/Kconfig

@@ -31,6 +31,8 @@ source "drivers/staging/media/mt9t031/Kconfig"
 
 source "drivers/staging/media/omap4iss/Kconfig"
 
+source "drivers/staging/media/sunxi/Kconfig"
+
 source "drivers/staging/media/tegra-vde/Kconfig"
 
 source "drivers/staging/media/zoran/Kconfig"

diff --git a/drivers/staging/media/Makefile b/drivers/staging/media/Makefile
index 503fbe47fa58..42948f805548 100644
--- a/drivers/staging/media/Makefile
+++ b/drivers/staging/media/Makefile

@@ -5,5 +5,6 @@ obj-$(CONFIG_SOC_CAMERA_IMX074)	+= imx074/
 obj-$(CONFIG_SOC_CAMERA_MT9T031)	+= mt9t031/
 obj-$(CONFIG_VIDEO_DM365_VPFE)	+= davinci_vpfe/
 obj-$(CONFIG_VIDEO_OMAP4)	+= omap4iss/
+obj-$(CONFIG_VIDEO_SUNXI)	+= sunxi/
 obj-$(CONFIG_TEGRA_VDE)		+= tegra-vde/
 obj-$(CONFIG_VIDEO_ZORAN)	+= zoran/

diff --git a/drivers/staging/media/sunxi/Kconfig b/drivers/staging/media/sunxi/Kconfig
new file mode 100644
index 000000000000..c78d92240ceb
--- /dev/null
+++ b/drivers/staging/media/sunxi/Kconfig

@@ -0,0 +1,15 @@
+config VIDEO_SUNXI
+	bool "Allwinner sunXi family Video Devices"
+	depends on ARCH_SUNXI || COMPILE_TEST
+	help
+	  If you have an Allwinner SoC based on the sunXi family, say Y.
+
+	  Note that this option doesn't include new drivers in the
+	  kernel: saying N will just cause Kconfig to skip all the
+	  questions about Allwinner media devices.
+
+if VIDEO_SUNXI
+
+source "drivers/staging/media/sunxi/cedrus/Kconfig"
+
+endif

diff --git a/drivers/staging/media/sunxi/Makefile b/drivers/staging/media/sunxi/Makefile
new file mode 100644
index 000000000000..cee2846c3ecf
--- /dev/null
+++ b/drivers/staging/media/sunxi/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_VIDEO_SUNXI_CEDRUS)	+= cedrus/

diff --git a/drivers/staging/media/sunxi/cedrus/Kconfig b/drivers/staging/media/sunxi/cedrus/Kconfig
new file mode 100644
index 000000000000..afd7d7ee0388
--- /dev/null
+++ b/drivers/staging/media/sunxi/cedrus/Kconfig

@@ -0,0 +1,14 @@
+config VIDEO_SUNXI_CEDRUS
+	tristate "Allwinner Cedrus VPU driver"
+	depends on VIDEO_DEV && VIDEO_V4L2 && MEDIA_CONTROLLER
+	depends on HAS_DMA
+	depends on OF
+	select VIDEOBUF2_DMA_CONTIG
+	select MEDIA_REQUEST_API
+	select V4L2_MEM2MEM_DEV
+	help
+	  Support for the VPU found in Allwinner SoCs, also known as the Cedar
+	  video engine.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called sunxi-cedrus.

diff --git a/drivers/staging/media/sunxi/cedrus/Makefile b/drivers/staging/media/sunxi/cedrus/Makefile
new file mode 100644
index 000000000000..e9dc68b7bcb6
--- /dev/null
+++ b/drivers/staging/media/sunxi/cedrus/Makefile

@@ -0,0 +1,3 @@
+obj-$(CONFIG_VIDEO_SUNXI_CEDRUS) += sunxi-cedrus.o
+
+sunxi-cedrus-y = cedrus.o cedrus_video.o cedrus_hw.o cedrus_dec.o cedrus_mpeg2.o

diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c
new file mode 100644
index 000000000000..7c0f90253135
--- /dev/null
+++ b/drivers/staging/media/sunxi/cedrus/cedrus.c

@@ -0,0 +1,420 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cedrus VPU driver
+ *
+ * Copyright (C) 2016 Florent Revest <florent.revest@free-electrons.com>
+ * Copyright (C) 2018 Paul Kocialkowski <paul.kocialkowski@bootlin.com>
+ * Copyright (C) 2018 Bootlin
+ *
+ * Based on the vim2m driver, that is:
+ *
+ * Copyright (c) 2009-2010 Samsung Electronics Co., Ltd.
+ * Pawel Osciak, <pawel@osciak.com>
+ * Marek Szyprowski, <m.szyprowski@samsung.com>
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-mem2mem.h>
+
+#include "cedrus.h"
+#include "cedrus_video.h"
+#include "cedrus_dec.h"
+#include "cedrus_hw.h"
+
+static const struct cedrus_control cedrus_controls[] = {
+	{
+		.id		= V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS,
+		.elem_size	= sizeof(struct v4l2_ctrl_mpeg2_slice_params),
+		.codec		= CEDRUS_CODEC_MPEG2,
+		.required	= true,
+	},
+	{
+		.id		= V4L2_CID_MPEG_VIDEO_MPEG2_QUANTIZATION,
+		.elem_size	= sizeof(struct v4l2_ctrl_mpeg2_quantization),
+		.codec		= CEDRUS_CODEC_MPEG2,
+		.required	= false,
+	},
+};
+
+#define CEDRUS_CONTROLS_COUNT	ARRAY_SIZE(cedrus_controls)
+
+void *cedrus_find_control_data(struct cedrus_ctx *ctx, u32 id)
+{
+	unsigned int i;
+
+	for (i = 0; ctx->ctrls[i] != NULL; i++)
+		if (ctx->ctrls[i]->id == id)
+			return ctx->ctrls[i]->p_cur.p;
+
+	return NULL;
+}
+
+static int cedrus_init_ctrls(struct cedrus_dev *dev, struct cedrus_ctx *ctx)
+{
+	struct v4l2_ctrl_handler *hdl = &ctx->hdl;
+	struct v4l2_ctrl *ctrl;
+	unsigned int ctrl_size;
+	unsigned int i;
+
+	v4l2_ctrl_handler_init(hdl, CEDRUS_CONTROLS_COUNT);
+	if (hdl->error) {
+		v4l2_err(&dev->v4l2_dev,
+			 "Failed to initialize control handler\n");
+		return hdl->error;
+	}
+
+	ctrl_size = sizeof(ctrl) * CEDRUS_CONTROLS_COUNT + 1;
+
+	ctx->ctrls = kzalloc(ctrl_size, GFP_KERNEL);
+	memset(ctx->ctrls, 0, ctrl_size);
+
+	for (i = 0; i < CEDRUS_CONTROLS_COUNT; i++) {
+		struct v4l2_ctrl_config cfg = { 0 };
+
+		cfg.elem_size = cedrus_controls[i].elem_size;
+		cfg.id = cedrus_controls[i].id;
+
+		ctrl = v4l2_ctrl_new_custom(hdl, &cfg, NULL);
+		if (hdl->error) {
+			v4l2_err(&dev->v4l2_dev,
+				 "Failed to create new custom control\n");
+
+			v4l2_ctrl_handler_free(hdl);
+			kfree(ctx->ctrls);
+			return hdl->error;
+		}
+
+		ctx->ctrls[i] = ctrl;
+	}
+
+	ctx->fh.ctrl_handler = hdl;
+	v4l2_ctrl_handler_setup(hdl);
+
+	return 0;
+}
+
+static int cedrus_request_validate(struct media_request *req)
+{
+	struct media_request_object *obj, *obj_safe;
+	struct v4l2_ctrl_handler *parent_hdl, *hdl;
+	struct cedrus_ctx *ctx = NULL;
+	struct v4l2_ctrl *ctrl_test;
+	unsigned int i;
+
+	list_for_each_entry_safe(obj, obj_safe, &req->objects, list) {
+		struct vb2_buffer *vb;
+
+		if (vb2_request_object_is_buffer(obj)) {
+			vb = container_of(obj, struct vb2_buffer, req_obj);
+			ctx = vb2_get_drv_priv(vb->vb2_queue);
+
+			break;
+		}
+	}
+
+	if (!ctx)
+		return -ENOENT;
+
+	parent_hdl = &ctx->hdl;
+
+	hdl = v4l2_ctrl_request_hdl_find(req, parent_hdl);
+	if (!hdl) {
+		v4l2_err(&ctx->dev->v4l2_dev, "Missing codec control(s)\n");
+		return -ENOENT;
+	}
+
+	for (i = 0; i < CEDRUS_CONTROLS_COUNT; i++) {
+		if (cedrus_controls[i].codec != ctx->current_codec ||
+		    !cedrus_controls[i].required)
+			continue;
+
+		ctrl_test = v4l2_ctrl_request_hdl_ctrl_find(hdl,
+			cedrus_controls[i].id);
+		if (!ctrl_test) {
+			v4l2_err(&ctx->dev->v4l2_dev,
+				 "Missing required codec control\n");
+			return -ENOENT;
+		}
+	}
+
+	v4l2_ctrl_request_hdl_put(hdl);
+
+	return vb2_request_validate(req);
+}
+
+static int cedrus_open(struct file *file)
+{
+	struct cedrus_dev *dev = video_drvdata(file);
+	struct cedrus_ctx *ctx = NULL;
+	int ret;
+
+	if (mutex_lock_interruptible(&dev->dev_mutex))
+		return -ERESTARTSYS;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx) {
+		mutex_unlock(&dev->dev_mutex);
+		return -ENOMEM;
+	}
+
+	v4l2_fh_init(&ctx->fh, video_devdata(file));
+	file->private_data = &ctx->fh;
+	ctx->dev = dev;
+
+	ret = cedrus_init_ctrls(dev, ctx);
+	if (ret)
+		goto err_free;
+
+	ctx->fh.m2m_ctx = v4l2_m2m_ctx_init(dev->m2m_dev, ctx,
+					    &cedrus_queue_init);
+	if (IS_ERR(ctx->fh.m2m_ctx)) {
+		ret = PTR_ERR(ctx->fh.m2m_ctx);
+		goto err_ctrls;
+	}
+
+	v4l2_fh_add(&ctx->fh);
+
+	mutex_unlock(&dev->dev_mutex);
+
+	return 0;
+
+err_ctrls:
+	v4l2_ctrl_handler_free(&ctx->hdl);
+err_free:
+	kfree(ctx);
+	mutex_unlock(&dev->dev_mutex);
+
+	return ret;
+}
+
+static int cedrus_release(struct file *file)
+{
+	struct cedrus_dev *dev = video_drvdata(file);
+	struct cedrus_ctx *ctx = container_of(file->private_data,
+					      struct cedrus_ctx, fh);
+
+	mutex_lock(&dev->dev_mutex);
+
+	v4l2_fh_del(&ctx->fh);
+	v4l2_m2m_ctx_release(ctx->fh.m2m_ctx);
+
+	v4l2_ctrl_handler_free(&ctx->hdl);
+	kfree(ctx->ctrls);
+
+	v4l2_fh_exit(&ctx->fh);
+
+	kfree(ctx);
+
+	mutex_unlock(&dev->dev_mutex);
+
+	return 0;
+}
+
+static const struct v4l2_file_operations cedrus_fops = {
+	.owner		= THIS_MODULE,
+	.open		= cedrus_open,
+	.release	= cedrus_release,
+	.poll		= v4l2_m2m_fop_poll,
+	.unlocked_ioctl	= video_ioctl2,
+	.mmap		= v4l2_m2m_fop_mmap,
+};
+
+static const struct video_device cedrus_video_device = {
+	.name		= CEDRUS_NAME,
+	.vfl_dir	= VFL_DIR_M2M,
+	.fops		= &cedrus_fops,
+	.ioctl_ops	= &cedrus_ioctl_ops,
+	.minor		= -1,
+	.release	= video_device_release_empty,
+	.device_caps	= V4L2_CAP_VIDEO_M2M_MPLANE | V4L2_CAP_STREAMING,
+};
+
+static const struct v4l2_m2m_ops cedrus_m2m_ops = {
+	.device_run	= cedrus_device_run,
+	.job_abort	= cedrus_job_abort,
+};
+