From: Dave Stevenson <dave.stevenson@raspberrypi.com>

With the vc-sm-cma driver we can support zero copy of buffers between
the kernel and VPU. Add this support to mmal-vchiq.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Jai Luthra <jai.luthra@ideasonboard.com>
---
 drivers/platform/raspberrypi/vchiq-mmal/Kconfig    |  3 +-
 .../platform/raspberrypi/vchiq-mmal/mmal-common.h  |  4 ++
 .../platform/raspberrypi/vchiq-mmal/mmal-vchiq.c   | 65 ++++++++++++++++++++--
 .../platform/raspberrypi/vchiq-mmal/mmal-vchiq.h   |  1 +
 4 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/raspberrypi/vchiq-mmal/Kconfig b/drivers/platform/raspberrypi/vchiq-mmal/Kconfig
index c99525a0bb4525d497c74984b8b44a9079279b6f..5df9198cdab1786353aeab287f83ea7f0630b317 100644
--- a/drivers/platform/raspberrypi/vchiq-mmal/Kconfig
+++ b/drivers/platform/raspberrypi/vchiq-mmal/Kconfig
@@ -1,6 +1,7 @@
 config BCM2835_VCHIQ_MMAL
 	tristate "BCM2835 MMAL VCHIQ service"
-	depends on BCM2835_VCHIQ
+	select BCM2835_VCHIQ
+	select BCM_VC_SM_CMA
 	help
 	  Enables the MMAL API over VCHIQ interface as used for the
 	  majority of the multimedia services on VideoCore.
diff --git a/drivers/platform/raspberrypi/vchiq-mmal/mmal-common.h b/drivers/platform/raspberrypi/vchiq-mmal/mmal-common.h
index b33129403a30347fe762d0377cacbda77434c211..6c5092a68b99594a0234f56b48b785fbc611bf5a 100644
--- a/drivers/platform/raspberrypi/vchiq-mmal/mmal-common.h
+++ b/drivers/platform/raspberrypi/vchiq-mmal/mmal-common.h
@@ -50,6 +50,10 @@ struct mmal_buffer {
 
 	struct mmal_msg_context *msg_context;
 
+	struct dma_buf *dma_buf;/* Exported dmabuf fd from videobuf2 */
+	void *vcsm_handle;	/* VCSM handle having imported the dmabuf */
+	u32 vc_handle;		/* VC handle to that dmabuf */
+
 	unsigned long length;
 	u32 mmal_flags;
 	s64 dts;
diff --git a/drivers/platform/raspberrypi/vchiq-mmal/mmal-vchiq.c b/drivers/platform/raspberrypi/vchiq-mmal/mmal-vchiq.c
index e76551948bd9c4f60bef1138280fe8dd9d32477b..fe6fb571b745e04545d2d7fe7f37a486792d398f 100644
--- a/drivers/platform/raspberrypi/vchiq-mmal/mmal-vchiq.c
+++ b/drivers/platform/raspberrypi/vchiq-mmal/mmal-vchiq.c
@@ -23,12 +23,13 @@
 #include <linux/slab.h>
 #include <linux/completion.h>
 #include <linux/raspberrypi/vchiq.h>
+#include <linux/raspberrypi/vchiq_arm.h>
+#include <linux/raspberrypi/vc_sm_knl.h>
 #include <linux/vmalloc.h>
 #include <media/videobuf2-vmalloc.h>
 
-#include <linux/raspberrypi/vchiq_arm.h>
-
 #include "mmal-common.h"
+#include "mmal-parameters.h"
 #include "mmal-vchiq.h"
 #include "mmal-msg.h"
 
@@ -422,8 +423,12 @@ buffer_from_host(struct vchiq_mmal_instance *instance,
 
 	/* buffer header */
 	m.u.buffer_from_host.buffer_header.cmd = 0;
-	m.u.buffer_from_host.buffer_header.data =
-		(u32)(unsigned long)buf->buffer;
+	if (port->zero_copy)
+		m.u.buffer_from_host.buffer_header.data = buf->vc_handle;
+	else
+		m.u.buffer_from_host.buffer_header.data =
+			(u32)(unsigned long)buf->buffer;
+
 	m.u.buffer_from_host.buffer_header.alloc_size = buf->buffer_size;
 	m.u.buffer_from_host.buffer_header.length = 0;	/* nothing used yet */
 	m.u.buffer_from_host.buffer_header.offset = 0;	/* no offset */
@@ -484,6 +489,20 @@ static void buffer_to_host_cb(struct vchiq_mmal_instance *instance,
 
 		msg_context->u.bulk.status = msg->h.status;
 
+	} else if (msg->u.buffer_from_host.is_zero_copy) {
+		/*
+		 * Zero copy buffer, so nothing to do.
+		 * Copy buffer info and make callback.
+		 */
+		msg_context->u.bulk.buffer_used =
+				msg->u.buffer_from_host.buffer_header.length;
+		msg_context->u.bulk.mmal_flags =
+				msg->u.buffer_from_host.buffer_header.flags;
+		msg_context->u.bulk.dts =
+				msg->u.buffer_from_host.buffer_header.dts;
+		msg_context->u.bulk.pts =
+				msg->u.buffer_from_host.buffer_header.pts;
+
 	} else if (msg->u.buffer_from_host.buffer_header.length == 0) {
 		/* empty buffer */
 		if (msg->u.buffer_from_host.buffer_header.flags &
@@ -1431,6 +1450,9 @@ int vchiq_mmal_port_parameter_set(struct vchiq_mmal_instance *instance,
 
 	mutex_unlock(&instance->vchiq_mutex);
 
+	if (parameter == MMAL_PARAMETER_ZERO_COPY && !ret)
+		port->zero_copy = !!(*(bool *)value);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(vchiq_mmal_port_parameter_set);
@@ -1599,6 +1621,31 @@ int vchiq_mmal_submit_buffer(struct vchiq_mmal_instance *instance,
 	unsigned long flags = 0;
 	int ret;
 
+	/*
+	 * We really want to do this in mmal_vchi_buffer_init but can't as
+	 * videobuf2 won't let us have the dmabuf there.
+	 */
+	if (port->zero_copy && buffer->dma_buf && !buffer->vcsm_handle) {
+		pr_debug("%s: import dmabuf %p\n", __func__, buffer->dma_buf);
+		ret = vc_sm_cma_import_dmabuf(buffer->dma_buf,
+					      &buffer->vcsm_handle);
+		if (ret) {
+			pr_err("%s: vc_sm_import_dmabuf_fd failed, ret %d\n",
+			       __func__, ret);
+			return ret;
+		}
+
+		buffer->vc_handle = vc_sm_cma_int_handle(buffer->vcsm_handle);
+		if (!buffer->vc_handle) {
+			pr_err("%s: vc_sm_int_handle failed %d\n",
+			       __func__, ret);
+			vc_sm_cma_free(buffer->vcsm_handle);
+			return ret;
+		}
+		pr_debug("%s: import dmabuf %p - got vc handle %08X\n",
+			 __func__, buffer->dma_buf, buffer->vc_handle);
+	}
+
 	ret = buffer_from_host(instance, port, buffer);
 	if (ret == -EINVAL) {
 		/* Port is disabled. Queue for when it is enabled. */
@@ -1632,6 +1679,16 @@ int mmal_vchi_buffer_cleanup(struct mmal_buffer *buf)
 		release_msg_context(msg_context);
 	buf->msg_context = NULL;
 
+	if (buf->vcsm_handle) {
+		int ret;
+
+		pr_debug("%s: vc_sm_cma_free on handle %p\n", __func__,
+			 buf->vcsm_handle);
+		ret = vc_sm_cma_free(buf->vcsm_handle);
+		if (ret)
+			pr_err("%s: vcsm_free failed, ret %d\n", __func__, ret);
+		buf->vcsm_handle = 0;
+	}
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mmal_vchi_buffer_cleanup);
diff --git a/drivers/platform/raspberrypi/vchiq-mmal/mmal-vchiq.h b/drivers/platform/raspberrypi/vchiq-mmal/mmal-vchiq.h
index 8c3959f6f97fb21bcaf2f21589ef291e754e7c19..9d31816f5be54d74bfdf42381b38e340279ffee4 100644
--- a/drivers/platform/raspberrypi/vchiq-mmal/mmal-vchiq.h
+++ b/drivers/platform/raspberrypi/vchiq-mmal/mmal-vchiq.h
@@ -49,6 +49,7 @@ typedef void (*vchiq_mmal_buffer_cb)(struct vchiq_mmal_instance  *instance,
 
 struct vchiq_mmal_port {
 	bool enabled;
+	u32 zero_copy:1;
 	u32 handle;
 	u32 type; /* port type, cached to use on port info set */
 	u32 index; /* port index, cached to use on port info set */

-- 
2.52.0

Hi Jai,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 3e7f562e20ee87a25e104ef4fce557d39d62fa85]

url:    https://github.com/intel-lab-lkp/linux/commits/Jai-Luthra/platform-raspberrypi-vchiq-mmal-Reset-buffers_with_vpu-on-port_enable/20260105-170249
base:   3e7f562e20ee87a25e104ef4fce557d39d62fa85
patch link:    https://lore.kernel.org/r/20260105-b4-vc-sm-cma-v2-4-4daea749ced9%40ideasonboard.com
patch subject: [PATCH v2 4/6] platform/raspberrypi: vchiq-mmal: Use vc-sm-cma to support zero copy
config: sh-kismet-CONFIG_BCM2835_VCHIQ-CONFIG_BCM2835_VCHIQ_MMAL-0-0 (https://download.01.org/0day-ci/archive/20260105/202601052123.hNOfRem6-lkp@intel.com/config)
reproduce: (https://download.01.org/0day-ci/archive/20260105/202601052123.hNOfRem6-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202601052123.hNOfRem6-lkp@intel.com/

kismet warnings: (new ones prefixed by >>)
>> kismet: WARNING: unmet direct dependencies detected for BCM2835_VCHIQ when selected by BCM2835_VCHIQ_MMAL
   WARNING: unmet direct dependencies detected for BCM2835_VCHIQ
     Depends on [n]: BCM_VIDEOCORE [=y] && HAS_DMA [=n]
     Selected by [y]:
     - BCM2835_VCHIQ_MMAL [=y] && BCM_VIDEOCORE [=y]
     - BCM_VC_SM_CMA [=y] && BCM_VIDEOCORE [=y]

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki