[PATCH 05/14] staging: mmal-vchiq: Use vc-sm-cma to support zero copy

From: Umang Jain
Date: Mon Nov 21 2022 - 16:50:04 EST

From: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>
---
.../staging/vc04_services/vchiq-mmal/Kconfig | 1 +
.../vc04_services/vchiq-mmal/mmal-common.h | 4 +
.../vc04_services/vchiq-mmal/mmal-vchiq.c | 83 +++++++++++++++++--
.../vc04_services/vchiq-mmal/mmal-vchiq.h | 1 +
4 files changed, 82 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/vc04_services/vchiq-mmal/Kconfig b/drivers/staging/vc04_services/vchiq-mmal/Kconfig
index c99525a0bb45..a7c1a7bf516e 100644
--- a/drivers/staging/vc04_services/vchiq-mmal/Kconfig
+++ b/drivers/staging/vc04_services/vchiq-mmal/Kconfig
@@ -1,6 +1,7 @@
config BCM2835_VCHIQ_MMAL
tristate "BCM2835 MMAL VCHIQ service"
depends on 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/staging/vc04_services/vchiq-mmal/mmal-common.h b/drivers/staging/vc04_services/vchiq-mmal/mmal-common.h
index 0443be8198ea..a643cad54b12 100644
--- a/drivers/staging/vc04_services/vchiq-mmal/mmal-common.h
+++ b/drivers/staging/vc04_services/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 */
+
u32 cmd; /* MMAL command. 0=data. */
unsigned long length;
u32 mmal_flags;
diff --git a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
index 1c0047eead7e..f26fb64a2785 100644
--- a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
+++ b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
@@ -27,9 +27,11 @@
#include <media/videobuf2-vmalloc.h>

#include "mmal-common.h"
+#include "mmal-parameters.h"
#include "mmal-vchiq.h"
#include "mmal-msg.h"

+#include "vc-sm-cma/vc_sm_knl.h"
/*
* maximum number of components supported.
* This matches the maximum permitted by default on the VPU
@@ -416,14 +418,27 @@ 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 */
- m.u.buffer_from_host.buffer_header.flags = 0; /* no flags */
- m.u.buffer_from_host.buffer_header.pts = MMAL_TIME_UNKNOWN;
- m.u.buffer_from_host.buffer_header.dts = MMAL_TIME_UNKNOWN;
+ if (port->type == MMAL_PORT_TYPE_OUTPUT) {
+ m.u.buffer_from_host.buffer_header.length = 0;
+ m.u.buffer_from_host.buffer_header.offset = 0;
+ m.u.buffer_from_host.buffer_header.flags = 0;
+ m.u.buffer_from_host.buffer_header.pts = MMAL_TIME_UNKNOWN;
+ m.u.buffer_from_host.buffer_header.dts = MMAL_TIME_UNKNOWN;
+ } else {
+ m.u.buffer_from_host.buffer_header.length = buf->length;
+ m.u.buffer_from_host.buffer_header.offset = 0;
+ m.u.buffer_from_host.buffer_header.flags = buf->mmal_flags;
+ m.u.buffer_from_host.buffer_header.pts = buf->pts;
+ m.u.buffer_from_host.buffer_header.dts = buf->dts;
+ }

/* clear buffer type specific data */
memset(&m.u.buffer_from_host.buffer_header_type_specific, 0,
@@ -575,6 +590,22 @@ 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;
+ msg_context->u.bulk.cmd =
+ msg->u.buffer_from_host.buffer_header.cmd;
+
} else if (msg->u.buffer_from_host.buffer_header.length == 0) {
/* empty buffer */
if (msg->u.buffer_from_host.buffer_header.flags &
@@ -1520,6 +1551,9 @@ 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);
@@ -1688,6 +1722,31 @@ 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. */
@@ -1721,6 +1780,16 @@ 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/staging/vc04_services/vchiq-mmal/mmal-vchiq.h b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.h
index e3ecd70b9951..9addd627ff5b 100644
--- a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.h
+++ b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.h
@@ -49,6 +49,7 @@ typedef void (*vchiq_mmal_buffer_cb)(

struct vchiq_mmal_port {
u32 enabled:1;
+ 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 */
--
2.37.3