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[PATCH v2 6/6] rpmsg: virtio_rpmsg: set buffer configuration to virtio

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Rpmsg is allocating buffer one dedicated communication link
with some specificity like number of buffers, size of one buffer...
These characteristics should be shared with remote coprocessor to
guarantee communication link coherency.

Proposal is to update rpmsg configuration fields in coprocessor firmware
resource table if it exists.

This is possible thanks to virtio set interface which allows to update
cfg fields of struct fw_rsc_vdev.

Signed-off-by: Loic Pallardy <loic.pallardy@st.com>
---
Changes since V1:
- Set virtio_cfg.da to -1 (any address) by default
- Add comment about IOMMU support
---
 drivers/rpmsg/virtio_rpmsg_bus.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 7c89210..90d4531 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -923,6 +923,27 @@ static int virtio_rpmsg_get_config(struct virtio_device *vdev)
 	return ret;
 }
 
+static void virtio_rpmsg_set_config(struct virtio_device *vdev)
+{
+	struct virtio_rpmsg_cfg virtio_cfg;
+	struct virtproc_info *vrp = vdev->priv;
+
+	/* fill virtio_cfg struct */
+	memset(&virtio_cfg, 0, sizeof(virtio_cfg));
+	virtio_cfg.id = VIRTIO_ID_RPMSG;
+	/*
+	 * IOMMU not managed at the time being, set device address to (-1)
+	 * meaning any address value.
+	 */
+	virtio_cfg.da = -1;
+	virtio_cfg.pa =	vrp->bufs_dma;
+	virtio_cfg.len = vrp->num_bufs * vrp->buf_size;
+	virtio_cfg.buf_size = vrp->buf_size;
+
+	vdev->config->set(vdev, RPMSG_CONFIG_OFFSET, &virtio_cfg,
+			  sizeof(virtio_cfg));
+}
+
 static int rpmsg_probe(struct virtio_device *vdev)
 {
 	vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
@@ -933,6 +954,7 @@ static int rpmsg_probe(struct virtio_device *vdev)
 	int err = 0, i;
 	size_t total_buf_space;
 	bool notify;
+	bool has_cfg = false;
 
 	vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
 	if (!vrp)
@@ -972,6 +994,9 @@ static int rpmsg_probe(struct virtio_device *vdev)
 	if (err < 0)
 		goto free_vrp;
 
+	if (err)
+		has_cfg = true;
+
 	/* Allocate buffer if none provided by low level platform driver */
 	if (!vrp->ext_buffer) {
 		total_buf_space = vrp->num_bufs * vrp->buf_size;
@@ -993,6 +1018,10 @@ static int rpmsg_probe(struct virtio_device *vdev)
 
 		/* and half is dedicated for TX */
 		vrp->sbufs = bufs_va + total_buf_space / 2;
+
+		/* Notify configuration to coprocessor */
+		if (has_cfg)
+			virtio_rpmsg_set_config(vdev);
 	}
 
 	/* set up the receive buffers */
-- 
1.9.1

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[PATCH v2 0/6] virtio_rpmsg: make rpmsg channel configurable Loic Pallardy <loic.pallardy@st.com> - 2017-01-31 14:00 +0100
  [PATCH v2 2/6] rpmsg: virtio_rpmsg_bus: fix sg_set_buf() when addr is not a valid kernel address Loic Pallardy <loic.pallardy@st.com> - 2017-01-31 14:00 +0100
  [PATCH v2 6/6] rpmsg: virtio_rpmsg: set buffer configuration to virtio Loic Pallardy <loic.pallardy@st.com> - 2017-01-31 14:00 +0100
  [PATCH v2 5/6] rpmsg: virtio_rpmsg: don't allocate buffer if provided by low level driver Loic Pallardy <loic.pallardy@st.com> - 2017-01-31 14:00 +0100
  [PATCH v2 1/6] rpmsg: virtio_rpmsg: set rpmsg_buf_size customizable Loic Pallardy <loic.pallardy@st.com> - 2017-01-31 14:00 +0100
  [PATCH v2 3/6] include: virtio_rpmsg: add virtio rpmsg configuration structure Loic Pallardy <loic.pallardy@st.com> - 2017-01-31 14:00 +0100
  Re: [PATCH v2 0/6] virtio_rpmsg: make rpmsg channel configurable Hugues FRUCHET <hugues.fruchet@st.com> - 2017-02-08 11:30 +0100

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