[PATCH v3 06/15] bus/vmbus: add ring mapping APIs

[Srikanth Kaka <srikanth.k@oneconvergence.com>]

Based on its channel id, mapping of primary channel or subchannel
is determined.

The primary channel memmory is mapped in the same way as done in
Linux. For the subchannel an mmap request is directly made after
determining the subchan memory offset

Signed-off-by: Srikanth Kaka <srikanth.k@oneconvergence.com>
Signed-off-by: Vag Singh <vag.singh@oneconvergence.com>
Signed-off-by: Anand Thulasiram <avelu@juniper.net>
---
 drivers/bus/vmbus/freebsd/vmbus_uio.c | 86 +++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/drivers/bus/vmbus/freebsd/vmbus_uio.c b/drivers/bus/vmbus/freebsd/vmbus_uio.c
index 41522ba2b5..b0c011dd9a 100644
--- a/drivers/bus/vmbus/freebsd/vmbus_uio.c
+++ b/drivers/bus/vmbus/freebsd/vmbus_uio.c
@@ -17,6 +17,12 @@
 
 #include "private.h"
 
+/* Macros to distinguish mmap request
+ * [7-0] - Device memory region
+ * [15-8]- Sub-channel id
+ */
+#define UH_SUBCHAN_MASK_SHIFT  8
+
 const char *driver_name = "hv_uio";
 static void *vmbus_map_addr;
 
@@ -210,3 +216,83 @@ vmbus_uio_map_resource_by_index(struct rte_vmbus_device *dev, int idx,
 	return 0;
 }
 
+static int vmbus_uio_map_primary(struct vmbus_channel *chan,
+				 void **ring_buf, uint32_t *ring_size)
+{
+	struct mapped_vmbus_resource *uio_res;
+
+	uio_res = vmbus_uio_find_resource(chan->device);
+	if (!uio_res) {
+		VMBUS_LOG(ERR, "can not find resources!");
+		return -ENOMEM;
+	}
+
+	if (uio_res->nb_maps < VMBUS_MAX_RESOURCE) {
+		VMBUS_LOG(ERR, "VMBUS: only %u resources found!",
+			  uio_res->nb_maps);
+		return -EINVAL;
+	}
+
+	*ring_size = uio_res->maps[HV_TXRX_RING_MAP].size / 2;
+	*ring_buf  = uio_res->maps[HV_TXRX_RING_MAP].addr;
+	return 0;
+}
+
+static int vmbus_uio_map_subchan(const struct rte_vmbus_device *dev,
+				 struct vmbus_channel *chan,
+				 void **ring_buf, uint32_t *ring_size)
+{
+	char ring_path[PATH_MAX];
+	size_t size;
+	void *mapaddr;
+	off_t offset;
+	int fd;
+
+	snprintf(ring_path, sizeof(ring_path),
+		 "/dev/hv_uio%d", dev->uio_num);
+
+	fd = open(ring_path, O_RDWR);
+	if (fd < 0) {
+		VMBUS_LOG(ERR, "Cannot open %s: %s",
+			  ring_path, strerror(errno));
+		return -errno;
+	}
+
+	/* subchannel rings are of the same size as primary */
+	size = dev->resource[HV_TXRX_RING_MAP].len;
+	offset = (chan->relid << UH_SUBCHAN_MASK_SHIFT) * PAGE_SIZE;
+
+	mapaddr = vmbus_map_resource(vmbus_map_addr, fd,
+				     offset, size, 0);
+	close(fd);
+
+	if (mapaddr == MAP_FAILED)
+		return -EIO;
+
+	*ring_size = size / 2;
+	*ring_buf = mapaddr;
+
+	vmbus_map_addr = RTE_PTR_ADD(mapaddr, size);
+	return 0;
+}
+
+int vmbus_uio_map_rings(struct vmbus_channel *chan)
+{
+	const struct rte_vmbus_device *dev = chan->device;
+	uint32_t ring_size;
+	void *ring_buf;
+	int ret;
+
+	/* Primary channel */
+	if (chan->subchannel_id == 0)
+		ret = vmbus_uio_map_primary(chan, &ring_buf, &ring_size);
+	else
+		ret = vmbus_uio_map_subchan(dev, chan, &ring_buf, &ring_size);
+
+	if (ret)
+		return ret;
+
+	vmbus_br_setup(&chan->txbr, ring_buf, ring_size);
+	vmbus_br_setup(&chan->rxbr, (char *)ring_buf + ring_size, ring_size);
+	return 0;
+}
-- 
2.30.2