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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [XEN][RFC PATCH v4 13/16] xen/arm: Implement device tree node addition functionalities
Update sysctl XEN_SYSCTL_dt_overlay to enable support for dtbo nodes addition
using device tree overlay.
xl dt_overlay add file.dtbo:
Each time overlay nodes are added using .dtbo, a new fdt(memcpy of
device_tree_flattened) is created and updated with overlay nodes. This
updated fdt is further unflattened to a dt_host_new. Next, it checks if any
of the overlay nodes already exists in the dt_host. If overlay nodes doesn't
exist then find the overlay nodes in dt_host_new, find the overlay node's
parent in dt_host and add the nodes as child under their parent in the
dt_host. The node is attached as the last node under target parent.
Finally, add IRQs, add device to IOMMUs, set permissions and map MMIO for
the
overlay node.
When a node is added using overlay, a new entry is allocated in the
overlay_track to keep the track of memory allocation due to addition of overlay
node. This is helpful for freeing the memory allocated when a device tree node
is removed.
Signed-off-by: Vikram Garhwal <vikram.garhwal@xxxxxxx>
---
xen/common/dt_overlay.c | 465 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 465 insertions(+)
diff --git a/xen/common/dt_overlay.c b/xen/common/dt_overlay.c
index 477341f0aa..f5426b9dab 100644
--- a/xen/common/dt_overlay.c
+++ b/xen/common/dt_overlay.c
@@ -38,9 +38,29 @@ static struct dt_device_node *find_last_descendants_node(
/* If last child_node also have children. */
if ( child_node->child )
child_node = find_last_descendants_node(child_node);
+
return child_node;
}
+/*
+ * Returns next node to the input node. If node has children then return
+ * last descendant's next node.
+*/
+static struct dt_device_node *dt_find_next_node(struct dt_device_node *dt,
+ struct dt_device_node *node)
+{
+ struct dt_device_node *np;
+
+ dt_for_each_device_node(dt, np)
+ if ( np == node )
+ break;
+
+ if ( np->child )
+ np = find_last_descendants_node(np);
+
+ return np->allnext;
+}
+
static int dt_overlay_remove_node(struct dt_device_node *device_node)
{
struct dt_device_node *np;
@@ -114,6 +134,74 @@ static int dt_overlay_remove_node(struct dt_device_node
*device_node)
return 0;
}
+static int dt_overlay_add_node(struct dt_device_node *device_node,
+ const char *parent_node_path)
+{
+ struct dt_device_node *parent_node;
+ struct dt_device_node *np, *np_last_descendant;
+ struct dt_device_node *next_node;
+ struct dt_device_node *device_node_last_descendant;
+
+ parent_node = dt_find_node_by_path(parent_node_path);
+
+ if ( parent_node == NULL )
+ {
+ dt_dprintk("Node not found. Overlay node will not be added\n");
+ return -EINVAL;
+ }
+
+ /* If parent has no child. */
+ if ( parent_node->child == NULL )
+ {
+ next_node = parent_node->allnext;
+ device_node->parent = parent_node;
+ parent_node->allnext = device_node;
+ parent_node->child = device_node;
+ }
+ else
+ {
+ /* If parent has at least one child node.
+ * Iterate to the last child node of parent.
+ */
+ for ( np = parent_node->child; np->sibling != NULL; np = np->sibling )
+ {
+ }
+
+ /* Iterate over all child nodes of np node. */
+ if ( np->child )
+ {
+ np_last_descendant = find_last_descendants_node(np);
+
+ next_node = np_last_descendant->allnext;
+ np_last_descendant->allnext = device_node;
+ }
+ else
+ {
+ next_node = np->allnext;
+ np->allnext = device_node;
+ }
+
+ device_node->parent = parent_node;
+ np->sibling = device_node;
+ np->sibling->sibling = NULL;
+ }
+
+ /* Iterate over all child nodes of device_node to add children too. */
+ if ( device_node->child )
+ {
+ device_node_last_descendant = find_last_descendants_node(device_node);
+ /* Plug next_node at the end of last children of device_node. */
+ device_node_last_descendant->allnext = next_node;
+ }
+ else
+ {
+ /* Now plug next_node at the end of device_node. */
+ device_node->allnext = next_node;
+ }
+
+ return 0;
+}
+
/* Basic sanity check for the dtbo tool stack provided to Xen. */
static int check_overlay_fdt(const void *overlay_fdt, uint32_t
overlay_fdt_size)
{
@@ -153,6 +241,79 @@ static unsigned int overlay_node_count(void *fdto)
return num_overlay_nodes;
}
+/*
+ * overlay_get_nodes_info will get full name with path for all the nodes which
+ * are in one level of __overlay__ tag. This is useful when checking node for
+ * duplication i.e. dtbo tries to add nodes which already exists in device
tree.
+ */
+static int overlay_get_nodes_info(const void *fdto, char ***nodes_full_path,
+ unsigned int num_overlay_nodes)
+{
+ int fragment;
+ unsigned int node_num = 0;
+
+ *nodes_full_path = xzalloc_bytes(num_overlay_nodes * sizeof(char *));
+
+ if ( *nodes_full_path == NULL )
+ return -ENOMEM;
+
+ fdt_for_each_subnode(fragment, fdto, 0)
+ {
+ int target;
+ int overlay;
+ int subnode;
+ const char *target_path;
+
+ target = fdt_overlay_target_offset(device_tree_flattened, fdto,
+ fragment, &target_path);
+ if ( target < 0 )
+ return target;
+
+ overlay = fdt_subnode_offset(fdto, fragment, "__overlay__");
+
+ /*
+ * overlay value can be < 0. But fdt_for_each_subnode() loop checks for
+ * overlay >= 0. So, no need for a overlay>=0 check here.
+ */
+ fdt_for_each_subnode(subnode, fdto, overlay)
+ {
+ const char *node_name = NULL;
+ int node_name_len = 0;
+ unsigned int target_path_len = strlen(target_path);
+ unsigned int node_full_name_len = 0;
+
+ node_name = fdt_get_name(fdto, subnode, &node_name_len);
+
+ if ( node_name == NULL )
+ return -EINVAL;
+
+ /*
+ * Magic number 2 is for adding '/'. This is done to keep the
+ * node_full_name in the correct full node name format.
+ */
+ node_full_name_len = target_path_len + node_name_len + 2;
+
+ (*nodes_full_path)[node_num] = xmalloc_bytes(node_full_name_len);
+
+ if ( (*nodes_full_path)[node_num] == NULL )
+ return -ENOMEM;
+
+ memcpy((*nodes_full_path)[node_num], target_path, target_path_len);
+
+ (*nodes_full_path)[node_num][target_path_len] = '/';
+
+ memcpy((*nodes_full_path)[node_num] + target_path_len + 1,
+ node_name, node_name_len);
+
+ (*nodes_full_path)[node_num][node_full_name_len - 1] = '\0';
+
+ node_num++;
+ }
+ }
+
+ return 0;
+}
+
static int handle_remove_irq_iommu(struct dt_device_node *device_node)
{
int rc = 0;
@@ -373,6 +534,302 @@ out:
return rc;
}
+/*
+ * Handles IRQ and IOMMU mapping for the overlay_node and all descendants of
the
+ * overlay_nodes.
+ */
+static int handle_add_irq_iommu(struct domain *d,
+ struct dt_device_node *overlay_node)
+{
+ int rc = 0;
+ unsigned int naddr, i, len;
+ u64 addr, size;
+ struct dt_device_node *np;
+
+ /* First let's handle the interrupts. */
+ rc = handle_device_interrupts(d, overlay_node, false);
+ if ( rc )
+ {
+ printk(XENLOG_ERR "Interrupt failed\n");
+ return rc;
+ }
+
+ /* Check if iommu property exists. */
+ if ( dt_get_property(overlay_node, "iommus", &len) )
+ {
+
+ /* Add device to IOMMUs. */
+ rc = iommu_add_dt_device(overlay_node);
+ if ( rc < 0 )
+ {
+ printk(XENLOG_ERR "Failed to add %s to the IOMMU\n",
+ dt_node_full_name(overlay_node));
+ return rc;
+ }
+ }
+
+ /* Set permissions. */
+ naddr = dt_number_of_address(overlay_node);
+
+ dt_dprintk("%s passthrough = %d naddr = %u\n",
+ dt_node_full_name(overlay_node), false, naddr);
+
+ /* Give permission for map MMIOs */
+ for ( i = 0; i < naddr; i++ )
+ {
+ struct map_range_data mr_data = { .d = d,
+ .p2mt = p2m_mmio_direct_c,
+ .skip_mapping = true };
+
+ rc = dt_device_get_address(overlay_node, i, &addr, &size);
+ if ( rc )
+ {
+ printk(XENLOG_ERR "Unable to retrieve address %u for %s\n",
+ i, dt_node_full_name(overlay_node));
+ return rc;
+ }
+
+ rc = map_range_to_domain(overlay_node, addr, size, &mr_data);
+ if ( rc )
+ return rc;
+ }
+
+ /* Map IRQ and IOMMU for overlay_node's children. */
+ for ( np = overlay_node->child; np != NULL; np = np->sibling)
+ {
+ rc = handle_add_irq_iommu(d, np);
+ }
+
+ return rc;
+}
+
+/*
+ * Adds device tree nodes under target node.
+ * We use tr->dt_host_new to unflatten the updated device_tree_flattened. This
+ * is done to avoid the removal of device_tree generation, iomem regions
mapping
+ * to hardware domain done by handle_node().
+ */
+static long handle_add_overlay_nodes(void *overlay_fdt,
+ uint32_t overlay_fdt_size)
+{
+ int rc = 0, j = 0, i;
+ struct dt_device_node *overlay_node, *prev_node, *next_node;
+ struct domain *d = hardware_domain;
+ struct overlay_track *tr = NULL;
+ char **nodes_full_path = NULL;
+ unsigned int new_fdt_size;
+
+ tr = xzalloc(struct overlay_track);
+ if ( tr == NULL )
+ {
+ return -ENOMEM;
+ }
+
+ new_fdt_size = fdt_totalsize(device_tree_flattened) +
+ fdt_totalsize(overlay_fdt);
+
+ tr->fdt = xzalloc_bytes(new_fdt_size);
+ if ( tr->fdt == NULL )
+ return -ENOMEM;
+
+ tr->num_nodes = overlay_node_count(overlay_fdt);
+ if ( tr->num_nodes == 0 )
+ {
+ xfree(tr->fdt);
+ return -ENOMEM;
+ }
+
+ tr->nodes_address = xzalloc_bytes(tr->num_nodes * sizeof(unsigned long));
+ if ( tr->nodes_address == NULL )
+ {
+ xfree(tr->fdt);
+ return -ENOMEM;
+ }
+
+ rc = check_overlay_fdt(overlay_fdt, overlay_fdt_size);
+ if ( rc )
+ {
+ xfree(tr->fdt);
+ return rc;
+ }
+
+ /*
+ * Keep a copy of overlay_fdt as fdt_overlay_apply will change the input
+ * overlay's content(magic) when applying overlay.
+ */
+ tr->overlay_fdt = xzalloc_bytes(overlay_fdt_size);
+ if ( tr->overlay_fdt == NULL )
+ {
+ xfree(tr->fdt);
+ return -ENOMEM;
+ }
+
+ memcpy(tr->overlay_fdt, overlay_fdt, overlay_fdt_size);
+
+ spin_lock(&overlay_lock);
+
+ memcpy(tr->fdt, device_tree_flattened,
+ fdt_totalsize(device_tree_flattened));
+
+ /* Open tr->fdt with more space to accommodate the overlay_fdt. */
+ fdt_open_into(tr->fdt, tr->fdt, new_fdt_size);
+
+ /*
+ * overlay_get_nodes_info is called to get the node information from dtbo.
+ * This is done before fdt_overlay_apply() because the overlay apply will
+ * erase the magic of overlay_fdt.
+ */
+ rc = overlay_get_nodes_info(overlay_fdt, &nodes_full_path,
+ tr->num_nodes);
+ if ( rc )
+ {
+ printk(XENLOG_ERR "Getting nodes information failed with error %d\n",
+ rc);
+ goto err;
+ }
+
+ rc = fdt_overlay_apply(tr->fdt, overlay_fdt);
+ if ( rc )
+ {
+ printk(XENLOG_ERR "Adding overlay node failed with error %d\n", rc);
+ goto err;
+ }
+
+ /*
+ * Check if any of the node already exists in dt_host. If node already
exits
+ * we can return here as this overlay_fdt is not suitable for overlay ops.
+ */
+ for ( j = 0; j < tr->num_nodes; j++ )
+ {
+ overlay_node = dt_find_node_by_path(nodes_full_path[j]);
+ if ( overlay_node != NULL )
+ {
+ printk(XENLOG_ERR "node %s exists in device tree\n",
+ nodes_full_path[j]);
+ rc = -EINVAL;
+ goto err;
+ }
+ }
+
+ /* Unflatten the tr->fdt into a new dt_host. */
+ rc = unflatten_device_tree(tr->fdt, &tr->dt_host_new);
+ if ( rc < 0 )
+ goto err;
+
+ for ( j = 0; j < tr->num_nodes; j++ )
+ {
+ dt_dprintk("Adding node: %s\n", nodes_full_path[j]);
+
+ /* Find the newly added node in tr->dt_host_new by it's full path. */
+ overlay_node = device_tree_find_node_by_path(tr->dt_host_new,
+ nodes_full_path[j]);
+ if ( overlay_node == NULL )
+ {
+ dt_dprintk("%s node not found\n", nodes_full_path[j]);
+ rc = -EFAULT;
+ goto remove_node;
+ }
+
+ /*
+ * Find previous and next node to overlay_node in dt_host_new. We will
+ * need these nodes to fix the dt_host_new mapping. When overlay_node
is
+ * take out of dt_host_new tree and added to dt_host, link between
+ * previous node and next_node is broken. We will need to refresh
+ * dt_host_new with correct linking for any other overlay nodes
+ * extraction in future.
+ */
+ dt_for_each_device_node(tr->dt_host_new, prev_node)
+ if ( prev_node->allnext == overlay_node )
+ break;
+
+ next_node = dt_find_next_node(tr->dt_host_new, overlay_node);
+
+ read_lock(&dt_host->lock);
+
+ /* Add the node to dt_host. */
+ rc = dt_overlay_add_node(overlay_node,
overlay_node->parent->full_name);
+ if ( rc )
+ {
+ read_unlock(&dt_host->lock);
+
+ /* Node not added in dt_host. */
+ goto remove_node;
+ }
+
+ read_unlock(&dt_host->lock);
+
+ prev_node->allnext = next_node;
+
+ overlay_node = dt_find_node_by_path(overlay_node->full_name);
+ if ( overlay_node == NULL )
+ {
+ /* Sanity check. But code will never come here. */
+ ASSERT_UNREACHABLE();
+ goto remove_node;
+ }
+
+ rc = handle_add_irq_iommu(d, overlay_node);
+
+ /* Keep overlay_node address in tracker. */
+ tr->nodes_address[j] = (unsigned long)overlay_node;
+ }
+
+ INIT_LIST_HEAD(&tr->entry);
+ list_add_tail(&tr->entry, &overlay_tracker);
+
+ spin_unlock(&overlay_lock);
+
+ if ( nodes_full_path != NULL )
+ {
+ for ( i = 0; i < tr->num_nodes && nodes_full_path[i] != NULL;
+ i++ )
+ {
+ xfree(nodes_full_path[i]);
+ }
+ xfree(nodes_full_path);
+ }
+
+ return rc;
+
+/*
+ * Failure case. We need to remove the nodes, free tracker(if tr exists) and
+ * tr->dt_host_new.
+ */
+remove_node:
+ tr->num_nodes = j;
+ rc = remove_nodes(tr);
+
+ if ( rc )
+ {
+ /* If removing node fails, this may cause memory leaks. */
+ printk(XENLOG_ERR "Removing node failed.\n");
+ spin_unlock(&overlay_lock);
+ return rc;
+ }
+
+err:
+ spin_unlock(&overlay_lock);
+
+ xfree(tr->dt_host_new);
+ xfree(tr->fdt);
+ xfree(tr->overlay_fdt);
+ xfree(tr->nodes_address);
+
+ if ( nodes_full_path != NULL )
+ {
+ for ( i = 0; i < tr->num_nodes && nodes_full_path[i] != NULL;
+ i++ )
+ {
+ xfree(nodes_full_path[i]);
+ }
+ xfree(nodes_full_path);
+ }
+
+ xfree(tr);
+
+ return rc;
+}
+
long dt_sysctl(struct xen_sysctl_dt_overlay *op)
{
long ret = 0;
@@ -397,6 +854,14 @@ long dt_sysctl(struct xen_sysctl_dt_overlay *op)
switch ( op->overlay_op )
{
+ case XEN_SYSCTL_DT_OVERLAY_ADD:
+ ret = handle_add_overlay_nodes(overlay_fdt, op->overlay_fdt_size);
+
+ if ( ret )
+ xfree(overlay_fdt);
+
+ break;
+
case XEN_SYSCTL_DT_OVERLAY_REMOVE:
ret = handle_remove_overlay_nodes(overlay_fdt, op->overlay_fdt_size);
xfree(overlay_fdt);
--
2.17.1
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