remoteproc: introduce rproc_get_by_phandle API

Allow users of remoteproc the ability to get a handle to an rproc by
passing a phandle supplied in the user's device tree node. This is
useful in situations that require manual booting of the rproc.

This patch uses the code removed by commit 40e575b1d0b3 ("remoteproc:
remove the get_by_name/put API") for the ref counting but is modified
to use a simple list and locking mechanism and has rproc_get_by_name
replaced with an rproc_get_by_phandle API.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
[fix order of Signed-off-by tags]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index e991512e04ed..e1a6d693b8bb 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -44,6 +44,9 @@
 
 #include "remoteproc_internal.h"
 
+static DEFINE_MUTEX(rproc_list_mutex);
+static LIST_HEAD(rproc_list);
+
 typedef int (*rproc_handle_resources_t)(struct rproc *rproc,
                                 struct resource_table *table, int len);
 typedef int (*rproc_handle_resource_t)(struct rproc *rproc,
@@ -1145,6 +1148,43 @@ out:
 EXPORT_SYMBOL(rproc_shutdown);
 
 /**
+ * rproc_get_by_phandle() - find a remote processor by phandle
+ * @phandle: phandle to the rproc
+ *
+ * Finds an rproc handle using the remote processor's phandle, and then
+ * return a handle to the rproc.
+ *
+ * This function increments the remote processor's refcount, so always
+ * use rproc_put() to decrement it back once rproc isn't needed anymore.
+ *
+ * Returns the rproc handle on success, and NULL on failure.
+ */
+struct rproc *rproc_get_by_phandle(phandle phandle)
+{
+        struct rproc *rproc = NULL, *r;
+        struct device_node *np;
+
+        np = of_find_node_by_phandle(phandle);
+        if (!np)
+                return NULL;
+
+        mutex_lock(&rproc_list_mutex);
+        list_for_each_entry(r, &rproc_list, node) {
+                if (r->dev.parent && r->dev.parent->of_node == np) {
+                        rproc = r;
+                        get_device(&rproc->dev);
+                        break;
+                }
+        }
+        mutex_unlock(&rproc_list_mutex);
+
+        of_node_put(np);
+
+        return rproc;
+}
+EXPORT_SYMBOL(rproc_get_by_phandle);
+
+/**
  * rproc_add() - register a remote processor
  * @rproc: the remote processor handle to register
  *
@@ -1173,6 +1213,11 @@ int rproc_add(struct rproc *rproc)
         if (ret < 0)
                 return ret;
 
+        /* expose to rproc_get_by_phandle users */
+        mutex_lock(&rproc_list_mutex);
+        list_add(&rproc->node, &rproc_list);
+        mutex_unlock(&rproc_list_mutex);
+
         dev_info(dev, "%s is available\n", rproc->name);
 
         dev_info(dev, "Note: remoteproc is still under development and considered experimental.\n");
@@ -1360,6 +1405,11 @@ int rproc_del(struct rproc *rproc)
         /* Free the copy of the resource table */
         kfree(rproc->cached_table);
 
+        /* the rproc is downref'ed as soon as it's removed from the klist */
+        mutex_lock(&rproc_list_mutex);
+        list_del(&rproc->node);
+        mutex_unlock(&rproc_list_mutex);
+
         device_del(&rproc->dev);
 
         return 0;