From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Vladimir Serbinenko <phcoder@gmail.com>
Date: Tue, 9 May 2017 08:40:29 +0200
Subject: [PATCH] fdtbus: Add ability to send/receive messages on parent
 busses.

---
 grub-core/bus/fdt.c   | 35 +++++++++++++++++------------------
 include/grub/fdtbus.h | 18 +++++++++++++++++-
 2 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/grub-core/bus/fdt.c b/grub-core/bus/fdt.c
index 34d53545732..135da497ba6 100644
--- a/grub-core/bus/fdt.c
+++ b/grub-core/bus/fdt.c
@@ -25,30 +25,22 @@ static grub_size_t root_address_cells, root_size_cells;
 /* Pointer to this symbol signals invalid mapping.  */
 char grub_fdtbus_invalid_mapping[1];
 
-struct grub_fdtbus_dev
-{
-  struct grub_fdtbus_dev *next;
-  struct grub_fdtbus_dev *parent;
-  int node;
-  struct grub_fdtbus_driver *driver;
-};
-
 struct grub_fdtbus_dev *devs;
 struct grub_fdtbus_driver *drivers;
 
-static int
-is_compatible (struct grub_fdtbus_driver *driver,
-	       int node)
+int
+grub_fdtbus_is_compatible (const char *compat_string,
+			   const struct grub_fdtbus_dev *dev)
 {
   grub_size_t compatible_size;
-  const char *compatible = grub_fdt_get_prop (dtb, node, "compatible",
+  const char *compatible = grub_fdt_get_prop (dtb, dev->node, "compatible",
 					      &compatible_size);
   if (!compatible)
     return 0;
   const char *compatible_end = compatible + compatible_size;
   while (compatible < compatible_end)
     {
-      if (grub_strcmp (driver->compatible, compatible) == 0)
+      if (grub_strcmp (compat_string, compatible) == 0)
 	return 1;
       compatible += grub_strlen (compatible) + 1;
     }
@@ -75,10 +67,12 @@ fdtbus_scan (struct grub_fdtbus_dev *parent)
       dev->parent = parent;
       devs = dev;
       FOR_LIST_ELEMENTS(driver, drivers)
-	if (!dev->driver && is_compatible (driver, node))
+	if (!dev->driver && grub_fdtbus_is_compatible (driver->compatible, dev))
 	  {
-	    if (driver->attach(dev) == GRUB_ERR_NONE)
+	    grub_dprintf ("fdtbus", "Attaching %s\n", driver->compatible);
+	    if (driver->attach (dev) == GRUB_ERR_NONE)
 	      {
+		grub_dprintf ("fdtbus", "Attached %s\n", driver->compatible);
 		dev->driver = driver;
 		break;
 	      }
@@ -92,13 +86,18 @@ void
 grub_fdtbus_register (struct grub_fdtbus_driver *driver)
 {
   struct grub_fdtbus_dev *dev;
+  grub_dprintf ("fdtbus", "Registering %s\n", driver->compatible);
   grub_list_push (GRUB_AS_LIST_P (&drivers),
 		  GRUB_AS_LIST (driver));
   for (dev = devs; dev; dev = dev->next)
-    if (!dev->driver && is_compatible (driver, dev->node))
+    if (!dev->driver && grub_fdtbus_is_compatible (driver->compatible, dev))
       {
-	if (driver->attach(dev) == GRUB_ERR_NONE)
-	  dev->driver = driver;
+	grub_dprintf ("fdtbus", "Attaching %s (%p)\n", driver->compatible, dev);
+	if (driver->attach (dev) == GRUB_ERR_NONE)
+	  {
+	    grub_dprintf ("fdtbus", "Attached %s\n", driver->compatible);
+	    dev->driver = driver;
+	  }
 	grub_print_error ();
       }
 }
diff --git a/include/grub/fdtbus.h b/include/grub/fdtbus.h
index 985837e55f6..f519c40ec35 100644
--- a/include/grub/fdtbus.h
+++ b/include/grub/fdtbus.h
@@ -22,7 +22,13 @@
 #include <grub/fdt.h>
 #include <grub/err.h>
 
-struct grub_fdtbus_dev;
+struct grub_fdtbus_dev
+{
+  struct grub_fdtbus_dev *next;
+  struct grub_fdtbus_dev *parent;
+  int node;
+  struct grub_fdtbus_driver *driver;
+};
 
 struct grub_fdtbus_driver
 {
@@ -33,6 +39,12 @@ struct grub_fdtbus_driver
 
   grub_err_t (*attach) (const struct grub_fdtbus_dev *dev);
   void (*detach) (const struct grub_fdtbus_dev *dev);
+
+  /* Message bus operations.  */
+  grub_err_t (*send) (const struct grub_fdtbus_dev *dev, const void *data, grub_size_t sz);
+  grub_err_t (*receive) (const struct grub_fdtbus_dev *dev, void *data, grub_size_t sz);
+  grub_err_t (*start) (const struct grub_fdtbus_dev *dev);
+  void (*stop) (const struct grub_fdtbus_dev *dev);
 };
 
 extern char EXPORT_VAR(grub_fdtbus_invalid_mapping)[1];
@@ -63,6 +75,10 @@ EXPORT_FUNC(grub_fdtbus_register) (struct grub_fdtbus_driver *driver);
 void
 EXPORT_FUNC(grub_fdtbus_unregister) (struct grub_fdtbus_driver *driver);
 
+int
+EXPORT_FUNC(grub_fdtbus_is_compatible) (const char *compat_string,
+					const struct grub_fdtbus_dev *dev);
+
 /* Must be called before any register(). */
 /* dtb is assumed to be unfreeable and must remain
    valid for lifetime of GRUB.