[dt] Allow for creation of standalone devices

We will want to be able to create the console device as early as
possible.  Refactor devicetree probing to remove the assumption that a
devicetree device must have a devicetree parent, and expose functions
to allow a standalone device to be created given only the offset of a
node within the tree.

The full device path is no longer trivial to construct with this
assumption removed.  The full path is currently used only for debug
messages.  Remove the stored full path, use just the node name for
debug messages, and ensure that the topology information previously
visible in the full path is reconstructible from the combined debug
output if needed.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/drivers/bus/devtree.c b/src/drivers/bus/devtree.c
index 796fe56a06bcd0613936d1b5cd374bd5f0723a1e..59bbc9bf7faa6ddd75b00a4d169317cf438917ba 100644 (file)
--- a/src/drivers/bus/devtree.c
+++ b/src/drivers/bus/devtree.c
@@ -39,7 +39,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/devtree.h>
 
 static struct dt_driver dt_node_driver __dt_driver;
-struct root_device dt_root_device __root_device;
 
 static void dt_remove_children ( struct dt_device *parent );
 
@@ -64,7 +63,7 @@ void * dt_ioremap ( struct dt_device *dt, unsigned int offset,
        /* Get parent node */
        if ( ( rc = fdt_parent ( &sysfdt, offset, &parent ) ) != 0 ) {
                DBGC ( dt, "DT %s could not locate parent: %s\n",
-                      dt->path, strerror ( rc ) );
+                      dt->name, strerror ( rc ) );
                return NULL;
        }
 
@@ -75,7 +74,7 @@ void * dt_ioremap ( struct dt_device *dt, unsigned int offset,
        if ( ( rc = fdt_reg_address ( &sysfdt, offset, &regs, index,
                                      &address ) ) != 0 ) {
                DBGC ( dt, "DT %s could not read region %d address: %s\n",
-                      dt->path, index, strerror ( rc ) );
+                      dt->name, index, strerror ( rc ) );
                return NULL;
        }
 
@@ -85,7 +84,7 @@ void * dt_ioremap ( struct dt_device *dt, unsigned int offset,
             ( ( rc = fdt_reg_size ( &sysfdt, offset, &regs, index,
                                     &size ) ) != 0 ) ) {
                DBGC ( dt, "DT %s could not read region %d size: %s\n",
-                      dt->path, index, strerror ( rc ) );
+                      dt->name, index, strerror ( rc ) );
                return NULL;
        }
 
@@ -93,13 +92,13 @@ void * dt_ioremap ( struct dt_device *dt, unsigned int offset,
        if ( ! len )
                len = size;
        DBGC ( dt, "DT %s region %d at %#08llx+%#04llx\n",
-              dt->path, index, ( ( unsigned long long ) address ),
+              dt->name, index, ( ( unsigned long long ) address ),
               ( ( unsigned long long ) size ) );
 
        /* Verify size */
        if ( len > size ) {
                DBGC ( dt, "DT %s region %d is too small (%#llx/%#zx bytes)\n",
-                      dt->path, index, ( ( unsigned long long ) size ), len );
+                      dt->name, index, ( ( unsigned long long ) size ), len );
                return NULL;
        }
 
@@ -107,7 +106,7 @@ void * dt_ioremap ( struct dt_device *dt, unsigned int offset,
        io_addr = ioremap ( address, len );
        if ( ! io_addr ) {
                DBGC ( dt, "DT %s could not map region %d\n",
-                      dt->path, index );
+                      dt->name, index );
                return NULL;
        }
 
@@ -119,7 +118,7 @@ void * dt_ioremap ( struct dt_device *dt, unsigned int offset,
  *
  * @v dt               Devicetree device
  * @v offset           Starting node offset
- * @ret driver         Driver, or NULL
+ * @ret driver         Driver
  */
 static struct dt_driver * dt_find_driver ( struct dt_device *dt,
                                           unsigned int offset ) {
@@ -135,19 +134,20 @@ static struct dt_driver * dt_find_driver ( struct dt_device *dt,
        /* Look for a compatible driver */
        for ( id = ids ; count-- ; id += ( strlen ( id ) + 1 ) ) {
                DBGC2 ( &sysfdt, "DT %s is compatible with %s\n",
-                       dt->path, id );
+                       dt->name, id );
                for_each_table_entry ( driver, DT_DRIVERS ) {
                        for ( i = 0 ; i < driver->id_count ; i++ ) {
                                if ( strcmp ( id, driver->ids[i] ) == 0 ) {
                                        DBGC ( dt, "DT %s has %s driver %s\n",
-                                              dt->path, id, driver->name );
+                                              dt->name, id, driver->name );
                                        return driver;
                                }
                        }
                }
        }
 
-       return NULL;
+       /* Use generic node driver if no other driver matches */
+       return &dt_node_driver;
 }
 
 /**
@@ -158,19 +158,11 @@ static struct dt_driver * dt_find_driver ( struct dt_device *dt,
  * @ret rc             Return status code
  */
 static int dt_probe ( struct dt_device *dt, unsigned int offset ) {
-       struct dt_driver *driver = NULL;
+       struct dt_driver *driver;
        int rc;
 
-       /* Identify driver.  Use the generic node driver if no other
-        * driver matches, or if this is the root device (which has no
-        * valid devicetree parent).
-        */
-       if ( offset > 0 )
-               driver = dt_find_driver ( dt, offset );
-       if ( ! driver )
-               driver = &dt_node_driver;
-
-       /* Record driver */
+       /* Identify driver */
+       driver = dt_find_driver ( dt, offset );
        dt->driver = driver;
        dt->dev.driver_name = driver->name;
 
@@ -178,7 +170,7 @@ static int dt_probe ( struct dt_device *dt, unsigned int offset ) {
        if ( ( rc = driver->probe ( dt, offset ) ) != 0 ) {
                if ( driver != &dt_node_driver ) {
                        DBGC ( dt, "DT %s could not probe: %s\n",
-                              dt->path, strerror ( rc ) );
+                              dt->name, strerror ( rc ) );
                }
                return rc;
        }
@@ -192,44 +184,44 @@ static int dt_probe ( struct dt_device *dt, unsigned int offset ) {
  * @v dt               Devicetree device
  */
 static void dt_remove ( struct dt_device *dt ) {
+       struct dt_driver *driver = dt->driver;
 
        /* Remove device */
-       dt->driver->remove ( dt );
+       driver->remove ( dt );
+       if ( driver != &dt_node_driver )
+               DBGC ( dt, "DT %s removed\n", dt->name );
 }
 
 /**
  * Probe devicetree node
  *
- * @v parent           Parent device, or NULL for root of tree
+ * @v parent           Parent generic device
  * @v offset           Starting node offset
- * @v name             Node name
  * @ret rc             Return status code
  */
-static int dt_probe_node ( struct dt_device *parent, unsigned int offset,
-                          const char *name ) {
+int dt_probe_node ( struct device *parent, unsigned int offset ) {
+       struct fdt_descriptor desc;
        struct dt_device *dt;
-       const char *ppath;
-       size_t path_len;
-       void *path;
+       const char *name;
        int rc;
 
+       /* Describe token */
+       if ( ( rc = fdt_describe ( &sysfdt, offset, &desc ) ) != 0 )
+               goto err_describe;
+
        /* Allocate and initialise device */
-       ppath = ( ( parent && parent->path[1] ) ? parent->path : "" );
-       path_len = ( strlen ( ppath ) + 1 /* "/" */ +
-                    strlen ( name ) + 1 /* NUL */ );
-       dt = zalloc ( sizeof ( *dt ) + path_len );
+       dt = zalloc ( sizeof ( *dt ) );
        if ( ! dt ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
-       path = ( ( ( void * ) dt ) + sizeof ( *dt ) );
-       sprintf ( path, "%s/%s", ppath, name );
-       dt->path = path;
+       name = ( offset ? desc.name : "root node" );
+       dt->name = dt->dev.name;
        snprintf ( dt->dev.name, sizeof ( dt->dev.name ), "%s", name );
        dt->dev.desc.bus_type = BUS_TYPE_DT;
-       dt->dev.parent = ( parent ? &parent->dev : &dt_root_device.dev );
+       dt->dev.parent = parent;
        INIT_LIST_HEAD ( &dt->dev.children );
-       list_add_tail ( &dt->dev.siblings, &dt->dev.parent->children );
+       list_add_tail ( &dt->dev.siblings, &parent->children );
 
        /* Probe device */
        if ( ( rc = dt_probe ( dt, offset ) ) != 0 )
@@ -242,15 +234,22 @@ static int dt_probe_node ( struct dt_device *parent, unsigned int offset,
        list_del ( &dt->dev.siblings );
        free ( dt );
  err_alloc:
+ err_describe:
        return rc;
 }
 
 /**
  * Remove devicetree node
  *
- * @v dt               Devicetree device
+ * @v parent           Parent generic device
  */
-static void dt_remove_node ( struct dt_device *dt ) {
+void dt_remove_node ( struct device *parent ) {
+       struct dt_device *dt;
+
+       /* Identify most recently added child */
+       dt = list_last_entry ( &parent->children, struct dt_device,
+                              dev.siblings );
+       assert ( dt != NULL );
 
        /* Remove driver */
        dt_remove ( dt );
@@ -279,7 +278,7 @@ static int dt_probe_children ( struct dt_device *parent,
                /* Describe token */
                if ( ( rc = fdt_describe ( &sysfdt, offset, &desc ) ) != 0 ) {
                        DBGC ( &sysfdt, "DT %s has malformed node: %s\n",
-                              parent->path, strerror ( rc ) );
+                              parent->name, strerror ( rc ) );
                        goto err_describe;
                }
 
@@ -288,8 +287,11 @@ static int dt_probe_children ( struct dt_device *parent,
                        break;
 
                /* Probe child node, if applicable */
-               if ( ( depth == 0 ) && desc.name && ( ! desc.data ) )
-                       dt_probe_node ( parent, desc.offset, desc.name );
+               if ( ( depth == 0 ) && desc.name && ( ! desc.data ) ) {
+                       DBGC2 ( &sysfdt, "DT %s is child of %s\n",
+                               desc.name, parent->name );
+                       dt_probe_node ( &parent->dev, desc.offset );
+               }
        }
 
        /* Fail if we have no children (so that this device will be freed) */
@@ -312,15 +314,10 @@ static int dt_probe_children ( struct dt_device *parent,
  * @v parent           Parent device
  */
 static void dt_remove_children ( struct dt_device *parent ) {
-       struct dt_device *dt;
-       struct dt_device *tmp;
 
        /* Remove all child nodes */
-       list_for_each_entry_safe ( dt, tmp, &parent->dev.children,
-                                  dev.siblings ) {
-               dt_remove_node ( dt );
-       }
-       assert ( list_empty ( &parent->dev.children ) );
+       while ( ! list_empty ( &parent->dev.children ) )
+               dt_remove_node ( &parent->dev );
 }
 
 /** Generic node driver */
@@ -336,10 +333,10 @@ static struct dt_driver dt_node_driver __dt_driver = {
  * @v rootdev          Devicetree root device
  * @ret rc             Return status code
  */
-static int dt_probe_all ( struct root_device *rootdev __unused ) {
+static int dt_probe_all ( struct root_device *rootdev ) {
 
        /* Probe root node */
-       return dt_probe_node ( NULL, 0, "" );
+       return dt_probe_node ( &rootdev->dev, 0 );
 }
 
 /**
@@ -348,13 +345,9 @@ static int dt_probe_all ( struct root_device *rootdev __unused ) {
  * @v rootdev          Devicetree root device
  */
 static void dt_remove_all ( struct root_device *rootdev ) {
-       struct dt_device *dt;
 
        /* Remove root node */
-       dt = list_first_entry ( &rootdev->dev.children, struct dt_device,
-                               dev.siblings );
-       assert ( dt != NULL );
-       dt_remove_node ( dt );
+       dt_remove_node ( &rootdev->dev );
 }
 
 /** Devicetree bus root device driver */

diff --git a/src/include/ipxe/devtree.h b/src/include/ipxe/devtree.h
index 46d8b5d864d914e2a94d403c81c3ba4f8955cc43..cdf173938beca43a804f1f3f836309b51194c312 100644 (file)
--- a/src/include/ipxe/devtree.h
+++ b/src/include/ipxe/devtree.h
@@ -15,12 +15,12 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 /** A devicetree device */
 struct dt_device {
+       /** Device name */
+       const char *name;
        /** Generic device */
        struct device dev;
        /** DMA device */
        struct dma_device dma;
-       /** Device path */
-       const char *path;
        /** Driver for this device */
        struct dt_driver *driver;
        /** Driver-private data */
@@ -79,5 +79,7 @@ static inline void * dt_get_drvdata ( struct dt_device *dt ) {
 
 extern void * dt_ioremap ( struct dt_device *dt, unsigned int offset,
                           unsigned int index, size_t len );
+extern int dt_probe_node ( struct device *parent, unsigned int offset );
+extern void dt_remove_node ( struct device *parent );
 
 #endif /* _IPXE_DEVTREE_H */