Loading Documentation/devicetree/bindings/unittest.txt 0 → 100644 +14 −0 Original line number Original line Diff line number Diff line * OF selftest platform device ** selftest Required properties: - compatible: must be "selftest" All other properties are optional. Example: selftest { compatible = "selftest"; status = "okay"; }; Documentation/devicetree/of_selftest.txt +3 −17 Original line number Original line Diff line number Diff line Loading @@ -63,7 +63,6 @@ struct device_node { struct device_node *parent; struct device_node *parent; struct device_node *child; struct device_node *child; struct device_node *sibling; struct device_node *sibling; struct device_node *allnext; /* next in list of all nodes */ ... ... }; }; Loading Loading @@ -99,12 +98,6 @@ child11 -> sibling12 -> sibling13 -> sibling14 -> null Figure 1: Generic structure of un-flattened device tree Figure 1: Generic structure of un-flattened device tree *allnext: it is used to link all the nodes of DT into a list. So, for the above tree the list would be as follows: root->child1->child11->sibling12->sibling13->child131->sibling14->sibling2-> child21->sibling22->sibling23->sibling3->child31->sibling32->sibling4->null Before executing OF selftest, it is required to attach the test data to Before executing OF selftest, it is required to attach the test data to machine's device tree (if present). So, when selftest_data_add() is called, machine's device tree (if present). So, when selftest_data_add() is called, at first it reads the flattened device tree data linked into the kernel image at first it reads the flattened device tree data linked into the kernel image Loading @@ -131,11 +124,6 @@ root ('/') test-child01 null null null test-child01 null null null allnext list: root->testcase-data->test-child0->test-child01->test-sibling1->test-sibling2 ->test-sibling3->null Figure 2: Example test data tree to be attached to live tree. Figure 2: Example test data tree to be attached to live tree. According to the scenario above, the live tree is already present so it isn't According to the scenario above, the live tree is already present so it isn't Loading Loading @@ -204,8 +192,6 @@ detached and then moving up the parent nodes are removed, and eventually the whole tree). selftest_data_remove() calls detach_node_and_children() that uses whole tree). selftest_data_remove() calls detach_node_and_children() that uses of_detach_node() to detach the nodes from the live device tree. of_detach_node() to detach the nodes from the live device tree. To detach a node, of_detach_node() first updates all_next linked list, by To detach a node, of_detach_node() either updates the child pointer of given attaching the previous node's allnext to current node's allnext pointer. And node's parent to its sibling or attaches the previous sibling to the given then, it either updates the child pointer of given node's parent to its node's sibling, as appropriate. That is it :) sibling or attaches the previous sibling to the given node's sibling, as appropriate. That is it :) Documentation/devicetree/overlay-notes.txt 0 → 100644 +133 −0 Original line number Original line Diff line number Diff line Device Tree Overlay Notes ------------------------- This document describes the implementation of the in-kernel device tree overlay functionality residing in drivers/of/overlay.c and is a companion document to Documentation/devicetree/dt-object-internal.txt[1] & Documentation/devicetree/dynamic-resolution-notes.txt[2] How overlays work ----------------- A Device Tree's overlay purpose is to modify the kernel's live tree, and have the modification affecting the state of the the kernel in a way that is reflecting the changes. Since the kernel mainly deals with devices, any new device node that result in an active device should have it created while if the device node is either disabled or removed all together, the affected device should be deregistered. Lets take an example where we have a foo board with the following base tree which is taken from [1]. ---- foo.dts ----------------------------------------------------------------- /* FOO platform */ / { compatible = "corp,foo"; /* shared resources */ res: res { }; /* On chip peripherals */ ocp: ocp { /* peripherals that are always instantiated */ peripheral1 { ... }; } }; ---- foo.dts ----------------------------------------------------------------- The overlay bar.dts, when loaded (and resolved as described in [2]) should ---- bar.dts ----------------------------------------------------------------- /plugin/; /* allow undefined label references and record them */ / { .... /* various properties for loader use; i.e. part id etc. */ fragment@0 { target = <&ocp>; __overlay__ { /* bar peripheral */ bar { compatible = "corp,bar"; ... /* various properties and child nodes */ } }; }; }; ---- bar.dts ----------------------------------------------------------------- result in foo+bar.dts ---- foo+bar.dts ------------------------------------------------------------- /* FOO platform + bar peripheral */ / { compatible = "corp,foo"; /* shared resources */ res: res { }; /* On chip peripherals */ ocp: ocp { /* peripherals that are always instantiated */ peripheral1 { ... }; /* bar peripheral */ bar { compatible = "corp,bar"; ... /* various properties and child nodes */ } } }; ---- foo+bar.dts ------------------------------------------------------------- As a result of the the overlay, a new device node (bar) has been created so a bar platform device will be registered and if a matching device driver is loaded the device will be created as expected. Overlay in-kernel API -------------------------------- The API is quite easy to use. 1. Call of_overlay_create() to create and apply an overlay. The return value is a cookie identifying this overlay. 2. Call of_overlay_destroy() to remove and cleanup the overlay previously created via the call to of_overlay_create(). Removal of an overlay that is stacked by another will not be permitted. Finally, if you need to remove all overlays in one-go, just call of_overlay_destroy_all() which will remove every single one in the correct order. Overlay DTS Format ------------------ The DTS of an overlay should have the following format: { /* ignored properties by the overlay */ fragment@0 { /* first child node */ target=<phandle>; /* phandle target of the overlay */ or target-path="/path"; /* target path of the overlay */ __overlay__ { property-a; /* add property-a to the target */ node-a { /* add to an existing, or create a node-a */ ... }; }; } fragment@1 { /* second child node */ ... }; /* more fragments follow */ } Using the non-phandle based target method allows one to use a base DT which does not contain a __symbols__ node, i.e. it was not compiled with the -@ option. The __symbols__ node is only required for the target=<phandle> method, since it contains the information required to map from a phandle to a tree location. Documentation/devicetree/todo.txt +0 −1 Original line number Original line Diff line number Diff line Loading @@ -2,7 +2,6 @@ Todo list for devicetree: === General structure === === General structure === - Switch from custom lists to (h)list_head for nodes and properties structure - Switch from custom lists to (h)list_head for nodes and properties structure - Remove of_allnodes list and iterate using list of child nodes alone === CONFIG_OF_DYNAMIC === === CONFIG_OF_DYNAMIC === - Switch to RCU for tree updates and get rid of global spinlock - Switch to RCU for tree updates and get rid of global spinlock Loading arch/powerpc/mm/numa.c +1 −2 Original line number Original line Diff line number Diff line Loading @@ -1711,12 +1711,11 @@ static void stage_topology_update(int core_id) static int dt_update_callback(struct notifier_block *nb, static int dt_update_callback(struct notifier_block *nb, unsigned long action, void *data) unsigned long action, void *data) { { struct of_prop_reconfig *update; struct of_reconfig_data *update = data; int rc = NOTIFY_DONE; int rc = NOTIFY_DONE; switch (action) { switch (action) { case OF_RECONFIG_UPDATE_PROPERTY: case OF_RECONFIG_UPDATE_PROPERTY: update = (struct of_prop_reconfig *)data; if (!of_prop_cmp(update->dn->type, "cpu") && if (!of_prop_cmp(update->dn->type, "cpu") && !of_prop_cmp(update->prop->name, "ibm,associativity")) { !of_prop_cmp(update->prop->name, "ibm,associativity")) { u32 core_id; u32 core_id; Loading Loading
Documentation/devicetree/bindings/unittest.txt 0 → 100644 +14 −0 Original line number Original line Diff line number Diff line * OF selftest platform device ** selftest Required properties: - compatible: must be "selftest" All other properties are optional. Example: selftest { compatible = "selftest"; status = "okay"; };
Documentation/devicetree/of_selftest.txt +3 −17 Original line number Original line Diff line number Diff line Loading @@ -63,7 +63,6 @@ struct device_node { struct device_node *parent; struct device_node *parent; struct device_node *child; struct device_node *child; struct device_node *sibling; struct device_node *sibling; struct device_node *allnext; /* next in list of all nodes */ ... ... }; }; Loading Loading @@ -99,12 +98,6 @@ child11 -> sibling12 -> sibling13 -> sibling14 -> null Figure 1: Generic structure of un-flattened device tree Figure 1: Generic structure of un-flattened device tree *allnext: it is used to link all the nodes of DT into a list. So, for the above tree the list would be as follows: root->child1->child11->sibling12->sibling13->child131->sibling14->sibling2-> child21->sibling22->sibling23->sibling3->child31->sibling32->sibling4->null Before executing OF selftest, it is required to attach the test data to Before executing OF selftest, it is required to attach the test data to machine's device tree (if present). So, when selftest_data_add() is called, machine's device tree (if present). So, when selftest_data_add() is called, at first it reads the flattened device tree data linked into the kernel image at first it reads the flattened device tree data linked into the kernel image Loading @@ -131,11 +124,6 @@ root ('/') test-child01 null null null test-child01 null null null allnext list: root->testcase-data->test-child0->test-child01->test-sibling1->test-sibling2 ->test-sibling3->null Figure 2: Example test data tree to be attached to live tree. Figure 2: Example test data tree to be attached to live tree. According to the scenario above, the live tree is already present so it isn't According to the scenario above, the live tree is already present so it isn't Loading Loading @@ -204,8 +192,6 @@ detached and then moving up the parent nodes are removed, and eventually the whole tree). selftest_data_remove() calls detach_node_and_children() that uses whole tree). selftest_data_remove() calls detach_node_and_children() that uses of_detach_node() to detach the nodes from the live device tree. of_detach_node() to detach the nodes from the live device tree. To detach a node, of_detach_node() first updates all_next linked list, by To detach a node, of_detach_node() either updates the child pointer of given attaching the previous node's allnext to current node's allnext pointer. And node's parent to its sibling or attaches the previous sibling to the given then, it either updates the child pointer of given node's parent to its node's sibling, as appropriate. That is it :) sibling or attaches the previous sibling to the given node's sibling, as appropriate. That is it :)
Documentation/devicetree/overlay-notes.txt 0 → 100644 +133 −0 Original line number Original line Diff line number Diff line Device Tree Overlay Notes ------------------------- This document describes the implementation of the in-kernel device tree overlay functionality residing in drivers/of/overlay.c and is a companion document to Documentation/devicetree/dt-object-internal.txt[1] & Documentation/devicetree/dynamic-resolution-notes.txt[2] How overlays work ----------------- A Device Tree's overlay purpose is to modify the kernel's live tree, and have the modification affecting the state of the the kernel in a way that is reflecting the changes. Since the kernel mainly deals with devices, any new device node that result in an active device should have it created while if the device node is either disabled or removed all together, the affected device should be deregistered. Lets take an example where we have a foo board with the following base tree which is taken from [1]. ---- foo.dts ----------------------------------------------------------------- /* FOO platform */ / { compatible = "corp,foo"; /* shared resources */ res: res { }; /* On chip peripherals */ ocp: ocp { /* peripherals that are always instantiated */ peripheral1 { ... }; } }; ---- foo.dts ----------------------------------------------------------------- The overlay bar.dts, when loaded (and resolved as described in [2]) should ---- bar.dts ----------------------------------------------------------------- /plugin/; /* allow undefined label references and record them */ / { .... /* various properties for loader use; i.e. part id etc. */ fragment@0 { target = <&ocp>; __overlay__ { /* bar peripheral */ bar { compatible = "corp,bar"; ... /* various properties and child nodes */ } }; }; }; ---- bar.dts ----------------------------------------------------------------- result in foo+bar.dts ---- foo+bar.dts ------------------------------------------------------------- /* FOO platform + bar peripheral */ / { compatible = "corp,foo"; /* shared resources */ res: res { }; /* On chip peripherals */ ocp: ocp { /* peripherals that are always instantiated */ peripheral1 { ... }; /* bar peripheral */ bar { compatible = "corp,bar"; ... /* various properties and child nodes */ } } }; ---- foo+bar.dts ------------------------------------------------------------- As a result of the the overlay, a new device node (bar) has been created so a bar platform device will be registered and if a matching device driver is loaded the device will be created as expected. Overlay in-kernel API -------------------------------- The API is quite easy to use. 1. Call of_overlay_create() to create and apply an overlay. The return value is a cookie identifying this overlay. 2. Call of_overlay_destroy() to remove and cleanup the overlay previously created via the call to of_overlay_create(). Removal of an overlay that is stacked by another will not be permitted. Finally, if you need to remove all overlays in one-go, just call of_overlay_destroy_all() which will remove every single one in the correct order. Overlay DTS Format ------------------ The DTS of an overlay should have the following format: { /* ignored properties by the overlay */ fragment@0 { /* first child node */ target=<phandle>; /* phandle target of the overlay */ or target-path="/path"; /* target path of the overlay */ __overlay__ { property-a; /* add property-a to the target */ node-a { /* add to an existing, or create a node-a */ ... }; }; } fragment@1 { /* second child node */ ... }; /* more fragments follow */ } Using the non-phandle based target method allows one to use a base DT which does not contain a __symbols__ node, i.e. it was not compiled with the -@ option. The __symbols__ node is only required for the target=<phandle> method, since it contains the information required to map from a phandle to a tree location.
Documentation/devicetree/todo.txt +0 −1 Original line number Original line Diff line number Diff line Loading @@ -2,7 +2,6 @@ Todo list for devicetree: === General structure === === General structure === - Switch from custom lists to (h)list_head for nodes and properties structure - Switch from custom lists to (h)list_head for nodes and properties structure - Remove of_allnodes list and iterate using list of child nodes alone === CONFIG_OF_DYNAMIC === === CONFIG_OF_DYNAMIC === - Switch to RCU for tree updates and get rid of global spinlock - Switch to RCU for tree updates and get rid of global spinlock Loading
arch/powerpc/mm/numa.c +1 −2 Original line number Original line Diff line number Diff line Loading @@ -1711,12 +1711,11 @@ static void stage_topology_update(int core_id) static int dt_update_callback(struct notifier_block *nb, static int dt_update_callback(struct notifier_block *nb, unsigned long action, void *data) unsigned long action, void *data) { { struct of_prop_reconfig *update; struct of_reconfig_data *update = data; int rc = NOTIFY_DONE; int rc = NOTIFY_DONE; switch (action) { switch (action) { case OF_RECONFIG_UPDATE_PROPERTY: case OF_RECONFIG_UPDATE_PROPERTY: update = (struct of_prop_reconfig *)data; if (!of_prop_cmp(update->dn->type, "cpu") && if (!of_prop_cmp(update->dn->type, "cpu") && !of_prop_cmp(update->prop->name, "ibm,associativity")) { !of_prop_cmp(update->prop->name, "ibm,associativity")) { u32 core_id; u32 core_id; Loading
