On Sat, Jun 02, 2018 at 09:17:13PM +0000, Pascal Vizeli wrote: > Signed-off-by: Pascal Vizeli <pvizeli@xxxxxxxxxx> This lacks the original Signed-off-by tag from Jan. In case Jan didn't provide a Signed-off-by tag please ignore. What are your changes compared to Jans version? Just rebased or more? > --- > Documentation/user/devicetree.rst | 101 ++++++++- > arch/sandbox/dts/Makefile | 5 +- > arch/sandbox/dts/sandbox.dts | 6 + > commands/oftree.c | 65 +++++- > drivers/of/Kconfig | 6 + > drivers/of/Makefile | 1 + > drivers/of/overlay.c | 234 ++++++++++++++++++++ > drivers/of/resolver.c | 346 ++++++++++++++++++++++++++++++ > include/of.h | 71 ++++++ > scripts/Makefile.lib | 5 +- > 10 files changed, 831 insertions(+), 9 deletions(-) > create mode 100644 drivers/of/overlay.c > create mode 100644 drivers/of/resolver.c > > diff --git a/Documentation/user/devicetree.rst b/Documentation/user/devicetree.rst > index 17934d86e..b2220997d 100644 > --- a/Documentation/user/devicetree.rst > +++ b/Documentation/user/devicetree.rst > @@ -21,7 +21,7 @@ The internal devicetree > ----------------------- > > The devicetree consulted by barebox plays a special role. It is referred to > -as the "internal devicetree." The barebox devicetree commands work on this > +as the "internal devicetree". The barebox devicetree commands work on this > devicetree. The devicetree source (DTS) files are kept in sync with the kernel DTS > files. As the FDT files are meant to be backward compatible, it should always be possible > to start a kernel with the barebox internal devicetree. However, since the barebox > @@ -83,3 +83,102 @@ you can exchange the internal devicetree during runtime using the > > oftree -f > oftree -l /new/dtb > + > +Devicetree overlays > +------------------- > + > +Since version 3.19, the Linux kernel supports applying "devicetree overlays" to > +its loaded device tree. This can be used to inform the kernel about additional > +non-discoverable devices after the system has booted, which is useful for modular > +boards and FPGAs. The details of the overlay format are specified in the Linux > +`kernel documentation <https://www.kernel.org/doc/Documentation/devicetree/overlay-notes.txt>`_ > +and an updated DTC is required to compile the overlays. > + > +The use cases for overlays in barebox are a bit different: > + > +* some of the modular devices are needed to boot Linux to userspace, but barebox > + can detect which module variant is connected > +* one of several parallel or LVDS displays (which use timing data from devicetree) > + can be connected to the SoC and should be used for boot messages > +* a generic Linux (distribution) kernel should be booted on a modular > + system and support additional hardware on modules > + > +barebox supports applying overlays in the internal devicetree was well using the > +:ref:`command_oftree` command with option ``-o``: > + > +.. code-block:: sh > + > + $ ./barebox -d arch/sandbox/dts/sandbox.dtb -i arch/sandbox/dts/sandbox-overlay.dtbo > + add fd0 backed by file arch/sandbox/dts/sandbox-overlay.dtbo > + > + barebox 2015.02.0 #26 Wed Mar 4 09:41:19 CET 2015 > + ... > + barebox@barebox sandbox:/ of_dump > + ... > + dummy@0 { > + status = "disabled"; > + linux,phandle = <0x1>; > + phandle = <0x1>; > + }; > + dummy@1 { > + status = "disabled"; > + linux,phandle = <0x2>; > + phandle = <0x2>; > + }; > + __symbols__ { > + dummy0 = "/dummy@0"; > + dummy1 = "/dummy@1"; > + }; > + ... > + barebox@barebox sandbox:/ of_dump -f /dev/fd0 > + { > + fragment@0 { > + target = <0xdeadbeef>; > + __overlay__ { > + status = "okay"; > + child { > + compatible = "barebox,dummy"; > + }; > + }; > + }; > + fragment@1 { > + target = <0xdeadbeef>; > + __overlay__ { > + status = "okay"; > + child { > + compatible = "barebox,dummy"; > + }; > + }; > + }; > + __fixups__ { > + dummy0 = "/fragment@0:target:0"; > + dummy1 = "/fragment@1:target:0"; > + }; > + }; > + barebox@barebox sandbox:/ oftree -o /dev/fd0 > + barebox@barebox sandbox:/ of_dump > + ... > + dummy@0 { > + linux,phandle = <0x1>; > + phandle = <0x1>; > + status = "okay"; > + child { > + compatible = "barebox,dummy"; > + }; > + }; > + dummy@1 { > + linux,phandle = <0x2>; > + phandle = <0x2>; > + status = "okay"; > + child { > + compatible = "barebox,dummy"; > + }; > + }; > + __symbols__ { > + dummy0 = "/dummy@0"; > + dummy1 = "/dummy@1"; > + }; > + ... > + > +If you need to use a different base devicetree instead of the one compiled into > +barebox, it needs to be replaced as described in the previous section. > diff --git a/arch/sandbox/dts/Makefile b/arch/sandbox/dts/Makefile > index 6f6838857..ede219e6f 100644 > --- a/arch/sandbox/dts/Makefile > +++ b/arch/sandbox/dts/Makefile > @@ -1,6 +1,7 @@ > ifeq ($(CONFIG_OFTREE),y) > dtb-y += \ > - sandbox.dtb > + sandbox.dtb \ > + sandbox-overlay.dtbo > endif > > # just to build a built-in.o. Otherwise compilation fails when no devicetree is > @@ -8,4 +9,4 @@ endif > obj- += dummy.o > > always := $(dtb-y) > -clean-files := *.dtb *.dtb.S .*.dtc .*.pre .*.dts > +clean-files := *.dtb *.dtb.S .*.dtc .*.pre .*.dts *.dtbo > diff --git a/arch/sandbox/dts/sandbox.dts b/arch/sandbox/dts/sandbox.dts > index 2595aa13f..1b99a4960 100644 > --- a/arch/sandbox/dts/sandbox.dts > +++ b/arch/sandbox/dts/sandbox.dts > @@ -3,5 +3,11 @@ > #include "skeleton.dtsi" > > / { > + dummy0: dummy@0 { > + status = "disabled"; > + }; > > + dummy1: dummy@1 { > + status = "disabled"; > + }; > }; > diff --git a/commands/oftree.c b/commands/oftree.c > index 8a47c0be5..e0624ad34 100644 > --- a/commands/oftree.c > +++ b/commands/oftree.c > @@ -2,6 +2,7 @@ > * oftree.c - device tree command support > * > * Copyright (c) 2011 Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>, Pengutronix > + * Copyright (C) 2015 Pengutronix, Jan Luebbe <jlu@xxxxxxxxxxxxxx> > * > * based on U-Boot code by: > * > @@ -48,11 +49,14 @@ static int do_oftree(int argc, char *argv[]) > int probe = 0; > char *load = NULL; > char *save = NULL; > + char *overlay = NULL; > int free_of = 0; > int ret; > struct device_node *root; > + int ovinfo_cnt; > + struct of_overlay_info *ovinfo; > > - while ((opt = getopt(argc, argv, "pfl:s:")) > 0) { > + while ((opt = getopt(argc, argv, "pfl:o:s:")) > 0) { > switch (opt) { > case 'l': > load = optarg; > @@ -68,6 +72,9 @@ static int do_oftree(int argc, char *argv[]) > case 'f': > free_of = 1; > break; > + case 'o': > + overlay = optarg; > + break; > case 's': > save = optarg; > break; > @@ -84,7 +91,7 @@ static int do_oftree(int argc, char *argv[]) > return 0; > } > > - if (!probe && !load && !save) > + if (!probe && !load && !save && !overlay) > return COMMAND_ERROR_USAGE; > > if (save) { > @@ -123,6 +130,53 @@ static int do_oftree(int argc, char *argv[]) > } > } > > + if (IS_ENABLED(CONFIG_OFTREE_OVERLAY) && overlay) { Better make the overlay handling code a separate function, the result is probably a bit better readable. > + struct device_node *ov; > + > + root = of_get_root_node(); > + if (!root) { > + printf("no oftree loaded\n"); > + goto out; > + } > + > + fdt = read_file(overlay, &size); > + if (!fdt) { > + printf("unable to read %s\n", overlay); > + return 1; > + } > + > + ov = of_unflatten_dtb(fdt); > + free(fdt); > + > + if (IS_ERR(ov)) { > + printf("parse oftree: %s\n", strerror(-ret)); > + return PTR_ERR(ov); > + } > + > + ret = of_resolve(ov); > + if (ret) { > + printf("resolve oftree overlay: %s\n", strerror(-ret)); > + of_delete_node(ov); > + goto out; > + } > + > + ret = of_build_overlay_info(ov, &ovinfo_cnt, &ovinfo); > + if (ret) { > + printf("prepare oftree overlay: %s\n", strerror(-ret)); > + of_delete_node(ov); > + goto out; > + } > + > + ret = of_overlay(ovinfo_cnt, ovinfo); > + if (ret) { > + printf("apply oftree overlay: %s\n", strerror(-ret)); > + of_delete_node(ov); > + goto out; > + } > + > + of_delete_node(ov); > + } It's probably an interesting option to be able to apply the overlay to the devicetree the kernel is started with rather than the live tree. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
