From aab94339cd85d726abeae78fc02351fc1910e6a4 Mon Sep 17 00:00:00 2001 From: Dirk Brandewie Date: Wed, 22 Dec 2010 11:57:26 -0800 Subject: of: Add support for linking device tree blobs into vmlinux This patch adds support for linking device tree blob(s) into vmlinux. Modifies asm-generic/vmlinux.lds.h to add linking .dtb sections into vmlinux. To maintain compatiblity with the of/fdt driver code platforms MUST copy the blob to a non-init memory location before the kernel frees the .init.* sections in the image. Modifies scripts/Makefile.lib to add a kbuild command to compile DTS files to device tree blobs and a rule to create objects to wrap the blobs for linking. STRUCT_ALIGNMENT is defined in vmlinux.lds.h for use in the rule to create wrapper objects for the dtb in Makefile.lib. The STRUCT_ALIGN() macro in vmlinux.lds.h is modified to use the STRUCT_ALIGNMENT definition. The DTB's are placed on 32 byte boundries to allow parsing the blob with driver/of/fdt.c during early boot without having to copy the blob to get the structure alignment GCC expects. A DTB is linked in by adding the DTB object to the list of objects to be linked into vmlinux in the archtecture specific Makefile using obj-y += foo.dtb.o Signed-off-by: Dirk Brandewie Acked-by: Michal Marek [grant.likely@secretlab.ca: cleaned up whitespace inconsistencies] Signed-off-by: Grant Likely --- Documentation/kbuild/makefiles.txt | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 0ef00bd6e54d..86e3cd0d26a0 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -1136,6 +1136,21 @@ When kbuild executes, the following steps are followed (roughly): resulting in the target file being recompiled for no obvious reason. + dtc + Create flattend device tree blob object suitable for linking + into vmlinux. Device tree blobs linked into vmlinux are placed + in an init section in the image. Platform code *must* copy the + blob to non-init memory prior to calling unflatten_device_tree(). + + Example: + #arch/x86/platform/ce4100/Makefile + clean-files := *dtb.S + + DTC_FLAGS := -p 1024 + obj-y += foo.dtb.o + + $(obj)/%.dtb: $(src)/%.dts + $(call cmd,dtc) --- 6.7 Custom kbuild commands -- cgit v1.2.1 From 9ed030d728f3bd03b6e869357da02725afda19a7 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Wed, 17 Nov 2010 13:00:48 +0100 Subject: misc/at24: parse device tree data Information about the pagesize and read-only-status may also come from the devicetree. Parse this data, too, and act accordingly. While we are here, change the initialization printout a bit. write_max is useful to know to detect performance bottlenecks, the rest is superfluous. Signed-off-by: Wolfram Sang Signed-off-by: Grant Likely --- Documentation/powerpc/dts-bindings/eeprom.txt | 28 +++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/powerpc/dts-bindings/eeprom.txt (limited to 'Documentation') diff --git a/Documentation/powerpc/dts-bindings/eeprom.txt b/Documentation/powerpc/dts-bindings/eeprom.txt new file mode 100644 index 000000000000..4342c10de1bf --- /dev/null +++ b/Documentation/powerpc/dts-bindings/eeprom.txt @@ -0,0 +1,28 @@ +EEPROMs (I2C) + +Required properties: + + - compatible : should be "," + If there is no specific driver for , a generic + driver based on is selected. Possible types are: + 24c00, 24c01, 24c02, 24c04, 24c08, 24c16, 24c32, 24c64, + 24c128, 24c256, 24c512, 24c1024, spd + + - reg : the I2C address of the EEPROM + +Optional properties: + + - pagesize : the length of the pagesize for writing. Please consult the + manual of your device, that value varies a lot. A wrong value + may result in data loss! If not specified, a safety value of + '1' is used which will be very slow. + + - read-only: this parameterless property disables writes to the eeprom + +Example: + +eeprom@52 { + compatible = "atmel,24c32"; + reg = <0x52>; + pagesize = <32>; +}; -- cgit v1.2.1