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authorUsama Arif <usama.arif@arm.com>2020-07-29 15:35:52 +0100
committerRichard Purdie <richard.purdie@linuxfoundation.org>2020-08-08 09:18:12 +0100
commit6f9d4614e976f3420f6dad1bee0aeac57446f2d4 (patch)
tree94ac3aa96f272872253244fbf264349bfd61306f /documentation/ref-manual/ref-classes.xml
parent392c117e7ab05da10a374f695d5232e7527ab5de (diff)
downloadpoky-6f9d4614e976f3420f6dad1bee0aeac57446f2d4.tar.gz
ref-manual: Add documentation for kernel-fitimage
This documents kernel-fitimage.bbclass as well as the variables that are required to use the class to create a FIT image. (From yocto-docs rev: 3aeca3b342e5be92be562f6dea6b71390c31b636) Signed-off-by: Usama Arif <usama.arif@arm.com> Cc: Richard Purdie <richard.purdie@linuxfoundation.org> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
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diff --git a/documentation/ref-manual/ref-classes.xml b/documentation/ref-manual/ref-classes.xml
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--- a/documentation/ref-manual/ref-classes.xml
+++ b/documentation/ref-manual/ref-classes.xml
@@ -1880,8 +1880,82 @@ This check was removed for YP 2.3 release
1880 1880
1881 <para> 1881 <para>
1882 The <filename>kernel-fitimage</filename> class provides support to 1882 The <filename>kernel-fitimage</filename> class provides support to
1883 pack zImages. 1883 pack a kernel Image, device trees and a RAM disk into a single
1884 FIT image. In theory, a FIT image can support any number of kernels,
1885 RAM disks and device-trees.
1886 However, <filename>kernel-fitimage</filename> currently only supports
1887 limited usescases: just one kernel image, an optional RAM disk, and
1888 any number of device tree.
1884 </para> 1889 </para>
1890
1891 <para>
1892 To create a FIT image, it is required that
1893 <filename><link linkend='var-KERNEL_CLASSES'>KERNEL_CLASSES</link></filename>
1894 is set to "kernel-fitimage" and
1895 <filename><link linkend='var-KERNEL_IMAGETYPE'>KERNEL_IMAGETYPE</link></filename>
1896 is set to "fitImage".
1897 </para>
1898
1899 <para>
1900 The options for the device tree compiler passed to mkimage -D feature
1901 when creating the FIT image are specified using the
1902 <filename><link linkend='var-UBOOT_MKIMAGE_DTCOPTS'>UBOOT_MKIMAGE_DTCOPTS</link></filename>
1903 variable.
1904 </para>
1905
1906 <para>
1907 Only a single kernel can be added to the FIT image created by
1908 <filename>kernel-fitimage</filename> and the kernel image in FIT is
1909 mandatory.
1910 The address where the kernel image is to be loaded by U-boot is
1911 specified by
1912 <filename><link linkend='var-UBOOT_LOADADDRESS'>UBOOT_LOADADDRESS</link></filename>
1913 and the entrypoint by
1914 <filename><link linkend='var-UBOOT_ENTRYPOINT'>UBOOT_ENTRYPOINT</link></filename>.
1915 </para>
1916
1917 <para>
1918 Multiple device trees can be added to the FIT image created by
1919 <filename>kernel-fitimage</filename> and the device tree is optional.
1920 The address where the device tree is to be loaded by U-boot is
1921 specified by
1922 <filename><link linkend='var-UBOOT_DTBO_LOADADDRESS'>UBOOT_DTBO_LOADADDRESS</link></filename>
1923 for device tree overlays and by
1924 <filename><link linkend='var-UBOOT_DTB_LOADADDRESS'>UBOOT_DTB_LOADADDRESS</link></filename>
1925 for device tree binaries.
1926 </para>
1927
1928 <para>
1929 Only a single RAM disk can be added to the FIT image created by
1930 <filename>kernel-fitimage</filename> and the RAM disk in FIT is
1931 optional.
1932 The address where the RAM disk image is to be loaded by U-boot
1933 is specified by
1934 <filename><link linkend='var-UBOOT_RD_LOADADDRESS'>UBOOT_RD_LOADADDRESS</link></filename>
1935 and the entrypoint by
1936 <filename><link linkend='var-UBOOT_RD_ENTRYPOINT'>UBOOT_RD_ENTRYPOINT</link></filename>.
1937 The ramdisk is added to FIT image when
1938 <filename><link linkend='var-INITRAMFS_IMAGE'>INITRAMFS_IMAGE</link></filename>
1939 is specified.
1940 </para>
1941
1942 <para>
1943 The FIT image generated by <filename>kernel-fitimage</filename> class
1944 is signed when the variables
1945 <filename><link linkend='var-UBOOT_SIGN_ENABLE'>UBOOT_SIGN_ENABLE</link></filename>,
1946 <filename><link linkend='var-UBOOT_MKIMAGE_DTCOPTS'>UBOOT_MKIMAGE_DTCOPTS</link></filename>,
1947 <filename><link linkend='var-UBOOT_SIGN_KEYDIR'>UBOOT_SIGN_KEYDIR</link></filename>
1948 and
1949 <filename><link linkend='var-UBOOT_SIGN_KEYNAME'>UBOOT_SIGN_KEYNAME</link></filename>
1950 are set appropriately.
1951 The default values used for
1952 <filename><link linkend='var-FIT_HASH_ALG'>FIT_HASH_ALG</link></filename>
1953 and
1954 <filename><link linkend='var-FIT_SIGN_ALG'>FIT_SIGN_ALG</link></filename>
1955 in <filename>kernel-fitimage</filename> are "sha256" and "rsa2048"
1956 respectively.
1957 </para>
1958
1885</section> 1959</section>
1886 1960
1887<section id='ref-classes-kernel-grub'> 1961<section id='ref-classes-kernel-grub'>