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/* SPDX-License-Identifier: GPL-2.0+ */
/* environment for Raspberry Pi boards */
dhcpuboot=usb start; dhcp u-boot.uimg; bootm
/* Environment */
stdin=serial,usbkbd
stdout=serial,vidconsole
stderr=serial,vidconsole
/* DFU over USB/UDC */
#ifdef CONFIG_CMD_DFU
dfu_alt_info=u-boot.bin fat 0 1;uboot.env fat 0 1;
config.txt fat 0 1;
#ifdef CONFIG_ARM64
dfu_alt_info+=Image fat 0 1
#else
dfu_alt_info+=zImage fat 0 1
#endif
#endif /* CONFIG_CMD_DFU */
/*
* Memory layout for where various images get loaded by boot scripts:
*
* I suspect address 0 is used as the SMP pen on the RPi2, so avoid this.
*
* Older versions of the boot firmware place the firmware-loaded DTB at 0x100,
* newer versions place it in high memory. So prevent U-Boot from doing its own
* DTB + initrd relocation so that we won't accidentally relocate the initrd
* over the firmware-loaded DTB and generally try to lay out things starting
* from the bottom of RAM.
*
* kernel_addr_r has different constraints on ARM and Aarch64. For 32-bit ARM,
* it must be within the first 128M of RAM in order for the kernel's
* CONFIG_AUTO_ZRELADDR option to work. The kernel itself will be decompressed
* to 0x8000 but the decompressor clobbers 0x4000-0x8000 as well. The
* decompressor also likes to relocate itself to right past the end of the
* decompressed kernel, so in total the sum of the compressed and
* decompressed kernel needs to be reserved.
*
* For Aarch64, the kernel image is uncompressed and must be loaded at
* text_offset bytes (specified in the header of the Image) into a 2MB
* boundary. The 'booti' command relocates the image if necessary. Linux uses
* a default text_offset of 0x80000. In summary, loading at 0x80000
* satisfies all these constraints and reserving memory up to 0x02400000
* permits fairly large (roughly 36M) kernels.
*
* scriptaddr and pxefile_addr_r can be pretty much anywhere that doesn't
* conflict with something else. Reserving 1M for each of them at
* 0x05400000-0x05500000 and 0x05500000-0x05600000 should be plenty.
*
* On ARM, both the DTB and any possible initrd must be loaded such that they
* fit inside the lowmem mapping in Linux. In practice, this usually means not
* more than ~700M away from the start of the kernel image but this number can
* be larger OR smaller depending on e.g. the 'vmalloc=xxxM' command line
* parameter given to the kernel. So reserving memory from low to high
* satisfies this constraint again. Reserving 1M at 0x05600000-0x05700000 for
* the DTB leaves rest of the free RAM to the initrd starting at 0x05700000.
* This means that the board must have at least 128MB of RAM available to
* U-Boot, more if the initrd is large.
*
* For compressed kernels, the maximum size is just under 32MB, with an area for
* decompression at 0x02000000 with space for 52MB, which is plenty for current
* kernels.
*
* limit bootm_size to 512MB so that all boot images stay within the bottom
* 512MB of memory
*/
bootm_size=0x20000000
kernel_addr_r=0x00080000
kernel_comp_addr_r=0x02000000
kernel_comp_size=0x03400000
scriptaddr=0x05400000
pxefile_addr_r=0x05500000
fdt_addr_r=0x05600000
ramdisk_addr_r=0x05700000
boot_targets=mmc usb pxe dhcp
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