Subject: [PATCH v4 3/3] gnu: u-boot: Enlarge space available for kernel.

From: Herman Rimm <[email-masked]>
Date: Mon, 31 Mar 2025 20:19:27 +0200

* gnu/packages/bootloaders.scm (u-boot)[source]: Add patch.
* gnu/packages/patches/u-boot-50M-kernel.patch: Add file.
* gnu/local.mk (dist_patch_DATA): Register patch.

Change-Id: Ib0074d888a3553543b491e9198f9b9a1162722f3
---
 gnu/local.mk                                 |  1 +
 gnu/packages/bootloaders.scm                 |  1 +
 gnu/packages/patches/u-boot-50M-kernel.patch | 55 ++++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 gnu/packages/patches/u-boot-50M-kernel.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 955b8fb1ddf..3bb421b49e7 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -2339,6 +2339,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/tuxpaint-stamps-path.patch		\
   %D%/packages/patches/tvm_fix_cpptest_build.patch              \
   %D%/packages/patches/twinkle-bcg729.patch			\
+  %D%/packages/patches/u-boot-50M-kernel.patch			\
   %D%/packages/patches/u-boot-allow-disabling-openssl.patch	\
   %D%/packages/patches/u-boot-nintendo-nes-serial.patch		\
   %D%/packages/patches/u-boot-rockchip-inno-usb.patch		\
diff --git a/gnu/packages/bootloaders.scm b/gnu/packages/bootloaders.scm
index 5a030360226..8a2ca8cfda3 100644
--- a/gnu/packages/bootloaders.scm
+++ b/gnu/packages/bootloaders.scm
@@ -769,6 +769,7 @@ (define u-boot
        (sha256
         (base32 "1i1v86bnixh8hyqbwwr5iwdnnadmg2fqxw9g526fvclsbvl8lz0v"))
        (patches (search-patches "u-boot-allow-disabling-openssl.patch"
+                                "u-boot-50M-kernel.patch"
                                 "u-boot-rockchip-inno-usb.patch"))))
     (build-system gnu-build-system)
     (native-inputs
diff --git a/gnu/packages/patches/u-boot-50M-kernel.patch b/gnu/packages/patches/u-boot-50M-kernel.patch
new file mode 100644
index 00000000000..c4d054dd42d
--- /dev/null
+++ b/gnu/packages/patches/u-boot-50M-kernel.patch
@@ -0,0 +1,55 @@
+From: Herman Rimm <[email-masked]>
+Date: Mon, Sep 16 2024 19:24:02 +0200
+Subject: [PATCH] Configure Raspberry Pis to reserve 50 MB for linux kernels.
+
+---
+The 6.9 and newer linux-libre-arm64-generic kernels for Guix can be
+larger than the allocated 36 MB.  This patch is not submitted upstream.
+
+diff --git a/board/raspberrypi/rpi/rpi.env b/board/raspberrypi/rpi/rpi.env
+index 30228285edd..666883e9212 100644
+--- a/board/raspberrypi/rpi/rpi.env
++++ b/board/raspberrypi/rpi/rpi.env
+@@ -43,22 +43,22 @@ dfu_alt_info+=zImage fat 0 1
+  *   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.
++ *   satisfies all these constraints and reserving memory up to 0x03400000
++ *   permits fairly large (roughly 50M) 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
+- * 0x02400000-0x02500000 and 0x02500000-0x02600000 should be plenty.
++ * 0x03200000-0x03300000 and 0x03300000-0x03400000 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 0x02600000-0x02700000 for
+- * the DTB leaves rest of the free RAM to the initrd starting at 0x02700000.
++ * satisfies this constraint again. Reserving 1M at 0x03400000-0x03500000 for
++ * the DTB leaves rest of the free RAM to the initrd starting at 0x03500000.
+  * Even with the smallest possible CPU-GPU memory split of the CPU getting
+- * only 64M, the remaining 25M starting at 0x02700000 should allow quite
++ * only 64M, the remaining 11M starting at 0x03500000 should allow quite
+  * large initrds before they start colliding with U-Boot.
+  */
+ #ifdef CONFIG_ARM64
+@@ -69,9 +69,9 @@ fdt_high=ffffffff
+ initrd_high=ffffffff
+ #endif
+ kernel_addr_r=0x00080000
+-scriptaddr=0x02400000
+-pxefile_addr_r=0x02500000
+-fdt_addr_r=0x02600000
+-ramdisk_addr_r=0x02700000
++scriptaddr=0x03200000
++pxefile_addr_r=0x03300000
++fdt_addr_r=0x03400000
++ramdisk_addr_r=0x03500000
+ 
+ boot_targets=mmc usb pxe dhcp
-- 
2.48.1