rpi3: Add support for direct Linux kernel boot
This option allows the Trusted Firmware to pass the correct arguments to
a 32 or 64-bit Linux kernel without the need of an intermediate loader
such as U-Boot.
Change-Id: I2b22e8933fad6a614588ace559f893e97329801f
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/plat/rpi3/platform.mk b/plat/rpi3/platform.mk
index 2f18af6..4276c84 100644
--- a/plat/rpi3/platform.mk
+++ b/plat/rpi3/platform.mk
@@ -114,6 +114,9 @@
# BL33 images are in AArch64 by default
RPI3_BL33_IN_AARCH32 := 0
+# Assume that BL33 isn't the Linux kernel by default
+RPI3_DIRECT_LINUX_BOOT := 0
+
# BL32 location
RPI3_BL32_RAM_LOCATION := tdram
ifeq (${RPI3_BL32_RAM_LOCATION}, tsram)
@@ -129,9 +132,17 @@
$(eval $(call add_define,RPI3_BL32_RAM_LOCATION_ID))
$(eval $(call add_define,RPI3_BL33_IN_AARCH32))
+$(eval $(call add_define,RPI3_DIRECT_LINUX_BOOT))
+$(eval $(call add_define,RPI3_PRELOADED_DTB_BASE))
# Verify build config
# -------------------
+#
+ifneq (${RPI3_DIRECT_LINUX_BOOT}, 0)
+ ifndef RPI3_PRELOADED_DTB_BASE
+ $(error Error: RPI3_PRELOADED_DTB_BASE needed if RPI3_DIRECT_LINUX_BOOT=1)
+ endif
+endif
ifneq (${LOAD_IMAGE_V2}, 1)
$(error Error: rpi3 needs LOAD_IMAGE_V2=1)
diff --git a/plat/rpi3/rpi3_bl31_setup.c b/plat/rpi3/rpi3_bl31_setup.c
index 4ea1bcf..5bbb13c 100644
--- a/plat/rpi3/rpi3_bl31_setup.c
+++ b/plat/rpi3/rpi3_bl31_setup.c
@@ -96,6 +96,34 @@
if (bl33_image_ep_info.pc == 0) {
panic();
}
+
+#if RPI3_DIRECT_LINUX_BOOT
+# if RPI3_BL33_IN_AARCH32
+ /*
+ * According to the file ``Documentation/arm/Booting`` of the Linux
+ * kernel tree, Linux expects:
+ * r0 = 0
+ * r1 = machine type number, optional in DT-only platforms (~0 if so)
+ * r2 = Physical address of the device tree blob
+ */
+ VERBOSE("rpi3: Preparing to boot 32-bit Linux kernel\n");
+ bl33_image_ep_info.args.arg0 = 0U;
+ bl33_image_ep_info.args.arg1 = ~0U;
+ bl33_image_ep_info.args.arg2 = (u_register_t) RPI3_PRELOADED_DTB_BASE;
+# else
+ /*
+ * According to the file ``Documentation/arm64/booting.txt`` of the
+ * Linux kernel tree, Linux expects the physical address of the device
+ * tree blob (DTB) in x0, while x1-x3 are reserved for future use and
+ * must be 0.
+ */
+ VERBOSE("rpi3: Preparing to boot 64-bit Linux kernel\n");
+ bl33_image_ep_info.args.arg0 = (u_register_t) RPI3_PRELOADED_DTB_BASE;
+ bl33_image_ep_info.args.arg1 = 0ULL;
+ bl33_image_ep_info.args.arg2 = 0ULL;
+ bl33_image_ep_info.args.arg3 = 0ULL;
+# endif /* RPI3_BL33_IN_AARCH32 */
+#endif /* RPI3_DIRECT_LINUX_BOOT */
}
void bl31_plat_arch_setup(void)