On 30.10.18 14:44, Auer, Lukas wrote:
On Tue, 2018-10-30 at 14:19 +0100, Alexander Graf wrote:
On 30.10.18 13:55, Lukas Auer wrote:
The device tree passed by the prior boot stage can be used to boot Linux. Store it as environment variable "prior_stage_dtb", so that it can be used as part of the boot command.
Signed-off-by: Lukas Auer lukas.auer@aisec.fraunhofer.de
Changes in v2:
- New patch
arch/Kconfig | 1 + arch/riscv/cpu/cpu.c | 7 +++++++ arch/riscv/include/asm/u-boot-riscv.h | 1 + 3 files changed, 9 insertions(+)
diff --git a/arch/Kconfig b/arch/Kconfig index 9fdd2f7e66..883e4a9308 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -74,6 +74,7 @@ config RISCV imply MTD imply TIMER imply CMD_DM
- imply ARCH_MISC_INIT
config SANDBOX bool "Sandbox" diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c index d9f820c44c..e06a8c6bab 100644 --- a/arch/riscv/cpu/cpu.c +++ b/arch/riscv/cpu/cpu.c @@ -53,3 +53,10 @@ int print_cpuinfo(void)
return 0; }
+int arch_misc_init(void) +{
- env_set_hex("prior_stage_dtb", prior_stage_fdt_address);
Please reuse one of the many other variable names we have for this already, such as "fdtaddr".
I will change the variable name.
One thing I would always recommend is that if you have a prior stage DT passed on to U-Boot is that U-Boot makes use of that (CONFIG_OF_BOARD). That again means that the DT is already available in $fdtcontroladdr and there is very little use for yet another env variable.
Alex
We are actually using the device tree passed to U-Boot (using CONFIG_OF_PRIOR_STAGE). The reason I'm adding the device tree address to the environment is so that it can be used to boot Linux. RISC-V Linux does not include any device trees, they are instead stored directly on the SoC (though this might change). This is therefore important to have and this is the best way I could think of, of implementing it.
Oh, I'm in 100% agreement that this is the right choice. I'm just surprised we have 2 Kconfig options to basically do the same thing. The RPi uses CONFIG_OF_BOARD while newer BCM chips seem to use CONFIG_PRIOR_STAGE. It's slightly counterintuitive :).
What I was saying is that U-Boot should be a consumer of said "platform device tree" and thus exposes it as $fdtcontroladdr into the environment. So instead of
# bootefi $kernel_addr_r $fdtaddr
you could as well just use
# bootefi $kernel_addr_r $fdtcontroladdr
which the distro scripts automatically do for you, so you already have what you asked for :).
Alex