On Wed, May 28, 2025 at 04:11:26PM +0200, Michael Tretter wrote:
> The upstream OP-TEE expects a device tree to be able to initialize the
> dynamic shared memory. Therefore, barebox should pass a device tree that
> contains memory nodes through the TF-A to OP-TEE.
>
> OP-TEE may modify the passed fdt. Thus, barebox copies the fdt from the
> fixed size rodata area to the rk_scratch area and allocates a
> configurable memory area for the fdt to allow fdt modification.
>
> OP-TEE has the CFG_DTB_MAX_SIZE config option for the maximum size of
> the fdt. barebox must reserve at least that much memory for the fdt to
> avoid out of bounds accesses from OP-TEE.
>
> Unfortunately, the downstream TF-A fails to start if barebox passes its
> device tree and it is not possible to detect if the loaded TF-A is able
> to handle the device tree. Add a config option to pass the device tree
> if it is possible.
>
> Signed-off-by: Michael Tretter <m.tret...@pengutronix.de>
> ---
> Changes in v2:
> - pass copy of fdt in scratch space to TF-A
> - add config option for fdt size
> - add documentation for CONFIG_ARCH_ROCKCHIP_ATF_PASS_FDT
> ---
> Documentation/boards/rockchip.rst | 4 ++++
> arch/arm/mach-rockchip/Kconfig | 23 +++++++++++++++++++++++
> arch/arm/mach-rockchip/atf.c | 24 ++++++++++++------------
> include/mach/rockchip/bootrom.h | 3 +++
> 4 files changed, 42 insertions(+), 12 deletions(-)
>
> diff --git a/Documentation/boards/rockchip.rst
> b/Documentation/boards/rockchip.rst
> index
> b2b04abb03cd1926bb59799af5f6a8c11d410cc2..8bce92865e3eda193412180c7295b5a35b3531e8
> 100644
> --- a/Documentation/boards/rockchip.rst
> +++ b/Documentation/boards/rockchip.rst
> @@ -94,6 +94,10 @@ With these barebox can be compiled as:
> .. note:: The RK3566 and RK3568 seem to share the bl31 and bl32 firmware
> files,
> whereas the memory initialization blob is different.
>
> +.. note:: The bl31 from the rkbin repository seems to be unable to handle
> + device trees of a larger size (for example, if CONFIG_OF_OVERLAY_LIVE is
> + enabled). Disable CONFIG_ARCH_ROCKCHIP_ATF_PASS_FDT in this case.
> +
> Creating a bootable SD card
> ---------------------------
>
> diff --git a/arch/arm/mach-rockchip/Kconfig b/arch/arm/mach-rockchip/Kconfig
> index
> 98dfd11c182b9fee6e3c958653ad4fa8a7d98d84..1b72dc4b8a16ce9dca742ff1173fc2208a0e619d
> 100644
> --- a/arch/arm/mach-rockchip/Kconfig
> +++ b/arch/arm/mach-rockchip/Kconfig
> @@ -141,6 +141,29 @@ config ARCH_ROCKCHIP_ATF
> useful for debugging early startup, but for all other cases,
> say y here.
>
> +config ARCH_ROCKCHIP_ATF_PASS_FDT
> + bool "Pass device tree to TF-A"
> + depends on ARCH_ROCKCHIP_ATF
> + help
> + Enable this option if you are using an upstream OP-TEE that uses the
> + device tree to initialize dynamic shared memory, which is passed
> + through the upstream TF-A.
> +
> + Disable the option if you are using a downstream TF-A since it
> + doesn't always cope with device trees. Supposedly this happens if the
> + device tree is too large, for example if CONFIG_OF_OVERLAY_LIVE is
> + enabled.
> +
> +config ARCH_ROCKCHIP_ATF_FDT_SIZE
> + hex
> + default 0x0
> + default 0x60000 if ARCH_ROCKCHIP_ATF_PASS_FDT
> + prompt "Reserved size for the FDT blob passed to the TF-A"
> + help
> + Set this size to CFG_DTB_MAX_SIZE in the OP-TEE configuration. OP-TEE
> + may modify the passed device tree and increase it's size. This
> + ensures that barebox reserves enough memory for the modifications.
> +
> config ARCH_ROCKCHIP_OPTEE
> bool "Build rockchip OP-TEE binary into barebox"
> depends on ARCH_ROCKCHIP_ATF
> diff --git a/arch/arm/mach-rockchip/atf.c b/arch/arm/mach-rockchip/atf.c
> index
> cfa6df043b34c0f36919048237c7ecf33dfe0724..f4a71ef2dc8dffc6ceb4f97ee542f5b83858120b
> 100644
> --- a/arch/arm/mach-rockchip/atf.c
> +++ b/arch/arm/mach-rockchip/atf.c
> @@ -183,21 +183,21 @@ void __noreturn rk3588_barebox_entry(void *fdt)
> rk_scratch = (void *)arm_mem_scratch(endmem);
>
> if (current_el() == 3) {
> + void *fdt_scratch = NULL;
> +
> rk3588_lowlevel_init();
> rockchip_store_bootrom_iram(IOMEM(RK3588_IRAM_BASE));
>
> - /*
> - * The downstream TF-A doesn't cope with our device tree when
> - * CONFIG_OF_OVERLAY_LIVE is enabled, supposedly because it is
> - * too big for some reason. Otherwise it doesn't have any
> visible
> - * effect if we pass a device tree or not, except that the TF-A
> - * fills in the ethernet MAC address into the device tree.
> - * The upstream TF-A doesn't use the device tree at all.
> - *
> - * Pass NULL for now until we have a good reason to pass a real
> - * device tree.
> - */
> - rk3588_atf_load_bl31(NULL);
> +#ifdef CONFIG_ARCH_ROCKCHIP_ATF_PASS_FDT
> + pr_debug("Copy fdt to scratch area 0x%p (%zu bytes)\n",
> + rk_scratch->fdt, sizeof(rk_scratch->fdt));
> + if (fdt_open_into(fdt, rk_scratch->fdt,
> sizeof(rk_scratch->fdt)) == 0)
> + fdt_scratch = rk_scratch->fdt;
> + else
> + pr_warn("Failed to copy fdt to scratch: Continue
> without fdt\n");
> +#endif
I converted this to if (IS_ENABLED(CONFIG_ARCH_ROCKCHIP_ATF_PASS_FDT))
while applying.
Sascha
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
