Hello Marco.
On 11/10/25 9:34 PM, Marco Felsch wrote:
> The helper provides a common FDT load mechanism to load the (compressed)
> DTB to the provided destination address. Early FDTs may required by
> other BL3x binaries like BL31 (TF-A) and BL32 (OP-TEE).
>
> Signed-off-by: Marco Felsch <[email protected]>
> ---
> arch/Kconfig | 3 +++
> include/pbl.h | 2 ++
> pbl/Kconfig | 11 +++++++++
> pbl/fdt.c | 75
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 91 insertions(+)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index
> 55618bf896c25f2afa2786706e27fce6ab4b3a39..edd574879b244d3843f1b5a06e1e25c5d4acbc8d
> 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -62,6 +62,9 @@ config ARCH_DMA_DEFAULT_COHERENT
> config ARCH_HAS_DMA_WRITE_COMBINE
> bool
>
> +config ARCH_HAS_EARLY_FDT_SUPPORT
> + bool
> +
> config ARCH_HAS_ASAN_FIBER_API
> bool
>
> diff --git a/include/pbl.h b/include/pbl.h
> index
> 9db4652e833bf5e82fd42a1cae19e94c4f2f868f..bf0c9e2ba29428361cb16a572295e66f20acdd82
> 100644
> --- a/include/pbl.h
> +++ b/include/pbl.h
> @@ -31,6 +31,8 @@ fdt_device_get_match_data(const void *fdt, const char
> *nodepath,
>
> int pbl_barebox_verify(const void *compressed_start, unsigned int len,
> const void *hash, unsigned int hash_len);
> +int pbl_load_fdt(const void *fdt, void *dest, int destsize);
> +
> #endif
>
> void __noreturn barebox_pbl_entry(ulong, ulong, void *);
> diff --git a/pbl/Kconfig b/pbl/Kconfig
> index
> cab9325d16e8625bcca10125b3281062abffedbc..ea2086f33ea405ecd7b00065eaf9874218152b3a
> 100644
> --- a/pbl/Kconfig
> +++ b/pbl/Kconfig
> @@ -65,6 +65,17 @@ config PBL_VERIFY_PIGGY
> depends on ARM || MIPS || RISCV
> bool "Verify barebox proper hash before decompression" if COMPILE_TEST
>
> +config PBL_EARLY_FDT_LOAD
> + bool "Enable early FDT loading"
> + depends on ARCH_HAS_EARLY_FDT_SUPPORT
> + select LIBFDT
> + help
> + This enables the support to decompress and load the barebox builtin
> DTB
> + during the pbl (BL2) phase.
> +
> + This is useful for BL31 and BL32 firmwares which may use the DTB for
> + device configuration.
There are ARM terms, but this is the generic pbl/Kconfig. I should the
symbol here should have no prompt and instead should be selected by an
architecture specific symbol if and only if the functionality will
actually be used.
Thanks,
Ahmad
> +
> config PBL_CLOCKSOURCE
> bool
>
> diff --git a/pbl/fdt.c b/pbl/fdt.c
> index
> ac377446caeafb1beaeb211aa8bdec8767ae21fe..0cd9f5a0f11723e9f9b6848e8553da481b92f2be
> 100644
> --- a/pbl/fdt.c
> +++ b/pbl/fdt.c
> @@ -1,8 +1,10 @@
> // SPDX-License-Identifier: GPL-2.0
> +#include <compressed-dtb.h>
> #include <linux/libfdt.h>
> #include <pbl.h>
> #include <linux/printk.h>
> #include <stdio.h>
> +#include <uncompress.h>
>
> static const __be32 *fdt_parse_reg(const __be32 *reg, uint32_t n,
> uint64_t *val)
> @@ -185,3 +187,76 @@ const void *fdt_device_get_match_data(const void *fdt,
> const char *nodepath,
>
> return NULL;
> }
> +
> +static int pbl_open_dtbz_into(const void *fdt, void *buf, int bufsize)
> +{
> + const struct barebox_boarddata_compressed_dtb *compressed_dtb;
> + int ret;
> +
> + if (!fdt_blob_can_be_decompressed(fdt)) {
> + pr_warn("DTB can't be decompressed\n");
> + return -EINVAL;
> + }
> +
> + compressed_dtb = fdt;
> +
> + if (IS_ENABLED(CONFIG_IMAGE_COMPRESSION_NONE)) {
> + ret = fdt_open_into(compressed_dtb->data, buf, bufsize);
> + if (ret)
> + pr_warn("Failed to open uncompressed DTB with %s\n",
> + fdt_strerror(ret));
> + return ret ? -EINVAL : 0;
> + }
> +
> + if (bufsize < compressed_dtb->datalen_uncompressed) {
> + pr_warn("FDT buffer to small, min. %u bytes required\n",
> + compressed_dtb->datalen_uncompressed);
> + return -EINVAL;
> + }
> +
> + ret = pbl_dtbz_uncompress(buf, (void *)compressed_dtb->data,
> + compressed_dtb->datalen);
> + if (ret) {
> + pr_warn("Failed to uncompress DTB err=%d\n", ret);
> + return ret;
> + }
> +
> + if (!blob_is_fdt(buf)) {
> + pr_warn("Failed to determine FDT type for uncompressed DTB\n");
> + return -EINVAL;
> + }
> +
> + /* Required to setup size data structures to allow runtime adaptions */
> + ret = fdt_open_into(buf, buf, bufsize);
> + if (ret)
> + pr_warn("Failed to open decompressed DTB with %s\n",
> fdt_strerror(ret));
> +
> + return ret ? -EINVAL : 0;
> +}
> +
> +int pbl_load_fdt(const void *fdt, void *dest, int destsize)
> +{
> + int ret;
> +
> + if (!IS_ENABLED(CONFIG_PBL_EARLY_FDT_LOAD))
> + return -ENOTSUPP;
> +
> + if (destsize == 0) {
> + pr_warn("Skip early FDT load due to dest buffer size of
> 0-bytes\n");
> + return -EINVAL;
> + }
> +
> + if (blob_is_fdt(fdt)) {
> + ret = fdt_open_into(fdt, dest, destsize);
> + if (ret)
> + pr_warn("Failed to uncompressed DTB with %s\n",
> + fdt_strerror(ret));
> + return ret ? -EINVAL : 0;
> + } else if (blob_is_compressed_fdt(fdt)) {
> + return pbl_open_dtbz_into(fdt, dest, destsize);
> + }
> +
> + pr_warn("FDT detection failed\n");
> +
> + return -EINVAL;
> +}
>
--
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