Hello Joel, Am 16.02.22 um 16:04 schrieb Joel Sherrill:
On Wed, Feb 16, 2022 at 3:22 AM Christian Mauderer <christian.maude...@embedded-brains.de> wrote:A device tree binary has to be 8 byte aligned in memory. This is checked since RTEMS commit 34052ef78cf8724dee73e9279b2c6bff8cfed234 "libfdt: Add FDT alignment check to fdt_check_header()". --- bsps/arm/imxrt/dts/imxrt1050-evkb.c | 2 +- bsps/arm/imxrt/dts/imxrt1050-evkb.dts | 2 +- bsps/arm/imxrt/include/bsp.h | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/bsps/arm/imxrt/dts/imxrt1050-evkb.c b/bsps/arm/imxrt/dts/imxrt1050-evkb.c index 301e790c6b..ecae160a8e 100644 --- a/bsps/arm/imxrt/dts/imxrt1050-evkb.c +++ b/bsps/arm/imxrt/dts/imxrt1050-evkb.c @@ -6,7 +6,7 @@ #include <sys/types.h> -const unsigned char imxrt_dtb[] = { +const unsigned char imxrt_dtb[] __attribute__(( __aligned__(8) )) = { 0xd0, 0x0d, 0xfe, 0xed, 0x00, 0x00, 0x3f, 0xf6, 0x00, 0x00, 0x00, 0x38, 0x00, 0x00, 0x3b, 0xf8, 0x00, 0x00, 0x00, 0x28, 0x00, 0x00, 0x00, 0x11, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xbe, diff --git a/bsps/arm/imxrt/dts/imxrt1050-evkb.dts b/bsps/arm/imxrt/dts/imxrt1050-evkb.dts index 9310371428..dae7e8939f 100644 --- a/bsps/arm/imxrt/dts/imxrt1050-evkb.dts +++ b/bsps/arm/imxrt/dts/imxrt1050-evkb.dts @@ -31,7 +31,7 @@ * export BSP_DIR="${RTEMS_SRC_DIR}/bsps/arm/imxrt/" * arm-rtems6-cpp -P -x assembler-with-cpp -I "${BSP_DIR}/include/" -include "${BSP_DIR}/dts/imxrt1050-evkb.dts" /dev/null | \ * dtc -O dtb -o "${BSP_DIR}/dts/imxrt1050-evkb.dtb" -b 0 -p 64 - * rtems-bin2c -C -N imxrt_dtb "${BSP_DIR}/dts/imxrt1050-evkb.dtb" "${BSP_DIR}/dts/imxrt1050-evkb.c" + * rtems-bin2c -A 8 -C -N imxrt_dtb "${BSP_DIR}/dts/imxrt1050-evkb.dtb" "${BSP_DIR}/dts/imxrt1050-evkb.c" */ /dts-v1/; diff --git a/bsps/arm/imxrt/include/bsp.h b/bsps/arm/imxrt/include/bsp.h index d7e37628e5..9f3b913a17 100644 --- a/bsps/arm/imxrt/include/bsp.h +++ b/bsps/arm/imxrt/include/bsp.h @@ -57,7 +57,7 @@ extern "C" { #define BSP_FEATURE_IRQ_EXTENSION #define BSP_FDT_IS_SUPPORTED -extern const unsigned char imxrt_dtb[]; +extern const unsigned char imxrt_dtb[] __attribute__(( __aligned__(8) ));Why not use RTEMS_ALIGNED?
Because I generated the imxrt1050-evkb.c using the new option in the rtems-bin2c and I wanted to use the same name for the prototypes in the header. If I would have used RTEMS_ALIGNED in the code generated by rtems-bin2c, it would have been necessary to add the header for RTEMS_ALIGNED in the generated code. I wanted to avoid that so rtems-bin2c generated code doesn't get new dependencies.
And is it assumed that if the user wants to provide a different device tree, they will follow the same naming? Otherwise, why are symbols in the public facing bsp.h.
The i.MXRT doesn't have a bootloader that could provide the device tree. Therefore at the moment I just linked the device tree into the binary. Using a fixed name was the simplest method for allowing a user to replace the device tree blob. The bsp_fdt_get just retuns the pointer to that blob:
https://git.rtems.org/rtems/tree/bsps/arm/imxrt/start/bspstart.c?id=d24da94f620af3b8446a8305056bf690339bbeac#n74 The commands that I documented generate exactly that name: https://docs.rtems.org/branches/master/user/bsps/bsps-arm.html#fdtBy the way: I will have to update the docuentation too as soon as this patch is pushed. Thanks for the hint.
The alternative would have been to move the bsp_fdt_get into a separate C file and skip the symbols in the bsp.h header. In that case, a user would have to add his own device tree blob and overwrite the bsp_fdt_get so that it returns his own blob. That seemed like an unnecessary extra step.
Best regards Christian
extern const size_t imxrt_dtb_size; void *imx_get_reg_of_node(const void *fdt, int node); -- 2.31.1 _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
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