On Tue, Jun 25, 2024 at 10:08:06AM +0100, Conor Dooley wrote: > The firmware on the Icicle is capable of providing a devicetree in a1 to > U-Boot, but until now the devicetree has been packaged in a "payload" [1] > alongside U-Boot (or other bootloaders/RTOSes) and appended to the image. > The address of this appended devicetree is placed in a1 by the firmware. > This meant that the mechanism used by OF_SEPARATE to locate the > devicetree at the end of the image would pick up the one provided by the > firmware when u-boot-nodtb.bin was in the payload and U-Boot's devicetree > when u-boot.bin was. > > The firmware is now going to be capable of providing a minimal devicetree > (quite cut down due to severe space constraints), but this devicetree is > linked into the firmware that runs out of the L2 rather than at the end > of the U-Boot image. Implement board_fdt_blob_setup() so that this > devicetree can be optionally used, and the devicetree provided in the > "payload" can be used without relying on "happening" to implement the > same strategy as OF_SEPARATE expects in combination with > u-boot-nodtb.bin. Unlike other RISC-V boards, the firmware provided > devicetree is only used when OF_BOARD is set, so that the almost > certainly more complete devicetree in U-Boot will be used unless > explicitly requested otherwise. > > Link: > https://github.com/polarfire-soc/hart-software-services/blob/master/tools/hss-payload-generator/README.md > [1] > Signed-off-by: Conor Dooley <conor.doo...@microchip.com> > --- > CC: Ivan Griffin <ivan.grif...@microchip.com> > CC: Padmarao Begari <padmarao.beg...@microchip.com> > CC: Cyril Jean <cyril.j...@microchip.com> > CC: Tom Rini <tr...@konsulko.com> > CC: Conor Dooley <conor.doo...@microchip.com> > CC: u-boot@lists.denx.de > --- > board/microchip/mpfs_icicle/mpfs_icicle.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/board/microchip/mpfs_icicle/mpfs_icicle.c > b/board/microchip/mpfs_icicle/mpfs_icicle.c > index 4d7d843dfa3..2c1f7175f0e 100644 > --- a/board/microchip/mpfs_icicle/mpfs_icicle.c > +++ b/board/microchip/mpfs_icicle/mpfs_icicle.c > @@ -9,6 +9,7 @@ > #include <init.h> > #include <asm/global_data.h> > #include <asm/io.h> > +#include <asm/sections.h> > > DECLARE_GLOBAL_DATA_PTR; > > @@ -50,6 +51,24 @@ static void read_device_serial_number(u8 *response, u8 > response_size) > response_buf[idx] = readb(MPFS_SYS_SERVICE_MAILBOX + idx); > } > > +void *board_fdt_blob_setup(int *err) > +{ > + *err = 0; > + /* > + * The devicetree provided by the previous stage is very minimal due to > + * severe space constraints. The firmware performs no fixups etc. > + * U-Boot, if providing a devicetree, almost certainly has a better > + * more complete one than the firmware so that provided by the firmware > + * is ignored for OF_SEPARATE. > + */ > + if (IS_ENABLED(CONFIG_OF_BOARD)) { > + if (gd->arch.firmware_fdt_addr) > + return (ulong *)(uintptr_t)gd->arch.firmware_fdt_addr; > + } > + > + return (ulong *)_end; > +} > + > int board_init(void) > { > /* For now nothing to do here. */
I'm adding in Simon and Ilias as this touches on one of those frequent topics about how device trees can/should be passed along to us. -- Tom
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