Re: [PATCH 1/1 RFC] treewide: Deprecate OF_PRIOR_STAGE

Ilias Apalodimas
2021-09-25T17:50:02Z

Hi Mark,

On Sat, Sep 25, 2021 at 07:01:07PM +0200, Mark Kettenis wrote:
> > From: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > Date: Fri, 24 Sep 2021 16:12:51 +0300
> >
> > Forgot to include Mark, which showed some interest for MBPs
>
> Well, I am currently using OF_BOARD, so this doesn't affect me. I was
> merely pointing out that having OF_PRIOR_STAGE makes some sense as it
> clearly indicates that the DT is coming from an earlier firmware
> stage. OF_BOARD is more flexible and could be used to read the DT
> from an onboard ROM or something like that.

Sure, the naming is something we'd loose. But it doesn't truly offer us any
advantage does it? Unless we know of a board that can read the DT from an
onboard ROM *or* a register. That would make some sense in having 2 config
options, so that a user could specify which DT he wants. But even in that
case, I'd prefer the config to be easier and hide the details under the hood.

E.g have a callback that reads the register and if you don't find any valid
DTB go read a ROM (which is close too what I suggested on a following mail).
The obvious disadvantage of this approach would be not allowing someone to
explicitly request which DT to read, but I can live with that.

Regards
/Ilias
>
> > On Fri, 24 Sept 2021 at 16:10, Ilias Apalodimas
> > <ilias.apalodimas@linaro.org> wrote:
> > >
> > > At some point back in 2018 prior_stage_fdt_address and OF_PRIOR_STAGE got
> > > introduced, in order to support a DTB handed over by an earlier stage boot
> > > loader. However we have another option in the Kconfig (OF_BOARD) which has
> > > identical semantics.
> > >
> > > A good example of this is RISC-V boards which during their startup,
> > > pick up the DTB from a1 and copy it in their private gd_t. Apart from that
> > > they also copy it to prior_stage_fdt_address, if the Kconfig option is
> > > selected, which seems unnecessary(??).
> > >
> > > This is mostly an RFC, trying to figure out if I am missing some subtle
> > > functionality, which would justify having 2 Kconfig options doing similar
> > > things present.
> > >
> > > - Should we do this?
> > > - Doesn't OF_BOARD and OF_PRIOR_STAGE practically mean "Someone else is
> > > going to pass me my DTB". Why should we care if that someone is a prior
> > > bootloader or runtime memory generated on the fly by U-Boot? It all
> > > boils down to having a *board* specific callback for that.
> > > - RISC-V binman should get rid of the option as well if we decide to go
> > > though with this (but I have no idea what RISC-V expects there).
> > > - Can we apply similar logic to OF_HOSTFILE? It seems like we could just
> > > have a board_fdt_blob_setup() for the sandbox that reads the file we
> > > want and get rid of another Kconfig option.
> > >
> > > Note that the original board which introduced CONFIG_OF_PRIOR_STAGE is still
> > > there. If someone cares enough I guess he could fix that as well, but I don't
> > > have the board around, so I prefer keeping it as is and mark the option as
> > > deprecated. For that board we could also keep the prior_stage_fdt_address
> > > without the Kconfig option and simply copy the location there, but the
> > > board must define it's own board_fdt_blob_setup(). That would get rid of
> > > the Kconfig option entirely instead of limiting it to that board only.
> > >
> > > Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > > ---
> > > arch/riscv/cpu/cpu.c | 3 ---
> > > arch/riscv/cpu/start.S | 5 -----
> > > board/emulation/qemu-riscv/qemu-riscv.c | 8 ++++++++
> > > board/sifive/unleashed/unleashed.c | 10 ++++------
> > > board/sifive/unmatched/unmatched.c | 10 ++++------
> > > configs/ae350_rv32_defconfig | 2 +-
> > > configs/ae350_rv32_spl_defconfig | 2 +-
> > > configs/ae350_rv64_defconfig | 2 +-
> > > configs/ae350_rv64_spl_defconfig | 2 +-
> > > configs/bcm7260_defconfig | 2 +-
> > > configs/qemu-riscv32_defconfig | 2 +-
> > > configs/qemu-riscv32_smode_defconfig | 2 +-
> > > configs/qemu-riscv32_spl_defconfig | 2 +-
> > > configs/qemu-riscv64_defconfig | 2 +-
> > > configs/qemu-riscv64_smode_defconfig | 2 +-
> > > configs/qemu-riscv64_spl_defconfig | 2 +-
> > > dts/Kconfig | 3 ++-
> > > lib/fdtdec.c | 4 ++++
> > > 18 files changed, 33 insertions(+), 32 deletions(-)
> > >
> > > diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
> > > index c894ac10b536..e16f1df30254 100644
> > > --- a/arch/riscv/cpu/cpu.c
> > > +++ b/arch/riscv/cpu/cpu.c
> > > @@ -16,9 +16,6 @@
> > > * The variables here must be stored in the data section since they are used
> > > * before the bss section is available.
> > > */
> > > -#ifdef CONFIG_OF_PRIOR_STAGE
> > > -phys_addr_t prior_stage_fdt_address __section(".data");
> > > -#endif
> > > #ifndef CONFIG_XIP
> > > u32 hart_lottery __section(".data") = 0;
> > >
> > > diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
> > > index 308b0a97a58f..76850ec9be2c 100644
> > > --- a/arch/riscv/cpu/start.S
> > > +++ b/arch/riscv/cpu/start.S
> > > @@ -142,11 +142,6 @@ call_harts_early_init:
> > > bnez tp, secondary_hart_loop
> > > #endif
> > >
> > > -#ifdef CONFIG_OF_PRIOR_STAGE
> > > - la t0, prior_stage_fdt_address
> > > - SREG s1, 0(t0)
> > > -#endif
> > > -
> > > jal board_init_f_init_reserve
> > >
> > > SREG s1, GD_FIRMWARE_FDT_ADDR(gp)
> > > diff --git a/board/emulation/qemu-riscv/qemu-riscv.c b/board/emulation/qemu-riscv/qemu-riscv.c
> > > index dcfd3f20bee6..7dfe471dee15 100644
> > > --- a/board/emulation/qemu-riscv/qemu-riscv.c
> > > +++ b/board/emulation/qemu-riscv/qemu-riscv.c
> > > @@ -14,6 +14,8 @@
> > > #include <virtio_types.h>
> > > #include <virtio.h>
> > >
> > > +DECLARE_GLOBAL_DATA_PTR;
> > > +
> > > int board_init(void)
> > > {
> > > /*
> > > @@ -69,3 +71,9 @@ int board_fit_config_name_match(const char *name)
> > > return 0;
> > > }
> > > #endif
> > > +void *board_fdt_blob_setup(void)
> > > +{
> > > + /* Stored the DTB address there during our init */
> > > + return (void *)gd->arch.firmware_fdt_addr;
> > > +}
> > > +
> > > diff --git a/board/sifive/unleashed/unleashed.c b/board/sifive/unleashed/unleashed.c
> > > index 8cd514df3005..9aa2b3e6f43a 100644
> > > --- a/board/sifive/unleashed/unleashed.c
> > > +++ b/board/sifive/unleashed/unleashed.c
> > > @@ -116,12 +116,10 @@ int misc_init_r(void)
> > >
> > > void *board_fdt_blob_setup(void)
> > > {
> > > - if (IS_ENABLED(CONFIG_OF_SEPARATE)) {
> > > - if (gd->arch.firmware_fdt_addr)
> > > - return (ulong *)gd->arch.firmware_fdt_addr;
> > > - else
> > > - return (ulong *)&_end;
> > > - }
> > > + if (gd->arch.firmware_fdt_addr)
> > > + return (ulong *)gd->arch.firmware_fdt_addr;
> > > + else
> > > + return (ulong *)&_end;
> > > }
> > >
> > > int board_init(void)
> > > diff --git a/board/sifive/unmatched/unmatched.c b/board/sifive/unmatched/unmatched.c
> > > index d90b252baef7..b703f9c3efc3 100644
> > > --- a/board/sifive/unmatched/unmatched.c
> > > +++ b/board/sifive/unmatched/unmatched.c
> > > @@ -13,12 +13,10 @@
> > >
> > > void *board_fdt_blob_setup(void)
> > > {
> > > - if (IS_ENABLED(CONFIG_OF_SEPARATE)) {
> > > - if (gd->arch.firmware_fdt_addr)
> > > - return (ulong *)gd->arch.firmware_fdt_addr;
> > > - else
> > > - return (ulong *)&_end;
> > > - }
> > > + if (gd->arch.firmware_fdt_addr)
> > > + return (ulong *)gd->arch.firmware_fdt_addr;
> > > + else
> > > + return (ulong *)&_end;
> > > }
> > >
> > > int board_init(void)
> > > diff --git a/configs/ae350_rv32_defconfig b/configs/ae350_rv32_defconfig
> > > index 4e7a1686a64d..8b6c0b8a4a0a 100644
> > > --- a/configs/ae350_rv32_defconfig
> > > +++ b/configs/ae350_rv32_defconfig
> > > @@ -15,7 +15,7 @@ CONFIG_CMD_SF_TEST=y
> > > # CONFIG_CMD_SETEXPR is not set
> > > CONFIG_BOOTP_PREFER_SERVERIP=y
> > > CONFIG_CMD_CACHE=y
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_ENV_OVERWRITE=y
> > > CONFIG_ENV_IS_IN_SPI_FLASH=y
> > > CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> > > diff --git a/configs/ae350_rv32_spl_defconfig b/configs/ae350_rv32_spl_defconfig
> > > index 34c6af6e7e17..a0fe9b9a71df 100644
> > > --- a/configs/ae350_rv32_spl_defconfig
> > > +++ b/configs/ae350_rv32_spl_defconfig
> > > @@ -19,7 +19,7 @@ CONFIG_CMD_SF_TEST=y
> > > # CONFIG_CMD_SETEXPR is not set
> > > CONFIG_BOOTP_PREFER_SERVERIP=y
> > > CONFIG_CMD_CACHE=y
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_ENV_OVERWRITE=y
> > > CONFIG_ENV_IS_IN_SPI_FLASH=y
> > > CONFIG_BOOTP_SEND_HOSTNAME=y
> > > diff --git a/configs/ae350_rv64_defconfig b/configs/ae350_rv64_defconfig
> > > index 05eee371ac2f..b12a8810a221 100644
> > > --- a/configs/ae350_rv64_defconfig
> > > +++ b/configs/ae350_rv64_defconfig
> > > @@ -16,7 +16,7 @@ CONFIG_CMD_SF_TEST=y
> > > # CONFIG_CMD_SETEXPR is not set
> > > CONFIG_BOOTP_PREFER_SERVERIP=y
> > > CONFIG_CMD_CACHE=y
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_board=y
> > > CONFIG_ENV_OVERWRITE=y
> > > CONFIG_ENV_IS_IN_SPI_FLASH=y
> > > CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> > > diff --git a/configs/ae350_rv64_spl_defconfig b/configs/ae350_rv64_spl_defconfig
> > > index 9cd7848c92eb..9ad312505db3 100644
> > > --- a/configs/ae350_rv64_spl_defconfig
> > > +++ b/configs/ae350_rv64_spl_defconfig
> > > @@ -20,7 +20,7 @@ CONFIG_CMD_SF_TEST=y
> > > # CONFIG_CMD_SETEXPR is not set
> > > CONFIG_BOOTP_PREFER_SERVERIP=y
> > > CONFIG_CMD_CACHE=y
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_ENV_OVERWRITE=y
> > > CONFIG_ENV_IS_IN_SPI_FLASH=y
> > > CONFIG_BOOTP_SEND_HOSTNAME=y
> > > diff --git a/configs/bcm7260_defconfig b/configs/bcm7260_defconfig
> > > index a42a6acb06d5..be0c945dc811 100644
> > > --- a/configs/bcm7260_defconfig
> > > +++ b/configs/bcm7260_defconfig
> > > @@ -22,7 +22,7 @@ CONFIG_CMD_CACHE=y
> > > CONFIG_CMD_EXT2=y
> > > CONFIG_CMD_EXT4=y
> > > CONFIG_CMD_FS_GENERIC=y
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_ENV_OVERWRITE=y
> > > CONFIG_ENV_IS_IN_MMC=y
> > > CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
> > > diff --git a/configs/qemu-riscv32_defconfig b/configs/qemu-riscv32_defconfig
> > > index 8ac16cf4186e..6fe133c268d7 100644
> > > --- a/configs/qemu-riscv32_defconfig
> > > +++ b/configs/qemu-riscv32_defconfig
> > > @@ -9,6 +9,6 @@ CONFIG_DISPLAY_BOARDINFO=y
> > > CONFIG_CMD_BOOTEFI_SELFTEST=y
> > > CONFIG_CMD_NVEDIT_EFI=y
> > > # CONFIG_CMD_MII is not set
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> > > CONFIG_DM_MTD=y
> > > diff --git a/configs/qemu-riscv32_smode_defconfig b/configs/qemu-riscv32_smode_defconfig
> > > index 05eda439618f..c67e8206d1ab 100644
> > > --- a/configs/qemu-riscv32_smode_defconfig
> > > +++ b/configs/qemu-riscv32_smode_defconfig
> > > @@ -10,6 +10,6 @@ CONFIG_DISPLAY_BOARDINFO=y
> > > CONFIG_CMD_BOOTEFI_SELFTEST=y
> > > CONFIG_CMD_NVEDIT_EFI=y
> > > # CONFIG_CMD_MII is not set
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> > > CONFIG_DM_MTD=y
> > > diff --git a/configs/qemu-riscv32_spl_defconfig b/configs/qemu-riscv32_spl_defconfig
> > > index ee81e552724d..77e81fac3af7 100644
> > > --- a/configs/qemu-riscv32_spl_defconfig
> > > +++ b/configs/qemu-riscv32_spl_defconfig
> > > @@ -12,6 +12,6 @@ CONFIG_DISPLAY_CPUINFO=y
> > > CONFIG_DISPLAY_BOARDINFO=y
> > > CONFIG_CMD_SBI=y
> > > # CONFIG_CMD_MII is not set
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> > > CONFIG_DM_MTD=y
> > > diff --git a/configs/qemu-riscv64_defconfig b/configs/qemu-riscv64_defconfig
> > > index daf5d655d01f..90e87672aab0 100644
> > > --- a/configs/qemu-riscv64_defconfig
> > > +++ b/configs/qemu-riscv64_defconfig
> > > @@ -10,6 +10,6 @@ CONFIG_DISPLAY_BOARDINFO=y
> > > CONFIG_CMD_BOOTEFI_SELFTEST=y
> > > CONFIG_CMD_NVEDIT_EFI=y
> > > # CONFIG_CMD_MII is not set
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> > > CONFIG_DM_MTD=y
> > > diff --git a/configs/qemu-riscv64_smode_defconfig b/configs/qemu-riscv64_smode_defconfig
> > > index 4a6416e2540b..0a8393903368 100644
> > > --- a/configs/qemu-riscv64_smode_defconfig
> > > +++ b/configs/qemu-riscv64_smode_defconfig
> > > @@ -13,6 +13,6 @@ CONFIG_DISPLAY_BOARDINFO=y
> > > CONFIG_CMD_BOOTEFI_SELFTEST=y
> > > CONFIG_CMD_NVEDIT_EFI=y
> > > # CONFIG_CMD_MII is not set
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> > > CONFIG_DM_MTD=y
> > > diff --git a/configs/qemu-riscv64_spl_defconfig b/configs/qemu-riscv64_spl_defconfig
> > > index 429d4d814e65..a15e82dd3ee1 100644
> > > --- a/configs/qemu-riscv64_spl_defconfig
> > > +++ b/configs/qemu-riscv64_spl_defconfig
> > > @@ -13,6 +13,6 @@ CONFIG_DISPLAY_CPUINFO=y
> > > CONFIG_DISPLAY_BOARDINFO=y
> > > CONFIG_CMD_SBI=y
> > > # CONFIG_CMD_MII is not set
> > > -CONFIG_OF_PRIOR_STAGE=y
> > > +CONFIG_OF_BOARD=y
> > > CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> > > CONFIG_DM_MTD=y
> > > diff --git a/dts/Kconfig b/dts/Kconfig
> > > index dabe0080c1ef..2c5b2ec2d1f8 100644
> > > --- a/dts/Kconfig
> > > +++ b/dts/Kconfig
> > > @@ -107,7 +107,7 @@ config OF_EMBED
> > > Boards in the mainline U-Boot tree should not use it.
> > >
> > > config OF_BOARD
> > > - bool "Provided by the board at runtime"
> > > + bool "Provided by the board (e.g a previous loader) at runtime"
> > > depends on !SANDBOX
> > > help
> > > If this option is enabled, the device tree will be provided by
> > > @@ -124,6 +124,7 @@ config OF_HOSTFILE
> > >
> > > config OF_PRIOR_STAGE
> > > bool "Prior stage bootloader DTB for DT control"
> > > + depends on ARCH_BCMSTB
> > > help
> > > If this option is enabled, the device tree used for DT
> > > control will be read from a device tree binary, at a memory
> > > diff --git a/lib/fdtdec.c b/lib/fdtdec.c
> > > index 7358cb6dd168..8d0db5ac6173 100644
> > > --- a/lib/fdtdec.c
> > > +++ b/lib/fdtdec.c
> > > @@ -1581,6 +1581,10 @@ int fdtdec_setup(void)
> > > return -1;
> > > }
> > > # elif defined(CONFIG_OF_PRIOR_STAGE)
> > > + /*
> > > + * obsolete don't use this on newer boards. Prefer CONFIG_OF_BOARD
> > > + * instead
> > > + */
> > > gd->fdt_blob = (void *)(uintptr_t)prior_stage_fdt_address;
> > > # endif
> > > # ifndef CONFIG_SPL_BUILD
> > > --
> > > 2.33.0
> > >
> >