On 28/06/24 05:48, Rob Herring wrote: > On Wed, Jun 26, 2024 at 10:33 PM Chris Packham > <chris.packham@xxxxxxxxxxxxxxxxxxx> wrote: >> The bootloader used on the Realtek RTL9302C boards is an ancient vendor >> fork of U-Boot that doesn't understand device trees. So to run a modern >> kernel it is necessary use one of the APPENDED_DTB options. >> >> When appending the DTB the inintrd information, if present, needs to be >> inserted into the /chosen device tree node. The bootloader provides the >> initrd start/size via the firmware environment. Add a fdt fixup that >> will update the device tree with the initrd information. > Is this really specific to this board/soc? Based on my sample size of 1 I can't say. I thought this was a quirk of the realtek SDK version of U-Boot because it's based on something old and dt unaware. I did think about putting this code in a more generic place but in the end I went with something less invasive figuring it could be expanded on later if needed. > I think there are lots of MIPS boards in this state. If anyone can confirm that I'd be happy to make the workaround kick in if the fw_env has an initrd_start in it. I'm not sure if there is any risk in that approach. I don't know how other mips boards are currently booting using the generic board support. > The code to handle all the possible > combinations of bootloader handoff information and sources of DTB is > quite the mess. Just for DTB source you have bootloader DTB, appended > DTB, or built-in DTB (and there's even logic if you have multiple of > those). Contrast that to arm32 ('the zoo"), where you have 2 choices: > bootloader DTB or appended DTB with legacy bootloader parameters > transferred to DTB. All the uglyness is contained and the kernel boot > deals with 1 possibility. </rant> > >> Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx> >> --- >> >> Notes: >> Changes in v3: >> - None >> Changes in v2: >> - update compatible string >> >> arch/mips/generic/Makefile | 1 + >> arch/mips/generic/board-realtek.c | 81 +++++++++++++++++++++++++++++++ >> 2 files changed, 82 insertions(+) >> create mode 100644 arch/mips/generic/board-realtek.c >> >> diff --git a/arch/mips/generic/Makefile b/arch/mips/generic/Makefile >> index 56011d738441..ea0e4ad5e600 100644 >> --- a/arch/mips/generic/Makefile >> +++ b/arch/mips/generic/Makefile >> @@ -13,3 +13,4 @@ obj-$(CONFIG_LEGACY_BOARD_SEAD3) += board-sead3.o >> obj-$(CONFIG_LEGACY_BOARD_OCELOT) += board-ocelot.o >> obj-$(CONFIG_MACH_INGENIC) += board-ingenic.o >> obj-$(CONFIG_VIRT_BOARD_RANCHU) += board-ranchu.o >> +obj-$(CONFIG_MACH_REALTEK_RTL) += board-realtek.o >> diff --git a/arch/mips/generic/board-realtek.c b/arch/mips/generic/board-realtek.c >> new file mode 100644 >> index 000000000000..cd83fbf1968c >> --- /dev/null >> +++ b/arch/mips/generic/board-realtek.c >> @@ -0,0 +1,81 @@ >> +// SPDX-License-Identifier: GPL-2.0-or-later > Kernel license by default is GPL-2.0-only. Why do something different? Copy and paste from the existing arch/mips/generic/board-*.c. I'm fine with making it GPL-2.0-only >> +/* >> + * Copyright (C) 2024 Allied Telesis >> + */ >> + >> +#include <linux/errno.h> >> +#include <linux/libfdt.h> >> +#include <linux/of_address.h> > You aren't using this header. Ack. >> +#include <linux/types.h> >> + >> +#include <asm/fw/fw.h> >> +#include <asm/machine.h> >> + >> +static __init int realtek_add_initrd(void *fdt) >> +{ >> + int node, err; >> + u32 start, size; >> + >> + node = fdt_path_offset(fdt, "/chosen"); >> + if (node < 0) { >> + pr_err("/chosen node not found\n"); >> + return -ENOENT; >> + } >> + >> + start = fw_getenvl("initrd_start"); >> + size = fw_getenvl("initrd_size"); >> + >> + if (start == 0 && size == 0) >> + return 0; >> + >> + pr_info("Adding initrd info from environment\n"); >> + >> + err = fdt_setprop_u32(fdt, node, "linux,initrd-start", start); >> + if (err) { >> + pr_err("unable to set initrd-start: %d\n", err); >> + return err; >> + } >> + >> + err = fdt_setprop_u32(fdt, node, "linux,initrd-end", start + size); >> + if (err) { >> + pr_err("unable to set initrd-end: %d\n", err); >> + return err; >> + } >> + >> + return 0; >> +} >> + >> +static const struct mips_fdt_fixup realtek_fdt_fixups[] __initconst = { >> + { realtek_add_initrd, "add initrd" }, >> + {}, >> +}; >> + >> +static __init const void *realtek_fixup_fdt(const void *fdt, const void *match_data) >> +{ >> + static unsigned char fdt_buf[16 << 10] __initdata; >> + int err; >> + >> + if (fdt_check_header(fdt)) >> + panic("Corrupt DT"); >> + >> + fw_init_cmdline(); >> + >> + err = apply_mips_fdt_fixups(fdt_buf, sizeof(fdt_buf), fdt, realtek_fdt_fixups); >> + if (err) >> + panic("Unable to fixup FDT: %d", err); >> + >> + return fdt_buf; >> + >> +} >> + >> +static const struct of_device_id realtek_of_match[] __initconst = { >> + { >> + .compatible = "realtek,rtl9302", >> + }, >> + {} >> +}; >> + >> +MIPS_MACHINE(realtek) = { >> + .matches = realtek_of_match, >> + .fixup_fdt = realtek_fixup_fdt, >> +}; >> -- >> 2.45.2 >> >>