Re: [PATCH 1/5] arm: apple: Add initial support for Apple's M1 SoC

[Mark Kettenis <mark.kettenis@xs4all.nl>]

> From: Bin Meng <bmeng.cn@gmail.com>
> Date: Sun, 19 Sep 2021 09:17:07 +0800
> 
> Hi Mark,
> 
> On Sun, Sep 19, 2021 at 9:04 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> >
> > Hi Mark,
> >
> > On Sat, Sep 18, 2021 at 9:55 PM Mark Kettenis <kettenis@openbsd.org> wrote:
> > >
> > > Add support for Apple's M1 SoC that is used in "Apple Silicon"
> > > Macs.  This builds a basic U-Boot that can be used as a payload
> > > for the m1n1 boot loader being developed by the Asahi Linux
> > > project.
> > >
> > > Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
> > > ---
> > >  arch/arm/Kconfig                    |  22 ++++
> > >  arch/arm/Makefile                   |   1 +
> > >  arch/arm/mach-apple/Kconfig         |  18 ++++
> > >  arch/arm/mach-apple/Makefile        |   4 +
> > >  arch/arm/mach-apple/board.c         | 158 ++++++++++++++++++++++++++++
> > >  arch/arm/mach-apple/lowlevel_init.S |  16 +++
> > >  configs/apple_m1_defconfig          |  14 +++
> > >  include/configs/apple.h             |  38 +++++++
> > >  8 files changed, 271 insertions(+)
> > >  create mode 100644 arch/arm/mach-apple/Kconfig
> > >  create mode 100644 arch/arm/mach-apple/Makefile
> > >  create mode 100644 arch/arm/mach-apple/board.c
> > >  create mode 100644 arch/arm/mach-apple/lowlevel_init.S
> > >  create mode 100644 configs/apple_m1_defconfig
> > >  create mode 100644 include/configs/apple.h
> > >
> > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > > index b5bd3284cd..7cdea1f615 100644
> > > --- a/arch/arm/Kconfig
> > > +++ b/arch/arm/Kconfig
> > > @@ -895,6 +895,26 @@ config ARCH_NEXELL
> > >         select DM
> > >         select GPIO_EXTRA_HEADER
> > >
> > > +config ARCH_APPLE
> > > +       bool "Apple SoCs"
> > > +       select ARM64
> > > +       select LINUX_KERNEL_IMAGE_HEADER
> > > +       select POSITION_INDEPENDENT
> > > +       select BLK
> > > +       select DM
> > > +       select DM_KEYBOARD
> > > +       select DM_SERIAL
> > > +       select DM_USB
> > > +       select DM_VIDEO
> > > +       select CMD_USB
> > > +       select MISC
> > > +       select OF_CONTROL
> > > +       select OF_BOARD
> > > +       select USB
> > > +       imply CMD_DM
> > > +       imply CMD_GPT
> > > +       imply DISTRO_DEFAULTS
> > > +
> > >  config ARCH_OWL
> > >         bool "Actions Semi OWL SoCs"
> > >         select DM
> > > @@ -1932,6 +1952,8 @@ config ISW_ENTRY_ADDR
> > >           image headers.
> > >  endif
> > >
> > > +source "arch/arm/mach-apple/Kconfig"
> > > +
> > >  source "arch/arm/mach-aspeed/Kconfig"
> > >
> > >  source "arch/arm/mach-at91/Kconfig"
> > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> > > index c68e598a67..44178c204b 100644
> > > --- a/arch/arm/Makefile
> > > +++ b/arch/arm/Makefile
> > > @@ -51,6 +51,7 @@ PLATFORM_CPPFLAGS += $(arch-y) $(tune-y)
> > >
> > >  # Machine directory name.  This list is sorted alphanumerically
> > >  # by CONFIG_* macro name.
> > > +machine-$(CONFIG_ARCH_APPLE)           += apple
> > >  machine-$(CONFIG_ARCH_ASPEED)          += aspeed
> > >  machine-$(CONFIG_ARCH_AT91)            += at91
> > >  machine-$(CONFIG_ARCH_BCM283X)         += bcm283x
> > > diff --git a/arch/arm/mach-apple/Kconfig b/arch/arm/mach-apple/Kconfig
> > > new file mode 100644
> > > index 0000000000..66cab91b2a
> > > --- /dev/null
> > > +++ b/arch/arm/mach-apple/Kconfig
> > > @@ -0,0 +1,18 @@
> > > +if ARCH_APPLE
> > > +
> > > +config SYS_TEXT_BASE
> > > +       default 0x00000000
> > > +
> > > +config SYS_CONFIG_NAME
> > > +       default "apple"
> > > +
> > > +config SYS_SOC
> > > +       default "m1"
> > > +
> > > +config SYS_MALLOC_LEN
> > > +       default 0x4000000
> > > +
> > > +config SYS_MALLOC_F_LEN
> > > +       default 0x4000
> > > +
> > > +endif
> > > diff --git a/arch/arm/mach-apple/Makefile b/arch/arm/mach-apple/Makefile
> > > new file mode 100644
> > > index 0000000000..e74a8c9df1
> > > --- /dev/null
> > > +++ b/arch/arm/mach-apple/Makefile
> > > @@ -0,0 +1,4 @@
> > > +# SPDX-License-Identifier: GPL-2.0+
> > > +
> > > +obj-y += board.o
> > > +obj-y += lowlevel_init.o
> > > diff --git a/arch/arm/mach-apple/board.c b/arch/arm/mach-apple/board.c
> > > new file mode 100644
> > > index 0000000000..0c8b35292e
> > > --- /dev/null
> > > +++ b/arch/arm/mach-apple/board.c
> > > @@ -0,0 +1,158 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +/*
> > > + * (C) Copyright 2021 Mark Kettenis <kettenis@openbsd.org>
> > > + */
> > > +
> > > +#include <common.h>
> > > +#include <efi_loader.h>
> > > +
> > > +#include <asm/armv8/mmu.h>
> > > +#include <asm/global_data.h>
> > > +#include <asm/io.h>
> > > +#include <asm/system.h>
> > > +
> > > +DECLARE_GLOBAL_DATA_PTR;
> > > +
> > > +static struct mm_region apple_mem_map[] = {
> > > +       {
> > > +               /* I/O */
> > > +               .virt = 0x200000000,
> > > +               .phys = 0x200000000,
> > > +               .size = 8UL * SZ_1G,
> > > +               .attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
> > > +                        PTE_BLOCK_NON_SHARE |
> > > +                        PTE_BLOCK_PXN | PTE_BLOCK_UXN
> > > +       }, {
> > > +               /* I/O */
> > > +               .virt = 0x500000000,
> > > +               .phys = 0x500000000,
> > > +               .size = 2UL * SZ_1G,
> > > +               .attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
> > > +                        PTE_BLOCK_NON_SHARE |
> > > +                        PTE_BLOCK_PXN | PTE_BLOCK_UXN
> > > +       }, {
> > > +               /* I/O */
> > > +               .virt = 0x680000000,
> > > +               .phys = 0x680000000,
> > > +               .size = SZ_512M,
> > > +               .attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
> > > +                        PTE_BLOCK_NON_SHARE |
> > > +                        PTE_BLOCK_PXN | PTE_BLOCK_UXN
> > > +       }, {
> > > +               /* PCIE */
> > > +               .virt = 0x6a0000000,
> > > +               .phys = 0x6a0000000,
> > > +               .size = SZ_512M,
> > > +               .attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRE) |
> > > +                        PTE_BLOCK_INNER_SHARE |
> > > +                        PTE_BLOCK_PXN | PTE_BLOCK_UXN
> > > +       }, {
> > > +               /* PCIE */
> > > +               .virt = 0x6c0000000,
> > > +               .phys = 0x6c0000000,
> > > +               .size = SZ_1G,
> > > +               .attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRE) |
> > > +                        PTE_BLOCK_INNER_SHARE |
> > > +                        PTE_BLOCK_PXN | PTE_BLOCK_UXN
> > > +       }, {
> > > +               /* RAM */
> > > +               .virt = 0x800000000,
> > > +               .phys = 0x800000000,
> > > +               .size = 8UL * SZ_1G,
> > > +               .attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
> > > +                        PTE_BLOCK_INNER_SHARE
> > > +       }, {
> > > +               /* Empty entry for framebuffer */
> > > +               0,
> > > +       }, {
> > > +               /* List terminator */
> > > +               0,
> > > +       }
> > > +};
> > > +
> > > +struct mm_region *mem_map = apple_mem_map;
> > > +
> > > +int board_init(void)
> > > +{
> > > +       return 0;
> > > +}
> > > +
> > > +int dram_init(void)
> > > +{
> > > +       int index, node, ret;
> > > +       fdt_addr_t base;
> > > +       fdt_size_t size;
> > > +
> > > +       ret = fdtdec_setup_mem_size_base();
> > > +       if (ret)
> > > +               return ret;
> > > +
> > > +       /* Update RAM mapping. */
> >
> > nits: please remove the ending .
> >
> > > +       index = ARRAY_SIZE(apple_mem_map) - 3;
> 
> This is error prone. Someone else updating apple_mem_map may create an
> incorrect index for us.

I don't see a better way without introducing more complexity.

> > > +       apple_mem_map[index].virt = gd->ram_base;
> > > +       apple_mem_map[index].phys = gd->ram_base;
> > > +       apple_mem_map[index].size = gd->ram_size;
> > > +
> > > +       node = fdt_path_offset(gd->fdt_blob, "/chosen/framebuffer");
> > > +       if (node < 0)
> > > +               return 0;
> > > +
> > > +       base = fdtdec_get_addr_size(gd->fdt_blob, node, "reg", &size);
> > > +       if (base == FDT_ADDR_T_NONE)
> > > +               return 0;
> > > +
> > > +       /* Add framebuffer mapping. */
> >
> > ditto
> >
> > > +       index = ARRAY_SIZE(apple_mem_map) - 2;
> > > +       apple_mem_map[index].virt = base;
> > > +       apple_mem_map[index].phys = base;
> > > +       apple_mem_map[index].size = size;
> > > +       apple_mem_map[index].attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL_NC) |
> > > +               PTE_BLOCK_INNER_SHARE | PTE_BLOCK_PXN | PTE_BLOCK_UXN;
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +int dram_init_banksize(void)
> > > +{
> > > +       return fdtdec_setup_memory_banksize();
> > > +}
> > > +
> > > +#define APPLE_WDT_BASE         0x23d2b0000ULL
> > > +
> > > +#define APPLE_WDT_SYS_CTL_ENABLE       BIT(2)
> > > +
> > > +typedef struct apple_wdt {
> > > +       u32     reserved0[3];
> > > +       u32     chip_ctl;
> > > +       u32     sys_tmr;
> > > +       u32     sys_cmp;
> > > +       u32     reserved1;
> > > +       u32     sys_ctl;
> > > +} apple_wdt_t;
> > > +
> > > +void reset_cpu(void)
> >
> > This looks like we should add a new sysreset driver for Apple Arm SoC.
> >
> > > +{
> > > +       apple_wdt_t *wdt = (apple_wdt_t *)APPLE_WDT_BASE;
> > > +
> > > +       writel(0, &wdt->sys_cmp);
> > > +       writel(APPLE_WDT_SYS_CTL_ENABLE, &wdt->sys_ctl);
> > > +
> > > +       while(1)
> > > +               wfi();
> > > +}
> > > +
> > > +extern long fw_dtb_pointer;
> > > +
> > > +void *board_fdt_blob_setup(void)
> > > +{
> > > +       return (void *)fw_dtb_pointer;
> > > +}
> > > +
> > > +ulong board_get_usable_ram_top(ulong total_size)
> > > +{
> > > +       /*
> > > +        * Top part of RAM is used by firmware for things like the
> > > +        * framebuffer.  This gives us plenty of room to play with.
> > > +        */
> > > +       return 0x980000000;
> > > +}
> > > diff --git a/arch/arm/mach-apple/lowlevel_init.S b/arch/arm/mach-apple/lowlevel_init.S
> > > new file mode 100644
> > > index 0000000000..0f5313163e
> > > --- /dev/null
> > > +++ b/arch/arm/mach-apple/lowlevel_init.S
> > > @@ -0,0 +1,16 @@
> > > +/* SPDX-License-Identifier: GPL-2.0+ */
> > > +/*
> > > + * (C) Copyright 2021 Mark Kettenis <kettenis@openbsd.org>
> > > + */
> > > +
> > > +.align 8
> > > +.global fw_dtb_pointer
> > > +fw_dtb_pointer:
> > > +       .quad   0
> >
> > Is this filled in by m1n1?
> 
> Sorry I misread, so this is passed by m1n1 and filled in by U-Boot. I
> think we should stop using CONFIG_OF_BOARD, and for such case we
> should use CONFIG_OF_PRIOR_STAGE.

Yes, CONFIG_OF_PRIOR_STAGE would work as well.  But Tom was talking
about removing that option in favour of CONFIG_OF_BOARD the other day.

> > > +
> > > +.global save_boot_params
> > > +save_boot_params:
> > > +       adr     x1, fw_dtb_pointer
> > > +       str     x0, [x1]
> > > +
> > > +       b       save_boot_params_ret
> 
> Regards,
> Bin
>