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

From: Bin Meng bmeng.cn@gmail.com Date: Sun, 19 Sep 2021 09:04:56 +0800

Hi Bin,

Thanks for taking a look.

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 .

Really? The current codebase has both styles... But sure, I can make that change.

...

•   index = ARRAY_SIZE(apple_mem_map) - 3;
  

•   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.

Could be. This is actually a watchdog device that is used to reset the machine. So I suppose I should add a watchdog driver and use SYSRESET_WATCHDOG. Slight worry is that this relies on a lot more DM code. Does that mean the reset isn't available during early boot?

If it is acceptable, I would like to add the watchdog device in a future series, once the device tree bindings for the watchdog have been hammered out.

...

+{

•   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?

...

+.global save_boot_params +save_boot_params:

•   adr     x1, fw_dtb_pointer
  

•   str     x0, [x1]
  

•   b       save_boot_params_ret
  

diff --git a/configs/apple_m1_defconfig b/configs/apple_m1_defconfig new file mode 100644 index 0000000000..a7ae15576b --- /dev/null +++ b/configs/apple_m1_defconfig @@ -0,0 +1,14 @@ +CONFIG_ARM=y +CONFIG_ARCH_APPLE=y +# CONFIG_DISPLAY_CPUINFO is not set +# CONFIG_MMC is not set +# CONFIG_NET is not set +CONFIG_VIDEO_SIMPLE=y +CONFIG_DISPLAY_BOARDINFO_LATE=y +CONFIG_USB_XHCI_HCD=y +CONFIG_USB_XHCI_DWC3=y +CONFIG_USB_KEYBOARD=y +CONFIG_USB_STORAGE=y +CONFIG_USE_PREBOOT=y +CONFIG_PREBOOT="usb start" +# CONFIG_GENERATE_SMBIOS_TABLE is not set diff --git a/include/configs/apple.h b/include/configs/apple.h new file mode 100644 index 0000000000..1c246af002 --- /dev/null +++ b/include/configs/apple.h @@ -0,0 +1,38 @@ +#ifndef __CONFIG_H +#define __CONFIG_H

+#include <linux/sizes.h>

+#define CONFIG_SYS_LOAD_ADDR 0x880000000

+#define CONFIG_SYS_SDRAM_BASE 0x880000000

+#define CONFIG_LNX_KRNL_IMG_TEXT_OFFSET_BASE CONFIG_SYS_TEXT_BASE

+/* Environment */ +#define ENV_DEVICE_SETTINGS \

•   "stdin=serial,usbkbd\0" \
  

•   "stdout=serial,vidconsole\0" \
  

•   "stderr=serial,vidconsole\0"
  

+#define ENV_MEM_LAYOUT_SETTINGS \

•   "fdt_addr_r=0x960100000\0" \
  

•   "kernel_addr_r=0x960200000\0"
  

+#if CONFIG_IS_ENABLED(CMD_USB)

•   #define BOOT_TARGET_USB(func) func(USB, usb, 0)
  

+#else

•   #define BOOT_TARGET_USB(func)
  

+#endif

+#define BOOT_TARGET_DEVICES(func) \

•   BOOT_TARGET_USB(func)
  

+#include <config_distro_bootcmd.h>

+#define CONFIG_EXTRA_ENV_SETTINGS \

•   ENV_DEVICE_SETTINGS \
  

•   ENV_MEM_LAYOUT_SETTINGS \
  

•   BOOTENV
  

+#endif

Regards, Bin