In RISC-V, M-mode software can reserve physical memory regions by setting appropriate physical memory protection (PMP) csr. As the PMP csr are accessible only in M-mode, S-mode U-Boot can not read this configuration directly. However, M-mode software can pass this information via reserved-memory node in device tree so that S-mode software can access this information.
This patch provides a framework to copy to the reserved-memory node from one DT to another. This will be used to update the DT used by U-Boot and the DT passed to the next stage OS.
Signed-off-by: Atish Patra atish.patra@wdc.com --- arch/riscv/cpu/start.S | 1 + arch/riscv/include/asm/global_data.h | 1 + arch/riscv/include/asm/u-boot-riscv.h | 2 + arch/riscv/lib/Makefile | 1 + arch/riscv/lib/asm-offsets.c | 1 + arch/riscv/lib/fdt_fixup.c | 102 ++++++++++++++++++++++++++ 6 files changed, 108 insertions(+) create mode 100644 arch/riscv/lib/fdt_fixup.c
diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index 6b3ff99c3882..0282685c2906 100644 --- a/arch/riscv/cpu/start.S +++ b/arch/riscv/cpu/start.S @@ -121,6 +121,7 @@ call_board_init_f_0:
jal board_init_f_init_reserve
+ SREG s1, GD_FIRMWARE_FDT_ADDR(gp) /* save the boot hart id to global_data */ SREG tp, GD_BOOT_HART(gp)
diff --git a/arch/riscv/include/asm/global_data.h b/arch/riscv/include/asm/global_data.h index b74bd7e738bb..51ac8d1c98e2 100644 --- a/arch/riscv/include/asm/global_data.h +++ b/arch/riscv/include/asm/global_data.h @@ -15,6 +15,7 @@ /* Architecture-specific global data */ struct arch_global_data { long boot_hart; /* boot hart id */ + phys_addr_t firmware_fdt_addr; #ifdef CONFIG_SIFIVE_CLINT void __iomem *clint; /* clint base address */ #endif diff --git a/arch/riscv/include/asm/u-boot-riscv.h b/arch/riscv/include/asm/u-boot-riscv.h index 49febd588102..543a1688db8f 100644 --- a/arch/riscv/include/asm/u-boot-riscv.h +++ b/arch/riscv/include/asm/u-boot-riscv.h @@ -17,5 +17,7 @@ int cleanup_before_linux(void); /* board/.../... */ int board_init(void); void board_quiesce_devices(void); +int riscv_board_reserved_mem_fixup(void *fdt); +int riscv_fdt_copy_resv_mem_node(const void *src_fdt, void *dest_fdt);
#endif /* _U_BOOT_RISCV_H_ */ diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile index adadbf4bcbef..d132b59ce32c 100644 --- a/arch/riscv/lib/Makefile +++ b/arch/riscv/lib/Makefile @@ -24,6 +24,7 @@ obj-y += reset.o obj-y += setjmp.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_SPL_BUILD) += spl.o +obj-y += fdt_fixup.o
# For building EFI apps CFLAGS_$(EFI_CRT0) := $(CFLAGS_EFI) diff --git a/arch/riscv/lib/asm-offsets.c b/arch/riscv/lib/asm-offsets.c index 4fa4fd371473..7301c1b98e23 100644 --- a/arch/riscv/lib/asm-offsets.c +++ b/arch/riscv/lib/asm-offsets.c @@ -14,6 +14,7 @@ int main(void) { DEFINE(GD_BOOT_HART, offsetof(gd_t, arch.boot_hart)); + DEFINE(GD_FIRMWARE_FDT_ADDR, offsetof(gd_t, arch.firmware_fdt_addr)); #ifndef CONFIG_XIP DEFINE(GD_AVAILABLE_HARTS, offsetof(gd_t, arch.available_harts)); #endif diff --git a/arch/riscv/lib/fdt_fixup.c b/arch/riscv/lib/fdt_fixup.c new file mode 100644 index 000000000000..1fce41490973 --- /dev/null +++ b/arch/riscv/lib/fdt_fixup.c @@ -0,0 +1,102 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2020 Western Digital Corporation or its affiliates + * + */ + +#include <common.h> +#include <fdt_support.h> +#include <mapmem.h> + +DECLARE_GLOBAL_DATA_PTR; + +/** + * riscv_fdt_copy_resv_mem_node() - Copy reserve memory node entry + * @src: Pointer to the source device tree from which reserved memory node + * needs to be copied. + * @dst: Pointer to the destination device tree to which reserved memory node + * needs to be copied. + * + * Return: 0 on success or if source doesn't have reserved memory node. + * Error if copy process failed. + */ +int riscv_fdt_copy_resv_mem_node(const void *src, void *dst) +{ + u32 phandle; + struct fdt_memory pmp_mem; + fdt_addr_t addr; + fdt_size_t size; + int offset, node, err, rmem_offset; + bool nomap = true; + char basename[32] = {0}; + int bname_len; + int max_len = sizeof(basename); + const char *name; + char *temp; + + offset = fdt_path_offset(src, "/reserved-memory"); + if (offset < 0) { + printf("No reserved memory region found in source FDT\n"); + return 0; + } + + fdt_for_each_subnode(node, src, offset) { + name = fdt_get_name(src, node, NULL); + + addr = fdtdec_get_addr_size_auto_noparent(src, node, + "reg", 0, &size, + false); + if (addr == FDT_ADDR_T_NONE) { + debug("failed to read address/size for %s\n", name); + continue; + } + strncpy(basename, name, max_len); + temp = strchr(basename, '@'); + if (temp) { + bname_len = strnlen(basename, max_len) - strnlen(temp, + max_len); + *(basename + bname_len) = '\0'; + } + pmp_mem.start = addr; + pmp_mem.end = addr + size - 1; + err = fdtdec_add_reserved_memory(dst, basename, &pmp_mem, + &phandle); + if (err < 0) { + printf("failed to add reserved memory: %d\n", err); + return err; + } + if (!fdt_getprop(src, node, "no-map", NULL)) + nomap = false; + if (nomap) { + rmem_offset = fdt_node_offset_by_phandle(dst, phandle); + fdt_setprop_empty(dst, rmem_offset, "no-map"); + } + } + + return 0; +} + +/** + * riscv_board_reserved_mem_fixup() - Fix up reserved memory node for a board + * @fdt: Pointer to the device tree in which reserved memory node needs to be + * added. + * + * In RISC-V, any board compiled with OF_SEPARATE needs to copy the reserved + * memory node from the device tree provided by the firmware to the device tree + * used by U-Boot. This is a common function that individual board fixup + * functions can invoke. + * + * Return: 0 on success or error otherwise. + */ +int riscv_board_reserved_mem_fixup(void *fdt) +{ + int err; + void *src_fdt_addr; + + src_fdt_addr = map_sysmem(gd->arch.firmware_fdt_addr, 0); + err = riscv_fdt_copy_resv_mem_node(src_fdt_addr, fdt); + if (err < 0) + return err; + + return 0; +}