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.
In U-boot, any board may use the DT in following ways. 1. OF_SEPARTE: It ignores the DT from previous stage and uses the DT from U-Boot sources. 2. OF_PRIOR_STATE: It reuses the DT from previous stage. For case 1: U-Boot needs to parse the reserved-memory node from the DT passed from the previous stage and update the DT in use.
This patch provides a framework to do that from any RISC-V boards.
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 | 1 + arch/riscv/lib/asm-offsets.c | 1 + arch/riscv/lib/bootm.c | 37 +++++++++++++++++++++++++++ 5 files changed, 41 insertions(+)
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..b7bea0ba184d 100644 --- a/arch/riscv/include/asm/u-boot-riscv.h +++ b/arch/riscv/include/asm/u-boot-riscv.h @@ -17,5 +17,6 @@ int cleanup_before_linux(void); /* board/.../... */ int board_init(void); void board_quiesce_devices(void); +int riscv_board_reserved_mem_fixup(void *fdt);
#endif /* _U_BOOT_RISCV_H_ */ 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/bootm.c b/arch/riscv/lib/bootm.c index f927694ae32f..3a4d0bf14c86 100644 --- a/arch/riscv/lib/bootm.c +++ b/arch/riscv/lib/bootm.c @@ -19,6 +19,7 @@ #include <dm/device.h> #include <dm/root.h> #include <u-boot/zlib.h> +#include <mapmem.h>
DECLARE_GLOBAL_DATA_PTR;
@@ -26,6 +27,42 @@ __weak void board_quiesce_devices(void) { }
+int riscv_board_reserved_mem_fixup(void *fdt) +{ + uint32_t phandle; + struct fdt_memory pmp_mem; + int err; + void *src_fdt_addr; + int offset, node; + phys_addr_t addr, size; + + src_fdt_addr = map_sysmem(gd->arch.firmware_fdt_addr, 0); + offset = fdt_path_offset(src_fdt_addr, "/reserved-memory"); + if (offset < 0) { + printf("No reserved memory region found in FDT\n"); + return offset; + } + + fdt_for_each_subnode(node, src_fdt_addr, offset) { + const char *name = fdt_get_name(src_fdt_addr, node, NULL); + + addr = fdtdec_get_addr_size(src_fdt_addr, node, "reg", &size); + if (addr == FDT_ADDR_T_NONE) { + debug("failed to read address/size for %s\n", name); + continue; + } + pmp_mem.start = addr; + pmp_mem.end = addr + size; + err = fdtdec_add_reserved_memory(fdt, name, &pmp_mem, &phandle); + if (err < 0) { + printf("failed to add reserved memory: %d\n", err); + return err; + } + } + + return 0; +} + int arch_fixup_fdt(void *blob) { u32 size;