[PATCH v6 3/6] riscv: Provide a mechanism to fix DT for reserved memory
Atish Patra
atish.patra at wdc.com
Sat Apr 18 21:32:25 CEST 2020
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 at wdc.com>
Reviewed-by: Bin Meng <bmeng.cn at gmail.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;
+}
--
2.25.1
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