riscv: Provide a mechanism to fix DT for reserved memory

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>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
index fce098272f2a524b6a4d570fdae192f25b31ddb7..5f1c220e0ca84102581ed1fa95e80013cbdc83b3 100644 (file)
--- a/arch/riscv/cpu/start.S
+++ b/arch/riscv/cpu/start.S
@@ -119,6 +119,7 @@ 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 72fb4b4d922e4001c0ad1bbff81b27c1cce7ab26..6c50149218b49c4a3004f0b70d622825fec8973d 100644 (file)
--- 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 49febd588102a825f3c6edae199358ed46b76a01..543a1688db8fc6a10766d0f66d856644fd01758a 100644 (file)
--- 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 bd7b2c4d162b398ca72fe0210dc79549ce6c0843..b5e93244e0ecb18f2a49f5b64333ebd2cf138369 100644 (file)
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -24,6 +24,7 @@ obj-y += reset.o
 obj-y   += setjmp.o
 obj-$(CONFIG_$(SPL_)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 4fa4fd371473baa140a893e7a9d367ca967d63c1..7301c1b98e2363a011e5c06b6268812ed01a6325 100644 (file)
--- 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 (file)
index 0000000..1fce414
--- /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;
+}