Re: [PATCH v3 3/5] riscv: Provide a mechanism to fix DT for reserved memory

On Wed, Mar 18, 2020 at 5:19 AM Atish Patra atish.patra@wdc.com wrote:

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 | 1 + arch/riscv/lib/asm-offsets.c | 1 + arch/riscv/lib/bootm.c | 68 +++++++++++++++++++++++++++ 5 files changed, 72 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..5e907e96701c 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 +27,73 @@ __weak void board_quiesce_devices(void) { }

+int riscv_fdt_copy_resv_mem_node(const void *src, void *dst)

We probably need find a better place for this routine, see below comments for riscv_board_reserved_mem_fixup().

We need make this routine public in u-boot-riscv.h as well.

+{

•   uint32_t phandle;
  

•   struct fdt_memory pmp_mem;
  

•   fdt_addr_t addr;
  

•   fdt_size_t size;
  

•   int offset, node, err, rmem_offset;
  

•   bool nomap = false;
  

•   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,
  

•                                                     true);
  

•           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';
  

nits: need space around +

•           }
  

•           pmp_mem.start = addr;
  

•           pmp_mem.end = addr + size;
  

•           err = fdtdec_add_reserved_memory(dst, basename, &pmp_mem,
  

•                                            &phandle);
  

•           if (err < 0) {
  

•                   printf("failed to add reserved memory: %d\n", err);
  

•                   return err;
  

•           }
  

•           rmem_offset = fdt_node_offset_by_phandle(dst, phandle);
  

nits: this line can be put in the "if (nomap)" block below

•           nomap = fdt_get_property(src, node, "no-map", NULL);
  

•           if (nomap)
  

•                   fdt_setprop_empty(dst, rmem_offset, "no-map");
  

•   }
  

•   return 0;
  

+}

+int riscv_board_reserved_mem_fixup(void *fdt)

This routine should not be put to boom.c as it's nothing related to bootm. Maybe arch/riscv/lib/fdt.c ?

+{

•   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;
  

+}

int arch_fixup_fdt(void *blob) { u32 size; -- 2.25.1