From 9c407347b496124849665aca6b76f48118891707 Mon Sep 17 00:00:00 2001 From: Masahisa Kojima Date: Mon, 17 Mar 2025 14:03:57 +0530 Subject: fdt: add support for adding pmem nodes One of the problems an OS may face, when running in EFI, is that a mounted ISO, after calling ExitBootServices goes away, if that ISO is resident in RAM memory as a ramdisk. ACPI has NFIT and NVDIMM support to provide ramdisks to the OS, but we don't have anything in place for DTs. Linux and device trees have support for persistent memory devices. So add a function that can inject a pmem node in a DT, so we can pass information on the ramdisk the OS. Signed-off-by: Masahisa Kojima Signed-off-by: Sughosh Ganu Reviewed-by: Ilias Apalodimas Signed-off-by: Ilias Apalodimas --- boot/fdt_support.c | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) (limited to 'boot/fdt_support.c') diff --git a/boot/fdt_support.c b/boot/fdt_support.c index 49efeec3681..92f2f534ee0 100644 --- a/boot/fdt_support.c +++ b/boot/fdt_support.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -464,7 +465,6 @@ void do_fixup_by_compat_u32(void *fdt, const char *compat, do_fixup_by_compat(fdt, compat, prop, &tmp, 4, create); } -#ifdef CONFIG_ARCH_FIXUP_FDT_MEMORY /* * fdt_pack_reg - pack address and size array into the "reg"-suitable stream */ @@ -493,6 +493,7 @@ static int fdt_pack_reg(const void *fdt, void *buf, u64 *address, u64 *size, return p - (char *)buf; } +#ifdef CONFIG_ARCH_FIXUP_FDT_MEMORY #if CONFIG_NR_DRAM_BANKS > 4 #define MEMORY_BANKS_MAX CONFIG_NR_DRAM_BANKS #else @@ -2222,3 +2223,39 @@ int fdt_valid(struct fdt_header **blobp) } return 1; } + +int fdt_fixup_pmem_region(void *fdt, u64 pmem_start, u64 pmem_size) +{ + char node_name[32]; + int nodeoffset, len; + int err; + u8 tmp[4 * 16]; /* Up to 64-bit address + 64-bit size */ + + if (!IS_ALIGNED(pmem_start, SZ_2M) || + !IS_ALIGNED(pmem_start + pmem_size, SZ_2M)) { + printf("Start and end address must be 2MiB aligned\n"); + return -1; + } + + snprintf(node_name, sizeof(node_name), "pmem@%llx", pmem_start); + nodeoffset = fdt_find_or_add_subnode(fdt, 0, node_name); + if (nodeoffset < 0) + return nodeoffset; + + err = fdt_setprop_string(fdt, nodeoffset, "compatible", "pmem-region"); + if (err) + return err; + err = fdt_setprop_empty(fdt, nodeoffset, "volatile"); + if (err) + return err; + + len = fdt_pack_reg(fdt, tmp, &pmem_start, &pmem_size, 1); + err = fdt_setprop(fdt, nodeoffset, "reg", tmp, len); + if (err < 0) { + printf("WARNING: could not set pmem %s %s.\n", "reg", + fdt_strerror(err)); + return err; + } + + return 0; +} -- cgit v1.2.3