Re: [PATCH v2 48/71] bootstd: Support reading the device tree with EFI

From: Simon Glass sjg@chromium.org Date: Sat, 7 Jan 2023 19:50:24 -0700

With EFI booting the device tree is required but is not actually specified in any way. The normal method is to use a fdtfile environment variable to get the filename, then look for that file on the media.

Implement this in the bootmeth.

Signed-off-by: Simon Glass sjg@chromium.org

Hi Simon,

The distroboot scripts also reads dtb files from the root directory of the ESP (so without the "dtb/" prefix). This code needs to do that as well otherwise some folks will run with a different device tree after switching to bootstd.

The construction of a fallback dtb filename based on soc, board and boardver is only done for (32-bit) arm and not for arm64. It isn't done for riscv either. That feels to me like someone recognized that was a bit of a mistake and shouldn't be done for modern targets. So I think that code should be under the same

#if defined(CONFIG_ARM) && !defined(CONFIG_ARM64)

as it is now in config_distro_bootcmd.h.

Cheers,

Mark

(no changes since v1)

boot/bootmeth_efi.c | 105 +++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 99 insertions(+), 6 deletions(-)

diff --git a/boot/bootmeth_efi.c b/boot/bootmeth_efi.c index 77b4ba22470..53a0489b93c 100644 --- a/boot/bootmeth_efi.c +++ b/boot/bootmeth_efi.c @@ -143,10 +143,32 @@ static int distro_efi_check(struct udevice *dev, struct bootflow_iter *iter) return 0; }

+static void distro_efi_get_fdt_name(char *fname, int size) +{

• const char *fdt_fname;
• fdt_fname = env_get("fdtfile");
• if (fdt_fname) {

• snprintf(fname, size, "dtb/%s", fdt_fname);
  

• log_debug("Using device tree: %s\n", fname);
  

• } else {

• const char *soc = env_get("soc");
  

• const char *board = env_get("board");
  

• const char *boardver = env_get("boardver");
  

• /* cf the code in label_boot() which seems very complex */
  

• snprintf(fname, size, "dtb/%s%s%s%s.dtb",
  

• 	 soc ? soc : "", soc ? "-" : "", board ? board : "",
  

• 	 boardver ? boardver : "");
  

• log_debug("Using default device tree: %s\n", fname);
  

• }

+}

static int distro_efi_read_bootflow_file(struct udevice *dev, struct bootflow *bflow) { struct blk_desc *desc = NULL;

• ulong fdt_addr, size; char fname[256]; int ret;

@@ -170,15 +192,43 @@ static int distro_efi_read_bootflow_file(struct udevice *dev, if (ret) return log_msg_ret("read", -EINVAL);

• distro_efi_get_fdt_name(fname, sizeof(fname));
• bflow->fdt_fname = strdup(fname);
• if (!bflow->fdt_fname)

• return log_msg_ret("fil", -ENOMEM);
  

• fdt_addr = env_get_hex("fdt_addr_r", 0);
• ret = bootmeth_common_read_file(dev, bflow, fname, fdt_addr, &size);
• if (!ret) {

• bflow->fdt_size = size;
  

• bflow->fdt_addr = fdt_addr;
  

• /*
  

•  * TODO: Apply extension overlay
  

•  *
  

•  * Here we need to load and apply the extension overlay. This is
  

•  * not implemented. See do_extension_apply(). The extension
  

•  * stuff needs an implementation in boot/extension.c so it is
  

•  * separate from the command code. Really the extension stuff
  

•  * should use the device tree and a uclass / driver interface
  

•  * rather than implementing its own list
  

•  */
  

• } else {

• log_debug("No device tree available\n");
  

• }
• return 0;

}

static int distro_efi_read_bootflow_net(struct bootflow *bflow) {

• const char *addr_str;

• char file_addr[17], fname[256];
• char *tftp_argv[] = {"tftp", file_addr, fname, NULL};
• struct cmd_tbl cmdtp = {}; /* dummy */
• const char *addr_str, *fdt_addr_str; int ret, arch, size;
• ulong addr, fdt_addr; char str[36];

• ulong addr;

  ret = get_efi_pxe_vci(str, sizeof(str)); if (ret)

@@ -216,6 +266,25 @@ static int distro_efi_read_bootflow_net(struct bootflow *bflow) efi_set_bootdev("Net", "", bflow->fname, map_sysmem(addr, 0), bflow->size);

• /* read the DT file also */

• fdt_addr_str = env_get("fdt_addr_r");

• if (!fdt_addr_str)

• return log_msg_ret("fdt", -EINVAL);
  

• fdt_addr = hextoul(fdt_addr_str, NULL);

• sprintf(file_addr, "%lx", fdt_addr);

• distro_efi_get_fdt_name(fname, sizeof(fname));

• bflow->fdt_fname = strdup(fname);

• if (!bflow->fdt_fname)

• return log_msg_ret("fil", -ENOMEM);
  

• if (!do_tftpb(&cmdtp, 0, 3, tftp_argv)) {

• bflow->fdt_size = env_get_hex("filesize", 0);
  

• bflow->fdt_addr = fdt_addr;
  

• } else {

• log_debug("No device tree available\n");
  

• }

• bflow->state = BOOTFLOWST_READY;

  return 0;

@@ -243,15 +312,39 @@ static int distro_efi_read_bootflow(struct udevice *dev, struct bootflow *bflow)

int distro_efi_boot(struct udevice *dev, struct bootflow *bflow) {

• ulong kernel, fdt; char cmd[50];

• /* A non-zero buffer indicates the kernel is there */

• if (bflow->buf) {

• kernel = (ulong)map_to_sysmem(bflow->buf);
  

• /*
  

•  * use the provided device tree if available, else fall back to
  

•  * the control FDT
  

•  */
  

• if (bflow->fdt_fname)
  

• 	fdt = bflow->fdt_addr;
  

• else
  

• 	fdt = (ulong)map_to_sysmem(gd->fdt_blob);
  

• } else {

• /*
  

•  * This doesn't actually work for network devices:
  

•  *
  

•  * do_bootefi_image() No UEFI binary known at 0x02080000
  

•  *
  

•  * But this is the same behaviour for distro boot, so it can be
  

•  * fixed here.
  

•  */
  

• kernel = env_get_hex("kernel_addr_r", 0);
  

• fdt = env_get_hex("fdt_addr_r", 0);
  

• }

• /*

  • At some point we can add a real interface to bootefi so we can call

• * this directly. For now, go through the CLI like distro boot.
  

• * this directly. For now, go through the CLI, like distro boot.
  

  */

• snprintf(cmd, sizeof(cmd), "bootefi %lx %lx",

•  (ulong)map_to_sysmem(bflow->buf),
  

•  (ulong)map_to_sysmem(gd->fdt_blob));
  

• snprintf(cmd, sizeof(cmd), "bootefi %lx %lx", kernel, fdt); if (run_command(cmd, 0)) return log_msg_ret("run", -EINVAL);

-- 2.39.0.314.g84b9a713c41-goog