[U-Boot] [PATCH 4/4] distro: Add efi pxe boot code

[Alexander Graf <agraf@suse.de>]

Now that we can expose network functionality to EFI applications,
the logical next step is to load them via pxe to execute them as
well.

This patch adds the necessary bits to the distro script to automatically
load and execute EFI payloads. It identifies the dhcp client as a uEFI
capable PXE client, hoping the server returns a tftp path to a workable
EFI binary that we can then execute.

To enable boards that don't come with a working device tree preloaded,
this patch also adds support to load a device tree from the /dtb directory
on the remote tftp server.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 include/config_distro_bootcmd.h | 37 ++++++++++++++++++++++++++++++++++++-
 net/bootp.c                     | 13 +++++++++++--
 2 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h
index 7f67344..c18731e 100644
--- a/include/config_distro_bootcmd.h
+++ b/include/config_distro_bootcmd.h
@@ -230,13 +230,48 @@
 #endif
 
 #if defined(CONFIG_CMD_DHCP)
+#if defined(CONFIG_EFI_LOADER)
+#if defined(CONFIG_ARM64)
+#define BOOTENV_EFI_PXE_VCI "PXEClient:Arch:00011:UNDI:003000"
+#elif defined(CONFIG_ARM)
+#define BOOTENV_EFI_PXE_VCI "PXEClient:Arch:00010:UNDI:003000"
+#else
+#define BOOTENV_EFI_PXE_VCI "PXEClient:Arch:00000:UNDI:003000"
+#endif
+
+/*
+ * Ask the dhcp server for an EFI binary. If we get one, check for a
+ * device tree in the same folder. Then boot everything. If the file was
+ * not an EFI binary, we just return from the bootefi command and continue.
+ */
+#define BOOTENV_EFI_RUN_DHCP \
+	"setenv efi_fdtfile ${fdtfile}; "                                 \
+	BOOTENV_EFI_SET_FDTFILE_FALLBACK                                  \
+	"setenv efi_old_vci ${bootp_vci};"                                \
+	"setenv bootp_vci " BOOTENV_EFI_PXE_VCI ";"                       \
+	"if dhcp ${kernel_addr_r}; then "                                 \
+		"tftpboot ${fdt_addr_r} dtb/${efi_fdtfile};"              \
+		"if fdt addr ${fdt_addr_r}; then "                        \
+			"bootefi ${kernel_addr_r} ${fdt_addr_r}; "        \
+		"else "                                                   \
+			"bootefi ${kernel_addr_r} ${fdtcontroladdr};"     \
+		"fi;"                                                     \
+	"fi;"                                                             \
+	"setenv bootp_vci ${efi_old_vci};"                                \
+	"setenv efi_fdtfile;"                                             \
+	"setenv efi_old_vci;"
+#else
+#define BOOTENV_EFI_RUN_DHCP
+#endif
 #define BOOTENV_DEV_DHCP(devtypeu, devtypel, instance) \
 	"bootcmd_dhcp=" \
 		BOOTENV_RUN_NET_USB_START \
 		BOOTENV_RUN_NET_PCI_ENUM \
 		"if dhcp ${scriptaddr} ${boot_script_dhcp}; then " \
 			"source ${scriptaddr}; " \
-		"fi\0"
+		"fi;" \
+		BOOTENV_EFI_RUN_DHCP \
+		"\0"
 #define BOOTENV_DEV_NAME_DHCP(devtypeu, devtypel, instance) \
 	"dhcp "
 #else
diff --git a/net/bootp.c b/net/bootp.c
index d718e35..85dc524 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -413,12 +413,21 @@ static void bootp_timeout_handler(void)
 
 static u8 *add_vci(u8 *e)
 {
+	char *vci = NULL;
+	char *env_vci = getenv("bootp_vci");
+
 #if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_NET_VCI_STRING)
-	put_vci(e, CONFIG_SPL_NET_VCI_STRING);
+	vci = CONFIG_SPL_NET_VCI_STRING;
 #elif defined(CONFIG_BOOTP_VCI_STRING)
-	put_vci(e, CONFIG_BOOTP_VCI_STRING);
+	vci = CONFIG_BOOTP_VCI_STRING;
 #endif
 
+	if (env_vci)
+		vci = env_vci;
+
+	if (vci)
+		put_vci(e, vci);
+
 	return e;
 }
 
-- 
1.8.5.6