efi_selftest: add tool to download dtb

For validating the fixed up device tree we need a tool to need to save it
to a file.

dtbdump.efi copies the configuration table with the device tree to a file
on the same partition from which dtbdump.efi was invoked. The file name can
be entered on the console.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

lib/efi_selftest/Makefile

@@ -8,6 +8,8 @@
 asflags-y += -DHOST_ARCH="$(HOST_ARCH)"
 ccflags-y += -DHOST_ARCH="$(HOST_ARCH)"
 
+CFLAGS_dtbdump_exit.o := $(CFLAGS_EFI) -Os -ffreestanding
+CFLAGS_REMOVE_dtbdump.o := $(CFLAGS_NON_EFI)
 CFLAGS_efi_selftest_miniapp_exit.o := $(CFLAGS_EFI) -Os -ffreestanding
 CFLAGS_REMOVE_efi_selftest_miniapp_exit.o := $(CFLAGS_NON_EFI)
 CFLAGS_efi_selftest_miniapp_return.o := $(CFLAGS_EFI) -Os -ffreestanding
@@ -76,6 +78,9 @@ efi_selftest_miniapp_exception.efi \
 efi_selftest_miniapp_exit.efi \
 efi_selftest_miniapp_return.efi
 
+always += \
+dtbdump.efi
+
 $(obj)/efi_miniapp_file_image_exception.h: $(obj)/efi_selftest_miniapp_exception.efi
 	$(obj)/../../tools/file2include $(obj)/efi_selftest_miniapp_exception.efi > \
 	$(obj)/efi_miniapp_file_image_exception.h

lib/efi_selftest/dtbdump.c

@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
+ *
+ * dtbdump.efi saves the device tree provided as a configuration table
+ * to a file.
+ */
+
+#include <common.h>
+#include <efi_api.h>
+
+#define BUFFER_SIZE 64
+#define ESC 0x17
+#define DEFAULT_FILENAME L"dtb.dtb"
+
+static struct efi_simple_text_output_protocol *cerr;
+static struct efi_simple_text_output_protocol *cout;
+static struct efi_simple_text_input_protocol *cin;
+static struct efi_boot_services *bs;
+static const efi_guid_t fdt_guid = EFI_FDT_GUID;
+static const efi_guid_t loaded_image_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
+static const efi_guid_t guid_simple_file_system_protocol =
+					EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
+
+/**
+ * input() - read string from console
+ *
+ * @buffer:		input buffer
+ * @buffer_size:	buffer size
+ * Return:		status code
+ */
+static efi_status_t efi_input(u16 *buffer, efi_uintn_t buffer_size)
+{
+	struct efi_input_key key = {0};
+	efi_uintn_t index;
+	efi_uintn_t pos = 0;
+	u16 outbuf[2] = L" ";
+	efi_status_t ret;
+
+	/* Drain the console input */
+	ret = cin->reset(cin, true);
+	for (;;) {
+		ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
+		if (ret != EFI_SUCCESS)
+			continue;
+		ret = cin->read_key_stroke(cin, &key);
+		if (ret != EFI_SUCCESS)
+			continue;
+		switch (key.scan_code) {
+		case 0x17: /* Escape */
+			cout->output_string(cout, L"\nAborted\n");
+			return EFI_ABORTED;
+		default:
+			break;
+		}
+		switch (key.unicode_char) {
+		case 0x08: /* Backspace */
+			if (pos) {
+				buffer[pos--] = 0;
+				cout->output_string(cout, L"\b \b");
+			}
+			break;
+		case 0x0a: /* Linefeed */
+		case 0x0d: /* Carriage return */
+			return EFI_SUCCESS;
+		default:
+			break;
+		}
+		/* Ignore surrogate codes */
+		if (key.unicode_char >= 0xD800 && key.unicode_char <= 0xDBFF)
+			continue;
+		if (key.unicode_char >= 0x20 &&
+		    pos < buffer_size - 1) {
+			*outbuf = key.unicode_char;
+			buffer[pos++] = key.unicode_char;
+			cout->output_string(cout, outbuf);
+		}
+	}
+}
+
+/*
+ * Convert FDT value to host endianness.
+ *
+ * @val		FDT value
+ * @return	converted value
+ */
+static u32 f2h(fdt32_t val)
+{
+	char *buf = (char *)&val;
+	char i;
+
+	/* Swap the bytes */
+	i = buf[0]; buf[0] = buf[3]; buf[3] = i;
+	i = buf[1]; buf[1] = buf[2]; buf[2] = i;
+	return *(u32 *)buf;
+}
+
+/**
+ * get_dtb() - get device tree
+ *
+ * @systable:	system table
+ * Return:	device tree or NULL
+ */
+void *get_dtb(struct efi_system_table *systable)
+{
+	void *dtb = NULL;
+	efi_uintn_t i;
+
+	for (i = 0; i < systable->nr_tables; ++i) {
+		if (!memcmp(&systable->tables[i].guid, &fdt_guid,
+			    sizeof(efi_guid_t))) {
+			dtb = systable->tables[i].table;
+			break;
+		}
+	}
+	return dtb;
+}
+
+/**
+ * efi_main() - entry point of the EFI application.
+ *
+ * @handle:	handle of the loaded image
+ * @systable:	system table
+ * @return:	status code
+ */
+efi_status_t EFIAPI efi_main(efi_handle_t handle,
+			     struct efi_system_table *systable)
+{
+	efi_uintn_t ret;
+	u16 filename[BUFFER_SIZE] = {0};
+	efi_uintn_t dtb_size;
+	struct efi_loaded_image *loaded_image;
+	struct efi_simple_file_system_protocol *file_system;
+	struct efi_file_handle *root, *file;
+	struct fdt_header *dtb;
+
+	cerr = systable->std_err;
+	cout = systable->con_out;
+	cin = systable->con_in;
+	bs = systable->boottime;
+
+	cout->set_attribute(cout, EFI_LIGHTGRAY | EFI_BACKGROUND_BLACK);
+	cout->clear_screen(cout);
+	cout->set_attribute(cout, EFI_YELLOW | EFI_BACKGROUND_BLACK);
+	cout->output_string(cout, L"DTB Dump\n\n");
+	cout->set_attribute(cout, EFI_LIGHTGRAY | EFI_BACKGROUND_BLACK);
+
+	dtb = get_dtb(systable);
+	if (!dtb) {
+		cerr->output_string(cout, L"DTB not found\n");
+		return EFI_NOT_FOUND;
+	}
+	if (f2h(dtb->magic) != FDT_MAGIC) {
+		cerr->output_string(cout, L"Wrong device tree magic\n");
+		return EFI_NOT_FOUND;
+	}
+	dtb_size = f2h(dtb->totalsize);
+
+	cout->output_string(cout, L"Filename (" DEFAULT_FILENAME ")?\n");
+	ret = efi_input(filename, sizeof(filename));
+	if (ret != EFI_SUCCESS)
+		return ret;
+	if (!*filename)
+		memcpy(filename, DEFAULT_FILENAME, sizeof(DEFAULT_FILENAME));
+
+	cout->output_string(cout, L"\n");
+
+	ret = bs->open_protocol(handle, &loaded_image_guid,
+				(void **)&loaded_image, NULL, NULL,
+				EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+	if (ret != EFI_SUCCESS) {
+		cerr->output_string(cout,
+				    L"Loaded image protocol not found\n");
+		return ret;
+	}
+
+	/* Open the simple file system protocol */
+	ret = bs->open_protocol(loaded_image->device_handle,
+				&guid_simple_file_system_protocol,
+				(void **)&file_system, NULL, NULL,
+				EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+	if (ret != EFI_SUCCESS) {
+		cerr->output_string(
+			cout, L"Failed to open simple file system protocol\n");
+		return ret;
+	}
+
+	/* Open volume */
+	ret = file_system->open_volume(file_system, &root);
+	if (ret != EFI_SUCCESS) {
+		cerr->output_string(cerr, L"Failed to open volume\n");
+		return ret;
+	}
+	/* Create file */
+	ret = root->open(root, &file, filename,
+			 EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE |
+			 EFI_FILE_MODE_CREATE, EFI_FILE_ARCHIVE);
+	if (ret == EFI_SUCCESS) {
+		/* Write file */
+		ret = file->write(file, &dtb_size, dtb);
+		if (ret != EFI_SUCCESS)
+			cerr->output_string(cerr, L"Failed to write file\n");
+		file->close(file);
+	} else {
+		cerr->output_string(cerr, L"Failed to open file\n");
+	}
+	root->close(root);
+
+	if (ret == EFI_SUCCESS) {
+		cout->output_string(cout, filename);
+		cout->output_string(cout, L" written\n");
+	}
+
+	return ret;
+}