efi: Add start-up library code

When running as an EFI application, U-Boot must request memory from EFI,
and provide access to the boot services U-Boot needs.

Add library code to perform these tasks. This includes efi_main() which is
the entry point from EFI. U-Boot is built as a shared library.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

lib/efi/efi.c

@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ * EFI information obtained here:
+ * http://wiki.phoenix.com/wiki/index.php/EFI_BOOT_SERVICES
+ *
+ * Common EFI functions
+ */
+
+#include <common.h>
+#include <debug_uart.h>
+#include <errno.h>
+#include <linux/err.h>
+#include <linux/types.h>
+#include <efi.h>
+#include <efi_api.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * Unfortunately we cannot access any code outside what is built especially
+ * for the stub. lib/string.c is already being built for the U-Boot payload
+ * so it uses the wrong compiler flags. Add our own memset() here.
+ */
+static void efi_memset(void *ptr, int ch, int size)
+{
+	char *dest = ptr;
+
+	while (size-- > 0)
+		*dest++ = ch;
+}
+
+/*
+ * Since the EFI stub cannot access most of the U-Boot code, add our own
+ * simple console output functions here. The EFI app will not use these since
+ * it can use the normal console.
+ */
+void efi_putc(struct efi_priv *priv, const char ch)
+{
+	struct efi_simple_text_output_protocol *con = priv->sys_table->con_out;
+	uint16_t ucode[2];
+
+	ucode[0] = ch;
+	ucode[1] = '\0';
+	con->output_string(con, ucode);
+}
+
+void efi_puts(struct efi_priv *priv, const char *str)
+{
+	while (*str)
+		efi_putc(priv, *str++);
+}
+
+int efi_init(struct efi_priv *priv, const char *banner, efi_handle_t image,
+	     struct efi_system_table *sys_table)
+{
+	efi_guid_t loaded_image_guid = LOADED_IMAGE_PROTOCOL_GUID;
+	struct efi_boot_services *boot = sys_table->boottime;
+	struct efi_loaded_image *loaded_image;
+	int ret;
+
+	efi_memset(priv, '\0', sizeof(*priv));
+	priv->sys_table = sys_table;
+	priv->boot = sys_table->boottime;
+	priv->parent_image = image;
+	priv->run = sys_table->runtime;
+
+	efi_puts(priv, "U-Boot EFI ");
+	efi_puts(priv, banner);
+	efi_putc(priv, ' ');
+
+	ret = boot->open_protocol(priv->parent_image, &loaded_image_guid,
+				  (void **)&loaded_image, &priv->parent_image,
+				  NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+	if (ret) {
+		efi_puts(priv, "Failed to get loaded image protocol\n");
+		return ret;
+	}
+	priv->image_data_type = loaded_image->image_data_type;
+
+	return 0;
+}
+
+void *efi_malloc(struct efi_priv *priv, int size, efi_status_t *retp)
+{
+	struct efi_boot_services *boot = priv->boot;
+	void *buf = NULL;
+
+	*retp = boot->allocate_pool(priv->image_data_type, size, &buf);
+
+	return buf;
+}
+
+void efi_free(struct efi_priv *priv, void *ptr)
+{
+	struct efi_boot_services *boot = priv->boot;
+
+	boot->free_pool(ptr);
+}