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>
diff --git a/lib/efi/efi_app.c b/lib/efi/efi_app.c
new file mode 100644
index 0000000..452ab5d
--- /dev/null
+++ b/lib/efi/efi_app.c
@@ -0,0 +1,139 @@
+/*
+ * 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
+ *
+ * This file implements U-Boot running as an EFI application.
+ */
+
+#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;
+
+static struct efi_priv *global_priv;
+
+struct efi_system_table *efi_get_sys_table(void)
+{
+	return global_priv->sys_table;
+}
+
+unsigned long efi_get_ram_base(void)
+{
+	return global_priv->ram_base;
+}
+
+static efi_status_t setup_memory(struct efi_priv *priv)
+{
+	struct efi_boot_services *boot = priv->boot;
+	efi_physical_addr_t addr;
+	efi_status_t ret;
+	int pages;
+
+	/*
+	 * Use global_data_ptr instead of gd since it is an assignment. There
+	 * are very few assignments to global_data in U-Boot and this makes
+	 * it easier to find them.
+	 */
+	global_data_ptr = efi_malloc(priv, sizeof(struct global_data), &ret);
+	if (!global_data_ptr)
+		return ret;
+	memset(gd, '\0', sizeof(*gd));
+
+	gd->malloc_base = (ulong)efi_malloc(priv, CONFIG_SYS_MALLOC_F_LEN,
+					    &ret);
+	if (!gd->malloc_base)
+		return ret;
+	pages = CONFIG_EFI_RAM_SIZE >> 12;
+
+	/*
+	 * Don't allocate any memory above 4GB. U-Boot is a 32-bit application
+	 * so we want it to load below 4GB.
+	 */
+	addr = 1ULL << 32;
+	ret = boot->allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
+				   priv->image_data_type, pages, &addr);
+	if (ret) {
+		printf("(using pool %lx) ", ret);
+		priv->ram_base = (ulong)efi_malloc(priv, CONFIG_EFI_RAM_SIZE,
+						   &ret);
+		if (!priv->ram_base)
+			return ret;
+		priv->use_pool_for_malloc = true;
+	} else {
+		priv->ram_base = addr;
+	}
+	gd->ram_size = pages << 12;
+
+	return 0;
+}
+
+static void free_memory(struct efi_priv *priv)
+{
+	struct efi_boot_services *boot = priv->boot;
+
+	if (priv->use_pool_for_malloc)
+		efi_free(priv, (void *)priv->ram_base);
+	else
+		boot->free_pages(priv->ram_base, gd->ram_size >> 12);
+
+	efi_free(priv, (void *)gd->malloc_base);
+	efi_free(priv, gd);
+	global_data_ptr = NULL;
+}
+
+/**
+ * efi_main() - Start an EFI image
+ *
+ * This function is called by our EFI start-up code. It handles running
+ * U-Boot. If it returns, EFI will continue. Another way to get back to EFI
+ * is via reset_cpu().
+ */
+efi_status_t efi_main(efi_handle_t image, struct efi_system_table *sys_table)
+{
+	struct efi_priv local_priv, *priv = &local_priv;
+	efi_status_t ret;
+
+	/* Set up access to EFI data structures */
+	efi_init(priv, "App", image, sys_table);
+
+	global_priv = priv;
+
+	/*
+	 * Set up the EFI debug UART so that printf() works. This is
+	 * implemented in the EFI serial driver, serial_efi.c. The application
+	 * can use printf() freely.
+	 */
+	debug_uart_init();
+
+	ret = setup_memory(priv);
+	if (ret) {
+		printf("Failed to set up memory: ret=%lx\n", ret);
+		return ret;
+	}
+
+	printf("starting\n");
+
+	board_init_f(GD_FLG_SKIP_RELOC);
+	board_init_r(NULL, 0);
+	free_memory(priv);
+
+	return EFI_SUCCESS;
+}
+
+void reset_cpu(ulong addr)
+{
+	struct efi_priv *priv = global_priv;
+
+	free_memory(priv);
+	printf("U-Boot EFI exiting\n");
+	priv->boot->exit(priv->parent_image, EFI_SUCCESS, 0, NULL);
+}