board: intel: Add new slimbootloader board

Add slimbootloader board to run U-boot as a Slim Bootloader payload
- Add new board/intel/slimbootloader directory with minimum codes
- Add slimbootloader configuration files
- Add doc/board/intel/slimbootloader.rst

Signed-off-by: Aiden Park <aiden.park@intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: add slimbootloader board MAINTAINERS file]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/board/intel/slimbootloader/slimbootloader.c b/board/intel/slimbootloader/slimbootloader.c
new file mode 100644
index 0000000000..f50eeb823f
--- /dev/null
+++ b/board/intel/slimbootloader/slimbootloader.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Intel Corporation <www.intel.com>
+ */
+
+#include <common.h>
+
+int board_early_init_r(void)
+{
+	/*
+	 * Make sure PCI bus is enumerated so that peripherals on the PCI bus
+	 * can be discovered by their drivers.
+	 *
+	 * Slim Bootloader has already done PCI bus enumeration before loading
+	 * U-Boot, so U-Boot needs to preserve PCI configuration.
+	 * Therefore, '# CONFIG_PCI_PNP is not set' is included in defconfig.
+	 */
+	pci_init();
+
+	return 0;
+}