From a3774c1c3c28e4ed89a36383ca73970b809bae94 Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan.agner@toradex.com>
Date: Wed, 16 Aug 2017 11:00:54 -0700
Subject: [PATCH] spl: add serial download protocol (SDP) support
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Add USB serial download protocol support to SPL. If the SoC started
in recovery mode the SPL will immediately switch to SDP and wait for
further downloads/commands from the host side.

Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>
Reviewed-by: Łukasz Majewski <lukma@denx.de>
---
 common/spl/Kconfig          |  6 ++++++
 common/spl/Makefile         |  1 +
 common/spl/spl_sdp.c        | 37 +++++++++++++++++++++++++++++++++++++
 drivers/usb/gadget/Makefile |  1 +
 4 files changed, 45 insertions(+)
 create mode 100644 common/spl/spl_sdp.c

diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 582b685dad..9446cd9b42 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -668,6 +668,12 @@ config SPL_DFU_RAM
 
 endchoice
 
+config SPL_USB_SDP_SUPPORT
+	bool "Support SDP (Serial Download Protocol)"
+	help
+	  Enable Serial Download Protocol (SDP) device support in SPL. This
+	  allows to download images into memory and execute (jump to) them
+	  using the same protocol as implemented by the i.MX family's boot ROM.
 endif
 
 config SPL_WATCHDOG_SUPPORT
diff --git a/common/spl/Makefile b/common/spl/Makefile
index fde0d09a5a..e229947b53 100644
--- a/common/spl/Makefile
+++ b/common/spl/Makefile
@@ -30,4 +30,5 @@ obj-$(CONFIG_$(SPL_TPL_)SATA_SUPPORT) += spl_sata.o
 obj-$(CONFIG_$(SPL_TPL_)DFU_SUPPORT) += spl_dfu.o
 obj-$(CONFIG_$(SPL_TPL_)SPI_LOAD) += spl_spi.o
 obj-$(CONFIG_$(SPL_TPL_)RAM_SUPPORT) += spl_ram.o
+obj-$(CONFIG_$(SPL_TPL_)USB_SDP_SUPPORT) += spl_sdp.o
 endif
diff --git a/common/spl/spl_sdp.c b/common/spl/spl_sdp.c
new file mode 100644
index 0000000000..350bcdb056
--- /dev/null
+++ b/common/spl/spl_sdp.c
@@ -0,0 +1,37 @@
+/*
+ * (C) Copyright 2016 Toradex
+ * Author: Stefan Agner <stefan.agner@toradex.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <spl.h>
+#include <usb.h>
+#include <g_dnl.h>
+#include <sdp.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int spl_sdp_load_image(struct spl_image_info *spl_image,
+			      struct spl_boot_device *bootdev)
+{
+	int ret;
+	const int controller_index = 0;
+
+	g_dnl_clear_detach();
+	g_dnl_register("usb_dnl_sdp");
+
+	ret = sdp_init(controller_index);
+	if (ret) {
+		error("SDP init failed: %d", ret);
+		return -ENODEV;
+	}
+
+	/* This command typically does not return but jumps to an image */
+	sdp_handle(controller_index);
+	error("SDP ended");
+
+	return -EINVAL;
+}
+SPL_LOAD_IMAGE_METHOD("USB SDP", 0, BOOT_DEVICE_BOARD, spl_sdp_load_image);
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 6a007d1bcb..7258099c1c 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_USB_ETHER) += epautoconf.o config.o usbstring.o
 ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_SPL_USB_GADGET_SUPPORT) += g_dnl.o
 obj-$(CONFIG_SPL_DFU_SUPPORT) += f_dfu.o
+obj-$(CONFIG_SPL_USB_SDP_SUPPORT) += f_sdp.o
 endif
 
 # new USB gadget layer dependencies
-- 
2.25.1