[PATCH 27/28] ethernet: Add a bootmethod

[Simon Glass <sjg@chromium.org>]

Add a bootmethod for Ethernet. It uses the distro boot mechanism to
locate a file.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

 MAINTAINERS               |  1 +
 configs/sandbox_defconfig |  1 +
 net/Kconfig               |  9 +++++
 net/Makefile              |  1 +
 net/eth-uclass.c          |  8 +++++
 net/eth_bootmethod.c      | 76 +++++++++++++++++++++++++++++++++++++++
 6 files changed, 96 insertions(+)
 create mode 100644 net/eth_bootmethod.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 246c5e60270..74e8eaafb10 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -643,6 +643,7 @@ F:	doc/usage/bootmethod.rst
 F:	drivers/mmc/mmc_bootmethod.c
 F:	include/bootmethod.h
 F:	include/distro.h
+F:	net/eth_bootmethod.c
 F:	test/boot/bootmethod.c
 
 BTRFS
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index 31a8d6a1d90..321d32be73e 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -116,6 +116,7 @@ CONFIG_ENV_IS_IN_EXT4=y
 CONFIG_ENV_EXT4_INTERFACE="host"
 CONFIG_ENV_EXT4_DEVICE_AND_PART="0:0"
 CONFIG_ENV_IMPORT_FDT=y
+# CONFIG_BOOTMETHOD_ETH is not set
 CONFIG_BOOTP_SEND_HOSTNAME=y
 CONFIG_NETCONSOLE=y
 CONFIG_IP_DEFRAG=y
diff --git a/net/Kconfig b/net/Kconfig
index ba0ca813ce5..6f92fe44a8c 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -14,6 +14,15 @@ config PROT_UDP
 	  Enable a generic udp framework that allows defining a custom
 	  handler for udp protocol.
 
+config BOOTMETHOD_ETH
+	bool "Enable bootmethod for ethernet"
+	depends on BOOTMETHOD
+	default y
+	help
+	  Provide a bootmethod for ethernet so that is it possible to boot
+	  an operationg system over the network, using the PXE (Preboot
+	  Execution Environment) protocol.
+
 config BOOTP_SEND_HOSTNAME
 	bool "Send hostname to DNS server"
 	help
diff --git a/net/Makefile b/net/Makefile
index fb3eba840ff..c86bbd90349 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_CMD_DNS)  += dns.o
 obj-$(CONFIG_DM_DSA)   += dsa-uclass.o
 ifdef CONFIG_DM_ETH
 obj-$(CONFIG_NET)      += eth-uclass.o
+obj-$(CONFIG_$(SPL_TPL_)BOOTMETHOD_ETH) += eth_bootmethod.o
 else
 obj-$(CONFIG_NET)      += eth_legacy.o
 endif
diff --git a/net/eth-uclass.c b/net/eth-uclass.c
index 0da0e85be03..0284215b113 100644
--- a/net/eth-uclass.c
+++ b/net/eth-uclass.c
@@ -8,6 +8,7 @@
 #define LOG_CATEGORY UCLASS_ETH
 
 #include <common.h>
+#include <bootmethod.h>
 #include <bootstage.h>
 #include <dm.h>
 #include <env.h>
@@ -473,6 +474,8 @@ int eth_initialize(void)
 
 static int eth_post_bind(struct udevice *dev)
 {
+	int ret;
+
 	if (strchr(dev->name, ' ')) {
 		printf("\nError: eth device name \"%s\" has a space!\n",
 		       dev->name);
@@ -482,6 +485,11 @@ static int eth_post_bind(struct udevice *dev)
 #ifdef CONFIG_DM_ETH_PHY
 	eth_phy_binds_nodes(dev);
 #endif
+	if (CONFIG_IS_ENABLED(BOOTMETHOD_ETH)) {
+		ret = bootmethod_setup_for_dev(dev, "eth_bootmethod");
+		if (ret)
+			return log_msg_ret("bootmethod", ret);
+	}
 
 	return 0;
 }
diff --git a/net/eth_bootmethod.c b/net/eth_bootmethod.c
new file mode 100644
index 00000000000..bc8843add80
--- /dev/null
+++ b/net/eth_bootmethod.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootmethod for ethernet
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <bootmethod.h>
+#include <command.h>
+#include <distro.h>
+#include <dm.h>
+#include <net.h>
+
+static int eth_get_bootflow(struct udevice *dev, int seq,
+			    struct bootflow *bflow)
+{
+	char name[60];
+	int ret;
+
+	/*
+	 * Like distro boot, this assumes there is only one Ethernet device.
+	 * In this case, that means that @eth is ignored
+	 */
+	if (seq)
+		return log_msg_ret("dhcp", -ESHUTDOWN);
+
+	bflow->seq = seq;
+	snprintf(name, sizeof(name), "%s.%d", dev->name, seq);
+	bflow->name = strdup(name);
+	if (!bflow->name)
+		return log_msg_ret("name", -ENOMEM);
+	if (!bflow->name)
+		return log_msg_ret("name", -ENOMEM);
+	bflow->state = BOOTFLOWST_BASE;
+
+	/*
+	 * There is not a direct interface to the network stack so run
+	 * everything through the command-line interpreter for now.
+	 *
+	 * Don't bother checking the result of dhcp. It can fail with:
+	 *
+	 * DHCP client bound to address 192.168.4.50 (4 ms)
+	 * *** Warning: no boot file name; using 'C0A80432.img'
+	 * Using smsc95xx_eth device
+	 * TFTP from server 192.168.4.1; our IP address is 192.168.4.50
+	 * Filename 'C0A80432.img'.
+	 * Load address: 0x200000
+	 * Loading: *
+	 * TFTP error: 'File not found' (1)
+	 *
+	 * This is not a real failure, since we don't actually care if the
+	 * boot file exists.
+	 */
+	run_command("dhcp", 0);
+	bflow->state = BOOTFLOWST_MEDIA;
+
+	if (CONFIG_IS_ENABLED(BOOTMETHOD_DISTRO)) {
+		ret = distro_net_setup(bflow);
+		if (ret)
+			return log_msg_ret("distro", ret);
+	}
+
+	return 0;
+}
+
+struct bootmethod_ops eth_bootmethod_ops = {
+	.get_bootflow	= eth_get_bootflow,
+};
+
+U_BOOT_DRIVER(eth_bootmethod) = {
+	.name		= "eth_bootmethod",
+	.id		= UCLASS_BOOTMETHOD,
+	.ops		= &eth_bootmethod_ops,
+};
-- 
2.33.0.rc1.237.g0d66db33f3-goog