sandbox: Allow ethernet to be disabled at runtime

For bootstd tests it is seldom useful to have ethernet enabled. Add a way
to disable it, so that ethernet operations like tftpboot do nothing.

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

arch/sandbox/cpu/state.c

@@ -12,6 +12,7 @@
 #include <os.h>
 #include <asm/malloc.h>
 #include <asm/state.h>
+#include <asm/test.h>
 
 /* Main state record for the sandbox */
 static struct sandbox_state main_state;
@@ -366,6 +367,7 @@ void state_reset_for_test(struct sandbox_state *state)
 	state->sysreset_allowed[SYSRESET_POWER_OFF] = true;
 	state->sysreset_allowed[SYSRESET_COLD] = true;
 	state->allow_memio = false;
+	sandbox_set_eth_enable(true);
 
 	memset(&state->wdt, '\0', sizeof(state->wdt));
 	memset(state->spi, '\0', sizeof(state->spi));
@@ -444,6 +446,20 @@ int state_load_other_fdt(const char **bufp, int *sizep)
 	return 0;
 }
 
+void sandbox_set_eth_enable(bool enable)
+{
+	struct sandbox_state *state = state_get_current();
+
+	state->disable_eth = !enable;
+}
+
+bool sandbox_eth_enabled(void)
+{
+	struct sandbox_state *state = state_get_current();
+
+	return !state->disable_eth;
+}
+
 int state_init(void)
 {
 	state = &main_state;

arch/sandbox/include/asm/state.h

@@ -96,6 +96,7 @@ struct sandbox_state {
 	const char *select_unittests;	/* Unit test to run */
 	bool handle_signals;		/* Handle signals within sandbox */
 	bool autoboot_keyed;		/* Use keyed-autoboot feature */
+	bool disable_eth;		/* Disable Ethernet devices */
 
 	/* Pointer to information for each SPI bus/cs */
 	struct sandbox_spi_info spi[CONFIG_SANDBOX_SPI_MAX_BUS]

arch/sandbox/include/asm/test.h

@@ -344,4 +344,20 @@ void sandbox_set_fake_efi_mgr_dev(struct udevice *dev, bool fake_dev);
  */
 int sandbox_load_other_fdt(void **fdtp, int *sizep);
 
+/**
+ * sandbox_set_eth_enable() - Enable / disable Ethernet
+ *
+ * Allows control of whether Ethernet packets are actually send/received
+ *
+ * @enable: true to enable Ethernet, false to disable
+ */
+void sandbox_set_eth_enable(bool enable);
+
+/**
+ * sandbox_eth_enabled() - Check if Ethernet is enabled
+ *
+ * Returns: true if Ethernet is enabled on sandbox, False if not
+ */
+bool sandbox_eth_enabled(void);
+
 #endif

include/test/test.h

@@ -169,4 +169,29 @@ static inline int test_load_other_fdt(struct unit_test_state *uts)
 	return ret;
 }
 
+/**
+ * test_set_eth_enable() - Enable / disable Ethernet
+ *
+ * Allows control of whether Ethernet packets are actually send/received
+ *
+ * @enable: true to enable Ethernet, false to disable
+ */
+static inline void test_set_eth_enable(bool enable)
+{
+#ifdef CONFIG_SANDBOX
+	sandbox_set_eth_enable(enable);
+#endif
+}
+
+/* Allow ethernet to be disabled for testing purposes */
+static inline bool test_eth_enabled(void)
+{
+	bool enabled = true;
+
+#ifdef CONFIG_SANDBOX
+	enabled = sandbox_eth_enabled();
+#endif
+	return enabled;
+}
+
 #endif /* __TEST_TEST_H */

net/net.c

@@ -106,6 +106,7 @@
 #endif
 #include <watchdog.h>
 #include <linux/compiler.h>
+#include <test/test.h>
 #include "arp.h"
 #include "bootp.h"
 #include "cdp.h"
@@ -465,6 +466,9 @@ restart:
 	debug_cond(DEBUG_INT_STATE, "--- net_loop Init\n");
 	net_init_loop();
 
+	if (!test_eth_enabled())
+		return 0;
+
 	switch (net_check_prereq(protocol)) {
 	case 1:
 		/* network not configured */