sim: Test DIRECT_XIP configuration

Perform simplistic test of the DIRECT_XIP configuration (both with
single and multi-images).  This verifies that the bootloader indicates
the upgrade image should be booted.

Signed-off-by: David Brown <david.brown@linaro.org>

sim/src/image.rs

@@ -969,6 +969,35 @@ impl Images {
         }
     }
 
+    /// Test the direct XIP configuration.  With this mode, flash images are never moved, and the
+    /// bootloader merely selects which partition is the proper one to boot.
+    pub fn run_direct_xip(&self) -> bool {
+        if !Caps::DirectXip.present() {
+            return false;
+        }
+
+        // Clone the flash so we can tell if unchanged.
+        let mut flash = self.flash.clone();
+
+        let result = c::boot_go(&mut flash, &self.areadesc, None, true);
+
+        // Ensure the boot was successful.
+        let resp = if let Some(resp) = result.resp() {
+            resp
+        } else {
+            panic!("Boot didn't return a valid result");
+        };
+
+        // This configuration should always try booting from the first upgrade slot.
+        if let Some((offset, _, dev_id)) = self.areadesc.find(FlashId::Image1) {
+            assert_eq!(offset, resp.image_off as usize);
+            assert_eq!(dev_id, resp.flash_dev_id);
+        } else {
+            panic!("Unable to find upgrade image");
+        }
+        false
+    }
+
     /// Adds a new flash area that fails statistically
     fn mark_bad_status_with_rate(&self, flash: &mut SimMultiFlash, slot: usize,
                                  rate: f32) {

sim/tests/core.rs

@@ -59,6 +59,8 @@ sim_test!(status_write_fails_complete, make_image(&NO_DEPS, true), run_with_stat
 sim_test!(status_write_fails_with_reset, make_image(&NO_DEPS, true), run_with_status_fails_with_reset());
 sim_test!(downgrade_prevention, make_image(&REV_DEPS, true), run_nodowngrade());
 
+sim_test!(direct_xip_first, make_no_upgrade_image(&NO_DEPS), run_direct_xip());
+
 // Test various combinations of incorrect dependencies.
 test_shell!(dependency_combos, r, {
     // Only test setups with two images.