flashrom_tester: partial_lock: Use WriteProtectState cache

partial_lock test was bypassing the WriteProtectState cache of the
software write protect by directly calling env.cmd.wp_range. It was also
unnesesarily disabling software WP. Fix those issues and more clearly
document what the test is doing and expecting.

BUG=b:244663741
BRANCH=None
TEST=flashrom_tester --libflashrom host

Change-Id: Ic3f89ff5d22e74e4e6c94e755b936e58cb27182d
Signed-off-by: Evan Benn <evanbenn@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/69418
Reviewed-by: Peter Marheine <pmarheine@chromium.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 24 insertions, 4 deletions

diff --git a/util/flashrom_tester/src/tester.rs b/util/flashrom_tester/src/tester.rs
index d19e45cf..1fa44a84 100644
--- a/util/flashrom_tester/src/tester.rs
+++ b/util/flashrom_tester/src/tester.rs
@@ -246,6 +246,24 @@ impl<'a> WriteProtectState<'a> {
         }
     }
 
+    // Set software write protect with a custom range
+    pub fn set_range(&mut self, range: (i64, i64), enable: bool) -> Result<&mut Self, String> {
+        info!("set_range request={}, current={}", enable, self.current.sw);
+        self.cmd
+            .wp_range(range, enable)
+            .map_err(|e| e.to_string())?;
+        let actual_state = Self::get_sw(self.cmd).map_err(|e| e.to_string())?;
+        if actual_state != enable {
+            Err(format!(
+                "set_range request={}, real={}",
+                enable, actual_state
+            ))
+        } else {
+            self.current.sw = enable;
+            Ok(self)
+        }
+    }
+
     /// Set the hardware write protect if supported and check that the state is as expected.
     pub fn set_hw(&mut self, enable: bool) -> Result<&mut Self, String> {
         info!("set_hw request={}, current={}", enable, self.current.hw);
diff --git a/util/flashrom_tester/src/tests.rs b/util/flashrom_tester/src/tests.rs
index e6968c81..3e39e4d5 100644
--- a/util/flashrom_tester/src/tests.rs
+++ b/util/flashrom_tester/src/tests.rs
@@ -272,10 +272,12 @@ fn partial_lock_test(section: LayoutNames) -> impl Fn(&mut TestEnv) -> TestResul
         env.ensure_golden()?;
 
         let (wp_section_name, start, len) = utils::layout_section(env.layout(), section);
-        // Disable software WP so we can do range protection, but hardware WP
-        // must remain enabled for (most) range protection to do anything.
-        env.wp.set_hw(false)?.set_sw(false)?;
-        env.cmd.wp_range((start, len), true)?;
+        // Disable hardware WP so we can modify the protected range.
+        env.wp.set_hw(false)?;
+        // Then enable software WP so the range is enforced and enable hardware
+        // WP so that flashrom does not disable software WP during the
+        // operation.
+        env.wp.set_range((start, len), true)?;
         env.wp.set_hw(true)?;
 
         // Check that we cannot write to the protected region.