Use a long pulse of INT_AP_L for SPS

This patch adds a feature to extend each level of GPIO_INT_AP_L at
least for 100 microseconds. The assertion (low GPIO_INT_AP_L)
duration might be shorter only if AP asserts a SPS CS before
INT_AP_L deassertion, because it means means AP recognized
GPIO_INT_AP_L assertion already.

This patch increases the flash usage by 280 bytes.

BUG=b:148691139
TEST=None

Signed-off-by: Namyoon Woo <namyoon@google.com>
Change-Id: Ie74b236bc5352e9fc21fe600c12946e50955160a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2114430
Tested-by: Namyoon Woo <namyoon@chromium.org>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Commit-Queue: Namyoon Woo <namyoon@chromium.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/board/cr50/board.h b/board/cr50/board.h
index 540f4c622d..ea0ac15dae 100644
--- a/board/cr50/board.h
+++ b/board/cr50/board.h
@@ -366,6 +366,27 @@ int ec_is_on(void);
 int ec_is_rx_allowed(void);
 int servo_is_connected(void);
 
+/*
+ * Assert INT_AP_L to acknowledge AP that cr50 is ready for next TPM command.
+ * NOTE: must be called by ISR only.
+ *
+ * Returns 1 if it successfully asserted (or scheduled to assert), or
+ *         0 if the extended long pulse was disabled.
+ */
+int assert_int_ap(void);
+
+/*
+ * Deassert INT_AP_L immediately.
+ * NOTE: must be called by ISR only.
+ */
+void deassert_int_ap(void);
+
+/* Register a function that should be called when INT_AP_L extension starts. */
+void int_ap_register(void (*func_enable)(void));
+
+void int_ap_extension_enable(void);
+void int_ap_extension_stop_pulse(void);
+
 /* Moving from legacy versions might require NVMEM transition. */
 int board_nvmem_legacy_check_needed(void);