[silicon_creator,pwrmgr] Create method to enable watchdog reset

Currently the library exports a very generic method to search
for a bitmask in the DT and it requires users to manually poke at
the pwrmgr registers. This is not really in the spirit of the
silicon_creator libraries and it can be misused.

This commit makes the search function internal and create a specific
method to enable the watch reset request, which is the only user
currently.

Signed-off-by: Amaury Pouly <[email protected]>

Author: pamaury

sw/device/silicon_creator/lib/drivers/pwrmgr.c

@@ -4,6 +4,7 @@
 
 #include "sw/device/silicon_creator/lib/drivers/pwrmgr.h"
 
+#include "hw/top/dt/dt_aon_timer.h"
 #include "hw/top/dt/dt_api.h"
 #include "hw/top/dt/dt_pwrmgr.h"
 #include "sw/device/lib/base/abs_mmio.h"
@@ -21,6 +22,29 @@ enum {
   kSyncConfig = (1 << PWRMGR_CFG_CDC_SYNC_SYNC_BIT),
 };
 
+/**
+ * A power manager request type.
+ */
+typedef enum pwrmgr_req_type {
+  kPwrmgrReqTypeWakeup,
+  kPwrmgrReqTypeReset,
+} pwr_mgr_req_type_t;
+
+/**
+ * Obtain a bit index of wakeup/reset request for a device and a signal.
+ *
+ * Given a module instance (identified by its instance ID) and a wakeup
+ * or reset request index from this module, return the source bit index
+ * that, once shifted into a bitmask, can be programmed into the pwrmgr
+ * `RESET_EN` register.
+ *
+ * @param req_type Request type (wake up or reset request).
+ * @param inst_id A DT instance ID.
+ * @param signal_idx Signal index.
+ * @param[out] source_idx The source index corresponding to the wakeup or reset
+ * requested.
+ * @return `kErrorOk` if a signal matches, or a `kErrorPwrmgr` error otherwise.
+ */
 OT_WARN_UNUSED_RESULT
 rom_error_t pwrmgr_find_request_source(pwr_mgr_req_type_t req_type,
                                        dt_instance_id_t inst_id,
@@ -50,6 +74,22 @@ rom_error_t pwrmgr_find_request_source(pwr_mgr_req_type_t req_type,
   }
 }
 
+void pwrmgr_enable_watchdog_reset_request(void) {
+  uint32_t pwrmgr_base = dt_pwrmgr_primary_reg_block(kDtPwrmgrAon);
+  uint32_t enabled_resets = 0;
+  size_t reset_source = 0;
+
+  // Tell pwrmgr we want watchdog reset events to reset the chip.
+  HARDENED_CHECK_EQ(
+      pwrmgr_find_request_source(kPwrmgrReqTypeReset,
+                                 dt_aon_timer_instance_id(kDtAonTimerAon),
+                                 kDtAonTimerResetReqAonTimer, &reset_source),
+      kErrorOk);
+  enabled_resets = bitfield_bit32_write(0, reset_source, true);
+  sec_mmio_write32(pwrmgr_base + PWRMGR_RESET_EN_REG_OFFSET, enabled_resets);
+  pwrmgr_cdc_sync(1);
+}
+
 void pwrmgr_cdc_sync(uint32_t n) {
   // We want to timeout if the CDC bit doesn't self clear.  It should take
   // approximately 4 AON ticks to complete.  We wait 25% longer (5 ticks).

sw/device/silicon_creator/lib/drivers/pwrmgr.h

@@ -31,32 +31,9 @@ enum {
 };
 
 /**
- * A power manager request type.
+ * Enable the watchdog reset request so that the watchdog can reset the chip.
  */
-typedef enum pwrmgr_req_type {
-  kPwrmgrReqTypeWakeup,
-  kPwrmgrReqTypeReset,
-} pwr_mgr_req_type_t;
-
-/**
- * Obtain a bit index of wakeup/reset request for a device and a signal.
- *
- * Given a module instance (identified by its instance ID) and a wakeup
- * or reset request index from this module, return the source bit index
- * that, once shifted into a bitmask, can be programmed into the pwrmgr
- * `RESET_EN` register.
- *
- * @param req_type Request type (wake up or reset request).
- * @param inst_id A DT instance ID.
- * @param signal_idx Signal index.
- * @param[out] source_idx The source index corresponding to the wakeup or reset
- * requested.
- * @return `kErrorOk` if a signal matches, or a `kErrorPwrmgr` error otherwise.
- */
-OT_WARN_UNUSED_RESULT
-rom_error_t pwrmgr_find_request_source(pwr_mgr_req_type_t req_type,
-                                       dt_instance_id_t inst_id,
-                                       size_t signal_idx, size_t *source_idx);
+void pwrmgr_enable_watchdog_reset_request(void);
 
 /**
  * Synchronize across clock domain.

sw/device/silicon_creator/lib/drivers/watchdog.c

@@ -6,7 +6,6 @@
 
 #include "hw/top/dt/dt_aon_timer.h"
 #include "hw/top/dt/dt_api.h"
-#include "hw/top/dt/dt_pwrmgr.h"
 #include "sw/device/lib/base/abs_mmio.h"
 #include "sw/device/silicon_creator/lib/base/sec_mmio.h"
 #include "sw/device/silicon_creator/lib/drivers/lifecycle.h"
@@ -75,19 +74,7 @@ void watchdog_init(lifecycle_state_t lc_state) {
 
 void watchdog_configure(watchdog_config_t config) {
   SEC_MMIO_ASSERT_WRITE_INCREMENT(kWatchdogSecMmioConfigure, 4);
-  uint32_t pwrmgr_base = dt_pwrmgr_primary_reg_block(kDtPwrmgrAon);
-  uint32_t enabled_resets = 0;
-  size_t reset_source = 0;
-
-  // Tell pwrmgr we want watchdog reset events to reset the chip.
-  HARDENED_CHECK_EQ(
-      pwrmgr_find_request_source(kPwrmgrReqTypeReset,
-                                 dt_aon_timer_instance_id(kDtAonTimerAon),
-                                 kDtAonTimerResetReqAonTimer, &reset_source),
-      kErrorOk);
-  enabled_resets = bitfield_bit32_write(0, reset_source, true);
-  sec_mmio_write32(pwrmgr_base + PWRMGR_RESET_EN_REG_OFFSET, enabled_resets);
-  pwrmgr_cdc_sync(1);
+  pwrmgr_enable_watchdog_reset_request();
 
   // Set the watchdog bite and bark thresholds.
   sec_mmio_write32(aon_timer_base() + AON_TIMER_WDOG_CTRL_REG_OFFSET,