Add tick task

Adds a new HOOK_TICK event which is called every 250ms (LM4) or 500ms
(STM32).  This will be used to consolidate a number of tasks which do
small amounts of work infrequently, and previously needed their own
task functions.

This CL adds the tick task; subsequent CLs will consolidate watchdog
and other tasks into tick hooks.

BUG=chrome-os-partner:15714
BRANCH=none
TEST=taskinfo shows TICK task as lowest priority

Change-Id: I9068ee99d56a5bf5c12afd86ad51998c013f4954
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/36908
Reviewed-by: Simon Glass <sjg@chromium.org>

11 files changed, 34 insertions, 0 deletions

diff --git a/board/bds/ec.tasklist b/board/bds/ec.tasklist
index 2e5408dd5b..2b619f192b 100644
--- a/board/bds/ec.tasklist
+++ b/board/bds/ec.tasklist
@@ -15,6 +15,7 @@
  * 's' is the stack size in bytes; must be a multiple of 8
  */
 #define CONFIG_TASK_LIST \
+	TASK(TICK, hook_task, NULL, TASK_STACK_SIZE) \
 	TASK(WATCHDOG, watchdog_task, NULL, TASK_STACK_SIZE) \
 	TASK(LIGHTBAR, lightbar_task, NULL, TASK_STACK_SIZE) \
 	TASK(CONSOLE, console_task, NULL, TASK_STACK_SIZE)
diff --git a/board/daisy/ec.tasklist b/board/daisy/ec.tasklist
index dc07f50e26..25c4675852 100644
--- a/board/daisy/ec.tasklist
+++ b/board/daisy/ec.tasklist
@@ -15,6 +15,7 @@
  * 's' is the stack size in bytes; must be a multiple of 8
  */
 #define CONFIG_TASK_LIST \
+	TASK(TICK, hook_task, NULL, TASK_STACK_SIZE) \
 	TASK(WATCHDOG, watchdog_task, NULL, TASK_STACK_SIZE) \
 	TASK(VBOOTHASH, vboot_hash_task, NULL, TASK_STACK_SIZE) \
 	TASK(POWERLED, power_led_task, NULL, TASK_STACK_SIZE) \
diff --git a/board/link/ec.tasklist b/board/link/ec.tasklist
index 1bfebe2463..3b32e22540 100644
--- a/board/link/ec.tasklist
+++ b/board/link/ec.tasklist
@@ -15,6 +15,7 @@
  * 's' is the stack size in bytes; must be a multiple of 8
  */
 #define CONFIG_TASK_LIST \
+	TASK(TICK, hook_task, NULL, TASK_STACK_SIZE) \
 	TASK(WATCHDOG, watchdog_task, NULL, WATCHDOG_TASK_STACK_SIZE) \
 	TASK(LPC, lpc_task, NULL, TASK_STACK_SIZE) \
 	TASK(VBOOTHASH, vboot_hash_task, NULL, LARGER_TASK_STACK_SIZE) \
diff --git a/board/snow/ec.tasklist b/board/snow/ec.tasklist
index 7c99047a1f..811fa9238a 100644
--- a/board/snow/ec.tasklist
+++ b/board/snow/ec.tasklist
@@ -15,6 +15,7 @@
  * 's' is the stack size in bytes; must be a multiple of 8
  */
 #define CONFIG_TASK_LIST \
+	TASK(TICK, hook_task, NULL, TASK_STACK_SIZE) \
 	TASK(WATCHDOG, watchdog_task, NULL, 256) \
 	TASK(VBOOTHASH, vboot_hash_task, NULL, TASK_STACK_SIZE) \
 	TASK(POWERLED, power_led_task, NULL, 256) \
diff --git a/board/spring/ec.tasklist b/board/spring/ec.tasklist
index 1957b14c85..474a5160d3 100644
--- a/board/spring/ec.tasklist
+++ b/board/spring/ec.tasklist
@@ -15,6 +15,7 @@
  * 's' is the stack size in bytes; must be a multiple of 8
  */
 #define CONFIG_TASK_LIST \
+	TASK(TICK, hook_task, NULL, TASK_STACK_SIZE) \
 	TASK(WATCHDOG, watchdog_task, NULL, 256) \
 	TASK(VBOOTHASH, vboot_hash_task, NULL, TASK_STACK_SIZE) \
 	TASK(PMU_TPS65090_CHARGER, pmu_charger_task, NULL, TASK_STACK_SIZE) \
diff --git a/chip/lm4/config.h b/chip/lm4/config.h
index 7a39262ba6..aa40382b42 100644
--- a/chip/lm4/config.h
+++ b/chip/lm4/config.h
@@ -15,6 +15,9 @@
 /* Use a bigger console output buffer */
 #define CONFIG_UART_TX_BUF_SIZE 8192
 
+/* Interval between HOOK_TICK notifications */
+#define HOOK_TICK_INTERVAL (250 * MSEC)
+
 /****************************************************************************/
 /* Memory mapping */
 
diff --git a/chip/stm32/config.h b/chip/stm32/config.h
index ddd79f39bc..bc7283396a 100644
--- a/chip/stm32/config.h
+++ b/chip/stm32/config.h
@@ -24,6 +24,9 @@
 /* Default task stack size */
 #define TASK_STACK_SIZE 488
 
+/* Interval between HOOK_TICK notifications */
+#define HOOK_TICK_INTERVAL (500 * MSEC)
+
 /* support programming on-chip flash */
 #define CONFIG_FLASH
 
diff --git a/common/hooks.c b/common/hooks.c
index 81d84b3d00..385f0e0478 100644
--- a/common/hooks.c
+++ b/common/hooks.c
@@ -7,6 +7,7 @@
 
 #include "hooks.h"
 #include "link_defs.h"
+#include "timer.h"
 #include "util.h"
 
 struct hook_ptrs {
@@ -29,6 +30,7 @@ static const struct hook_ptrs hook_list[] = {
 	{__hooks_chipset_shutdown, __hooks_chipset_shutdown_end},
 	{__hooks_ac_change, __hooks_ac_change_end},
 	{__hooks_lid_change, __hooks_lid_change_end},
+	{__hooks_tick, __hooks_tick_end},
 };
 
 void hook_notify(enum hook_type type)
@@ -59,3 +61,17 @@ void hook_notify(enum hook_type type)
 		}
 	}
 }
+
+void hook_task(void)
+{
+	while (1) {
+		uint64_t t = get_time().val;
+
+		hook_notify(HOOK_TICK);
+
+		/* Use up the rest of our hook tick interval */
+		t = get_time().val - t;
+		if (t < HOOK_TICK_INTERVAL)
+			usleep(HOOK_TICK_INTERVAL - t);
+	}
+}
diff --git a/core/cortex-m/ec.lds.S b/core/cortex-m/ec.lds.S
index be0e20fdd8..7097ced5a5 100644
--- a/core/cortex-m/ec.lds.S
+++ b/core/cortex-m/ec.lds.S
@@ -96,6 +96,10 @@ SECTIONS
         *(.rodata.HOOK_LID_CHANGE)
         __hooks_lid_change_end = .;
 
+        __hooks_tick = .;
+        *(.rodata.HOOK_TICK)
+        __hooks_tick_end = .;
+
         . = ALIGN(4);
         *(.rodata*)
 
diff --git a/core/cortex-m/link_defs.h b/core/cortex-m/link_defs.h
index 86c6b0a311..44332c74bc 100644
--- a/core/cortex-m/link_defs.h
+++ b/core/cortex-m/link_defs.h
@@ -38,6 +38,8 @@ extern const struct hook_data __hooks_ac_change[];
 extern const struct hook_data __hooks_ac_change_end[];
 extern const struct hook_data __hooks_lid_change[];
 extern const struct hook_data __hooks_lid_change_end[];
+extern const struct hook_data __hooks_tick[];
+extern const struct hook_data __hooks_tick_end[];
 
 /* Host commands */
 extern const struct host_command __hcmds[];
diff --git a/include/hooks.h b/include/hooks.h
index 8124257877..2c691fb639 100644
--- a/include/hooks.h
+++ b/include/hooks.h
@@ -47,6 +47,7 @@ enum hook_type {
 	HOOK_AC_CHANGE,        /* AC power plugged in or removed */
 	HOOK_LID_CHANGE,       /* Lid opened or closed.  Based on debounced lid
 				* state, not raw lid GPIO input. */
+	HOOK_TICK,             /* Periodic tick, every HOOK_TICK_INTERVAL */
 };
 
 struct hook_data {