Change PECI_TJMAX to a board config option

BUG=chrome-os-partner:24455
BRANCH=none
TEST=Manual: Verify that CONIFG_PECI_TJMAX set per-board matches
the value queried over the PECI bus with the restricted
"peciprobe" command.

Change-Id: I8e99a23a66f26d6101e01cc751d0a8ca79686321
Signed-off-by: Dave Parker <dparker@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/179682
Reviewed-by: Alec Berg <alecaberg@chromium.org>

6 files changed, 17 insertions, 13 deletions

diff --git a/board/falco/board.h b/board/falco/board.h
index a9af0ddef3..dd47dca788 100644
--- a/board/falco/board.h
+++ b/board/falco/board.h
@@ -25,6 +25,7 @@
 #define CONFIG_KEYBOARD_BOARD_CONFIG
 #define CONFIG_KEYBOARD_PROTOCOL_8042
 #define CONFIG_LOW_POWER_IDLE
+#define CONFIG_PECI_TJMAX 100
 #define CONFIG_POWER_BUTTON
 #define CONFIG_POWER_BUTTON_X86
 #define CONFIG_SWITCH_DEDICATED_RECOVERY
diff --git a/board/link/board.h b/board/link/board.h
index 1443154247..c99e6c16ef 100644
--- a/board/link/board.h
+++ b/board/link/board.h
@@ -27,6 +27,7 @@
 #define CONFIG_KEYBOARD_PROTOCOL_8042
 #define CONFIG_LED_DRIVER_DS2413
 #define CONFIG_ONEWIRE
+#define CONFIG_PECI_TJMAX 105
 #define CONFIG_POWER_BUTTON
 #define CONFIG_POWER_BUTTON_X86
 #define CONFIG_PWM
diff --git a/board/peppy/board.h b/board/peppy/board.h
index 61b79b320d..b10330dfe1 100644
--- a/board/peppy/board.h
+++ b/board/peppy/board.h
@@ -27,6 +27,7 @@
 #define CONFIG_KEYBOARD_PROTOCOL_8042
 #define CONFIG_LED_COMMON
 #define CONFIG_LOW_POWER_IDLE
+#define CONFIG_PECI_TJMAX 100
 #define CONFIG_POWER_BUTTON
 #define CONFIG_POWER_BUTTON_X86
 #define CONFIG_SWITCH_DEDICATED_RECOVERY
diff --git a/board/samus/board.h b/board/samus/board.h
index 09daf86757..7496b97958 100644
--- a/board/samus/board.h
+++ b/board/samus/board.h
@@ -38,6 +38,7 @@
 #define   CONFIG_CHARGER_SENSE_RESISTOR_AC 10
 #define   CONFIG_CHARGER_INPUT_CURRENT 2000
 #define CONFIG_FANS 2
+#define CONFIG_PECI_TJMAX 100
 #define CONFIG_PWM
 #define CONFIG_PWM_KBLIGHT
 #define CONFIG_SWITCH_DEDICATED_RECOVERY
diff --git a/chip/lm4/peci.c b/chip/lm4/peci.c
index d66956202b..052e2ddc06 100644
--- a/chip/lm4/peci.c
+++ b/chip/lm4/peci.c
@@ -16,15 +16,6 @@
 #include "temp_sensor.h"
 #include "util.h"
 
-/*
- * Max junction temperature for processor in degrees C.  This is correct for
- * Ivy Bridge and Haswell; future chips don't have PECI.
- *
- * In theory we could read TjMax from the processor via PECI, but that requires
- * closed-source Intel PECI commands.
- */
-#define PECI_TJMAX 105
-
 /* Initial PECI baud rate */
 #define PECI_BAUD_RATE 100000
 
@@ -79,9 +70,9 @@ int peci_temp_sensor_get_val(int idx, int *temp_ptr)
 	 * Require at least two valid samples. When the AP transitions into S0,
 	 * it is possible, depending on the timing of the PECI sample, to read
 	 * an invalid temperature. This is very rare, but when it does happen
-	 * the temperature returned is PECI_TJMAX. Requiring two valid samples
-	 * here assures us that one bad maximum temperature reading when
-	 * entering S0 won't cause us to trigger an over temperature.
+	 * the temperature returned is CONFIG_PECI_TJMAX. Requiring two valid
+	 * samples here assures us that one bad maximum temperature reading
+	 * when entering S0 won't cause us to trigger an over temperature.
 	 */
 	if (success_cnt < 2)
 		return EC_ERROR_UNKNOWN;
@@ -117,7 +108,7 @@ static void peci_freq_changed(void)
 		(PECI_POLL_INTERVAL_MS * (freq / 1000 / 4096));
 
 	/* Set up temperature monitoring to report in degrees K */
-	LM4_PECI_CTL = ((PECI_TJMAX + 273) << 22) | 0x0001 |
+	LM4_PECI_CTL = ((CONFIG_PECI_TJMAX + 273) << 22) | 0x0001 |
 		       (PECI_RETRY_COUNT << 12) |
 		       (PECI_ERROR_BYPASS << 11);
 }
diff --git a/include/config.h b/include/config.h
index c1d5c351cd..d3c749c92c 100644
--- a/include/config.h
+++ b/include/config.h
@@ -524,6 +524,15 @@
 /* Support PECI interface to x86 processor */
 #undef CONFIG_PECI
 
+/*
+ * Maximum operating temperature in degrees Celcius used on some x86
+ * processors. CPU chip temperature is reported relative to this value and
+ * is never reported greater than this value. Processor asserts PROCHOT#
+ * and starts throttling frequency and voltage at this temp. Operation may
+ * become unreliable if temperature exceeds this limit.
+ */
+#undef CONFIG_PECI_TJMAX
+
 /*****************************************************************************/
 /* PMU config */