Let AP read sensor IDs when DPTF thermal thresholds crossed

The spec does not mandate any way to read back the threshold settings
themselves, but when a threshold is crossed the AP needs a way to determine
which sensor(s) are responsible. Each reading of the EC_ACPI_MEM_TEMP_ID
register clears and returns one sensor ID that has crossed one of its
thresholds (in either direction) since the last read. A value of 0xFF means
"no new thresholds have tripped". Changing or enabling the thresholds for
any sensor will clear the unread event count for that sensor.

BUG=chrome-os-partner:23970
BRANCH=none
TEST=manual

On the host, set a couple of thresholds to low values so they trip
immediately (I'm testing on Link):

  # dptf() {
         [ "$#" -eq "2" ] || return;
         iotools io_write8 0x66 0x81
         iotools io_write8 0x62 $1
         iotools io_write8 0x62 $2
  }
  #

  # dptf 5 0
  # dptf 6 10
  # dptf 7 3

  # dptf 5 2
  # dptf 6 10
  # dptf 7 2

On the EC console, see that two thresholds have triggered, and that there
are two bits set in the AP seen mask:

  [45.755365 DPTF sensor 0, threshold -63 C, index 1, enabled]
  [45.768940 DPTF sensor 2, threshold -63 C, index 0, enabled]
  [46.169490 DPTF over threshold [0][1]
  [46.169820 DPTF over threshold [2][0]
  > dptftemp
  sensor   thresh0   thresh1
    0       ---        210*    I2C-USB C-Die
    1       ---        ---     I2C-USB C-Object
    2       210*       ---     I2C-PCH D-Die
    3       ---        ---     I2C-PCH D-Object
    4       ---        ---     I2C-Hinge C-Die
    5       ---        ---     I2C-Hinge C-Object
    6       ---        ---     I2C-Charger D-Die
    7       ---        ---     I2C-Charger D-Object
    8       ---        ---     ECInternal
    9       ---        ---     PECI
  AP seen mask: 0x00000005
  >

Read the EC_ACPI_MEM_TEMP_ID register from the host, to get the two active
sensor IDs (0 and 2), then 0xff when those are seen.

  # iotools io_write8 0x66 0x80; iotools io_write8 0x62 5; iotools io_read8 0x62
  0x00
  # iotools io_write8 0x66 0x80; iotools io_write8 0x62 5; iotools io_read8 0x62
  0x02
  # iotools io_write8 0x66 0x80; iotools io_write8 0x62 5; iotools io_read8 0x62
  0xff
  # iotools io_write8 0x66 0x80; iotools io_write8 0x62 5; iotools io_read8 0x62
  0xff
  #

Change-Id: I8f047a517357617f18ad59d21fa13409bc81821b
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/180224
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/common/acpi.c b/common/acpi.c
index 68c281b6e6..69cf3bc837 100644
--- a/common/acpi.c
+++ b/common/acpi.c
@@ -71,6 +71,11 @@ int acpi_ap_to_ec(int is_cmd, uint8_t value, uint8_t *resultptr)
 			result = dptf_get_fan_duty_target();
 			break;
 #endif
+#ifdef CONFIG_TEMP_SENSOR
+		case EC_ACPI_MEM_TEMP_ID:
+			result = dptf_query_next_sensor_event();
+			break;
+#endif
 		default:
 			CPRINTF("[%T ACPI read 0x%02x (ignored)]\n", acpi_addr);
 			break;