Now that we have a thermal zone we can add active cooling
by specifying active cooling points (_ACx) which can
be tied to fan objects that turn fans on/off using GPIO
pins.
Cc: Leif Lindholm <l...@nuviainc.com>
Cc: Pete Batard <p...@akeo.ie>
Cc: Andrei Warkentin <awarken...@vmware.com>
Cc: Ard Biesheuvel <ard.biesheu...@arm.com>
Cc: Samer El-Haj-Mahmoud <samer.el-haj-mahm...@arm.com>
Signed-off-by: Jeremy Linton <jeremy.lin...@arm.com>
Reviewed-by: Pete Batard <@pbatard>
---
Platform/RaspberryPi/AcpiTables/AcpiTables.inf | 1 +
Platform/RaspberryPi/AcpiTables/SsdtThermal.asl | 76 +++++++++++++++++++++++++
2 files changed, 77 insertions(+)
create mode 100644 Platform/RaspberryPi/AcpiTables/SsdtThermal.asl
diff --git a/Platform/RaspberryPi/AcpiTables/AcpiTables.inf
b/Platform/RaspberryPi/AcpiTables/AcpiTables.inf
index 28d2afe197..c40c32e16f 100644
--- a/Platform/RaspberryPi/AcpiTables/AcpiTables.inf
+++ b/Platform/RaspberryPi/AcpiTables/AcpiTables.inf
@@ -33,6 +33,7 @@
Csrt.aslc
Spcr.aslc
Pptt.aslc
+ SsdtThermal.asl
[Packages]
ArmPkg/ArmPkg.dec
diff --git a/Platform/RaspberryPi/AcpiTables/SsdtThermal.asl
b/Platform/RaspberryPi/AcpiTables/SsdtThermal.asl
new file mode 100644
index 0000000000..ee028173e1
--- /dev/null
+++ b/Platform/RaspberryPi/AcpiTables/SsdtThermal.asl
@@ -0,0 +1,76 @@
+/** @file
+ *
+ * Secondary System Description Table (SSDT) for active (fan) cooling
+ *
+ * Copyright (c) 2020, Arm Ltd. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause-Patent
+ *
+ **/
+
+#include <IndustryStandard/Bcm2711.h>
+#include <IndustryStandard/Bcm2836.h>
+#include <IndustryStandard/Bcm2836Gpio.h>
+
+#include <IndustryStandard/Acpi.h>
+
+DefinitionBlock (__FILE__, "SSDT", 5, "RPIFDN", "RPITHFAN", 2)
+{
+ External (\_SB_.EC00, DeviceObj)
+ External (\_SB_.EC00.TZ00, DeviceObj)
+
+ Scope (\_SB_.EC00)
+ {
+ // Define a NameOp we will modify during InstallTable
+ Name (GIOP, 0x2) //08 47 49 4f 50 0a 02 (value must be >1)
+ // Describe a fan
+ PowerResource (PFAN, 0, 0) {
+ OperationRegion (GPIO, SystemMemory, GPIO_BASE_ADDRESS, 0x1000)
+ Field (GPIO, DWordAcc, NoLock, Preserve) {
+ Offset (0x1C),
+ GPS0, 32,
+ GPS1, 32,
+ RES1, 32,
+ GPC0, 32,
+ GPC1, 32,
+ RES2, 32,
+ GPL1, 32,
+ GPL2, 32
+ }
+ // We are hitting a GPIO pin to on/off a fan.
+ // This assumes that UEFI has programmed the
+ // direction as OUT. Given the current limitations
+ // on the GPIO pins, its recommended to use
+ // the GPIO to switch a larger voltage/current
+ // for the fan rather than driving it directly.
+ Method (_STA) {
+ if (GPL1 & (1 << GIOP)) {
+ Return (1) // present and enabled
+ }
+ Return (0)
+ }
+ Method (_ON) { // turn fan on
+ Store (1 << GIOP, GPS0)
+ }
+ Method (_OFF) { // turn fan off
+ Store (1 << GIOP, GPC0)
+ }
+ }
+ Device (FAN0) {
+ // Note, not currently an ACPIv4 fan
+ // the latter adds speed control/detection
+ // but in the case of linux needs FIF, FPS, FSL, and FST
+ Name (_HID, EISAID ("PNP0C0B"))
+ Name (_PR0, Package () { PFAN })
+ }
+ }
+
+ // merge in an active cooling point.
+ Scope (\_SB_.EC00.TZ00)
+ {
+ Method (_AC0) { Return (3332) } // (60C) active cooling trip point,
+ // if this is lower than PSV then we
+ // prefer active cooling
+ Name (_AL0, Package () { \_SB_.EC00.FAN0 }) // the fan used for AC0 above
+ }
+}
--
2.13.7
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