Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 118 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/powerpc/opal/power-mgt.txt b/Documentation/devicetree/bindings/powerpc/opal/power-mgt.txt
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+IBM Power-Management Bindings
+=============================
+
+Linux running on baremetal POWER machines has access to the processor
+idle states. The description of these idle states is exposed via the
+node @power-mgt in the device-tree by the firmware.
+
+Definitions:
+----------------
+Typically each idle state has the following associated properties:
+
+- name: The name of the idle state as defined by the firmware.
+
+- flags: indicating some aspects of this idle states such as the
+         extent of state-loss, whether timebase is stopped on this
+         idle states and so on. The flag bits are as follows:
+
+- exit-latency: The latency involved in transitioning the state of the
+		CPU from idle to running.
+
+- target-residency: The minimum time that the CPU needs to reside in
+		    this idle state in order to accrue power-savings
+		    benefit.
+
+Properties
+----------------
+The following properties provide details about the idle states. These
+properties are exposed as arrays. Each entry in the property array
+provides the value of that property for the idle state associated with
+the array index of that entry.
+
+If idle-states are defined, then the properties
+"ibm,cpu-idle-state-names" and "ibm,cpu-idle-state-flags" are
+required. The other properties are required unless mentioned
+otherwise. The length of all the property arrays must be the same.
+
+- ibm,cpu-idle-state-names:
+	Array of strings containing the names of the idle states.
+
+- ibm,cpu-idle-state-flags:
+	Array of unsigned 32-bit values containing the values of the
+	flags associated with the the aforementioned idle-states. The
+	flag bits are as follows:
+		0x00000001 /* Decrementer would stop */
+		0x00000002 /* Needs timebase restore */
+		0x00001000 /* Restore GPRs like nap */
+		0x00002000 /* Restore hypervisor resource from PACA pointer */
+		0x00004000 /* Program PORE to restore PACA pointer */
+		0x00010000 /* This is a nap state (POWER7,POWER8) */
+		0x00020000 /* This is a fast-sleep state (POWER8)*/
+		0x00040000 /* This is a winkle state (POWER8) */
+		0x00080000 /* This is a fast-sleep state which requires a */
+			   /* software workaround for restoring the */
+			   /* timebase (POWER8) */
+		0x00800000 /* This state uses SPR PMICR instruction */
+			   /* (POWER8)*/
+		0x00100000 /* This is a fast stop state (POWER9) */
+		0x00200000 /* This is a deep-stop state (POWER9) */
+
+- ibm,cpu-idle-state-latencies-ns:
+	Array of unsigned 32-bit values containing the values of the
+	exit-latencies (in ns) for the idle states in
+	ibm,cpu-idle-state-names.
+
+- ibm,cpu-idle-state-residency-ns:
+	Array of unsigned 32-bit values containing the values of the
+	target-residency (in ns) for the idle states in
+	ibm,cpu-idle-state-names. On POWER8 this is an optional
+	property. If the property is absent, the target residency for
+	the "Nap", "FastSleep" are defined to 10000 and 300000000
+	respectively by the kernel. On POWER9 this property is required.
+
+- ibm,cpu-idle-state-psscr:
+	Array of unsigned 64-bit values containing the values for the
+	PSSCR for each of the idle states in ibm,cpu-idle-state-names.
+	This property is required on POWER9 and absent on POWER8.
+
+- ibm,cpu-idle-state-psscr-mask:
+	Array of unsigned 64-bit values containing the masks
+	indicating which psscr fields are set in the corresponding
+	entries of ibm,cpu-idle-state-psscr. This property is
+	required on POWER9 and absent on POWER8.
+
+	Whenever the firmware sets an entry in
+	ibm,cpu-idle-state-psscr-mask value to 0xf, it implies that
+	only the Requested Level (RL) field of the corresponding entry
+	in ibm,cpu-idle-state-psscr should be considered by the
+	kernel. For such idle states, the kernel would set the
+	remaining fields of the psscr to the following sane-default
+	values.
+
+		- ESL and EC bits are to 1. So wakeup from any stop
+		  state will be at vector 0x100.
+
+		- MTL and PSLL are set to the maximum allowed value as
+		  per the ISA, i.e. 15.
+
+		- The Transition Rate, TR is set to the Maximum value
+                  3.
+
+	For all the other values of the entry in
+	ibm,cpu-idle-state-psscr-mask, the kernel expects all the
+	psscr fields of the corresponding entry in
+	ibm,cpu-idle-state-psscr to be correctly set by the firmware.
+
+- ibm,cpu-idle-state-pmicr:
+	Array of unsigned 64-bit values containing the pmicr values
+	for the idle states in ibm,cpu-idle-state-names. This 64-bit
+	register value is to be set in pmicr for the corresponding
+	state if the flag indicates that pmicr SPR should be set. This
+	is an optional property on POWER8 and is absent on
+	POWER9.
+
+- ibm,cpu-idle-state-pmicr-mask:
+	Array of unsigned 64-bit values containing the mask indicating
+	which of the fields of the PMICR are set in the corresponding
+	entries in ibm,cpu-idle-state-pmicr. This is an optional
+	property on POWER8 and is absent on POWER9.