[PATCH v7 6/9] docs: misc-devices: (smpro-misc) Add documentation

Quan Nguyen
2022-03-21T08:15:53Z

Adds documentation for the Ampere(R)'s Altra(R) SMpro misc driver.

Signed-off-by: Thu Nguyen <thu@os.amperecomputing.com>
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
Changes in v7:
+ None

Changes in v6:
+ First introduced in v6 [Quan]

Documentation/misc-devices/index.rst | 1 +
Documentation/misc-devices/smpro-misc.rst | 82 +++++++++++++++++++++++
2 files changed, 83 insertions(+)
create mode 100644 Documentation/misc-devices/smpro-misc.rst

diff --git a/Documentation/misc-devices/index.rst b/Documentation/misc-devices/index.rst
index 7a6a6263cbab..284568eca747 100644
--- a/Documentation/misc-devices/index.rst
+++ b/Documentation/misc-devices/index.rst
@@ -27,6 +27,7 @@ fit into other categories.
max6875
pci-endpoint-test
smpro-errmon
+ smpro-misc
spear-pcie-gadget
uacce
xilinx_sdfec
diff --git a/Documentation/misc-devices/smpro-misc.rst b/Documentation/misc-devices/smpro-misc.rst
new file mode 100644
index 000000000000..7c856eb1a7f3
--- /dev/null
+++ b/Documentation/misc-devices/smpro-misc.rst
@@ -0,0 +1,82 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver Ampere(R) Altra(R) SMpro miscellaneous
+====================================================
+
+Supported chips:
+
+ * Ampere(R) Altra(R)
+
+ Prefix: 'smpro'
+
+ Reference: Altra SoC BMC Interface Specification
+
+Author: Thu Nguyen <thu@os.amperecomputing.com>
+
+Description
+-----------
+
+This driver support the monitoring and configuration of various miscellaneous
+data provided by Ampere(R) Altra(R) SMpro processor.
+At this time, these include:
+
+ * Reading Boot Progress information
+ * Configuring SoC Power Limit
+
+Sysfs entries
+-------------
+
+1) Boot progress
+
+SMpro misc driver creates the sysfs files ``boot_progress``.
+The format of ``boot_progress`` file is as below::
+
+<boot stage> <boot status> <boot progress>
+
+Where:
+
+* Boot stage::
+
+ 0: SMpro firmware booting.
+ 1: PMpro firmware booting.
+ 2: ATF BL1 firmware booting.
+ 3: DDR initialization.
+ 4: DDR training report status.
+ 5: ATF BL2 firmware booting.
+ 6: ATF BL31 firmware booting.
+ 7: ATF BL32 firmware booting.
+ 8: UEFI firmware booting.
+ 9: OS booting.
+
+* Boot status::
+
+ 0: Not started.
+ 1: Started.
+ 2: Complete without error.
+ 3: Failure.
+
+* boot progress: 32 bits boot progress code
+
+The sysfs ``boot_progress`` only reports the boot state when the host is booting.
+If the host is already booted, it returns latest state.
+
+Example::
+
+ #cat boot_progress
+ 0x01 0x02 0x808454A8
+
+2) SoC Power Limit
+
+SMpro misc driver creates the sysfs file ``soc_power_limit`` to get/set the SoC Power Limit.
+
+Reading this sysfs return the current setting of SoC Power Limit (W) in decimal string.
+Writing the desired value in decimal string to set the SoC Power Limit in Watt (W).
+The range of SoC Power Limit is 90-500(W) and will be ignored if out of range.
+
+Example::
+
+ #cat soc_power_limit
+ 90
+ #echo 95 > soc_power_limit
+ #cat soc_power_limit
+ 95
--
2.35.1