[PATCH v1 6/6] docs: misc: amd-sbi: Document SBTSI userspace interface

Akshay Gupta
2026-03-23T11:09:12Z

From: Prathima <Prathima.Lk@amd.com>

- Document AMD sideband IOCTL description defined
for SBTSI and its usage.
User space C-APIs are made available by esmi_oob_library [1],
which is provided by the E-SMS project [2].

Link: https://github.com/amd/esmi_oob_library [1]
Link: https://www.amd.com/en/developer/e-sms.html [2]

Reviewed-by: Akshay Gupta <Akshay.Gupta@amd.com>
Signed-off-by: Prathima <Prathima.Lk@amd.com>
---
Documentation/misc-devices/amd-sbi.rst | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/Documentation/misc-devices/amd-sbi.rst b/Documentation/misc-devices/amd-sbi.rst
index f91ddadefe48..ddff3cea8ed1 100644
--- a/Documentation/misc-devices/amd-sbi.rst
+++ b/Documentation/misc-devices/amd-sbi.rst
@@ -48,6 +48,20 @@ Access restrictions:
* APML Mailbox messages and Register xfer access are read-write,
* CPUID and MCA_MSR access is read-only.

+SBTSI device
+============
+
+apml_sbtsi driver under the drivers/misc/amd-sbi creates miscdevice
+/dev/sbtsi-* to let user space programs run APML TSI register xfer
+commands.
+
+The driver supports both I2C and I3C transports for SB-TSI targets.
+The transport is selected by the bus where the device is enumerated.
+
+Access restrictions:
+ * Only root user is allowed to open the file.
+ * APML TSI Register xfer access is read-write.
+
Driver IOCTLs
=============

@@ -63,6 +77,9 @@ Driver IOCTLs
.. c:macro:: SBRMI_IOCTL_REG_XFER_CMD
.. kernel-doc:: include/uapi/misc/amd-apml.h
:doc: SBRMI_IOCTL_REG_XFER_CMD
+.. c:macro:: SBTSI_IOCTL_REG_XFER_CMD
+.. kernel-doc:: include/uapi/misc/amd-apml.h
+ :doc: SBTSI_IOCTL_REG_XFER_CMD

User-space usage
================
@@ -92,6 +109,7 @@ The following IOCTLs are defined:
``#define SBRMI_IOCTL_CPUID_CMD _IOWR(SB_BASE_IOCTL_NR, 1, struct apml_cpuid_msg)``
``#define SBRMI_IOCTL_MCAMSR_CMD _IOWR(SB_BASE_IOCTL_NR, 2, struct apml_mcamsr_msg)``
``#define SBRMI_IOCTL_REG_XFER_CMD _IOWR(SB_BASE_IOCTL_NR, 3, struct apml_reg_xfer_msg)``
+``#define SBTSI_IOCTL_REG_XFER_CMD _IOWR(SB_BASE_IOCTL_NR, 4, struct apml_tsi_xfer_msg)``

User space C-APIs are made available by esmi_oob_library, hosted at
--
2.34.1