[PATCH v12 2/2] Documentation: Add document for UltraSoc SMB drivers
hejunhao
hejunhao3 at huawei.com
Sat Nov 12 02:06:24 PST 2022
Hi Yicong.
On 2022/11/10 20:08, Yicong Yang wrote:
> On 2022/11/9 21:50, Junhao He wrote:
>> From: Qi Liu <liuqi115 at huawei.com>
>>
>> This patch bring in documentation for UltraSoc SMB drivers.
>> It simply describes the device, sysfs interface and the
>> firmware bindings.
>>
>> Signed-off-by: Qi Liu <liuqi115 at huawei.com>
>> Signed-off-by: Junhao He <hejunhao3 at huawei.com>
>> ---
>> .../sysfs-bus-coresight-devices-ultra_smb | 31 +++++++
>> .../trace/coresight/ultrasoc-smb.rst | 80 +++++++++++++++++++
>> 2 files changed, 111 insertions(+)
>> create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-ultra_smb
>> create mode 100644 Documentation/trace/coresight/ultrasoc-smb.rst
>>
>> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-ultra_smb b/Documentation/ABI/testing/sysfs-bus-coresight-devices-ultra_smb
>> new file mode 100644
>> index 000000000000..deaefd508105
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-ultra_smb
>> @@ -0,0 +1,31 @@
>> +What: /sys/bus/coresight/devices/ultra_smb<N>/enable_sink
>> +Date: November 2022
>> +KernelVersion: 6.2
>> +Contact: Junhao He <hejunhao3 at huawei.com>
>> +Description: (RW) Add/remove a SMB device from a trace path. There can be
>> + multiple sources for a single SMB device.
>> +
>> +What: /sys/bus/coresight/devices/ultra_smb<N>/mgmt/buf_size
>> +Date: November 2022
>> +KernelVersion: 6.2
>> +Contact: Junhao He <hejunhao3 at huawei.com>
>> +Description: (Read) Shows the buffer size of each UltraSoc SMB device.
>> +
>> +What: /sys/bus/coresight/devices/ultra_smb<N>/mgmt/buf_status
>> +Date: November 2022
>> +KernelVersion: 6.2
>> +Contact: Junhao He <hejunhao3 at huawei.com>
>> +Description: (Read) Shows the value held by UltraSoc SMB status register.
>> + BIT(0) is zero means buffer is empty.
>> +
>> +What: /sys/bus/coresight/devices/ultra_smb<N>/mgmt/read_pos
>> +Date: November 2022
>> +KernelVersion: 6.2
>> +Contact: Junhao He <hejunhao3 at huawei.com>
>> +Description: (Read) Shows the value held by UltraSoc SMB Read Pointer register.
>> +
>> +What: /sys/bus/coresight/devices/ultra_smb<N>/mgmt/write_pos
>> +Date: November 2022
>> +KernelVersion: 6.2
>> +Contact: Junhao He <hejunhao3 at huawei.com>
>> +Description: (Read) Shows the value held by UltraSoc SMB Write Pointer register.
>> diff --git a/Documentation/trace/coresight/ultrasoc-smb.rst b/Documentation/trace/coresight/ultrasoc-smb.rst
>> new file mode 100644
>> index 000000000000..6d28ef0f6c88
>> --- /dev/null
>> +++ b/Documentation/trace/coresight/ultrasoc-smb.rst
>> @@ -0,0 +1,80 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
>> +======================================
>> +UltraSoc - HW Assisted Tracing on SoC
>> +======================================
>> + :Author: Qi Liu <liuqi115 at huawei.com>
>> + :Date: March 2022
>> +
>> +Introduction
>> +------------
>> +
>> +UltraSoc SMB is a per SCCL(Super CPU Cluster) hardware, and it provides a
>> +way to buffer and store CPU trace messages in a region of shared system
>> +memory. SMB is plugged as a coresight sink device and the corresponding
>> +trace generators (ETM) are plugged in as source devices.
>> +
>> +Sysfs files and directories
>> +---------------------------
>> +
>> +The SMB devices appear on the existing coresight bus alongside the other
>> +coresight devices::
>> +
>> + $# ls /sys/bus/coresight/devices/
>> + ultra_smb0 ultra_smb1 ultra_smb2 ultra_smb3
>> +
>> +The ``ultra_smb<N>`` named SMB associated with SCCL.::
>> +
>> + $# ls /sys/bus/coresight/devices/ultra_smb0
>> + enable_sink mgmt
>> + $# ls /sys/bus/coresight/devices/ultra_smb0/mgmt
>> + buf_size buf_status read_pos write_pos
>> +
>> +*Key file items are:-*
>> + * ``read_pos``: Shows the value held by UltraSoc SMB Read Pointer register.
>> + * ``write_pos``: Shows the value held by UltraSoc SMB Write Pointer register.
>> + * ``buf_status``: Shows the value held by UltraSoc SMB status register.
>> + BIT(0) is zero means buffer is empty.
>> + * ``buf_size``: Shows the buffer size of each UltraSoc SMB device.
>> +
>> +Firmware Bindings
>> +---------------------------
>> +
>> +SMB device is only supported with ACPI, and ACPI binding of SMB device
>> +describes SMB device indentifier, resource information and graph structure.
>> +
>> +SMB is identified by ACPI HID "HISI03A1", resource of device is declared using
>> +the _CRS method. Each SMB must present two base address, the first one is the
>> +configuration base address of SMB device, the second one is the base address of
>> +shared system memory.
>> +
>> +examples::
>> +
>> + Device(USMB) { \
>> + Name(_HID, "HISI03A1") \
>> + Name(_CRS, ResourceTemplate() { \
>> + MEM_RESRC(0x95100000, 0x951FFFFF, 0x100000) \
>> + MEM_RESRC(0x50000000, 0x53FFFFFF, 0x4000000) \
> I cannot find MEM_RESRC in ACPI Spec 6.4, any references? If it's a self defined macro just expand it here.
>
> btw, you need to cc linux-doc at vger.kernel.org.
>
> Thanks.
"MEM_RESERVE" is a macro. will update the doc and add cc.
Thanks for the comments!
>> + }) \
>> + Name(_DSD, Package() { \
>> + ToUUID("ab02a46b-74c7-45a2-bd68-f7d344ef2153"), \
>> + /* Use CoreSight Graph ACPI bindings to describe connections topology */
>> + Package() { \
>> + 0, \
>> + 1, \
>> + Package() { \
>> + 1, \
>> + ToUUID("3ecbc8b6-1d0e-4fb3-8107-e627f805c6cd"), \
>> + 8, \
>> + Package() {0x8, 0, \_SB.S00.SL11.CL28.F008, 0}, \
>> + Package() {0x9, 0, \_SB.S00.SL11.CL29.F009, 0}, \
>> + Package() {0xa, 0, \_SB.S00.SL11.CL2A.F010, 0}, \
>> + Package() {0xb, 0, \_SB.S00.SL11.CL2B.F011, 0}, \
>> + Package() {0xc, 0, \_SB.S00.SL11.CL2C.F012, 0}, \
>> + Package() {0xd, 0, \_SB.S00.SL11.CL2D.F013, 0}, \
>> + Package() {0xe, 0, \_SB.S00.SL11.CL2E.F014, 0}, \
>> + Package() {0xf, 0, \_SB.S00.SL11.CL2F.F015, 0}, \
>> + } \
>> + } \
>> + }) \
>> + }
>>
> .
>
Best regards,
Junhao.
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