[PATCH v15 2/2] Documentation: Add document for UltraSoc SMB driver

[hejunhao]

On 2022/12/21 12:02, Bagas Sanjaya wrote:
> On Tue, Dec 20, 2022 at 05:29:45PM +0800, Junhao He wrote:
>> 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..f6526882c627
>> --- /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:		December 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:		December 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:		December 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:		December 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:		December 2022
>> +KernelVersion:	6.2
>> +Contact:	Junhao He <hejunhao3 at huawei.com>
>> +Description:	(Read) Shows the value held by UltraSoc SMB Write Pointer register.
> s/Read/RO/ and s/value held by/value of/
Ok, will fix it.

Thanks.
>> diff --git a/Documentation/trace/coresight/ultrasoc-smb.rst b/Documentation/trace/coresight/ultrasoc-smb.rst
>> new file mode 100644
>> index 000000000000..056dd120e14c
>> --- /dev/null
>> +++ b/Documentation/trace/coresight/ultrasoc-smb.rst
>> @@ -0,0 +1,83 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
>> +======================================
>> +UltraSoc - HW Assisted Tracing on SoC
>> +======================================
>> +   :Author:   Qi Liu <liuqi115 at huawei.com>
>> +   :Date:     December 2022
>> +
>> +Introduction
>> +------------
>> +
>> +UltraSoc SMB is a per SCCL (Super CPU Cluster) hardware. It provides a
>> +way to buffer and store CPU trace messages in a region of shared system
>> +memory. The device acts as a coresight sink device and the
>> +corresponding trace generators (ETM) are attached as source devices.
>> +
>> +Sysfs files and directories
>> +---------------------------
>> +
>> +The SMB devices appear on the existing coresight bus alongside other
>> +devices::
>> +
>> +	$# ls /sys/bus/coresight/devices/
>> +	ultra_smb0   ultra_smb1   ultra_smb2   ultra_smb3
>> +
>> +The ``ultra_smb<N>`` names SMB device 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 on the read pointer register.
>> +   * ``write_pos``: Shows the value on the write pointer register.
>> +   * ``buf_status``: Shows the value on the status register.
>> +     BIT(0) is zero value which means the buffer is empty.
>> +   * ``buf_size``: Shows the buffer size of each device.
>> +
>> +Firmware Bindings
>> +-----------------
>> +
>> +The device is only supported with ACPI. Its binding describes device
>> +identifier, resource information and graph structure.
>> +
>> +The device is identified as ACPI HID "HISI03A1". Device resources are allocated
>> +using the _CRS method. Each device must present two base address; the first one
>> +is the configuration base address of the device, the second one is the 32-bit
>> +base address of shared system memory.
>> +
>> +Example::
>> +
>> +    Device(USMB) {                                               \
>> +      Name(_HID, "HISI03A1")                                     \
>> +      Name(_CRS, ResourceTemplate() {                            \
>> +          QWordMemory (ResourceConsumer, , MinFixed, MaxFixed, NonCacheable, \
>> +		       ReadWrite, 0x0, 0x95100000, 0x951FFFFF, 0x0, 0x100000) \
>> +          QWordMemory (ResourceConsumer, , MinFixed, MaxFixed, Cacheable, \
>> +		       ReadWrite, 0x0, 0x50000000, 0x53FFFFFF, 0x0, 0x4000000) \
>> +      })                                                         \
>> +      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},       \
>> +          }                                                      \
>> +        }                                                        \
>> +      })                                                         \
>> +    }
> This doc LGTM, thanks.
>
> For this doc,
>
> Reviewed-by: Bagas Sanjaya <bagasdotme at gmail.com>
Thanks for your comments.

Best regards,
Junhao.