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

[Bagas Sanjaya <bagasdotme@gmail.com>]

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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@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@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@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@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@huawei.com>
> +Description:	(Read) Shows the value held by UltraSoc SMB Write Pointer register.

s/Read/RO/ and s/value held by/value of/

> 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@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@gmail.com>

-- 
An old man doll... just what I always wanted! - Clara

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