[v13,2/2] Documentation: Add document for UltraSoc SMB drivers

  From: Qi Liu <liuqi115@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@huawei.com>
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 .../sysfs-bus-coresight-devices-ultra_smb     | 31 +++++++
 .../trace/coresight/ultrasoc-smb.rst          | 82 +++++++++++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-ultra_smb
 create mode 100644 Documentation/trace/coresight/ultrasoc-smb.rst
  

On Mon, Nov 14, 2022 at 05:03:16PM +0800, Junhao He wrote:
> diff --git a/Documentation/trace/coresight/ultrasoc-smb.rst b/Documentation/trace/coresight/ultrasoc-smb.rst
> new file mode 100644
> index 000000000000..b7fe3f5c7f53
> --- /dev/null
> +++ b/Documentation/trace/coresight/ultrasoc-smb.rst
> @@ -0,0 +1,82 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +======================================
> +UltraSoc - HW Assisted Tracing on SoC
> +======================================
> +   :Author:   Qi Liu <liuqi115@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.

The key list above doesn't look right, so I have applied the fixup:

---- >8 ----

diff --git a/Documentation/trace/coresight/ultrasoc-smb.rst b/Documentation/trace/coresight/ultrasoc-smb.rst
index b7fe3f5c7f53f7..5d0fa1a76b04d1 100644
--- a/Documentation/trace/coresight/ultrasoc-smb.rst
+++ b/Documentation/trace/coresight/ultrasoc-smb.rst
@@ -30,11 +30,12 @@ The ``ultra_smb<N>`` named SMB associated with SCCL.::
 	$# ls /sys/bus/coresight/devices/ultra_smb0/mgmt
 	buf_size  buf_status  read_pos  write_pos
 
-*Key file items are:-*
+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.
+     BIT(0) is zero means buffer is empty.
    * ``buf_size``: Shows the buffer size of each UltraSoc SMB device.
 
 Firmware Bindings

> +
> +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 32bits base
> +address of shared system memory.
> +
> +examples::
> +
> +    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},       \
> +          }                                                      \
> +        }                                                        \
> +      })                                                         \
> +    }

The rest of wordings also read a rather weird. What about below instead?

---- >8 ---- 

diff --git a/Documentation/trace/coresight/ultrasoc-smb.rst b/Documentation/trace/coresight/ultrasoc-smb.rst
index 5d0fa1a76b04d1..eee32cbf90d2ea 100644
--- a/Documentation/trace/coresight/ultrasoc-smb.rst
+++ b/Documentation/trace/coresight/ultrasoc-smb.rst
@@ -9,21 +9,21 @@ UltraSoc - HW Assisted Tracing on SoC
 Introduction
 ------------
 
-UltraSoc SMB is a per SCCL(Super CPU Cluster) hardware, and it provides a
+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. SMB is plugged as a coresight sink device and the corresponding
-trace generators (ETM) are plugged in as source devices.
+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 the other
-coresight devices::
+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>`` named SMB associated with SCCL.::
+The ``ultra_smb<N>`` names SMB device associated with SCCL.::
 
 	$# ls /sys/bus/coresight/devices/ultra_smb0
 	enable_sink   mgmt
@@ -32,24 +32,23 @@ The ``ultra_smb<N>`` named SMB associated with SCCL.::
 
 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.
+   * ``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
----------------------------
+-----------------
 
-SMB device is only supported with ACPI, and ACPI binding of SMB device
-describes SMB device indentifier, resource information and graph structure.
+The device is only supported with ACPI. Its binding describes device
+identifier, 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 32bits base
-address of shared system memory.
+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.
 
-examples::
+Example::
 
     Device(USMB) {                                               \
       Name(_HID, "HISI03A1")                                     \

Thanks.
  

On 11/15/22 14:33, hejunhao wrote:
> Hi Bagas,
> 
> will apply the fix  in next version.
> Thank you very much.
> 

Please don't top-post, reply inline with appropriate context instead.
I had to trim all the below context as a result.