Messages in this thread | | | Date | Mon, 6 Jun 2022 16:16:10 +0100 | Subject | Re: [PATCH v6 2/2] Documentation: Add document for UltraSoc SMB drivers | From | Suzuki K Poulose <> |
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Hi Qi
Please find my comments below.
On 06/06/2022 14:02, Qi Liu wrote: > This patch bring in a documentation for UltraSoc SMB drivers. > It simple descripts the device, sysfs interface and the > firmware bindings. > > Signed-off-by: Qi Liu <liuqi115@huawei.com> > --- > .../trace/coresight/ultrasoc-smb.rst | 80 +++++++++++++++++++ > 1 file changed, 80 insertions(+) > create mode 100644 Documentation/trace/coresight/ultrasoc-smb.rst > > diff --git a/Documentation/trace/coresight/ultrasoc-smb.rst b/Documentation/trace/coresight/ultrasoc-smb.rst > new file mode 100644 > index 000000000000..b4cfea82deb8 > --- /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@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
minor nit: alignment.
> +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. > +
--8>---
> +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 > +
These should also be placed in, with the appropriate format.
Documentation/ABI/testing/sysfs-bus-coresight-devices-ultra_smb
> +*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 > +--------------------------- > + > +Firmware binding of SMB device describes SMB device indentifier, resource > +information and graph structure.
Please could you mention that this is only supported with ACPI here ?
> + > +SMB is platform device and device id is "HISI03A1", resource of device is > +declared using the _CRS method. Each SMB must present two base address,
Simply say, the device is identified by ACPI HID "HISI03A1".
> +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) \ > + }) \ > + 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}, \ > + } \ > + } \ > + }) \ > + }
Rest looks fine to me
Suzuki
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