[edk2-devel] Question about the boundary and difference between System Firmware and UEFI CXL drivers

[edk2-devel] Question about the boundary and difference between System Firmware and UEFI CXL drivers

[Yuquan Wang]

[-- Attachment #1: Type: text/plain, Size: 686 bytes --]

Hi, folks
 
CXL Memory Device SW Guide [1] rev1.0 2.4 provides little description about the difference between System Firmware and
UEFI CXL drivers. IIRC, the UEFI drivers are part of system firmware, so I am confused about the boundary on them.
 
I greatly appreciate insight/help in this regard!

Many thanks
Yuquan



-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#112092): https://edk2.groups.io/g/devel/message/112092
Mute This Topic: https://groups.io/mt/103008846/7686176
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io]
-=-=-=-=-=-=-=-=-=-=-=-



[-- Attachment #2: Type: text/html, Size: 1807 bytes --]

Re: [edk2-devel] Question about the boundary and difference between System Firmware and UEFI CXL drivers

[Yuquan Wang]

[-- Attachment #1: Type: text/plain, Size: 503 bytes --]

Addition: [the link of  CXL Memory Device SW Guide]
https://cdrdv2-public.intel.com/643805/643805_CXL%20Memory%20Device%20SW%20Guide_Rev1p0.pdf


-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#112093): https://edk2.groups.io/g/devel/message/112093
Mute This Topic: https://groups.io/mt/103008846/7686176
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io]
-=-=-=-=-=-=-=-=-=-=-=-



[-- Attachment #2: Type: text/html, Size: 1436 bytes --]

Re: [edk2-devel] Question about the boundary and difference between System Firmware and UEFI CXL drivers

[Yoshinoya]

[-- Attachment #1: Type: text/plain, Size: 887 bytes --]

There is a description about UEFI Drivers in 1.4 Abbreviations in this doc.


UEFI Drivers : UEFI CXL Bus and memory device drivers.


I think UEFI CXL Drivers is a part of System Firmware(UEFI BIOS). 




These UEFI Drivers may do some basic configuation for some direct attached clx type-3 devices.







At 2023-12-06 15:13:00, "Yuquan Wang" <wangyuquan1236@phytium.com.cn> wrote:

Addition: [the link of  CXL Memory Device SW Guide]
https://cdrdv2-public.intel.com/643805/643805_CXL%20Memory%20Device%20SW%20Guide_Rev1p0.pdf


-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#112215): https://edk2.groups.io/g/devel/message/112215
Mute This Topic: https://groups.io/mt/103008846/7686176
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io]
-=-=-=-=-=-=-=-=-=-=-=-



[-- Attachment #2: Type: text/html, Size: 2232 bytes --]

Re: [edk2-devel] Question about the boundary and difference between System Firmware and UEFI CXL drivers

[Yuquan Wang]

[-- Attachment #1: Type: text/plain, Size: 1161 bytes --]

On 2023-12-08 15:42,  Yoshinoya wrote:
There is a description about UEFI Drivers in 1.4 Abbreviations in this doc.

UEFI Drivers : UEFI CXL Bus and memory device drivers.

I think UEFI CXL Drivers is a part of System Firmware(UEFI BIOS). 

These UEFI Drivers may do some basic configuation for some direct attached clx type-3 devices.
_._,_._

I found that description too, but in "Figure 34-High-level sequence: System Firmware boot" it shows that system firmware could 
enumerate CXL components and be followed with an optional UEFI Boot Sequence which also could enumerate CXL components
 (Figure 35). In my understanding, only UEFI CXL Bus and memory device drivers could enumerate CXL components, therefore, 
how system firmware could finish this responsibilty?

Many thanks
Yuquan


-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#112269): https://edk2.groups.io/g/devel/message/112269
Mute This Topic: https://groups.io/mt/103008846/7686176
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io]
-=-=-=-=-=-=-=-=-=-=-=-



[-- Attachment #2: Type: text/html, Size: 3473 bytes --]

Re: [edk2-devel] Question about the boundary and difference between System Firmware and UEFI CXL drivers

[Yoshinoya]

[-- Attachment #1: Type: text/plain, Size: 1945 bytes --]




CXL Device could be accessed and configured with CXL.io path.
UEFI Standard pci bus driver could enumerate CXL device as a normal pcie device through CXL.io path.


A dedicated CXL Device driver could be dispatched and run after standard pci bus enumeration.


Figure-35 is an addiontal boot path description with Figure-34 if system has a cxl type-3 persistent memory device. 


Anyway, there is not a very clear boundary between system firmware and a dedicated uefi driver.
Sometimes, a dedicated uefi driver could has integrated with a system firmware, as a part of UEFI BIOS.
Sometimes, a dedicated uefi driver's code could be implemented in a part of UEFI BIOS, and no seperate driver exists.










在 2023-12-11 15:09:34，"Yuquan Wang" <wangyuquan1236@phytium.com.cn> 写道：

On 2023-12-08 15:42,  Yoshinoya wrote:
|
There is a description about UEFI Drivers in 1.4 Abbreviations in this doc.


UEFI Drivers : UEFI CXL Bus and memory device drivers.


I think UEFI CXL Drivers is a part of System Firmware(UEFI BIOS). 




These UEFI Drivers may do some basic configuation for some direct attached clx type-3 devices.

_._,_._
|


I found that description too, but in "Figure 34-High-level sequence: System Firmware boot" it shows that system firmware could 
enumerate CXL components and be followed with an optional UEFI Boot Sequence which also could enumerate CXL components
 (Figure 35). In my understanding, only UEFI CXL Bus and memory device drivers could enumerate CXL components, therefore, 
how system firmware could finish this responsibilty?


Many thanks
Yuquan


-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#112498): https://edk2.groups.io/g/devel/message/112498
Mute This Topic: https://groups.io/mt/103008846/7686176
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io]
-=-=-=-=-=-=-=-=-=-=-=-



[-- Attachment #2: Type: text/html, Size: 4826 bytes --]