On 31/07/2021 09:29, Krzysztof Kozlowski wrote:

On 30/07/2021 21:02, Sam Protsenko wrote:

quoted

Hi Krzysztof,

On Fri, 30 Jul 2021 at 20:21, Krzysztof Kozlowski
[off-list ref] wrote:

quoted

On 30/07/2021 17:18, Krzysztof Kozlowski wrote:

quoted

On 30/07/2021 16:49, Sam Protsenko wrote:

quoted

This patch series adds initial platform support for Samsung Exynos850
SoC [1]. With this patchset it's possible to run the kernel with BusyBox
rootfs as a RAM disk. More advanced platform support (like MMC driver
additions) will be added later. The idea is to keep the first submission
minimal to ease the review, and then build up on top of that.

[1] https://www.samsung.com/semiconductor/minisite/exynos/products/mobileprocessor/exynos-850/

Great work!

Thanks, Krzysztof! And thank you for reviewing the whole series.

quoted

quoted

What's the SoC revision number (should be accessible via
/sys/bus/soc/devices/soc0/)? Recent wrap in numbering of Exynos chips
might bring confusion...

# cat /sys/devices/soc0/revision
0

soc_id but you're right it won't be set for unknown SoCs. You need to
extend drivers/soc/samsung/exynos-chipid.c to parse new values (E3830000
for product ID) and maybe new register offsets (previous offset is 0x0,
for 3830 is 0x10 I think). Also revision mask might change.

quoted

quoted

Judging by vendor's sources it is quite confusing. It looks mostly like
Exynos3830 but in few other cases it uses Exynos9 compatibles (Exynos9,
Exynos9820). Only in few places there is Exynos850. Marketing department
made it so confusing...  The revision embedded in SoC would be very
interesting.

As I understand, this SoC is called Exynos850 everywhere now.
Exynos3830 is its old name, not used anymore. As you noticed from
patch #2, it shares some definitions with Exynos9 SoC, so I guess some
software is similar for both architectures. Not sure about hardware
though, never worked with Exynos9 CPUs. Anyway, I asked Samsung
representatives about naming, and it seems like we should stick to
"Exynos850" name, even in code.

Since the chip identifies itself as E3830000, I would prefer naming
matching real product ID instead of what is pushed by marketing or sales
representatives. The marketing names don't have to follow any
engineering rules, they can be changed and renamed. Sales follows rather
money and corporate rules, not consistency for upstream project.

On the other hand we have already two exceptions for naming
inconsistency - Exynos3250 identifies itself as 3472 (which is confusing
because 3250 is two core and there is a separate quad-core
Exyons3472...) and Exynos5800 is actually marketing name for a revision
of Exynos5422. Maybe indeed will be easier to go with the branded name
850...


Best regards,
Krzysztof