Hi Konrad,
On 9/11/2023 5:17 PM, Konrad Dybcio wrote:
On 11.09.2023 07:59, Can Guo wrote:
From: "Bao D. Nguyen" <quic_nguyenb@xxxxxxxxxxx>
Retrieve UFS device version from UFS host controller's spare register
which is populated by bootloader, and use the UFS device version together
with host controller's HW version to decide the proper power modes which
should be used to configure the UFS PHY.
That sounds a bit fishy.. is there no bootloader-independent
solution to that? Can't we bring in the code that the bootloader
uses to determine these values?
Konrad
Agree, it is.
All these complexities come from one request from PHY design team -
power saving.
And to achieve power saving, Qualcomm UFS developers are requested to
use the
lowest hanging PHY settings which can sustain the Max agreed HS Gear
(btw host
and UFS device) during UFS's lifecycle in High Level OS, whereas the
power saving
request does not apply to bootloader, which works for only a few seconds
during
bootup. Hence, there is no such version detect code in bootloader - it
just uses the
highest PHY settings to configure PHY, boot up UFS and put UFS device
version in this
register.
Thanks,
Can Guo.
