On 2/14/2024 8:14 PM, Andrew Lunn wrote:
On Wed, Feb 14, 2024 at 02:49:41PM +0530, Kathiravan Thirumoorthy wrote:
On 1/26/2024 1:35 AM, Andrew Lunn wrote:
On Mon, Jan 22, 2024 at 11:26:58AM +0530, Kathiravan Thirumoorthy wrote:
gcc_snoc_nssnoc_clk, gcc_snoc_nssnoc_1_clk, gcc_nssnoc_nsscc_clk are
enabled by default and it's RCG is properly configured by bootloader.
Which bootloader? Mainline barebox?
Thanks for taking time to review the patches. I couldn't get time to respond
back, sorry for the delay.
I was referring to the U-boot which is delivered as part of the QSDK. I will
call it out explicitly in the next patch.
I've never used QSDK u-boot, so i can only make comments based on my
experience with other vendors build of u-boot. That experience is, its
broken for my use cases, and i try to replace it as soon as possible
with upstream.
I generally want to TFTP boot the kernel and the DT blob. Sometimes
vendor u-boot has networking disabled. Or the TFTP client is
missing. If it is there, the IP addresses are fixed, and i don't want
to modify my network to make it compatible with the vendor
requirements. If the IP addresses can be configured, sometimes there
is no FLASH support so its not possible to actually write the
configuration to FLASH so that it does the right thing on reboot
etc...
Often the vendor u-boot is a black box, no sources. Can you give me a
git URL for the u-boot in QSDK? If the sources are open, i could at
least rebuild it with everything turned on.
You can get the source at
https://git.codelinaro.org/clo/qsdk/oss/boot/u-boot-2016/-/tree/NHSS.QSDK.12.2?ref_type=heads
You should be able to TFTP the images, write into the flash and
configure the IP and so on...
But still, it is better that Linux makes no assumptions about what the
boot loader has done. That makes it much easier to change the
bootloader.
Some of the NSS clocks needs these clocks to be enabled. To avoid
these clocks being disabled by clock framework, drop these entries
from the clock table and enable it in the driver probe itself.
If they are critical clocks, i would expect a device to reference
them. The CCF only disabled unused clocks in late_initcall_sync(),
which means all drivers should of probed and taken a reference on any
clocks they require.
Some of the NSSCC clocks are enabled by bootloaders and CCF disables the
same (because currently there are no consumers for these clocks available in
the tree. These clocks are consumed by the Networking drivers which are
being upstreamed).
If there is no network drivers, you don't need clocks to the
networking hardware. So CCF turning them off seems correct.
Yeah agree with your comments.
QSDK's u-boot enables the network support, so the required NSSCC clocks
are turned ON and left it in ON state. CCF tries to disables the unused
NSSCC clocks but system goes for reboot.
Reason being, to access the NSSCC clocks, these GCC clocks
(gcc_snoc_nssnoc_clk, gcc_snoc_nssnoc_1_clk, gcc_nssnoc_nsscc_clk)
should be turned ON. But CCF disables these clocks as well due to the
lack of consumer.
Once you have actual drivers, this should solve itself, the drivers
will consume the clocks.
Given that, NSSCC is being built as module, there is no issue in booting
the kernel. But if you do insmod of the nsscc-ipq5332.ko, system will
reset.
Without the networking drivers, there is no need to install this module.
And as you stated, once the drivers are available, there will be no issues.
So can I explain the shortcomings of installing this module without the
networking drivers in cover letter and drop this patch all together?
However looking back, gcc_snoc_nssnoc_clk, gcc_snoc_nssnoc_1_clk,
gcc_nssnoc_nsscc_clk are consumed by the networking drivers only. So is it
okay to drop these clocks from the GCC driver and add it back once the
actual consumer needs it?
But why should you remove them. If nothing is using them, they should
be turned off.
Andrew
