Hello Dave,
It depends on what features you need to satisfy your use case (kernel + base + application). Stable older kernels can do some tasks well enough if they have the features you need in place. If you need newer features then what an older kernel provided, it can be a lot of work to back port. Also if the kernel is used in open networks then how to handle security is also something to consider.
I've not booted my OMAP2430 board for several years, however, I do have some old tablets and phones I start from time to time. The last kernel's I used on it were around the time frame of what you are using. It is very likely some newer snapshots were done on a per project basis.
Probably a good minimal kernel with basic drivers can be made at multiple points. I'm less sure about the state of open drivers with WL18xx. I'd suggest exploring that a bit more to see if it ends up dominating. For early WLAN, sometimes firmware and fragile DMA integrations were hard to work around.
Regards,
Richard W.
-----Original Message-----
From: David Russell <david.russell73@xxxxxxxxx>
Sent: Wednesday, August 11, 2021 7:54 AM
To: Tony Lindgren <tony@xxxxxxxxxxx>
Cc: Woodruff, Richard <r-woodruff2@xxxxxx>; linux-omap@xxxxxxxxxxxxxxx
Subject: Re: [EXTERNAL] OMAP2430 kernel hangs on ioremap of IVA2.1 addresses
Good Morning,
I have been upgrading a legacy project that runs on an OMAP2430 based on the linux-omap repo (tag v2.6.28-omap1) to mainline v5.10; I have been able to get the main application running, however I am concerned there are potentially many underlying issues I have not corrected nor even seen yet. I recalled Tony’s comment that the part is dated (of course there is no argument from me there) to the point that I am not sure to what extent anyone has used the latest mainline on an OMAP2xxx part (i.e., regression testing).
I am hopeful someone has a good suggestion to the following question: what mainline kernel version would be considered the most stable in regards to an OMAP2430 processor that may also include the TI WL18xx wifi driver? Or if they do not overlap, simply what is the latest mainline kernel version that would be most stable for OMAP2xxx? I am just afraid the v5.10 and v4.19 are so new that there are underlying issues that would take significant time to chase down; but if I can roll-back to an older version (yet newer than 2.6.28), that might get me closer to where I need to be.
Thanks for any suggestions,
Dave
> On Jun 8, 2021, at 11:20 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote:
>
> Hi,
>
> * Woodruff, Richard <r-woodruff2@xxxxxx> [210607 15:40]:
>> Guess: this bit in JTAG script used for IVA tests probably is missing and needs to be worked in. The generic linux-omap clock code probably handles the IVA clock but maybe not the resets.
>>
>> /* Enable IVA-ss functional clock (set bit 0) */
>> (*(int*)0x49006800) |= 0x1;
>>
>> /* Release l3s_idle_req */
>> (*(int*)0x49006810) |= (1 << 1);
>>
>> /* Release L3S reset and power-on reset (clear bit 1) at the same time */
>> (*(int*)0x49006850) &= ~(( 1 << 1));
>
> Heh and I thought nobody is using 2430 any longer :)
>
> FYI, the current mainline kernel actually can deal with all that using
> reset driver and genpd, see for example commits:
>
> ae57d1558908 ("ARM: dts: Configure interconnect target module for dra7
> iva")
> effe89e40037 ("soc: ti: omap-prm: Fix occasional abort on reset
> deassert for dra7 iva")
>
> Similar setup should also work for 2430 but needs the power domains
> configured for drivers/soc/ti/omap_prm.c at least for iva.
>
> David, I think what you're seeing is iva getting released from reset
> with an unconfigured MMU, and then the system will hang.
>
> Regards,
>
> Tony
