Hi Martin, On Fri, 18 Oct 2019 at 23:40, Martin Blumenstingl <martin.blumensti...@googlemail.com> wrote: > > Hi Anand, > > On Fri, Oct 18, 2019 at 4:04 PM Anand Moon <linux.am...@gmail.com> wrote: > [...] > > > Next step it to try narrow down the clock causing the issue. > > > Remove clk_ignore_unused from the command line and add CLK_INGORE_UNUSED > > > to the flag of some clocks your clock controller (g12a I think) until > > > > > > The peripheral clock gates already have this flag (something we should > > > fix someday) so don't bother looking there. > > > > > > Most likely the source of the pwm is getting disabled between the > > > late_init call and the probe of the PWM module. Since the pwm is already > > > active (w/o a driver), gating the clock source shuts dowm the power to > > > the cores. > > > > > > Looking a the possible inputs in pwm driver, I'd bet on fdiv4. > > > > > > > I had give this above steps a try but with little success. > > I am still looking into this much close. > it's not clear to me if you have only tested with the PWM and/or > FCLK_DIV4 clocks. can you please describe what you have tested so far? > Sorry for delayed response.
I had just looked into clk related to SD_EMMC_A/B/C, with adding CLK_IGNORE/CRITICAL. Also looked into clk_summary for eMMC and microSD card, to identify the root cause, but I failed to move ahead. > for reference - my way of debugging this in the past was: > 1. add some printks to clk_disable_unused_subtree (right after the > clk_core_is_enabled check) to see which clocks are being disabled > 2. add CLK_IGNORE_UNUSED or CLK_IS_CRITICAL to the clocks which are > being disabled based on the information from step #1 > 3. (at some point I had a working kernel with lots of clocks with > CLK_IGNORE_UNUSED/CLK_IS_CRITICAL) > 4. start dropping the CLK_IGNORE_UNUSED/CLK_IS_CRITICAL flags again > until you have traced it down to the clocks that are the actual issue > (so far I always had only one clock which caused issues, but it may be > multiple) > 5. investigate (and/or ask on the mailing list, Amlogic developers are > reading the mails here as well) for the few clocks from step #4 > Thanks for you valuable suggestion. I have your patch to debug this [0] https://patchwork.kernel.org/patch/9725921/mbox/ So from the fist step I could identify that all the clk were getting closed after some core cpu clk was failing. Here is the log. step1: [1] https://pastebin.com/p13F9HGG so I marked these clk as CLK_IGNORE_UNUSED and finally I made it to boot using microSD card. After this just I converted these CLK to CLK_IS_CRITICAL as mostly these are used the CPU clk for now. Here is boot log successful for as of now. Finally: [2] https://pastebin.com/qB6pMyGQ I know clk maintainer are against marking flags as *CLK_IS_CRITICAL* But this is just the step to move ahead. Attach is my local clk and dts patch.Just for testing. [3] clk_critical.patch Plz share your thought on this. > > Well I am not the expert in clk or bus configuration. > > but after looking into the datasheet of for clk configuration > > I found some bus are not configured correctly. > did you find any reason which indicates that the problem is related to a bus? > the issues I had were due to clocks not being assigned to their > consumers in .dts - that can be anything (from a bus to something > different). > Yes I feel each core bus should be independent as each clk PLL controls these bus. for example datasheet: *6-5 Clock Connections* What I feel currently missing with bus are clock gating (enable/disable of features). clock-controller reset-controller Here is the current overview of bus topology using latest u-boot (dm tree). [4] https://pastebin.com/MZ25bgiP Bet Regards -Anand
clk_critical.patch
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