[PATCH v4 2/4] clk: imx8mq: Add a clock driver for the imx8mq

[Heiko Thiery]

Hi,

Am Mi., 16. März 2022 um 08:14 Uhr schrieb Heiko Thiery
<heiko.thiery at gmail.com>:
>
> Hi Angus,
>
> Am Di., 15. März 2022 um 16:46 Uhr schrieb Angus Ainslie
> <angus.ainslie at puri.sm>:
> >
> > Hi Heiko,
> >
> > On 2022-03-15 08:35, Heiko Thiery wrote:
> >
> > Hi Angus and all,
> >
> >
> >
> >
> > Am Di., 15. März 2022 um 14:09 Uhr schrieb Angus Ainslie <angus at akkea.ca>:
> >>
> >> This is a DM clock driver based off the imx8mm u-boot driver and the linux
> >> kernel driver.
> >>
> >> All of the PLLs and clocks are initialized so the subsystems below are
> >> functional and tested.
> >>
> >> 1) USB host and peripheral
> >> 2) ECSPI
> >> 3) UART
> >> 4) I2C all busses
> >> 5) USDHC for eMMC support
> >> 6) USB storage
> >> 7) GPIO
> >> 8) DRAM
> >>
> >>
> > Snip
> >
> >
> > when adding this patch and enabling CLK_IMX8MQ I see the following on my board .. Any idea what I missed here?
> >
> > --- >8 ---
> > U-Boot SPL 2022.04-rc4-00008-g390d9bf9a1 (Mar 15 2022 - 16:26:59 +0100)
> > Trying to boot from SD card
> >
> >
> > U-Boot 2022.04-rc4-00008-g390d9bf9a1 (Mar 15 2022 - 16:26:59 +0100)
> >
> > CPU:   Freescale i.MX8MQ rev2.1 at 800 MHz
> > Reset cause: POR
> > Model: Kontron pITX-imx8m
> > DRAM:  alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > alloc space exhausted
> > 4 GiB
> >
> > My guess is that there was static code that was setting up the DRAM pll that isn't get executed now that there's a DM clock driver.
> >
> > I'd try enabling DEBUG in the clk-uclass and clk-composite drivers.
> >
> > Also look at what DRAM initialization code is not being run now. Our board doesn't have an DRAM specific initialization so there could be a bug in the DRAM setup.
>
> The problem was the MALLOC_F_LEN value. Increasing that the "alloc
> space exhausted" is gone.
>
> But with the enabled DM_SERIAL the problem of "No serial driver found"
> is still there and the board reboots. You said you have DM_SERIAL
> enabled and it works?

Meanwhile I figured out what the problem is with the 'No serial driver
found'. In the used dtb there are 'assigned-clocks' and
'assigned-clock-parents' set in the uart nodes. When removing this the
serial will work. I have to admit that I do not know why this is set
that way. I can only imagine that this was taken from the uboot-imx
tree.

---
assigned-clocks = <&clk IMX8MQ_CLK_UART1>;
assigned-clock-parents = <&clk IMX8MQ_SYS1_PLL_80M>;
---

see also here: https://source.denx.de/u-boot/u-boot/-/blob/master/arch/arm/dts/imx8mq-kontron-pitx-imx8m.dts#L315

-- 
Heiko