[PATCH 3/3] imx: power-domain: Get rid of SMCCC dependency

[Adam Ford]

On Sat, Apr 16, 2022 at 7:35 PM Marek Vasut <marex at denx.de> wrote:
>
> On 4/16/22 22:49, Adam Ford wrote:
> > On Thu, Apr 7, 2022 at 5:21 PM Tim Harvey <tharvey at gateworks.com> wrote:
> >>
> >> On Wed, Mar 30, 2022 at 8:04 PM Marek Vasut <marex at denx.de> wrote:
> >>>
> >>> This driver is the only SMCCC dependency in iMX8M U-Boot port. Rework
> >>> the driver based on Linux GPCv2 driver to directly control the GPCv2
> >>> block instead of using SMCCC calls. This way, U-Boot can operate the
> >>> i.MX8M power domains without depending on anything else.
> >>>
> >>> This is losely based on Linux GPCv2 driver. The GPU, VPU, MIPI power
> >>> domains are not supported to save space, since they are not useful in
> >>> the bootloader. The only domains kept are ones for HSIO, PCIe, USB.
> >>>
> >>> Signed-off-by: Marek Vasut <marex at denx.de>
> >>> Cc: Fabio Estevam <festevam at gmail.com>
> >>> Cc: Peng Fan <peng.fan at nxp.com>
> >>> Cc: Stefano Babic <sbabic at denx.de>
> >>> ---
> >>> NOTE: So far this is tested on MX8MM and MX8MN. MX8MQ is not tested.
> >
> > Sorry for the delay, I tested positive for Covid and needed to recover a bit.
> >
> > I have confirmed this makes the 8MQ hang during boot.
> >
> > Before patch series:
> >
> > U-Boot SPL 2022.04-00812-g9859465bfe (Apr 16 2022 - 15:41:46 -0500)
> > PMIC:  PFUZE100 ID=0x10
> > SEC0:  RNG instantiated
> > Normal Boot
> > Trying to boot from MMC2
> >
> >
> > U-Boot 2022.04-00812-g9859465bfe (Apr 16 2022 - 15:41:46 -0500)
> >
> > CPU:   Freescale i.MX8MQ rev2.1 at 1000 MHz
> > Reset cause: POR
> > Model: NXP i.MX8MQ EVK
> > DRAM:  3 GiB
> > Core:  59 devices, 16 uclasses, devicetree: separate
> > MMC:   FSL_SDHC: 0, FSL_SDHC: 1
> > Loading Environment from MMC... *** Warning - bad CRC, using default environment
> >
> > In:    serial
> > Out:   serial
> > Err:   serial
> > SEC0:  RNG instantiated
> > Net:   eth0: ethernet at 30be0000
> > Hit any key to stop autoboot:  0
> > u-boot=>
> >
> > After the patch:
> >
> > U-Boot SPL 2022.04-00822-gc2a24a7ce5 (Apr 16 2022 - 15:45:29 -0500)
> > PMIC:  PFUZE100 ID=0x10
> > SEC0:  RNG instantiated
> > Normal Boot
> > Trying to boot from MMC2
>
> There should be some sort of output from ATF here, which version did you
> use during your tests ?

I used the version from the imx8mq_evk.rst:

Note: srctree is U-Boot source directory
Get ATF from: https://source.codeaurora.org/external/imx/imx-atf
branch: imx_5.4.47_2.2.0

This works with U-Boot master.  I realize it has the ATF power domain
code, but with the SMCC stuff removed, it should be irrelevant.

>
> Did you set IMX_BOOT_UART_BASE correctly ?
>
> Did you set ATF_LOAD_ADDR correctly ?
>
If I didn't build it right, I don't think 'master' would have booted,
but it did.  I think I built it correctly.

> Do you get a hang when you revert only this specific patch ?

When I reverted the series, it booted again, but I can do a bisect
tomorrow to narrow down the specific patch in the series that causes
the issue.

adam
>
> The GPC is only used for USB and PCI on the MX8MQ, so you shouldn't be
> getting hang so early as to get no output at all.
>
> > <hang>
> >
> > I can test it on 8MN and 8MM, but it sounds like that's already been done.
>
> [...]