[PATCH v4 11/21] misc: altera_sysmgr: Add Altera System Manager driver

[Ang, Chee Hong]

> On 3/11/20 8:03 AM, Ang, Chee Hong wrote:
> >> On 3/11/20 7:35 AM, Ang, Chee Hong wrote:
> >> [...]
> >>
> >>>>>> Hmm, so you're just using misc_ops to still issue generic writes.
> >>>>>> From the discussion with Marek in the last version, I would have
> >>>>>> thought you wanted to create a higher level API instead of still
> >>>>>> tunnelling
> >>>> reads and writes?
> >>>>
> >>>> Any response to this?
> >>> Sorry, I missed this one
> >>> Actually I have created higher level API in ATF but I switch back to
> >>> generic writes because the higher level API in ATF doesn't apply to
> >>> Gen5/A10
> >> platforms.
> >>
> >> ATF doesn't apply to Gen5/A10 either though ?
> >>
> >>> Here is what I will do in my revision in system manager driver:
> >>> 1) drop misc_read/misc_write and use misc_ioctl instead in system
> >>> manager
> >>> 2) misc_ioctl() will support configuring EMAC/SDMMC
> >>> 3) For SoC64 running at EL2 (non-secure), misc_iotctl() will invoke
> >>> the ATF's 'high level' API
> >>> 4) For Gen/A10 and SoC64 running at EL3 (secure), the driver just
> >>> configure the EMAC/SDMMC registers in misc_iotcl() Is this better ?
> >> Can't you configure everything in secure-mode and just not configure
> >> anything anymore in non-secure mode ?
> > Yes. I can move all these configurations to SPL(secure mode) and remove them
> from EMAC/SDMMC drivers.
> > This will affect all platforms even Gen5/A10 even they don’t have the secure
> access problems.
> 
> Gen5/A10 are always in "secure" mode.
> 
> > All Gen5/A10/S10/Agilex share the same EMAC/SDMMC drivers.
> 
> Surely you can abstract this away somehow, e.g. with some function which is
> compiled-out on Gen5/A10, while it's compiled-in on Agilex and tells you
> whether you're in EL2/EL3 mode.
That's right. We have Gen5/A10 always in "secure" mode and
S10/Agilex can be in either "secure" or "non-secure" mode.
All of them share the same DW MMC/MAC drivers.
In all platforms, EMAC driver only active in U-Boot proper but not SPL.
This is not an issue for Gen5/A10 as SPL/U-Boot proper all run in "secure"
mode.
But this is not the case for S10/Agilex, EMAC driver is active only in U-Boot proper
which can be EL2 or EL3 depending whether you include ATF support. So 
the MAC driver has to somehow handle this PHY configuration in EL2 and EL3.
> 
> > For EMAC driver such as 'drivers/net/dwmac_socfpga.c', moving the PHY
> > settings into SPL will leave this EMAC driver just asserting reset to EMAC
> controller and nothing else.
> > EMAC node has to be enabled for SPL device tree as well for MAC PHY
> configuration.
> > If you think it is OK to split the SDMMC clock and EMAC PHY
> > configuration from SDMMC and EMAC drivers and put them in SPL, we can go
> this way.
> > I can just drop the 'system manager' driver and all those high level APIs in ATF.
> 
> If this is only about clock/PHY configuration, can't the clock/PHY driver for
> agilex just handle the EL2/EL3 stuff transparently ?
This is the clock phase settings specific to SDMMC controller.
That's why it is being configured in SDMCC driver instead of clock driver.
There is no PHY driver for EMAC PHY. It's current being handled in
DW MAC driver 'drivers/net/dwmac_socfpga.c'.
> --
> Best regards,
> Marek Vasut