On 2/24/20 3:21 AM, Ang, Chee Hong wrote: [...]
Currently, we have like 20+ secure registers allowed access by drivers running in non-secure mode (U-Boot proper / Linux). I don't think we want to define and maintain those high level interfaces for each of those secure register accesses in ATF and U-Boot.
See above.
OK. Then these secure access register should be set up in SPL (EL3). U-Boot drivers shouldn't access them at all because the driver may be running in SPL(EL3) and in U-Boot proper (EL2) too. I can take a look at those drivers accessing secure registers and try to move/decouple those secure access from U-Boot drivers to SPL (EL3) then we no longer need those secure register access functions.
I think that would be great, no ?
Since the SDMMC/DWMAC drivers read the device tree to configure the behaviour of the hardware via the secure registers. I think it should still be part of the driver instead of configuring the hardware in different places. I have proposed using ATF's high-level APIs to achieve this
when the driver is running in EL2.
I have already proposed this in other email threads. Are you OK with this approach ?
I think something more high level might be a good idea here.
What do you mean by 'more high level' ? We handle this in SPL (EL3) ?
Since you are the author of this 'drivers/net/dwmac_socfpga.c': https://gitlab.denx.de/u-boot/u-boot/blob/master/drivers/net/dwmac_socfpga.c... https://gitlab.denx.de/u-boot/u-boot/blob/master/arch/arm/dts/socfpga_strati...
Your driver selects the PHY interface (RGMII/RMII and etc) using the following register (part of System Manager): https://www.intel.com/content/www/us/en/programmable/hps/stratix-10/hps.html...
I personally think this PHY interface select for EMACx shouldn't be part of System Manager. I don't see the security benefits here by making this PHY interface select as 'secure zone' register.
Same applies to DW MMC driver as well: https://gitlab.denx.de/u-boot/u-boot/blob/master/drivers/mmc/socfpga_dw_mmc....
It sets the following register in System Manager (secure zone) to configure the SDMMC clocks: https://www.intel.com/content/www/us/en/programmable/hps/stratix-10/hps.html...
Don't you think these things should be part of driver itself as what we are doing now instead of removing these from drivers and place them in SPL (EL3)?