[PATCH] firmware: psci: Do not bind driver if U-Boot runs in EL3

[Michal Simek]

On 05. 08. 20 14:37, Michal Simek wrote:
> There is no reason to bind psci driver if U-Boot runs in EL3 because
> SMC/HVC instructions can't be called. That's why detect this state and
> don't let user to crash from prompt by performing reset or poweroff
> commands (if enabled).
> 
> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
> ---
> 
> Maybe there is a better way how to do it. Maybe do it in probe instead of
> bind. Feel free to comment but this doesn't look right behavior.
> 
> U-Boot SPL 2020.10-rc1-00046-g5fade0c9d867 (Aug 05 2020 - 14:36:03 +0200)
> PMUFW:	v1.1
> Loading new PMUFW cfg obj (2024 bytes)
> EL Level:	EL3
> Multiboot:	0
> Trying to boot from MMC2
> spl: could not initialize mmc. error: -19
> Trying to boot from MMC1
> spl_load_image_fat_os: error reading image u-boot.bin, err - -2
> 
> U-Boot 2020.10-rc1-00046-g5fade0c9d867 (Aug 05 2020 - 14:36:03 +0200)
> 
> Model: ZynqMP ZCU104 RevC
> Board: Xilinx ZynqMP
> DRAM:  2 GiB
> PMUFW:	v1.1
> EL Level:	EL3
> Chip ID:	zu7e
> Multiboot:	0
> WDT:   Started with servicing (60s timeout)
> NAND:  0 MiB
> MMC:   mmc at ff170000: 0
> In:    serial at ff000000
> Out:   serial at ff000000
> Err:   serial at ff000000
> Bootmode: LVL_SHFT_SD_MODE1
> Reset reason:	EXTERNAL
> Net:
> ZYNQ GEM: ff0e0000, mdio bus ff0e0000, phyaddr 12, interface rgmii-id
> eth0: ethernet at ff0e0000
> Hit any key to stop autoboot:  0
> ZynqMP>
> ZynqMP> reset
> resetting ...
> "Synchronous Abort" handler, esr 0x5e000000
> elr: 0000000008000194 lr : 0000000008000220 (reloc)
> elr: 000000007fec9194 lr : 000000007fec9220
> x0 : 0000000084000009 x1 : 0000000000000000
> x2 : 0000000000000000 x3 : 0000000000000000
> x4 : 0000000000000000 x5 : 0000000000000000
> x6 : 0000000000000000 x7 : 0000000000000000
> x8 : 000000007deaedb0 x9 : 000000000000000c
> x10: 00000000000007c4 x11: 000000007deae92c
> x12: 0000000000000006 x13: 000000000001869f
> x14: 000000007deaedb0 x15: 0000000000000002
> x16: 000000007ff2af5c x17: 0000000000000000
> x18: 000000007deb8db0 x19: 0000000000000000
> x20: 000000007ffb0268 x21: 0000000000000000
> x22: 000000007debc600 x23: 0000000000000001
> x24: 000000007ffc7898 x25: 0000000000000000
> x26: 0000000000000000 x27: 0000000000000000
> x28: 000000007debc640 x29: 000000007deaeaf0
> 
> Code: 00000000 f9020000 00000000 d4000003 (f94003e4)
> Resetting CPU ...
> 
>  ### ERROR ### Please RESET the board ###
> 
> ---
>  drivers/firmware/psci.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index 23cf807591c4..1bef7eea56fc 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -69,6 +69,9 @@ static int psci_probe(struct udevice *dev)
>  {
>  	const char *method;
>  
> +	if (current_el() == 3)
> +		return -EINVAL;
> +
>  	method = ofnode_read_string(dev_ofnode(dev), "method");
>  	if (!method) {
>  		pr_warn("missing \"method\" property\n");
> 

Just a note:
#include <asm/system.h>
is missing on latest. But let's discussed this before I send v2.

Thanks,
Michal