[BUG] USB boot issue on ROCKPro64 with UEFI

[BUG] USB boot issue on ROCKPro64 with UEFI

[Vincent Stehlé]

Hi U-Boot folks,

Hopefully this is the right way to report bugs. If not, please do not hesitate
to let me know.

I am hitting an issue with U-Boot v2021.07 on the ROCKPro64, when booting Linux
with UEFI from USB. The kernel EFI stub will hang:

  EFI stub: Booting Linux Kernel...
  EFI stub: Using DTB from configuration table
  EFI stub: Exiting boot services and installing virtual address map...

After tracking it down, it appears efi_exit_boot_services() is ultimately
calling OHCI hc_reset(), which hangs at this line:

  1804         if (ohci_readl(&ohci->regs->control) & OHCI_CTRL_IR) {

This seems to indicate reading the OHCI hardware control register cannot
complete, which hints at a clocking issue.

Looking in more details at the clocks changes performed on the
efi_exit_boot_services() path, a workaround is indeed to prevent the USB2PHY
clocks from being disabled (see the patch following this e-mail).

I don't know enough about the RK3399 clock tree to fully understand what is
going on here, and what would be a proper fix. Hopefully others will be able to
continue from there.

Best regards,

Vincent Stehlé
System Architect - Arm

Vincent Stehlé (1):
  clk: rk3399: do not disable the USB2PHY clk

 drivers/clk/rockchip/clk_rk3399.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.30.2

[PATCH WORKAROUND] clk: rk3399: do not disable the USB2PHY clk

[Vincent Stehlé]

When booting from USB with UEFI on the ROCKPro64, the Linux kernel EFI stub
will hang in efi_exit_boot_services due to OHCI hc_reset accessing the
hardware registers after the USB2PHY clocks have been disabled.

As a workaround, prevent the USB2PHY clocks from being disabled to repair
the boot.

Signed-off-by: Vincent Stehlé <vincent.stehle@arm.com>
---

                    THIS IS A WORKAROUND
                    PLEASE DO NOT APPLY!

 drivers/clk/rockchip/clk_rk3399.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/rockchip/clk_rk3399.c b/drivers/clk/rockchip/clk_rk3399.c
index f8cbda44551..9cf7d26a026 100644
--- a/drivers/clk/rockchip/clk_rk3399.c
+++ b/drivers/clk/rockchip/clk_rk3399.c
@@ -1213,10 +1213,10 @@ static int rk3399_clk_disable(struct clk *clk)
 		rk_setreg(&priv->cru->clkgate_con[5], BIT(6));
 		break;
 	case SCLK_USB2PHY0_REF:
-		rk_setreg(&priv->cru->clkgate_con[6], BIT(5));
+		/* WORKAROUND: leave enabled */
 		break;
 	case SCLK_USB2PHY1_REF:
-		rk_setreg(&priv->cru->clkgate_con[6], BIT(6));
+		/* WORKAROUND: leave enabled */
 		break;
 	case ACLK_GMAC:
 		rk_setreg(&priv->cru->clkgate_con[32], BIT(0));
-- 
2.30.2

Re: [BUG] USB boot issue on ROCKPro64 with UEFI

[Arnaud Patard]

Vincent Stehlé <vincent.stehle@arm.com> writes:

Hi,

> Hi U-Boot folks,
>
> Hopefully this is the right way to report bugs. If not, please do not hesitate
> to let me know.
>
> I am hitting an issue with U-Boot v2021.07 on the ROCKPro64, when booting Linux
> with UEFI from USB. The kernel EFI stub will hang:
>
>   EFI stub: Booting Linux Kernel...
>   EFI stub: Using DTB from configuration table
>   EFI stub: Exiting boot services and installing virtual address map...
>
> After tracking it down, it appears efi_exit_boot_services() is ultimately
> calling OHCI hc_reset(), which hangs at this line:
>
>   1804         if (ohci_readl(&ohci->regs->control) & OHCI_CTRL_IR) {
>
> This seems to indicate reading the OHCI hardware control register cannot
> complete, which hints at a clocking issue.
>
> Looking in more details at the clocks changes performed on the
> efi_exit_boot_services() path, a workaround is indeed to prevent the USB2PHY
> clocks from being disabled (see the patch following this e-mail).
>
> I don't know enough about the RK3399 clock tree to fully understand what is
> going on here, and what would be a proper fix. Hopefully others will be able to
> continue from there.

I may be wrong but seems like the issue solved by
https://patchwork.ozlabs.org/project/uboot/patch/20210406151059.1187379-1-icenowy@aosc.io/
Unfortunately, I think that there has been no progress since the
submission of this patch.

Arnaud

Re: [BUG] USB boot issue on ROCKPro64 with UEFI

[Vincent Stehlé]

On Fri, Sep 03, 2021 at 07:02:13PM +0200, Arnaud Patard wrote:
..
> I may be wrong but seems like the issue solved by
> https://patchwork.ozlabs.org/project/uboot/patch/20210406151059.1187379-1-icenowy@aosc.io/
> Unfortunately, I think that there has been no progress since the
> submission of this patch.

Hi Arnaud,

You are right, this patch solves the issue I am seeing on the ROCKPro64.
Thanks for the pointer.

Best regards,

Vincent Stehlé
System Architect - Arm