[PATCH] arm: mach-k3: Workaround errata ID i2331

[Bryan Brattlof]

Hi Vignesh!

On April  6, 2023 thus sayeth Vignesh Raghavendra:
> From: Nitin Yadav <n-yadav at ti.com>
> 
> Errata doc: https://www.ti.com/lit/pdf/sprz457
> Errata ID i2331 CPSW: Device lockup when reading CPSW registers
> 
> Details: A device lockup can occur during the second read of any CPSW
> subsystem register after any MAIN domain power on reset (POR). A MAIN
> domain POR occurs using the hardware MCU_PORz signal, or via software
> using CTRLMMR_RST_CTRL.SW_MAIN_POR or CTRLMMR_MCU_RST_CTRL.SW_MAIN_POR.
> After these resets, the processor and internal bus structures may get
> into a state which is only recoverable with full device reset using
> MCU_PORz.
> Due to this errata, Ethernet boot should not be used on this device.
> 
> Workaround(s): To avoid the lockup, a warm reset should be issued after
> a MAIN domain POR and before any access to the CPSW registers. The warm
> reset realigns internal clocks and prevents the lockup from happening.
> Workaround above errata by calling do_reset() in case of cold boot in
> order to trigger warm reset. This needs enabling SYSRESET driver in R5
> SPL to enable TI SCI reset driver.
> 
> Signed-off-by: Nitin Yadav <n-yadav at ti.com>
> Signed-off-by: Vignesh Raghavendra <vigneshr at ti.com>
> ---
>  arch/arm/mach-k3/am642_init.c  | 33 +++++++++++++++++++++++++++++++++
>  configs/am64x_evm_r5_defconfig |  3 +++
>  2 files changed, 36 insertions(+)
>

Thanks for sending this! 

Reviewed-by: Bryan Brattlof <bb at ti.com>

~Bryan