Re: [PATCH u-boot-marvell 5/9] arm: mvebu: a38x: serdes: Don't set PCIe Common Clock Configuration

[Stefan Roese <sr@denx.de>]

On 24.09.21 22:59, Marek Behún wrote:
> From: Pali Rohár <pali@kernel.org>
> 
> Enabling Common Clock Configuration bit in PCIe Root Port Link Control
> Register should not be done unconditionally. It is enabled by operating
> system as part of ASPM. Also after enabling Common Clock Configuration it
> is required to do more work, like retraining link. Some cards may be broken
> due to this incomplete Common Clock Configuration and some cards are broken
> and do not support ASPM at all.
> 
> Remove this incomplete code for Common Clock Configuration. It really
> should not be done in SerDes code as it is not related to SerDes, but to
> PCIe subsystem.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> Reviewed-by: Marek Behún <marek.behun@nic.cz>

Reviewed-by: Stefan Roese <sr@denx.de>

Thanks,
Stefan

> ---
>   .../mach-mvebu/serdes/a38x/high_speed_env_spec.c  | 15 ---------------
>   1 file changed, 15 deletions(-)
> 
> diff --git a/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c b/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
> index a712fa8994..824f4d3e3d 100644
> --- a/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
> +++ b/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
> @@ -1737,21 +1737,6 @@ int serdes_power_up_ctrl(u32 serdes_num, int serdes_power_up,
>   				reg_data |= (is_pex_by1 ? 1 : 4) << 4;
>   				reg_write(PEX0_RP_PCIE_CFG_OFFSET +
>   					  PCI_EXP_LNKCAP, reg_data);
> -
> -				/*
> -				 * Set Common Clock Configuration to indicates
> -				 * that both devices on the link use a
> -				 * distributed common reference clock.
> -				 */
> -				reg_data = reg_read(PEX_CFG_DIRECT_ACCESS(
> -						     pex_idx,
> -						     PEX_LINK_CTRL_STAT_REG));
> -				reg_data &= ~0x40;
> -				reg_data |= 0x40;
> -				reg_write(PEX_CFG_DIRECT_ACCESS(
> -					   pex_idx,
> -					   PEX_LINK_CTRL_STAT_REG),
> -					  reg_data);
>   			}
>   
>   			CHECK_STATUS(mv_seq_exec(serdes_num, PEX_POWER_UP_SEQ));
> 


Viele Grüße,
Stefan

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