Re: [PATCH v1] scsi: ufs: ufs-mediatek: Change dbg select by check hw version

[Bart Van Assche <bvanassche@xxxxxxx>]

On 8/30/21 05:11, peter.wang@xxxxxxxxxxxx wrote:
> +static void ufs_mtk_dbg_sel(struct ufs_hba *hba)
> +{
> +	static u32 hw_ver;
> +
> +	if (!hw_ver)
> +		hw_ver = ufshcd_readl(hba, REG_UFS_MTK_HW_VER);
> +
> +	if (((hw_ver >> 16) & 0xFF) >= 0x36) {
> +		ufshcd_writel(hba, 0x820820, REG_UFS_DEBUG_SEL);
> +		ufshcd_writel(hba, 0x0, REG_UFS_DEBUG_SEL_B0);
> +		ufshcd_writel(hba, 0x55555555, REG_UFS_DEBUG_SEL_B1);
> +		ufshcd_writel(hba, 0xaaaaaaaa, REG_UFS_DEBUG_SEL_B2);
> +		ufshcd_writel(hba, 0xffffffff, REG_UFS_DEBUG_SEL_B3);
> +	} else {
> +		ufshcd_writel(hba, 0x20, REG_UFS_DEBUG_SEL);
> +	}
> +}

Can ufs_mtk_dbg_sel() be called from multiple threads at the same time? 
Does the 'hw_ver' variable need to be protected against concurrent writes?

Thanks,

Bart.