linux-kernel - Re: [PATCH] soc: qcom: rpmh-rsc: Factor "tcs_reg_addr" and "tcs_cmd

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Date:   Tue, 14 Apr 2020 10:56:20 -0700
From:   Joe Perches <joe@...ches.com>
To:     Douglas Anderson <dianders@...omium.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     mkshah@...eaurora.org, mka@...omium.org, swboyd@...omium.org,
        evgreen@...omium.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] soc: qcom: rpmh-rsc: Factor "tcs_reg_addr" and
 "tcs_cmd_addr" calculation

On Tue, 2020-04-14 at 10:41 -0700, Douglas Anderson wrote:
> We can make some of the register access functions more readable by
> factoring out the calculations a little bit.

unrelated trivia:

> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
[]
>  static void write_tcs_reg_sync(struct rsc_drv *drv, int reg, int tcs_id,
>  			       u32 data)
>  {
> -	writel(data, drv->tcs_base + RSC_DRV_TCS_OFFSET * tcs_id + reg);
> +	writel(data, tcs_reg_addr(drv, reg, tcs_id));
>  	for (;;) {
> -		if (data == readl(drv->tcs_base + reg +
> -				  RSC_DRV_TCS_OFFSET * tcs_id))
> +		if (data == readl(tcs_reg_addr(drv, reg, tcs_id)))
>  			break;
>  		udelay(1);
>  	}

There a lockup potential here.

It might be better to use some max loop counter with
an error/warning emitted instead of a continuous retry.