linux-kernel - Re: [PATCH 3/4] memory: mtk-smi: Add sleep ctrl function

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Message-ID: <9631fe7c-b878-79b0-1680-80b0be089429@canonical.com>
Date:   Sat, 4 Dec 2021 12:48:41 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
To:     Yong Wu <yong.wu@...iatek.com>, Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>
Cc:     Krzysztof Kozlowski <krzk@...nel.org>,
        Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Tomasz Figa <tfiga@...omium.org>,
        linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux-foundation.org, youlin.pei@...iatek.com,
        anan.sun@...iatek.com, lc.kan@...iatek.com, yi.kuo@...iatek.com,
        anthony.huang@...iatek.com
Subject: Re: [PATCH 3/4] memory: mtk-smi: Add sleep ctrl function

On 03/12/2021 07:40, Yong Wu wrote:
> sleep control means that when the larb go to sleep, we should wait a bit

s/go/goes/

> until all the current commands are finished. thus, when the larb runtime

Please start every sentence with a capital letter.

> suspend, we need enable this function to wait until all the existed

s/suspend/suspends/
s/we need enable/we need to enable/

> command are finished. when the larb resume, just disable this function.

s/command/commands/
s/resume/resumes/

> This function only improve the safe of bus. Add a new flag for this

s/improve/improves/
s/the safe/the safety/

> function. Prepare for mt8186.

In total it is hard to parse, really.

> 
> Signed-off-by: Anan Sun <anan.sun@...iatek.com>
> Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> ---
>  drivers/memory/mtk-smi.c | 39 +++++++++++++++++++++++++++++++++++----
>  1 file changed, 35 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index b883dcc0bbfa..4b59b28e4d73 100644
> --- a/drivers/memory/mtk-smi.c
> +++ b/drivers/memory/mtk-smi.c
> @@ -8,6 +8,7 @@
>  #include <linux/device.h>
>  #include <linux/err.h>
>  #include <linux/io.h>
> +#include <linux/iopoll.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_platform.h>
> @@ -32,6 +33,10 @@
>  #define SMI_DUMMY			0x444
>  
>  /* SMI LARB */
> +#define SMI_LARB_SLP_CON                0x00c
> +#define SLP_PROT_EN                     BIT(0)
> +#define SLP_PROT_RDY                    BIT(16)
> +
>  #define SMI_LARB_CMD_THRT_CON		0x24
>  #define SMI_LARB_THRT_RD_NU_LMT_MSK	GENMASK(7, 4)
>  #define SMI_LARB_THRT_RD_NU_LMT		(5 << 4)
> @@ -81,6 +86,7 @@
>  
>  #define MTK_SMI_FLAG_THRT_UPDATE	BIT(0)
>  #define MTK_SMI_FLAG_SW_FLAG		BIT(1)
> +#define MTK_SMI_FLAG_SLEEP_CTL		BIT(2)
>  #define MTK_SMI_CAPS(flags, _x)		(!!((flags) & (_x)))
>  
>  struct mtk_smi_reg_pair {
> @@ -371,6 +377,24 @@ static const struct of_device_id mtk_smi_larb_of_ids[] = {
>  	{}
>  };
>  
> +static int mtk_smi_larb_sleep_ctrl(struct device *dev, bool to_sleep)
> +{

Make two functions instead. There is no single code reuse (shared)
between sleep and resume. In the same time bool arguments are confusing
when looking at caller and one never knows whether true means to resume
or to sleep. Having two functions is obvious. Obvious code is easier to
read and maintain.

> +	struct mtk_smi_larb *larb = dev_get_drvdata(dev);
> +	int ret = 0;
> +	u32 tmp;
> +
> +	if (to_sleep) {
> +		writel_relaxed(SLP_PROT_EN, larb->base + SMI_LARB_SLP_CON);
> +		ret = readl_poll_timeout_atomic(larb->base + SMI_LARB_SLP_CON,
> +						tmp, !!(tmp & SLP_PROT_RDY), 10, 1000);
> +		if (ret)
> +			dev_warn(dev, "sleep ctrl is not ready(0x%x).\n", tmp);
> +	} else {
> +		writel_relaxed(0, larb->base + SMI_LARB_SLP_CON);
> +	}
> +	return ret;
> +}
> +
>  static int mtk_smi_device_link_common(struct device *dev, struct device **com_dev)
>  {
>  	struct platform_device *smi_com_pdev;
> @@ -477,24 +501,31 @@ static int __maybe_unused mtk_smi_larb_resume(struct device *dev)
>  {
>  	struct mtk_smi_larb *larb = dev_get_drvdata(dev);
>  	const struct mtk_smi_larb_gen *larb_gen = larb->larb_gen;
> -	int ret;
> +	int ret = 0;

This line does not have a sense.

>  
>  	ret = clk_bulk_prepare_enable(larb->smi.clk_num, larb->smi.clks);
> -	if (ret < 0)
> +	if (ret)

Why changing this?



Best regards,
Krzysztof