Re: [PATCH v2 2/4] soc: mediatek: Add support of WAY_EN operations

From: AngeloGioacchino Del Regno  <angelogioacchino.delregno@collabora.com>
To: Markus Schneider-Pargmann <msp@baylibre.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Weiyi Lu <weiyi.lu@mediatek.com>
Cc: Fabien Parent <parent.f@gmail.com>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	Alexandre Bailon <abailon@baylibre.com>,
	Fabien Parent <fparent@baylibre.com>
Subject: Re: [PATCH v2 2/4] soc: mediatek: Add support of WAY_EN operations
Date: Mon, 25 Jul 2022 11:55:27 +0200	[thread overview]
Message-ID: <dccc2863-a9db-d9ea-01e1-a18cf0db1d1e@collabora.com> (raw)
In-Reply-To: <20220725081853.1636444-3-msp@baylibre.com>

Il 25/07/22 10:18, Markus Schneider-Pargmann ha scritto:
> From: Alexandre Bailon <abailon@baylibre.com>
> 
> This updates the power domain to support WAY_EN operations. These
> operations enable a path between different units of the chip and are
> labeled as 'way_en' in the register descriptions.
> 
> This operation is required by the mt8365 for the MM power domain.
> 
> Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
> Signed-off-by: Fabien Parent <fparent@baylibre.com>
> Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
> ---
> 
> Notes:
>      Changes in v2:
>      - some minor style fixes.
>      - Renamed 'wayen' to 'way_en' to clarify the meaning
>      - Updated commit message
> 
>   drivers/soc/mediatek/mtk-pm-domains.c | 64 +++++++++++++++++++++------
>   drivers/soc/mediatek/mtk-pm-domains.h | 28 +++++++-----
>   2 files changed, 68 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/soc/mediatek/mtk-pm-domains.c b/drivers/soc/mediatek/mtk-pm-domains.c
> index 5ced254b082b..d0eae2227813 100644
> --- a/drivers/soc/mediatek/mtk-pm-domains.c
> +++ b/drivers/soc/mediatek/mtk-pm-domains.c
> @@ -44,6 +44,7 @@ struct scpsys_domain {
>   	struct clk_bulk_data *subsys_clks;
>   	struct regmap *infracfg;
>   	struct regmap *smi;
> +	struct regmap *infracfg_nao;

What does "nao" mean?

Besides, please move that before *infracfg to at least keep the same type members
alphabetically sorted..

>   	struct regulator *supply;
>   };
>   
> @@ -116,23 +117,38 @@ static int scpsys_sram_disable(struct scpsys_domain *pd)
>   					MTK_POLL_TIMEOUT);
>   }
>   
> -static int _scpsys_bus_protect_enable(const struct scpsys_bus_prot_data *bpd, struct regmap *regmap)
> +static int _scpsys_bus_protect_enable(const struct scpsys_bus_prot_data *bpd,
> +				      struct regmap *regmap, struct regmap *infracfg_nao)
>   {
>   	int i, ret;
>   
>   	for (i = 0; i < SPM_MAX_BUS_PROT_DATA; i++) {
> -		u32 val, mask = bpd[i].bus_prot_mask;
> +		u32 mask = bpd[i].bus_prot_mask;
> +		u32 val = mask, sta_mask = mask;

You have modified the macros to use sta_mask as mask, so, why are you doing
that distinction in here between the two? You can simply keep assigning

		u32 mask = bpd[1].bus_prot_mask;
		u32 sta_mask = bpd[1].bus_prot_sta_mask;

> +		struct regmap *ack_regmap = regmap;

Double assignment. You're reassigning this if way_en == true.

>   
>   		if (!mask)
>   			break;
>   
> +		if (bpd[i].way_en) {
> +			if (!infracfg_nao)
> +				return -ENODEV;
> +
> +			val = 0;
> +			sta_mask = bpd[i].bus_prot_sta_mask;
> +			ack_regmap = infracfg_nao;
> +		}

		if (bpd[i].way_en) {
			ack_regmap = regmap_nao;
			val = 0;
		} else {
			ack_regmap = regmap;
			val = mask;
		}

> +
>   		if (bpd[i].bus_prot_reg_update)
> -			regmap_set_bits(regmap, bpd[i].bus_prot_set, mask);
> +			regmap_update_bits(regmap, bpd[i].bus_prot_set, mask, val);
>   		else
>   			regmap_write(regmap, bpd[i].bus_prot_set, mask);
>   
> -		ret = regmap_read_poll_timeout(regmap, bpd[i].bus_prot_sta,
> -					       val, (val & mask) == mask,
> +		if (bpd[i].ignore_clr_ack)
> +			continue;

You're adding that ignore_clr_ack here in the bus prot enablement function
which wasn't here before... and I didn't check carefully, but I think that
this is wrong: as the name says, it's to "ignore CLEAR ack", we're not doing
any clearing here, we're not in bus_protect_disable.

If you're really sure that this is not a mistake, you should guard it for way_en.

> +
> +		ret = regmap_read_poll_timeout(ack_regmap, bpd[i].bus_prot_sta,
> +					       val, (val & sta_mask) == sta_mask,
>   					       MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);
>   		if (ret)
>   			return ret;
> @@ -145,34 +161,49 @@ static int scpsys_bus_protect_enable(struct scpsys_domain *pd)
>   {
>   	int ret;
>   
> -	ret = _scpsys_bus_protect_enable(pd->data->bp_infracfg, pd->infracfg);
> +	ret = _scpsys_bus_protect_enable(pd->data->bp_infracfg,
> +					 pd->infracfg, pd->infracfg_nao);
>   	if (ret)
>   		return ret;
>   
> -	return _scpsys_bus_protect_enable(pd->data->bp_smi, pd->smi);
> +	return _scpsys_bus_protect_enable(pd->data->bp_smi, pd->smi, NULL);
>   }
>   
> +#define mask_cond(way_en, val, mask) \
> +	((way_en && ((val & mask) == mask)) || (!way_en && !(val & mask)))
> +
>   static int _scpsys_bus_protect_disable(const struct scpsys_bus_prot_data *bpd,
> -				       struct regmap *regmap)
> +				       struct regmap *regmap, struct regmap *infracfg_nao)
>   {
>   	int i, ret;
>   
>   	for (i = SPM_MAX_BUS_PROT_DATA - 1; i >= 0; i--) {
> -		u32 val, mask = bpd[i].bus_prot_mask;
> +		u32 val = 0, mask = bpd[i].bus_prot_mask;
> +		u32 sta_mask = mask;
> +		struct regmap *ack_regmap = regmap;
>   
>   		if (!mask)
>   			continue;
>   
> +		if (bpd[i].way_en) {
> +			if (!infracfg_nao)
> +				return -ENODEV;
> +
> +			val = mask;
> +			sta_mask = bpd[i].bus_prot_sta_mask;
> +			ack_regmap = infracfg_nao;
> +		}
> +
>   		if (bpd[i].bus_prot_reg_update)
> -			regmap_clear_bits(regmap, bpd[i].bus_prot_clr, mask);
> +			regmap_update_bits(regmap, bpd[i].bus_prot_clr, mask, val);
>   		else
>   			regmap_write(regmap, bpd[i].bus_prot_clr, mask);
>   
>   		if (bpd[i].ignore_clr_ack)
>   			continue;
>   
> -		ret = regmap_read_poll_timeout(regmap, bpd[i].bus_prot_sta,
> -					       val, !(val & mask),
> +		ret = regmap_read_poll_timeout(ack_regmap, bpd[i].bus_prot_sta,
> +					       val, mask_cond(bpd[i].way_en, val, sta_mask),

"I don't know why", my brain still keeps telling me that using different functions
for the WAY_EN (en/dis) is just better.

This commit seems to be overcomplicating two "easy" en/dis functions.

>   					       MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);
>   		if (ret)
>   			return ret;
> @@ -185,11 +216,12 @@ static int scpsys_bus_protect_disable(struct scpsys_domain *pd)
>   {
>   	int ret;
>   
> -	ret = _scpsys_bus_protect_disable(pd->data->bp_smi, pd->smi);
> +	ret = _scpsys_bus_protect_disable(pd->data->bp_smi, pd->smi, NULL);
>   	if (ret)
>   		return ret;
>   
> -	return _scpsys_bus_protect_disable(pd->data->bp_infracfg, pd->infracfg);
> +	return _scpsys_bus_protect_disable(pd->data->bp_infracfg,
> +			pd->infracfg, pd->infracfg_nao);
>   }
>   
>   static int scpsys_regulator_enable(struct regulator *supply)
> @@ -363,6 +395,10 @@ generic_pm_domain *scpsys_add_one_domain(struct scpsys *scpsys, struct device_no
>   			return ERR_CAST(pd->smi);
>   	}
>   
> +	pd->infracfg_nao = syscon_regmap_lookup_by_phandle_optional(node, "mediatek,infracfg_nao");
> +	if (IS_ERR(pd->infracfg_nao))
> +		return ERR_CAST(pd->infracfg_nao);
> +

I think that we should enforce a check here:

pd->infracfg_nao = syscon_regmap_lookup_by_phandle(node, "mediatek,infracfg_nao");
if (IS_ERR(pd->infracfg_nao)) {
	/* checking if infracfg_nao != NULL at every pwoeron/poweroff is largely
	 * suboptimal, as if it't present once, it's present always (!)
	 */
	if (we have WAY_EN)
		return ERR_CAST ...
	pd->infracfg_nao = NULL;
}

>   	num_clks = of_clk_get_parent_count(node);
>   	if (num_clks > 0) {
>   		/* Calculate number of subsys_clks */
> diff --git a/drivers/soc/mediatek/mtk-pm-domains.h b/drivers/soc/mediatek/mtk-pm-domains.h
> index daa24e890dd4..e788d6bdde9d 100644
> --- a/drivers/soc/mediatek/mtk-pm-domains.h
> +++ b/drivers/soc/mediatek/mtk-pm-domains.h
> @@ -39,23 +39,29 @@
>   
>   #define SPM_MAX_BUS_PROT_DATA		6
>   
> -#define _BUS_PROT(_mask, _set, _clr, _sta, _update, _ignore) {	\
> -		.bus_prot_mask = (_mask),			\
> -		.bus_prot_set = _set,				\
> -		.bus_prot_clr = _clr,				\
> -		.bus_prot_sta = _sta,				\
> -		.bus_prot_reg_update = _update,			\
> -		.ignore_clr_ack = _ignore,			\
> +#define _BUS_PROT(_mask, _sta_mask, _set, _clr, _sta, _update, _ignore, _way_en) {	\
> +		.bus_prot_mask = (_mask),				\
> +		.bus_prot_set = _set,					\
> +		.bus_prot_clr = _clr,					\
> +		.bus_prot_sta = _sta,					\
> +		.bus_prot_sta_mask = _sta_mask,				\
> +		.bus_prot_reg_update = _update,				\
> +		.ignore_clr_ack = _ignore,				\
> +		.way_en = _way_en,					\
>   	}
>   
>   #define BUS_PROT_WR(_mask, _set, _clr, _sta)			\
> -		_BUS_PROT(_mask, _set, _clr, _sta, false, false)
> +		_BUS_PROT(_mask, _mask, _set, _clr, _sta, false, false, false)
>   
>   #define BUS_PROT_WR_IGN(_mask, _set, _clr, _sta)		\
> -		_BUS_PROT(_mask, _set, _clr, _sta, false, true)
> +		_BUS_PROT(_mask, _mask, _set, _clr, _sta, false, true, false)
>   
>   #define BUS_PROT_UPDATE(_mask, _set, _clr, _sta)		\
> -		_BUS_PROT(_mask, _set, _clr, _sta, true, false)
> +		_BUS_PROT(_mask, _mask, _set, _clr, _sta, true, false, false)
> +
> +#define BUS_PROT_WAY_EN(_en_mask, _sta_mask, _set, _sta)	\
> +		_BUS_PROT(_en_mask, _sta_mask, _set, _set, _sta, true, false, \
> +			  true)
>   
>   #define BUS_PROT_UPDATE_TOPAXI(_mask)				\
>   		BUS_PROT_UPDATE(_mask,				\
> @@ -68,8 +74,10 @@ struct scpsys_bus_prot_data {
>   	u32 bus_prot_set;
>   	u32 bus_prot_clr;
>   	u32 bus_prot_sta;
> +	u32 bus_prot_sta_mask;
>   	bool bus_prot_reg_update;
>   	bool ignore_clr_ack;
> +	bool way_en;
>   };
>   
>   /**