Re: [PATCH v10 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

["Friday Yang (杨阳)" <Friday.Yang@mediatek.com>]

On Tue, 2025-08-12 at 11:43 +0000, Yong Wu (吴勇) wrote:
> On Wed, 2025-08-06 at 16:59 +0800, Friday Yang wrote:
> > To prevent handling glitch signals during MTCMOS on/off
> > transitions,
> > SMI requires clamp and reset operations. Parse the reset settings
> > for
> > SMI LARBs and the clamp settings for the SMI Sub-Common. Register
> > genpd callback for the SMI LARBs located in image, camera and IPE
> > subsystems, and apply reset and clamp operations within the
> > callback.
> > 
> > Signed-off-by: Friday Yang <friday.yang@mediatek.com>
> > ---
> >  drivers/memory/mtk-smi.c | 129
> > +++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 129 insertions(+)
> > 
> > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> > index 733e22f695ab..acc8904dd117 100644
> > --- a/drivers/memory/mtk-smi.c
> > +++ b/drivers/memory/mtk-smi.c
> > @@ -10,11 +10,15 @@
> >  #include <linux/err.h>
> >  #include <linux/io.h>
> >  #include <linux/iopoll.h>
> > +#include <linux/mfd/syscon.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_platform.h>
> >  #include <linux/platform_device.h>
> > +#include <linux/pm_domain.h>
> >  #include <linux/pm_runtime.h>
> > +#include <linux/regmap.h>
> > +#include <linux/reset.h>
> >  #include <linux/soc/mediatek/mtk_sip_svc.h>
> >  #include <soc/mediatek/smi.h>
> >  #include <dt-bindings/memory/mt2701-larb-port.h>
> > @@ -34,6 +38,8 @@
> >  #define SMI_FIFO_TH1			0x238
> >  #define SMI_FIFO_TH2			0x23c
> >  #define SMI_DCM				0x300
> > +#define SMI_COMMON_CLAMP_EN_SET		0x3c4
> > +#define SMI_COMMON_CLAMP_EN_CLR		0x3c8
> >  #define SMI_DUMMY			0x444
> >  
> >  /* SMI LARB */
> > @@ -134,6 +140,7 @@ struct mtk_smi_larb_gen {
> >  	unsigned int			larb_direct_to_common_mask;
> >  	unsigned int			flags_general;
> >  	const u8			(*ostd)[SMI_LARB_PORT_NR_MAX];
> > +	const u8			*clamp_port;
> >  };
> >  
> >  struct mtk_smi {
> > @@ -150,6 +157,7 @@ struct mtk_smi {
> >  };
> >  
> >  struct mtk_smi_larb { /* larb: local arbiter */
> > +	struct device			*dev;
> >  	struct mtk_smi			smi;
> >  	void __iomem			*base;
> >  	struct device			*smi_common_dev; /* common
> > or
> > sub-common dev */
> > @@ -157,6 +165,10 @@ struct mtk_smi_larb { /* larb: local arbiter
> > */
> >  	int				larbid;
> >  	u32				*mmu;
> >  	unsigned char			*bank;
> > +	struct regmap			*smi_comm_syscon; /* smi-
> > comm 
> > or sub-comm */
> > +	u8				smi_comm_in_port_id; /* smi-
> > comm or sub-comm */
> > +	struct notifier_block		nb;
> > +	struct reset_control		*rst_con;
> >  };
> >  
> >  static int
> > @@ -478,6 +490,19 @@ static const u8
> > mtk_smi_larb_mt8195_ostd[][SMI_LARB_PORT_NR_MAX] = {
> >  	[28] = {0x1a, 0x0e, 0x0a, 0x0a, 0x0c, 0x0e, 0x10,},
> >  };
> >  
> > +static const u8 mtk_smi_larb_clamp_port_mt8188[MTK_LARB_NR_MAX] =
> > {
> > +	[9]	= BIT(1), /* larb10 */
> > +	[10]	= BIT(2), /* larb11a */
> > +	[11]	= BIT(2), /* larb11b */
> > +	[12]	= BIT(3), /* larb11c */
> > +	[13]	= BIT(0), /* larb12 */
> > +	[16]	= BIT(1), /* larb15 */
> > +	[17]	= BIT(2), /* larb16a */
> > +	[18]	= BIT(2), /* larb16b */
> > +	[19]	= BIT(3), /* larb17a */
> > +	[20]	= BIT(3), /* larb17b */
> > +};
> > +
> >  static const struct mtk_smi_larb_gen mtk_smi_larb_mt2701 = {
> >  	.port_in_larb = {
> >  		LARB0_PORT_OFFSET, LARB1_PORT_OFFSET,
> > @@ -531,6 +556,7 @@ static const struct mtk_smi_larb_gen
> > mtk_smi_larb_mt8188 = {
> >  	.flags_general	            = MTK_SMI_FLAG_THRT_UPDATE |
> > MTK_SMI_FLAG_SW_FLAG |
> >  				      MTK_SMI_FLAG_SLEEP_CTL |
> > MTK_SMI_FLAG_CFG_PORT_SEC_CTL,
> >  	.ostd		            = mtk_smi_larb_mt8188_ostd,
> > +	.clamp_port                 = mtk_smi_larb_clamp_port_mt8188,
> >  };
> >  
> >  static const struct mtk_smi_larb_gen mtk_smi_larb_mt8192 = {
> > @@ -582,6 +608,45 @@ static void
> > mtk_smi_larb_sleep_ctrl_disable(struct mtk_smi_larb *larb)
> >  	writel_relaxed(0, larb->base + SMI_LARB_SLP_CON);
> >  }
> >  
> > +static int mtk_smi_larb_clamp_protect_enable(struct device *dev,
> > bool enable)
> > +{
> > +	struct mtk_smi_larb *larb = dev_get_drvdata(dev);
> > +	u32 reg;
> > +	int ret;
> > +
> > +	/* smi_comm_syscon may be NULL if the subsys doesn't have bus
> > glitch issues */
> > +	if (!larb->smi_comm_syscon)
> > +		return -EINVAL;
> > +
> > +	reg = enable ? SMI_COMMON_CLAMP_EN_SET :
> > SMI_COMMON_CLAMP_EN_CLR;
> > +
> > +	ret = regmap_write(larb->smi_comm_syscon, reg, larb-
> > > smi_comm_in_port_id);
> > 
> > +	if (ret)
> > +		dev_err(dev, "Unable to %s clamp for input port %d:
> > %d\n",
> > +			enable ? "enable" : "disable",
> > +			larb->smi_comm_in_port_id, ret);
> > +
> > +	return ret;
> > +}
> > +
> > +static int mtk_smi_genpd_callback(struct notifier_block *nb,
> > +				  unsigned long flags, void *data)
> > +{
> > +	struct mtk_smi_larb *larb = container_of(nb, struct
> > mtk_smi_larb, nb);
> > +	struct device *dev = larb->dev;
> > +
> > +	if (flags == GENPD_NOTIFY_PRE_ON || flags ==
> > GENPD_NOTIFY_PRE_OFF) {
> > +		/* disable related SMI sub-common port */
> > +		mtk_smi_larb_clamp_protect_enable(dev, true);
> > +	} else if (flags == GENPD_NOTIFY_ON) {
> > +		/* enable related SMI sub-common port */
> > +		reset_control_reset(larb->rst_con);
> > +		mtk_smi_larb_clamp_protect_enable(dev, false);
> > +	}
> > +
> > +	return NOTIFY_OK;
> > +}
> > +
> >  static int mtk_smi_device_link_common(struct device *dev, struct
> > device **com_dev)
> >  {
> >  	struct platform_device *smi_com_pdev;
> > @@ -638,6 +703,51 @@ static int mtk_smi_dts_clk_init(struct device
> > *dev, struct mtk_smi *smi,
> >  	return ret;
> >  }
> >  
> > +static int mtk_smi_larb_parse_clamp_optional(struct mtk_smi_larb
> > *larb)
> > +{
> > +	struct device *dev = larb->dev;
> > +	const struct mtk_smi_larb_gen *larb_gen = larb->larb_gen;
> > +	u32 larb_id;
> > +	int ret;
> > +
> > +	/*
> > +	 * Only SMI LARBs in camera, image and IPE subsys need to
> > +	 * apply clamp and reset operations, others can be skipped.
> > +	 */
> > +	ret = of_property_read_u32(dev->of_node, "mediatek,larb-id",
> > &larb_id);
> > +	if (ret || !larb_gen->clamp_port || !larb_gen-
> > > clamp_port[larb_id])
> > 
> > +		return 0;
> > +
> > +	larb->smi_comm_in_port_id = larb_gen->clamp_port[larb_id];
> > +	larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev-
> > > of_node,
> > 
> > +								"mediat
> > ek,smi");
> > +	if (IS_ERR(larb->smi_comm_syscon)) {
> > +		larb->smi_comm_syscon = NULL;
> > +		return dev_err_probe(dev, -EINVAL,
> > +				     "Unknown clamp port for larb
> > %d\n", larb_id);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int mtk_smi_larb_parse_reset_optional(struct mtk_smi_larb
> > *larb)
> > +{
> > +	struct device *dev = larb->dev;
> > +	int ret;
> > +
> > +	larb->rst_con = devm_reset_control_get_optional_exclusive(dev,
> > "larb");
> > +	if (!larb->rst_con)
> > +		return 0;
> > +
> > +	larb->nb.notifier_call = mtk_smi_genpd_callback;
> > +	ret = dev_pm_genpd_add_notifier(dev, &larb->nb);
> > +	if (ret)
> > +		return dev_err_probe(dev, -EINVAL,
> > +				     "Failed to add genpd callback
> > %d\n", ret);
> > +
> > +	return 0;
> > +}
> > +
> >  static int mtk_smi_larb_probe(struct platform_device *pdev)
> >  {
> >  	struct mtk_smi_larb *larb;
> > @@ -648,6 +758,7 @@ static int mtk_smi_larb_probe(struct
> > platform_device *pdev)
> >  	if (!larb)
> >  		return -ENOMEM;
> >  
> > +	larb->dev = dev;
> >  	larb->larb_gen = of_device_get_match_data(dev);
> >  	larb->base = devm_platform_ioremap_resource(pdev, 0);
> >  	if (IS_ERR(larb->base))
> > @@ -664,6 +775,14 @@ static int mtk_smi_larb_probe(struct
> > platform_device *pdev)
> >  	if (ret < 0)
> >  		return ret;
> >  
> > +	ret = mtk_smi_larb_parse_clamp_optional(larb);
> > +	if (ret)
> > +		goto err_link_remove;
> > +
> > +	ret = mtk_smi_larb_parse_reset_optional(larb);
> > +	if (ret)
> > +		goto err_link_remove;
> 
> 
> If we have "larb_gen->clamp_port[larb_id]", we must have the reset
> function, is this right? if yes,
> 
> if (larb->smi_comm_syscon && larb_gen->clamp_port[larb_id]) {
>    ret = mtk_smi_larb_parse_reset(larb);  // Not optional.
> }
> 
> and then we could remove the checking of larb->smi_comm_syscon in 
> mtk_smi_larb_clamp_protect_enable, it will be simpler.
> 
> Thanks.
> 

Thanks for comments.
You are right. We can fix it like this. Just determine whether
clamp and reset are required in 'mtk_smi_larb_probe'. If we
have "larb_gen->clamp_port[larb_id]", then clamp and reset operations
are required. And the '_optional' suffix should be removed from the
function name in this case.

in mtk_smi_larb_probe:
...
if (larb->larb_gen->clamp_port && larb->larb_gen->clamp_port[larb-
>larbid]) {
		ret = mtk_smi_larb_parse_clamp(larb, larb->larbid);
		if (ret)
			goto err_link_remove;

		ret = mtk_smi_larb_parse_reset(larb);
		if (ret)
			goto err_link_remove;
	}
...