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Message-ID: <4801f911-c453-4ee1-83b5-ee2ae6087488@collabora.com>
Date: Tue, 5 Aug 2025 10:09:38 +0200
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
To: Friday Yang (杨阳) <Friday.Yang@...iatek.com>,
"robh@...nel.org" <robh@...nel.org>,
"matthias.bgg@...il.com" <matthias.bgg@...il.com>,
Yong Wu (吴勇) <Yong.Wu@...iatek.com>,
"p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
"krzk@...nel.org" <krzk@...nel.org>,
"conor+dt@...nel.org" <conor+dt@...nel.org>
Cc: "linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
Project_Global_Chrome_Upstream_Group
<Project_Global_Chrome_Upstream_Group@...iatek.com>
Subject: Re: [PATCH v9 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp
for MT8188
Il 05/08/25 09:59, Friday Yang (杨阳) ha scritto:
> On Mon, 2025-08-04 at 15:08 +0200, AngeloGioacchino Del Regno wrote:
>> External email : Please do not click links or open attachments until
>> you have verified the sender or the content.
>>
>>
>> Il 04/08/25 14:51, Friday Yang ha scritto:
>>> 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@...iatek.com>
>>> ---
>>> drivers/memory/mtk-smi.c | 131
>>> +++++++++++++++++++++++++++++++++++++++
>>> 1 file changed, 131 insertions(+)
>>>
>>> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
>>> index 733e22f695ab..8c1bd245aac9 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_inport_id; /* smi-
>>> comm or sub-comm */
>>
>> one nit nere: smi_comm_in_port_id
>>
> Ok, I will rename 'smi_comm_inport_id' to 'smi_comm_in_port_id'.
>
>>> + 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_inport_id);
>>> + if (ret)
>>> + dev_err(dev, "Unable to %s clamp for input port %d:
>>> %d\n",
>>> + enable ? "enable" : "disable",
>>> + larb->smi_comm_inport_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 +703,53 @@ 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)
>>> + return -EINVAL;
>>
>> This looks wrong.
>>
> I will change to 'return 0' here.
>
>>> + if (!larb_gen->clamp_port || !larb_gen->clamp_port[larb_id])
>>> + return 0;
>>> +
>>> + larb->smi_comm_inport_id = larb_gen->clamp_port[larb_id];
>>> + larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev-
>>>> of_node,
>>> + "medi
>>> atek,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 +760,7 @@ 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 +777,14 @@ 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;
>>
>> That's optional, right?
>>
>> In function mtk_smi_larb_parse_clamp_optional(), you're returning
>> -EINVAL
>> and here you're failing probe, so that's not optional anymore.
>>
>> Regards,
>> Angelo
>>
> Yes, this clamp setting is optional. Not all smi larbs require it, only
> those within the ISP subsystem do. I understand your point that
> optional settings should not cause the probe to fail. Therefore, I
> could modify the code to 'return 0' if it fails to get 'larb_id',
> similar to when 'larb_gen->clamp_port' is NULL or 'larb_gen-
> clamp_port[larb_id]' is zero. Is this acceptable for you?
> Thanks.
Yes, that's ok.
Cheers,
Angelo
>
>>> +
>>> + ret = mtk_smi_larb_parse_reset_optional(larb);
>>> + if (ret)
>>> + goto err_link_remove;
>>> +
>>> pm_runtime_enable(dev);
>>> platform_set_drvdata(pdev, larb);
>>> ret = component_add(dev, &mtk_smi_larb_component_ops);
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