[PATCH v7 0/2] Add SMI reset and clamp for MediaTek MT8188 SoC

[PATCH v7 0/2] Add SMI reset and clamp for MediaTek MT8188 SoC

[Friday Yang]

Based on tag: next-20250429, linux-next/master

On the MediaTek MT8188 SoC platform, we encountered power-off failures
and SMI bus hang issues during camera stress tests. The issue arises
because bus glitches are sometimes produced when MTCMOS powers on or
off. While this is fairly normal, the software must handle these
glitches to avoid mistaking them for transaction signals. What's
more, this issue emerged only after the initial upstreaming of SMI
driver.

The software solutions can be summarized as follows:

1. Use CLAMP to disable the SMI sub-common port after turning off the
   LARB CG and before turning off the LARB MTCMOS.
2. Use CLAMP to disable/enable the SMI sub-common port.
3. Implement an AXI reset for SMI LARBs.

Changes v7:
- Remove the 'devm_pm_runtime_enable' change.

v6:
https://lore.kernel.org/lkml/20250408033206.12176-2-friday.yang@mediatek.com/
https://lore.kernel.org/lkml/20250408033206.12176-3-friday.yang@mediatek.com/
https://lore.kernel.org/lkml/20250408-bulky-optimistic-lobster-69ed77@shite/

friday.yang (2):
  dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188
  memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

 .../mediatek,smi-common.yaml                  |   2 +
 .../memory-controllers/mediatek,smi-larb.yaml |  19 +++
 drivers/memory/mtk-smi.c                      | 133 ++++++++++++++++++
 3 files changed, 154 insertions(+)

--
2.46.0

[PATCH v7 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Friday Yang]

From: "Friday Yang" <friday.yang@mediatek.com>

Add 'resets' and 'reset-names' properties for SMI LARBs to support
SMI reset operations.
On the MediaTek platform, some SMI LARBs are directly connected to
the SMI Common, while others are connected to the SMI Sub-Common,
which in turn is connected to the SMI Common. The hardware block
diagram can be described as follows.

             SMI-Common(Smart Multimedia Interface Common)
                 |
         +----------------+------------------+
         |                |                  |
         |                |                  |
         |                |                  |
         |                |                  |
         |                |                  |
       larb0       SMI-Sub-Common0     SMI-Sub-Common1
                   |      |     |      |             |
                  larb1  larb2 larb3  larb7       larb9

Signed-off-by: Friday Yang <friday.yang@mediatek.com>
Tested-by: Friday Yang <friday.yang@mediatek.com>
Reviewed-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>

---
 .../mediatek,smi-common.yaml                  |  2 ++
 .../memory-controllers/mediatek,smi-larb.yaml | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
index 0762e0ff66ef..3d98c08b2149 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
@@ -40,6 +40,7 @@ properties:
           - mediatek,mt8186-smi-common
           - mediatek,mt8188-smi-common-vdo
           - mediatek,mt8188-smi-common-vpp
+          - mediatek,mt8188-smi-sub-common
           - mediatek,mt8192-smi-common
           - mediatek,mt8195-smi-common-vdo
           - mediatek,mt8195-smi-common-vpp
@@ -108,6 +109,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - mediatek,mt8188-smi-sub-common
               - mediatek,mt8195-smi-sub-common
     then:
       required:
diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
index 2e7fac4b5094..fc5feb2eac1f 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
@@ -70,6 +70,12 @@ properties:
     description: the hardware id of this larb. It's only required when this
       hardware id is not consecutive from its M4U point of view.

+  resets:
+    maxItems: 1
+
+  reset-names:
+    const: larb
+
 required:
   - compatible
   - reg
@@ -126,6 +132,19 @@ allOf:
       required:
         - mediatek,larb-id

+  - if:  # only for image, camera and ipe subsys
+      properties:
+        compatible:
+          const: mediatek,mt8188-smi-larb
+        mediatek,larb-id:
+          enum:
+            [ 9, 10, 11, 12, 13, 16, 17, 18, 19, 20 ]
+
+    then:
+      required:
+        - resets
+        - reset-names
+
 additionalProperties: false

 examples:
--
2.46.0

[PATCH v7 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

[Friday Yang]

From: "Friday Yang" <friday.yang@mediatek.com>

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>
Tested-by: Friday Yang <friday.yang@mediatek.com>
Reviewed-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>

---
 drivers/memory/mtk-smi.c | 133 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)

diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
index c086c22511f7..f3745f549629 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>
@@ -36,6 +40,12 @@
 #define SMI_DCM				0x300
 #define SMI_DUMMY			0x444

+#define SMI_COMMON_CLAMP_EN		0x3c0
+#define SMI_COMMON_CLAMP_EN_SET		0x3c4
+#define SMI_COMMON_CLAMP_EN_CLR		0x3c8
+
+#define SMI_SUB_COMM_INPORT_NR		(8)
+
 /* SMI LARB */
 #define SMI_LARB_SLP_CON                0xc
 #define SLP_PROT_EN                     BIT(0)
@@ -134,6 +144,7 @@ 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 +161,7 @@ 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 +169,10 @@ struct mtk_smi_larb { /* larb: local arbiter */
 	int				larbid;
 	u32				*mmu;
 	unsigned char			*bank;
+	struct regmap			*sub_comm_syscon;
+	u8				sub_comm_inport;
+	struct notifier_block		nb;
+	struct reset_control		*rst_con;
 };

 static int
@@ -446,6 +462,19 @@ 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,
@@ -498,6 +527,7 @@ 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 = {
@@ -549,6 +579,46 @@ 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;
+
+	/* sub_comm_syscon could be NULL if larb directly linked to SMI common */
+	if (!larb->sub_comm_syscon)
+		return -EINVAL;
+
+	reg = enable ? SMI_COMMON_CLAMP_EN_SET : SMI_COMMON_CLAMP_EN_CLR;
+
+	ret = regmap_write(larb->sub_comm_syscon, reg,
+			   larb->sub_comm_inport);
+	if (ret)
+		dev_err(dev, "Unable to %s clamp for input port %d: %d\n",
+			enable ? "enable" : "disable",
+			larb->sub_comm_inport, 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;
@@ -605,6 +675,53 @@ 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;
+	if (!larb_gen->clamp_port || !larb_gen->clamp_port[larb_id])
+		return 0;
+
+	larb->sub_comm_inport = larb_gen->clamp_port[larb_id];
+	larb->sub_comm_syscon = syscon_regmap_lookup_by_phandle(dev->of_node,
+								"mediatek,smi");
+	if (IS_ERR(larb->sub_comm_syscon)) {
+		larb->sub_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;
@@ -615,6 +732,7 @@ 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))
@@ -631,6 +749,14 @@ 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;
+
 	pm_runtime_enable(dev);
 	platform_set_drvdata(pdev, larb);
 	ret = component_add(dev, &mtk_smi_larb_component_ops);
@@ -640,6 +766,7 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)

 err_pm_disable:
 	pm_runtime_disable(dev);
+err_link_remove:
 	device_link_remove(dev, larb->smi_common_dev);
 	return ret;
 }
@@ -770,6 +897,11 @@ static const struct mtk_smi_common_plat mtk_smi_common_mt8188_vpp = {
 	.init     = mtk_smi_common_mt8195_init,
 };

+static const struct mtk_smi_common_plat mtk_smi_sub_common_mt8188 = {
+	.type     = MTK_SMI_GEN2_SUB_COMM,
+	.has_gals = true,
+};
+
 static const struct mtk_smi_common_plat mtk_smi_common_mt8192 = {
 	.type     = MTK_SMI_GEN2,
 	.has_gals = true,
@@ -814,6 +946,7 @@ static const struct of_device_id mtk_smi_common_of_ids[] = {
 	{.compatible = "mediatek,mt8186-smi-common", .data = &mtk_smi_common_mt8186},
 	{.compatible = "mediatek,mt8188-smi-common-vdo", .data = &mtk_smi_common_mt8188_vdo},
 	{.compatible = "mediatek,mt8188-smi-common-vpp", .data = &mtk_smi_common_mt8188_vpp},
+	{.compatible = "mediatek,mt8188-smi-sub-common", .data = &mtk_smi_sub_common_mt8188},
 	{.compatible = "mediatek,mt8192-smi-common", .data = &mtk_smi_common_mt8192},
 	{.compatible = "mediatek,mt8195-smi-common-vdo", .data = &mtk_smi_common_mt8195_vdo},
 	{.compatible = "mediatek,mt8195-smi-common-vpp", .data = &mtk_smi_common_mt8195_vpp},
--
2.46.0

Re: [PATCH v7 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

[Krzysztof Kozlowski]

On 30/04/2025 11:45, Friday Yang wrote:
> From: "Friday Yang" <friday.yang@mediatek.com>
> 
> 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>
> Tested-by: Friday Yang <friday.yang@mediatek.com>

How is this possible? Are you claiming that none of other authors test
their patches? How testing would be not implied by authorship?

> Reviewed-by: Yong Wu <yong.wu@mediatek.com>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Acked-by: Rob Herring <robh@kernel.org>

Changelog says that v7 has only following changes:

  - Remove the 'devm_pm_runtime_enable' change.

While v6 had no such tags.

No clue what happened here, but looks like mess with the tags and really
incomplete changelog.

Best regards,
Krzysztof

Re: [PATCH v7 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Krzysztof Kozlowski]

On 30/04/2025 11:45, Friday Yang wrote:
> From: "Friday Yang" <friday.yang@mediatek.com>
> 
> Add 'resets' and 'reset-names' properties for SMI LARBs to support
> SMI reset operations.
> On the MediaTek platform, some SMI LARBs are directly connected to
> the SMI Common, while others are connected to the SMI Sub-Common,
> which in turn is connected to the SMI Common. The hardware block
> diagram can be described as follows.
> 
>              SMI-Common(Smart Multimedia Interface Common)
>                  |
>          +----------------+------------------+
>          |                |                  |
>          |                |                  |
>          |                |                  |
>          |                |                  |
>          |                |                  |
>        larb0       SMI-Sub-Common0     SMI-Sub-Common1
>                    |      |     |      |             |
>                   larb1  larb2 larb3  larb7       larb9
> 
> Signed-off-by: Friday Yang <friday.yang@mediatek.com>
> Tested-by: Friday Yang <friday.yang@mediatek.com>

That's not possible. Otherwise explain me how do you test bindings (and
using static checkers is not testing).


> Reviewed-by: Yong Wu <yong.wu@mediatek.com>

Where? Provide lore link. That's a v7 so I expect all your work to be
done public.


Best regards,
Krzysztof

Re: [PATCH v7 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

[Friday Yang (杨阳)]

On Sun, 2025-05-04 at 15:40 +0200, Krzysztof Kozlowski wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On 30/04/2025 11:45, Friday Yang wrote:
> > From: "Friday Yang" <friday.yang@mediatek.com>
> > 
> > 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>
> > Tested-by: Friday Yang <friday.yang@mediatek.com>
> 
> How is this possible? Are you claiming that none of other authors
> test
> their patches? How testing would be not implied by authorship?
> 

OK, I will remove this tag in the new version.

> > Reviewed-by: Yong Wu <yong.wu@mediatek.com>
> > Reviewed-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@collabora.com>
> > Acked-by: Rob Herring <robh@kernel.org>
> 
> Changelog says that v7 has only following changes:
> 
>   - Remove the 'devm_pm_runtime_enable' change.
> 
> While v6 had no such tags.
> 
> No clue what happened here, but looks like mess with the tags and
> really
> incomplete changelog.
> 

Apology for the miss, I will add more detailed descriptions and remove
the incorrect tags in the new version.

> Best regards,
> Krzysztof

Re: [PATCH v7 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Friday Yang (杨阳)]

On Sun, 2025-05-04 at 15:42 +0200, Krzysztof Kozlowski wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On 30/04/2025 11:45, Friday Yang wrote:
> > From: "Friday Yang" <friday.yang@mediatek.com>
> > 
> > Add 'resets' and 'reset-names' properties for SMI LARBs to support
> > SMI reset operations.
> > On the MediaTek platform, some SMI LARBs are directly connected to
> > the SMI Common, while others are connected to the SMI Sub-Common,
> > which in turn is connected to the SMI Common. The hardware block
> > diagram can be described as follows.
> > 
> >              SMI-Common(Smart Multimedia Interface Common)
> >                  |
> >          +----------------+------------------+
> >          |                |                  |
> >          |                |                  |
> >          |                |                  |
> >          |                |                  |
> >          |                |                  |
> >        larb0       SMI-Sub-Common0     SMI-Sub-Common1
> >                    |      |     |      |             |
> >                   larb1  larb2 larb3  larb7       larb9
> > 
> > Signed-off-by: Friday Yang <friday.yang@mediatek.com>
> > Tested-by: Friday Yang <friday.yang@mediatek.com>
> 
> That's not possible. Otherwise explain me how do you test bindings
> (and
> using static checkers is not testing).
> 
> 

You are right, I just used static check scripts to test this patch on
my local server. I will remove this tag in the new version.

> > Reviewed-by: Yong Wu <yong.wu@mediatek.com>
> 
> Where? Provide lore link. That's a v7 so I expect all your work to be
> done public.
> 
> 

This tag should be removed too. He just reviewed this patch in our
internal gerrit and did not reply in the public way.
Apology for the miss.

> Best regards,
> Krzysztof