[PATCH v1 0/3] mediatek-gen3: Add support for MT8196/MT6991

[PATCH v1 0/3] mediatek-gen3: Add support for MT8196/MT6991

[AngeloGioacchino Del Regno]

This series adds (at least partial) support for the MediaTek MT8196
Chromebook SoC and for the MT6991 Dimensity 9400 Smartphone SoC's
PCI-Express controller.

Some strange PEXTP settings were omitted, as the intention is to find
a way to set those bits *outside* of the PCI-Express driver itself as
the downstream implementation is using ugly syscons to make the PCIe
controller driver to change bits inside of a clock controller.

In the meanwhile, this is a set of clean changes that are required for
the controller inside those SoCs in *any* case; further development
will occur, with high hopes to find a solution outside of this driver.

AngeloGioacchino Del Regno (3):
  PCI: mediatek-gen3: Implement sys clock ready time setting
  dt-bindings: PCI: mediatek-gen3: Add support for MT6991/MT8196
  PCI: mediatek-gen3: Add support for MediaTek MT8196 SoC

 .../bindings/pci/mediatek-pcie-gen3.yaml      | 35 +++++++++++++++++++
 drivers/pci/controller/pcie-mediatek-gen3.c   | 24 +++++++++++++
 2 files changed, 59 insertions(+)

-- 
2.49.0

[PATCH v1 1/3] PCI: mediatek-gen3: Implement sys clock ready time setting

[AngeloGioacchino Del Regno]

In preparation to add support for the PCI-Express Gen3 controller
found in newer MediaTek SoCs, such as the Dimensity 9400 MT6991
and the MT8196 Chromebook SoC, add the definition for the PCIE
Resource Control register and a new sys_clk_rdy_time_us variable
in platform data.

If sys_clk_rdy_time_us is found (> 0), set the new value in the
aforementioned register only after configuring the controller to
RC mode, as this may otherwise be reset.

Overriding the register defaults for SYS_CLK_RDY_TIME allows to
work around sys_clk_rdy signal glitching in MT6991 and MT8196.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/pci/controller/pcie-mediatek-gen3.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index b55f5973414c..00c9f2532870 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -101,6 +101,9 @@
 #define PCIE_MSI_SET_ADDR_HI_BASE	0xc80
 #define PCIE_MSI_SET_ADDR_HI_OFFSET	0x04
 
+#define PCIE_RESOURCE_CTRL_REG		0xd2c
+#define PCIE_RSRC_SYS_CLK_RDY_TIME_MASK	GENMASK(7, 0)
+
 #define PCIE_ICMD_PM_REG		0x198
 #define PCIE_TURN_OFF_LINK		BIT(4)
 
@@ -148,6 +151,7 @@ enum mtk_gen3_pcie_flags {
  * struct mtk_gen3_pcie_pdata - differentiate between host generations
  * @power_up: pcie power_up callback
  * @phy_resets: phy reset lines SoC data.
+ * @sys_clk_rdy_time_us: System clock ready time override (microseconds)
  * @flags: pcie device flags.
  */
 struct mtk_gen3_pcie_pdata {
@@ -156,6 +160,7 @@ struct mtk_gen3_pcie_pdata {
 		const char *id[MAX_NUM_PHY_RESETS];
 		int num_resets;
 	} phy_resets;
+	u8 sys_clk_rdy_time_us;
 	u32 flags;
 };
 
@@ -436,6 +441,15 @@ static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie)
 		writel_relaxed(val, pcie->base + PCIE_CONF_LINK2_CTL_STS);
 	}
 
+	/* If parameter is present, adjust SYS_CLK_RDY_TIME to avoid glitching */
+	if (pcie->soc->sys_clk_rdy_time_us) {
+		val = readl_relaxed(pcie->base + PCIE_RESOURCE_CTRL_REG);
+		val &= ~PCIE_RSRC_SYS_CLK_RDY_TIME_MASK;
+		val |= FIELD_PREP(PCIE_RSRC_SYS_CLK_RDY_TIME_MASK,
+				  pcie->soc->sys_clk_rdy_time_us);
+		writel_relaxed(val, pcie->base + PCIE_RESOURCE_CTRL_REG);
+	}
+
 	/* Set class code */
 	val = readl_relaxed(pcie->base + PCIE_PCI_IDS_1);
 	val &= ~GENMASK(31, 8);
-- 
2.49.0

[PATCH v1 2/3] dt-bindings: PCI: mediatek-gen3: Add support for MT6991/MT8196

[AngeloGioacchino Del Regno]

Add compatible strings for MT8196 and MT6991 (which are fully
compatible between each other) and clock definitions.

These new SoCs don't have tl_96m and tl_32k clocks, but need
an AHB to APB bus clock and a low power clock.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 .../bindings/pci/mediatek-pcie-gen3.yaml      | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml b/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml
index 162406e0691a..02cddf0246ce 100644
--- a/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml
+++ b/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml
@@ -52,7 +52,12 @@ properties:
               - mediatek,mt8188-pcie
               - mediatek,mt8195-pcie
           - const: mediatek,mt8192-pcie
+      - items:
+          - enum:
+              - mediatek,mt6991-pcie
+          - const: mediatek,mt8196-pcie
       - const: mediatek,mt8192-pcie
+      - const: mediatek,mt8196-pcie
       - const: airoha,en7581-pcie
 
   reg:
@@ -212,6 +217,36 @@ allOf:
 
         mediatek,pbus-csr: false
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - mediatek,mt8196-pcie
+    then:
+      properties:
+        clocks:
+          minItems: 6
+
+        clock-names:
+          items:
+            - const: pl_250m
+            - const: tl_26m
+            - const: bus
+            - const: low_power
+            - const: peri_26m
+            - const: peri_mem
+
+        resets:
+          minItems: 1
+          maxItems: 2
+
+        reset-names:
+          minItems: 1
+          maxItems: 2
+
+        mediatek,pbus-csr: false
+
   - if:
       properties:
         compatible:
-- 
2.49.0

[PATCH v1 3/3] PCI: mediatek-gen3: Add support for MediaTek MT8196 SoC

[AngeloGioacchino Del Regno]

Introduce support for the PCI-Express Gen3 controller found in the
MT8196 (and MT6991) SoC by adding a compatible string and platform
specific data.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/pci/controller/pcie-mediatek-gen3.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index 00c9f2532870..43b99779274f 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -1359,6 +1359,15 @@ static const struct mtk_gen3_pcie_pdata mtk_pcie_soc_mt8192 = {
 	},
 };
 
+static const struct mtk_gen3_pcie_pdata mtk_pcie_soc_mt8196 = {
+	.power_up = mtk_pcie_power_up,
+	.phy_resets = {
+		.id[0] = "phy",
+		.num_resets = 1,
+	},
+	.sys_clk_rdy_time_us = 10,
+};
+
 static const struct mtk_gen3_pcie_pdata mtk_pcie_soc_en7581 = {
 	.power_up = mtk_pcie_en7581_power_up,
 	.phy_resets = {
@@ -1373,6 +1382,7 @@ static const struct mtk_gen3_pcie_pdata mtk_pcie_soc_en7581 = {
 static const struct of_device_id mtk_pcie_of_match[] = {
 	{ .compatible = "airoha,en7581-pcie", .data = &mtk_pcie_soc_en7581 },
 	{ .compatible = "mediatek,mt8192-pcie", .data = &mtk_pcie_soc_mt8192 },
+	{ .compatible = "mediatek,mt8196-pcie", .data = &mtk_pcie_soc_mt8196 },
 	{},
 };
 MODULE_DEVICE_TABLE(of, mtk_pcie_of_match);
-- 
2.49.0

Re: [PATCH v1 2/3] dt-bindings: PCI: mediatek-gen3: Add support for MT6991/MT8196

[Rob Herring]

On Mon, Jun 23, 2025 at 02:00:57PM +0200, AngeloGioacchino Del Regno wrote:
> Add compatible strings for MT8196 and MT6991 (which are fully
> compatible between each other) and clock definitions.
> 
> These new SoCs don't have tl_96m and tl_32k clocks, but need
> an AHB to APB bus clock and a low power clock.
> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
>  .../bindings/pci/mediatek-pcie-gen3.yaml      | 35 +++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml b/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml
> index 162406e0691a..02cddf0246ce 100644
> --- a/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml
> +++ b/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml
> @@ -52,7 +52,12 @@ properties:
>                - mediatek,mt8188-pcie
>                - mediatek,mt8195-pcie
>            - const: mediatek,mt8192-pcie
> +      - items:
> +          - enum:
> +              - mediatek,mt6991-pcie
> +          - const: mediatek,mt8196-pcie
>        - const: mediatek,mt8192-pcie
> +      - const: mediatek,mt8196-pcie
>        - const: airoha,en7581-pcie
>  
>    reg:
> @@ -212,6 +217,36 @@ allOf:
>  
>          mediatek,pbus-csr: false
>  
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - mediatek,mt8196-pcie
> +    then:
> +      properties:
> +        clocks:
> +          minItems: 6
> +
> +        clock-names:
> +          items:
> +            - const: pl_250m
> +            - const: tl_26m
> +            - const: bus
> +            - const: low_power
> +            - const: peri_26m
> +            - const: peri_mem
> +
> +        resets:
> +          minItems: 1

The min is already 1.

> +          maxItems: 2
> +
> +        reset-names:
> +          minItems: 1
> +          maxItems: 2

It would be good to define what the names are. I assume they are fixed 
and not just any of the allowed ones.

> +
> +        mediatek,pbus-csr: false
> +
>    - if:
>        properties:
>          compatible:
> -- 
> 2.49.0
>