[PATCH net-next v3 0/3] riscv: spacemit: Add ethernet support for K3

[PATCH net-next v3 0/3] riscv: spacemit: Add ethernet support for K3

[Inochi Amaoto]

Add initial support for ethernet controller of the Spacemit K3 SoC.
This ethernet controller is almost a standard Synopsys DesignWare
MAC (version 5.40a). This controller require a syscon device to
configure some basic features, like interface type and internal delay.

Change from v2:
- https://lore.kernel.org/netdev/20260121071315.940130-1-inochiama@gmail.com
patch 1:
1. remove not needed compatible for select
2. drop empty line in "spacemit,apmu" properties
3. add spacemit,apmu properties to required.
patch 3:
1. remove misused phy_fix_phy_mode_for_mac_delays.
2. use local tx clock instead of the clk_tx_i in the dwmac.

Change from v1:
- https://lore.kernel.org/netdev/20260120043609.910302-1-inochiama@gmail.com
patch 1:
1. remove phy clock
patch 3:
1. improve comment and include something special about Spacmit K3 dwmac
2. reorder the included file
3. fix wrong delay macro used in spacemit_dwmac_set_delay.
4. add check for maximum supported delay.
5. use DIV_ROUND_CLOSEST to calculate best delay configuration.
6. use assign for the ctrl register initial value.
7. fix input when calling of_property_read_u32().

Inochi Amaoto (3):
  dt-bindings: net: Add support for Spacemit K3 dwmac
  net: stmmac: platform: Add snps,dwmac-5.40a IP compatible string
  net: stmmac: Add glue layer for Spacemit K3 SoC

 .../devicetree/bindings/net/snps,dwmac.yaml   |   2 +
 .../bindings/net/spacemit,k3-dwmac.yaml       | 103 +++++++++
 drivers/net/ethernet/stmicro/stmmac/Kconfig   |  12 +
 drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
 .../ethernet/stmicro/stmmac/dwmac-spacemit.c  | 218 ++++++++++++++++++
 .../ethernet/stmicro/stmmac/stmmac_platform.c |   1 +
 6 files changed, 337 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/spacemit,k3-dwmac.yaml
 create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c

--
2.52.0

[PATCH net-next v3 1/3] dt-bindings: net: Add support for Spacemit K3 dwmac

[Inochi Amaoto]

The GMAC IP on Spacemit K3 is almost a standard Synopsys DesignWare
MAC (version 5.40a) with some extra clock.

Add necessary compatible string for this device.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 .../devicetree/bindings/net/snps,dwmac.yaml   |   2 +
 .../bindings/net/spacemit,k3-dwmac.yaml       | 103 ++++++++++++++++++
 2 files changed, 105 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/spacemit,k3-dwmac.yaml

diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
index dd3c72e8363e..a3fcb9a251fa 100644
--- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
+++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
@@ -34,6 +34,7 @@ select:
           - snps,dwmac-5.10a
           - snps,dwmac-5.20
           - snps,dwmac-5.30a
+          - snps,dwmac-5.40a
           - snps,dwxgmac
           - snps,dwxgmac-2.10
 
@@ -653,6 +654,7 @@ allOf:
                 - snps,dwmac-5.10a
                 - snps,dwmac-5.20
                 - snps,dwmac-5.30a
+                - snps,dwmac-5.40a
                 - snps,dwxgmac
                 - snps,dwxgmac-2.10
                 - st,spear600-gmac
diff --git a/Documentation/devicetree/bindings/net/spacemit,k3-dwmac.yaml b/Documentation/devicetree/bindings/net/spacemit,k3-dwmac.yaml
new file mode 100644
index 000000000000..fc024a927fcc
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/spacemit,k3-dwmac.yaml
@@ -0,0 +1,103 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/spacemit,k3-dwmac.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Spacemit K3 DWMAC glue layer
+
+maintainers:
+  - Inochi Amaoto <inochiama@gmail.com>
+
+select:
+  properties:
+    compatible:
+      contains:
+        const: spacemit,k3-dwmac
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - const: spacemit,k3-dwmac
+      - const: snps,dwmac-5.40a
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: GMAC main clock
+      - description: PTP clock
+      - description: TX clock
+
+  clock-names:
+    items:
+      - const: stmmaceth
+      - const: ptp_ref
+      - const: tx
+
+  interrupts:
+    minItems: 1
+    items:
+      - description: MAC interrupt
+      - description: MAC wake interrupt
+
+  interrupt-names:
+    minItems: 1
+    items:
+      - const: macirq
+      - const: eth_wake_irq
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    const: stmmaceth
+
+  spacemit,apmu:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      - items:
+          - description: phandle to the syscon node which control the glue register
+          - description: offset of the control register
+          - description: offset of the dline register
+    description:
+      A phandle to syscon with offset to control registers for this MAC
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+  - interrupt-names
+  - resets
+  - reset-names
+  - spacemit,apmu
+
+allOf:
+  - $ref: snps,dwmac.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    ethernet@cac80000 {
+      compatible = "spacemit,k3-dwmac", "snps,dwmac-5.40a";
+      reg = <0xcac80000 0x2000>;
+      clocks = <&syscon_apmu 66>, <&syscon_apmu 68>,
+               <&syscon_apmu 69>;
+      clock-names = "stmmaceth", "ptp_ref", "tx";
+      interrupts = <131 IRQ_TYPE_LEVEL_HIGH>, <276 IRQ_TYPE_LEVEL_HIGH>;
+      interrupt-names = "macirq", "eth_wake_irq";
+      phy-mode = "rgmii-id";
+      phy-handle = <&phy0>;
+      resets = <&syscon_apmu 67>;
+      reset-names = "stmmaceth";
+      spacemit,apmu = <&syscon_apmu 0x384 0x38c>;
+    };
+
-- 
2.52.0

Re: [PATCH net-next v3 1/3] dt-bindings: net: Add support for Spacemit K3 dwmac

[Rob Herring (Arm)]

On Wed, 28 Jan 2026 15:29:27 +0800, Inochi Amaoto wrote:
> The GMAC IP on Spacemit K3 is almost a standard Synopsys DesignWare
> MAC (version 5.40a) with some extra clock.
> 
> Add necessary compatible string for this device.
> 
> Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> ---
>  .../devicetree/bindings/net/snps,dwmac.yaml   |   2 +
>  .../bindings/net/spacemit,k3-dwmac.yaml       | 103 ++++++++++++++++++
>  2 files changed, 105 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/spacemit,k3-dwmac.yaml
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/net/spacemit,k3-dwmac.example.dtb: ethernet@cac80000 (spacemit,k3-dwmac): compatible: ['spacemit,k3-dwmac', 'snps,dwmac-5.40a'] does not contain items matching the given schema
	from schema $id: http://devicetree.org/schemas/net/snps,dwmac.yaml
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/net/spacemit,k3-dwmac.example.dtb: ethernet@cac80000 (spacemit,k3-dwmac): compatible: ['spacemit,k3-dwmac', 'snps,dwmac-5.40a'] does not contain items matching the given schema
	from schema $id: http://devicetree.org/schemas/net/spacemit,k3-dwmac.yaml
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/net/spacemit,k3-dwmac.example.dtb: ethernet@cac80000 (spacemit,k3-dwmac): Unevaluated properties are not allowed ('phy-handle', 'phy-mode' were unexpected)
	from schema $id: http://devicetree.org/schemas/net/spacemit,k3-dwmac.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.kernel.org/project/devicetree/patch/20260128072931.875041-2-inochiama@gmail.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

[PATCH net-next v3 2/3] net: stmmac: platform: Add snps,dwmac-5.40a IP compatible string

[Inochi Amaoto]

Add compatible string for 5.40a version that can avoid to define some
platform data in the glue layer.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 8979a50b5507..54c7b1537ab9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -396,6 +396,7 @@ static const char * const stmmac_gmac4_compats[] = {
 	"snps,dwmac-5.10a",
 	"snps,dwmac-5.20",
 	"snps,dwmac-5.30a",
+	"snps,dwmac-5.40a",
 	NULL
 };
 
-- 
2.52.0

[PATCH net-next v3 3/3] net: stmmac: Add glue layer for Spacemit K3 SoC

[Inochi Amaoto]

The etherenet controller on Spacemit K3 SoC is Synopsys DesignWare
MAC (version 5.40a), with the following special point:
1. The rate of the tx clock line is auto changed when the mac speed
   rate is changed, and no need for changing the input tx clock.
2. This controller require a extra syscon device to configure the
   interface type, enable wake up interrupt and delay configuration
   if needed.

Add Spacemit dwmac driver support on the Spacemit K3 SoC.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 drivers/net/ethernet/stmicro/stmmac/Kconfig   |  12 +
 drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
 .../ethernet/stmicro/stmmac/dwmac-spacemit.c  | 218 ++++++++++++++++++
 3 files changed, 231 insertions(+)
 create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c

diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index 907fe2e927f0..583a4692f5da 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
@@ -216,6 +216,18 @@ config DWMAC_SOPHGO
 	  for the stmmac device driver. This driver is used for the
 	  ethernet controllers on various Sophgo SoCs.
 
+config DWMAC_SPACEMIT
+	tristate "Spacemit dwmac support"
+	depends on OF && (ARCH_SPACEMIT || COMPILE_TEST)
+	select MFD_SYSCON
+	default m if ARCH_SPACEMIT
+	help
+	  Support for ethernet controllers on Spacemit RISC-V SoCs
+
+	  This selects the Spacemit platform specific glue layer support
+	  for the stmmac device driver. This driver is used for the
+	  Spacemit K3 ethernet controllers.
+
 config DWMAC_STARFIVE
 	tristate "StarFive dwmac support"
 	depends on OF && (ARCH_STARFIVE || COMPILE_TEST)
diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
index 7bf528731034..9e32045631d8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Makefile
+++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_RZN1)	+= dwmac-rzn1.o
 obj-$(CONFIG_DWMAC_S32)		+= dwmac-s32.o
 obj-$(CONFIG_DWMAC_SOCFPGA)	+= dwmac-altr-socfpga.o
 obj-$(CONFIG_DWMAC_SOPHGO)	+= dwmac-sophgo.o
+obj-$(CONFIG_DWMAC_SPACEMIT)	+= dwmac-spacemit.o
 obj-$(CONFIG_DWMAC_STARFIVE)	+= dwmac-starfive.o
 obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
 obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c
new file mode 100644
index 000000000000..d5cb91182963
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Spacemit DWMAC platform driver
+ *
+ * Copyright (C) 2026 Inochi Amaoto <inochiama@gmail.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/math.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#include "stmmac_platform.h"
+
+/* ctrl register bits */
+#define PHY_INTF_RGMII			BIT(3)
+#define PHY_INTF_MII			BIT(4)
+
+#define WAKE_IRQ_EN			BIT(9)
+#define PHY_IRQ_EN			BIT(12)
+
+/* dline register bits */
+#define RGMII_RX_DLINE_EN		BIT(0)
+#define RGMII_RX_DLINE_STEP		GENMASK(5, 4)
+#define RGMII_RX_DLINE_CODE		GENMASK(15, 8)
+#define RGMII_TX_DLINE_EN		BIT(16)
+#define RGMII_TX_DLINE_STEP		GENMASK(21, 20)
+#define RGMII_TX_DLINE_CODE		GENMASK(31, 24)
+
+#define MAX_DLINE_DELAY_CODE		0xff
+#define MAX_WORKED_DELAY		2800
+
+/* Note: the delay step value is at 0.1ps */
+static const unsigned int k3_delay_step_10x[4] = {
+	367, 493, 559, 685
+};
+
+static int spacemit_dwmac_set_delay(struct regmap *apmu,
+				    unsigned int dline_offset,
+				    unsigned int tx_code, unsigned int tx_config,
+				    unsigned int rx_code, unsigned int rx_config)
+{
+	unsigned int mask, val;
+
+	mask = RGMII_TX_DLINE_STEP | RGMII_TX_DLINE_CODE | RGMII_TX_DLINE_EN |
+	       RGMII_RX_DLINE_STEP | RGMII_RX_DLINE_CODE | RGMII_RX_DLINE_EN;
+	val = FIELD_PREP(RGMII_TX_DLINE_STEP, tx_config) |
+	      FIELD_PREP(RGMII_TX_DLINE_CODE, tx_code) | RGMII_TX_DLINE_EN |
+	      FIELD_PREP(RGMII_RX_DLINE_STEP, rx_config) |
+	      FIELD_PREP(RGMII_RX_DLINE_CODE, rx_code) | RGMII_RX_DLINE_EN;
+
+	return regmap_update_bits(apmu, dline_offset, mask, val);
+}
+
+static int spacemit_dwmac_detected_delay_value(unsigned int delay,
+					       unsigned int *config)
+{
+	unsigned int best_delay = 0;
+	unsigned int best_config = 0;
+	int best_code = 0;
+	int i;
+
+	if (delay == 0)
+		return 0;
+
+	if (delay > MAX_WORKED_DELAY)
+		return -EINVAL;
+
+	/*
+	 * Note K3 require a specific factor for calculate
+	 * the delay, in this scenario it is 0.9. So the
+	 * formula is code * step / 10 * 0.9
+	 */
+	for (i = 0; i < ARRAY_SIZE(k3_delay_step_10x); i++) {
+		unsigned int step = k3_delay_step_10x[i];
+		int code = DIV_ROUND_CLOSEST(delay * 10 * 10, step * 9);
+		unsigned int tmp = code * step * 9 / 10 / 10;
+
+		if (abs(tmp - delay) < abs(best_delay - delay)) {
+			best_code = code;
+			best_delay = tmp;
+			best_config = i;
+		}
+	}
+
+	*config = best_config;
+
+	return best_code;
+}
+
+static int spacemit_dwmac_fix_delay(struct plat_stmmacenet_data *plat_dat,
+				    struct regmap *apmu,
+				    unsigned int dline_offset,
+				    unsigned int tx_delay, unsigned int rx_delay)
+{
+	unsigned int rx_config = 0;
+	unsigned int tx_config = 0;
+	int rx_code;
+	int tx_code;
+
+	rx_code = spacemit_dwmac_detected_delay_value(rx_delay, &rx_config);
+	if (rx_code < 0)
+		return rx_code;
+
+	tx_code = spacemit_dwmac_detected_delay_value(tx_delay, &tx_config);
+	if (tx_code < 0)
+		return tx_code;
+
+	return spacemit_dwmac_set_delay(apmu, dline_offset,
+					tx_code, tx_config,
+					rx_code, rx_config);
+}
+
+static int spacemit_dwmac_update_ifconfig(struct plat_stmmacenet_data *plat_dat,
+					  struct stmmac_resources *stmmac_res,
+					  struct regmap *apmu,
+					  unsigned int ctrl_offset)
+{
+	unsigned int mask = PHY_INTF_MII | PHY_INTF_RGMII | WAKE_IRQ_EN;
+	unsigned int val = 0;
+
+	switch (plat_dat->phy_interface) {
+	case PHY_INTERFACE_MODE_MII:
+		val = PHY_INTF_MII;
+		break;
+
+	case PHY_INTERFACE_MODE_RMII:
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		val = PHY_INTF_RGMII;
+		break;
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	if (stmmac_res->wol_irq >= 0)
+		val |= WAKE_IRQ_EN;
+
+	return regmap_update_bits(apmu, ctrl_offset, mask, val);
+}
+
+static int spacemit_dwmac_probe(struct platform_device *pdev)
+{
+	struct plat_stmmacenet_data *plat_dat;
+	struct stmmac_resources stmmac_res;
+	struct device *dev = &pdev->dev;
+	unsigned int offset[2];
+	struct regmap *apmu;
+	struct clk *clk_tx;
+	u32 rx_delay = 0;
+	u32 tx_delay = 0;
+	int ret;
+
+	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to get platform resources\n");
+
+	plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
+	if (IS_ERR(plat_dat))
+		return dev_err_probe(dev, PTR_ERR(plat_dat),
+				     "failed to parse DT parameters\n");
+
+	clk_tx = devm_clk_get_enabled(&pdev->dev, "tx");
+	if (IS_ERR(clk_tx))
+		return dev_err_probe(&pdev->dev, PTR_ERR(clk_tx),
+				     "failed to get tx clock\n");
+
+	apmu = syscon_regmap_lookup_by_phandle_args(pdev->dev.of_node, "spacemit,apmu", 2, offset);
+	if (IS_ERR(apmu))
+		return dev_err_probe(dev, PTR_ERR(apmu),
+				"Failed to get apmu regmap\n");
+
+	ret = spacemit_dwmac_update_ifconfig(plat_dat, &stmmac_res,
+					     apmu, offset[0]);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to configure ifconfig\n");
+
+	of_property_read_u32(pdev->dev.of_node, "tx-internal-delay-ps", &tx_delay);
+	of_property_read_u32(pdev->dev.of_node, "rx-internal-delay-ps", &rx_delay);
+
+	ret = spacemit_dwmac_fix_delay(plat_dat, apmu, offset[1], tx_delay, rx_delay);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to configure delay\n");
+
+	return stmmac_dvr_probe(dev, plat_dat, &stmmac_res);
+}
+
+static const struct of_device_id spacemit_dwmac_match[] = {
+	{ .compatible = "spacemit,k3-dwmac" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, spacemit_dwmac_match);
+
+static struct platform_driver spacemit_dwmac_driver = {
+	.probe  = spacemit_dwmac_probe,
+	.remove = stmmac_pltfr_remove,
+	.driver = {
+		.name = "spacemit-dwmac",
+		.pm = &stmmac_pltfr_pm_ops,
+		.of_match_table = spacemit_dwmac_match,
+	},
+};
+module_platform_driver(spacemit_dwmac_driver);
+
+MODULE_AUTHOR("Inochi Amaoto <inochiama@gmail.com>");
+MODULE_DESCRIPTION("Spacemit DWMAC platform driver");
+MODULE_LICENSE("GPL");
-- 
2.52.0

Re: [PATCH net-next v3 3/3] net: stmmac: Add glue layer for Spacemit K3 SoC

[Vivian Wang]

Hi Inochi,

I have some comments below.

On 1/28/26 15:29, Inochi Amaoto wrote:
> The etherenet controller on Spacemit K3 SoC is Synopsys DesignWare
Typo: etherenet -> ethernet
> MAC (version 5.40a), with the following special point:
Nit: point -> points 
> 1. The rate of the tx clock line is auto changed when the mac speed
>    rate is changed, and no need for changing the input tx clock.
> 2. This controller require a extra syscon device to configure the
>    interface type, enable wake up interrupt and delay configuration
>    if needed.
>
> Add Spacemit dwmac driver support on the Spacemit K3 SoC.
>
> Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  12 +
>  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
>  .../ethernet/stmicro/stmmac/dwmac-spacemit.c  | 218 ++++++++++++++++++
>  3 files changed, 231 insertions(+)
>  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c
>
> [...]
>
> +
> +/* dline register bits */
> +#define RGMII_RX_DLINE_EN		BIT(0)
> +#define RGMII_RX_DLINE_STEP		GENMASK(5, 4)
> +#define RGMII_RX_DLINE_CODE		GENMASK(15, 8)
> +#define RGMII_TX_DLINE_EN		BIT(16)
> +#define RGMII_TX_DLINE_STEP		GENMASK(21, 20)
> +#define RGMII_TX_DLINE_CODE		GENMASK(31, 24)
> +
> +#define MAX_DLINE_DELAY_CODE		0xff
> +#define MAX_WORKED_DELAY		2800
> +
> +/* Note: the delay step value is at 0.1ps */
> +static const unsigned int k3_delay_step_10x[4] = {
> +	367, 493, 559, 685
> +};
> +
> +static int spacemit_dwmac_set_delay(struct regmap *apmu,
> +				    unsigned int dline_offset,
> +				    unsigned int tx_code, unsigned int tx_config,
> +				    unsigned int rx_code, unsigned int rx_config)
> +{
> +	unsigned int mask, val;
> +
> +	mask = RGMII_TX_DLINE_STEP | RGMII_TX_DLINE_CODE | RGMII_TX_DLINE_EN |
> +	       RGMII_RX_DLINE_STEP | RGMII_RX_DLINE_CODE | RGMII_RX_DLINE_EN;
> +	val = FIELD_PREP(RGMII_TX_DLINE_STEP, tx_config) |
> +	      FIELD_PREP(RGMII_TX_DLINE_CODE, tx_code) | RGMII_TX_DLINE_EN |
> +	      FIELD_PREP(RGMII_RX_DLINE_STEP, rx_config) |
> +	      FIELD_PREP(RGMII_RX_DLINE_CODE, rx_code) | RGMII_RX_DLINE_EN;
> +
> +	return regmap_update_bits(apmu, dline_offset, mask, val);
> +}
> +
> +static int spacemit_dwmac_detected_delay_value(unsigned int delay,
> +					       unsigned int *config)
> +{
> +	unsigned int best_delay = 0;
> +	unsigned int best_config = 0;
> +	int best_code = 0;
> +	int i;
> +
> +	if (delay == 0)
> +		return 0;
> +
> +	if (delay > MAX_WORKED_DELAY)
> +		return -EINVAL;
> +
> +	/*
> +	 * Note K3 require a specific factor for calculate
> +	 * the delay, in this scenario it is 0.9. So the
> +	 * formula is code * step / 10 * 0.9
> +	 */
> +	for (i = 0; i < ARRAY_SIZE(k3_delay_step_10x); i++) {
> +		unsigned int step = k3_delay_step_10x[i];
> +		int code = DIV_ROUND_CLOSEST(delay * 10 * 10, step * 9);
> +		unsigned int tmp = code * step * 9 / 10 / 10;
> +
> +		if (abs(tmp - delay) < abs(best_delay - delay)) {
> +			best_code = code;
> +			best_delay = tmp;
> +			best_config = i;
> +		}
> +	}
> +
> +	*config = best_config;
> +
> +	return best_code;

Is this really necessary? For K1 I just used the smallest step size.

It seems to me you have, for the smallest step size, about 36.7ps * 0.9
= 33ps per step. Theoretically speaking that lets you fine tune the
delay to within 1% of the 2ns total required RGMII delay (MAC + PCB +
PHY). In practice this number shouldn't be that marginal. 

Re: [PATCH net-next v3 3/3] net: stmmac: Add glue layer for Spacemit K3 SoC

[Inochi Amaoto]

On Wed, Jan 28, 2026 at 05:16:46PM +0800, Vivian Wang wrote:
> Hi Inochi,
> 
> I have some comments below.
> 
> On 1/28/26 15:29, Inochi Amaoto wrote:
> > The etherenet controller on Spacemit K3 SoC is Synopsys DesignWare
> Typo: etherenet -> ethernet
> > MAC (version 5.40a), with the following special point:
> Nit: point -> points 

Thanks

> > 1. The rate of the tx clock line is auto changed when the mac speed
> >    rate is changed, and no need for changing the input tx clock.
> > 2. This controller require a extra syscon device to configure the
> >    interface type, enable wake up interrupt and delay configuration
> >    if needed.
> >
> > Add Spacemit dwmac driver support on the Spacemit K3 SoC.
> >
> > Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> > ---
> >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  12 +
> >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> >  .../ethernet/stmicro/stmmac/dwmac-spacemit.c  | 218 ++++++++++++++++++
> >  3 files changed, 231 insertions(+)
> >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c
> >
> > [...]
> >
> > +
> > +/* dline register bits */
> > +#define RGMII_RX_DLINE_EN		BIT(0)
> > +#define RGMII_RX_DLINE_STEP		GENMASK(5, 4)
> > +#define RGMII_RX_DLINE_CODE		GENMASK(15, 8)
> > +#define RGMII_TX_DLINE_EN		BIT(16)
> > +#define RGMII_TX_DLINE_STEP		GENMASK(21, 20)
> > +#define RGMII_TX_DLINE_CODE		GENMASK(31, 24)
> > +
> > +#define MAX_DLINE_DELAY_CODE		0xff
> > +#define MAX_WORKED_DELAY		2800
> > +
> > +/* Note: the delay step value is at 0.1ps */
> > +static const unsigned int k3_delay_step_10x[4] = {
> > +	367, 493, 559, 685
> > +};
> > +
> > +static int spacemit_dwmac_set_delay(struct regmap *apmu,
> > +				    unsigned int dline_offset,
> > +				    unsigned int tx_code, unsigned int tx_config,
> > +				    unsigned int rx_code, unsigned int rx_config)
> > +{
> > +	unsigned int mask, val;
> > +
> > +	mask = RGMII_TX_DLINE_STEP | RGMII_TX_DLINE_CODE | RGMII_TX_DLINE_EN |
> > +	       RGMII_RX_DLINE_STEP | RGMII_RX_DLINE_CODE | RGMII_RX_DLINE_EN;
> > +	val = FIELD_PREP(RGMII_TX_DLINE_STEP, tx_config) |
> > +	      FIELD_PREP(RGMII_TX_DLINE_CODE, tx_code) | RGMII_TX_DLINE_EN |
> > +	      FIELD_PREP(RGMII_RX_DLINE_STEP, rx_config) |
> > +	      FIELD_PREP(RGMII_RX_DLINE_CODE, rx_code) | RGMII_RX_DLINE_EN;
> > +
> > +	return regmap_update_bits(apmu, dline_offset, mask, val);
> > +}
> > +
> > +static int spacemit_dwmac_detected_delay_value(unsigned int delay,
> > +					       unsigned int *config)
> > +{
> > +	unsigned int best_delay = 0;
> > +	unsigned int best_config = 0;
> > +	int best_code = 0;
> > +	int i;
> > +
> > +	if (delay == 0)
> > +		return 0;
> > +
> > +	if (delay > MAX_WORKED_DELAY)
> > +		return -EINVAL;
> > +
> > +	/*
> > +	 * Note K3 require a specific factor for calculate
> > +	 * the delay, in this scenario it is 0.9. So the
> > +	 * formula is code * step / 10 * 0.9
> > +	 */
> > +	for (i = 0; i < ARRAY_SIZE(k3_delay_step_10x); i++) {
> > +		unsigned int step = k3_delay_step_10x[i];
> > +		int code = DIV_ROUND_CLOSEST(delay * 10 * 10, step * 9);
> > +		unsigned int tmp = code * step * 9 / 10 / 10;
> > +
> > +		if (abs(tmp - delay) < abs(best_delay - delay)) {
> > +			best_code = code;
> > +			best_delay = tmp;
> > +			best_config = i;
> > +		}
> > +	}
> > +
> > +	*config = best_config;
> > +
> > +	return best_code;
> 
> Is this really necessary? For K1 I just used the smallest step size.
> 
> It seems to me you have, for the smallest step size, about 36.7ps * 0.9
> = 33ps per step. Theoretically speaking that lets you fine tune the
> delay to within 1% of the 2ns total required RGMII delay (MAC + PCB +
> PHY). In practice this number shouldn't be that marginal. 
> 

I think it is reasonable, I will take you advice and use the
smallest step size.

Regards,
Inochi

Re: [PATCH net-next v3 3/3] net: stmmac: Add glue layer for Spacemit K3 SoC

[Russell King (Oracle)]

On Wed, Jan 28, 2026 at 03:29:29PM +0800, Inochi Amaoto wrote:
> +#include <linux/clk.h>
> +#include <linux/math.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +
> +#include "stmmac_platform.h"
> +
> +/* ctrl register bits */
> +#define PHY_INTF_RGMII			BIT(3)
> +#define PHY_INTF_MII			BIT(4)

Please add a suitable prefix for these.

> +
> +#define WAKE_IRQ_EN			BIT(9)
> +#define PHY_IRQ_EN			BIT(12)

While you're renaming the PHY_INTF_*, you might wish to also add the
same prefix here to identify that they're all part of the same register.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

Re: [PATCH net-next v3 3/3] net: stmmac: Add glue layer for Spacemit K3 SoC

[Inochi Amaoto]

On Wed, Jan 28, 2026 at 10:43:35AM +0000, Russell King (Oracle) wrote:
> On Wed, Jan 28, 2026 at 03:29:29PM +0800, Inochi Amaoto wrote:
> > +#include <linux/clk.h>
> > +#include <linux/math.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/module.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/property.h>
> > +#include <linux/regmap.h>
> > +
> > +#include "stmmac_platform.h"
> > +
> > +/* ctrl register bits */
> > +#define PHY_INTF_RGMII			BIT(3)
> > +#define PHY_INTF_MII			BIT(4)
> 
> Please add a suitable prefix for these.
> 
> > +
> > +#define WAKE_IRQ_EN			BIT(9)
> > +#define PHY_IRQ_EN			BIT(12)
> 
> While you're renaming the PHY_INTF_*, you might wish to also add the
> same prefix here to identify that they're all part of the same register.
> 

I think this is good for me. I will add the "CTRL" prefix
to identify these are all from ctrl register.

Regards,
Inochi