[RFC PATCH net-next v4 2/3] net: stmmac: Add glue driver for Motorcomm YT6801 ethernet controller

Yao Zi
2025-12-16T18:04:02Z

Motorcomm YT6801 is a PCIe ethernet controller based on DWMAC4 IP. It
integrates an GbE phy, supporting WOL, VLAN tagging and various types
of offloading. It ships an on-chip eFuse for storing various vendor
configuration, including MAC address.

This patch adds basic glue code for the controller, allowing it to be
set up and transmit data at a reasonable speed. Features like WOL could
be implemented in the future.

Signed-off-by: Yao Zi <me@ziyao.cc>
Tested-by: Mingcong Bai <jeffbai@aosc.io>
Tested-by: Runhua He <hua@aosc.io>
Tested-by: Xi Ruoyao <xry111@xry111.site>
---
drivers/net/ethernet/stmicro/stmmac/Kconfig | 9 +
drivers/net/ethernet/stmicro/stmmac/Makefile | 1 +
.../ethernet/stmicro/stmmac/dwmac-motorcomm.c | 383 ++++++++++++++++++
3 files changed, 393 insertions(+)
create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c

diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index 907fe2e927f0..07088d03dbab 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
@@ -374,6 +374,15 @@ config DWMAC_LOONGSON
This selects the LOONGSON PCI bus support for the stmmac driver,
Support for ethernet controller on Loongson-2K1000 SoC and LS7A1000 bridge.

+config DWMAC_MOTORCOMM
+ tristate "Motorcomm PCI DWMAC support"
+ depends on PCI
+ select MOTORCOMM_PHY
+ select STMMAC_LIBPCI
+ help
+ This enables glue driver for Motorcomm DWMAC-based PCI Ethernet
+ controllers. Currently only YT6801 is supported.
+
config STMMAC_PCI
tristate "STMMAC PCI bus support"
depends on PCI
diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
index 7bf528731034..c9263987ef8d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Makefile
+++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
@@ -48,4 +48,5 @@ obj-$(CONFIG_STMMAC_LIBPCI) += stmmac_libpci.o
obj-$(CONFIG_STMMAC_PCI) += stmmac-pci.o
obj-$(CONFIG_DWMAC_INTEL) += dwmac-intel.o
obj-$(CONFIG_DWMAC_LOONGSON) += dwmac-loongson.o
+obj-$(CONFIG_DWMAC_MOTORCOMM) += dwmac-motorcomm.o
stmmac-pci-objs:= stmmac_pci.o
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c
new file mode 100644
index 000000000000..11ee470ac8f7
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c
@@ -0,0 +1,383 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DWMAC glue driver for Motorcomm PCI Ethernet controllers
+ *
+ * Copyright (c) 2025 Yao Zi <me@ziyao.cc>
+ */
+
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/stmmac.h>
+
+#include "dwmac4.h"
+#include "stmmac.h"
+#include "stmmac_libpci.h"
+
+#define DRIVER_NAME "dwmac-motorcomm"
+
+#define PCI_VENDOR_ID_MOTORCOMM 0x1f0a
+
+/* Register definition */
+#define EPHY_CTRL 0x1004
+/* Clearing this bit asserts resets for internal MDIO bus and PHY */
+#define EPHY_MDIO_PHY_RESET BIT(0)
+#define OOB_WOL_CTRL 0x1010
+#define OOB_WOL_CTRL_DIS BIT(0)
+#define MGMT_INT_CTRL0 0x1100
+#define MGMT_INT_CTRL0_MASK GENMASK(31, 16)
+#define MGMT_INT_CTRL0_MASK_RXCH GENMASK(3, 0)
+#define MGMT_INT_CTRL0_MASK_TXCH BIT(4)
+#define MGMT_INT_CTRL0_MASK_MISC BIT(5)
+#define INT_MODERATION 0x1108
+#define INT_MODERATION_RX GENMASK(11, 0)
+#define INT_MODERATION_TX GENMASK(27, 16)
+#define EFUSE_OP_CTRL_0 0x1500
+#define EFUSE_OP_MODE GENMASK(1, 0)
+#define EFUSE_OP_ROW_READ 0x1
+#define EFUSE_OP_START BIT(2)
+#define EFUSE_OP_ADDR GENMASK(15, 8)
+#define EFUSE_OP_CTRL_1 0x1504
+#define EFUSE_OP_DONE BIT(1)
+#define EFUSE_OP_RD_DATA GENMASK(31, 24)
+#define SYS_RESET 0x152c
+#define SYS_RESET_RESET BIT(31)
+#define GMAC_OFFSET 0x2000
+
+/* Constants */
+#define EFUSE_READ_TIMEOUT_US 20000
+#define EFUSE_PATCH_REGION_OFFSET 18
+#define EFUSE_PATCH_MAX_NUM 39
+#define EFUSE_ADDR_MACA0LR 0x1520
+#define EFUSE_ADDR_MACA0HR 0x1524
+
+struct motorcomm_efuse_patch {
+ __le16 addr;
+ __le32 data;
+} __packed;
+
+struct dwmac_motorcomm_priv {
+ void __iomem *base;
+ struct device *dev;
+};
+
+static int motorcomm_efuse_read_byte(struct dwmac_motorcomm_priv *priv,
+ u8 offset, u8 *byte)
+{
+ u32 reg;
+ int ret;
+
+ writel(FIELD_PREP(EFUSE_OP_MODE, EFUSE_OP_ROW_READ) |
+ FIELD_PREP(EFUSE_OP_ADDR, offset) |
+ EFUSE_OP_START, priv->base + EFUSE_OP_CTRL_0);
+
+ ret = readl_poll_timeout(priv->base + EFUSE_OP_CTRL_1,
+ reg, reg & EFUSE_OP_DONE, 2000,
+ EFUSE_READ_TIMEOUT_US);
+
+ *byte = FIELD_GET(EFUSE_OP_RD_DATA, reg);
+
+ return ret;
+}
+
+static int motorcomm_efuse_read_patch(struct dwmac_motorcomm_priv *priv,
+ u8 index,
+ struct motorcomm_efuse_patch *patch)
+{
+ u8 buf[sizeof(*patch)], offset;
+ int i, ret;
+
+ for (i = 0; i < sizeof(*patch); i++) {
+ offset = EFUSE_PATCH_REGION_OFFSET + sizeof(*patch) * index + i;
+
+ ret = motorcomm_efuse_read_byte(priv, offset, &buf[i]);
+ if (ret)
+ return ret;
+ }
+
+ memcpy(patch, buf, sizeof(*patch));
+
+ return 0;
+}
+
+static int motorcomm_efuse_get_patch_value(struct dwmac_motorcomm_priv *priv,
+ u16 addr, u32 *value)
+{
+ struct motorcomm_efuse_patch patch;
+ int i, ret;
+
+ for (i = 0; i < EFUSE_PATCH_MAX_NUM; i++) {
+ ret = motorcomm_efuse_read_patch(priv, i, &patch);
+ if (ret)
+ return ret;
+
+ if (patch.addr == 0) {
+ return -ENOENT;
+ } else if (le16_to_cpu(patch.addr) == addr) {
+ *value = le32_to_cpu(patch.data);
+ return 0;
+ }
+ }
+
+ return -ENOENT;
+}
+
+static int motorcomm_efuse_read_mac(struct dwmac_motorcomm_priv *priv, u8 *mac)
+{
+ u32 maca0lr, maca0hr;
+ int ret;
+
+ ret = motorcomm_efuse_get_patch_value(priv, EFUSE_ADDR_MACA0LR,
+ &maca0lr);
+ if (ret)
+ return dev_err_probe(priv->dev, ret,
+ "failed to read maca0lr from eFuse\n");
+
+ ret = motorcomm_efuse_get_patch_value(priv, EFUSE_ADDR_MACA0HR,
+ &maca0hr);
+ if (ret)
+ return dev_err_probe(priv->dev, ret,
+ "failed to read maca0hr from eFuse\n");
+
+ mac[0] = FIELD_GET(GENMASK(15, 8), maca0hr);
+ mac[1] = FIELD_GET(GENMASK(7, 0), maca0hr);
+ mac[2] = FIELD_GET(GENMASK(31, 24), maca0lr);
+ mac[3] = FIELD_GET(GENMASK(23, 16), maca0lr);
+ mac[4] = FIELD_GET(GENMASK(15, 8), maca0lr);
+ mac[5] = FIELD_GET(GENMASK(7, 0), maca0lr);
+
+ return 0;
+}
+
+static void motorcomm_deassert_mdio_phy_reset(struct dwmac_motorcomm_priv *priv)
+{
+ u32 reg = readl(priv->base + EPHY_CTRL);
+
+ reg |= EPHY_MDIO_PHY_RESET;
+
+ writel(reg, priv->base + EPHY_CTRL);
+}
+
+static void motorcomm_reset(struct dwmac_motorcomm_priv *priv)
+{
+ u32 reg = readl(priv->base + SYS_RESET);
+
+ reg &= ~SYS_RESET_RESET;
+ writel(reg, priv->base + SYS_RESET);
+
+ reg |= SYS_RESET_RESET;
+ writel(reg, priv->base + SYS_RESET);
+
+ motorcomm_deassert_mdio_phy_reset(priv);
+}
+
+static void motorcomm_init(struct dwmac_motorcomm_priv *priv)
+{
+ writel(0x0, priv->base + MGMT_INT_CTRL0);
+
+ writel(FIELD_PREP(INT_MODERATION_RX, 200) |
+ FIELD_PREP(INT_MODERATION_TX, 200),
+ priv->base + INT_MODERATION);
+
+ /*
+ * OOB WOL must be disabled during normal operation, or DMA interrupts
+ * cannot be delivered to the host.
+ */
+ writel(OOB_WOL_CTRL_DIS, priv->base + OOB_WOL_CTRL);
+}
+
+static int motorcomm_resume(struct device *dev, void *bsp_priv)
+{
+ struct dwmac_motorcomm_priv *priv = bsp_priv;
+ int ret;
+
+ ret = stmmac_pci_plat_resume(dev, bsp_priv);
+ if (ret)
+ return ret;
+
+ /*
+ * When recovering from D3hot, EPHY_MDIO_PHY_RESET is automatically
+ * asserted, and must be deasserted for normal operation.
+ */
+ motorcomm_deassert_mdio_phy_reset(priv);
+ motorcomm_init(priv);
+
+ return 0;
+}
+
+static struct plat_stmmacenet_data *
+motorcomm_default_plat_data(struct pci_dev *pdev)
+{
+ struct plat_stmmacenet_data *plat;
+ struct device *dev = &pdev->dev;
+
+ plat = stmmac_plat_dat_alloc(dev);
+ if (!plat)
+ return NULL;
+
+ plat->mdio_bus_data = devm_kzalloc(dev, sizeof(*plat->mdio_bus_data),
+ GFP_KERNEL);
+ if (!plat->mdio_bus_data)
+ return NULL;
+
+ plat->dma_cfg = devm_kzalloc(dev, sizeof(*plat->dma_cfg), GFP_KERNEL);
+ if (!plat->dma_cfg)
+ return NULL;
+
+ plat->axi = devm_kzalloc(dev, sizeof(*plat->axi), GFP_KERNEL);
+ if (!plat->axi)
+ return NULL;
+
+ plat->dma_cfg->pbl = DEFAULT_DMA_PBL;
+ plat->dma_cfg->pblx8 = true;
+ plat->dma_cfg->txpbl = 32;
+ plat->dma_cfg->rxpbl = 32;
+ plat->dma_cfg->eame = true;
+ plat->dma_cfg->mixed_burst = true;
+
+ plat->axi->axi_wr_osr_lmt = 1;
+ plat->axi->axi_rd_osr_lmt = 1;
+ plat->axi->axi_mb = true;
+ plat->axi->axi_blen_regval = DMA_AXI_BLEN4 | DMA_AXI_BLEN8 |
+ DMA_AXI_BLEN16 | DMA_AXI_BLEN32;
+
+ plat->bus_id = pci_dev_id(pdev);
+ plat->phy_interface = PHY_INTERFACE_MODE_GMII;
+ /*
+ * YT6801 requires an 25MHz clock input/oscillator to function, which
+ * is likely the source of CSR clock.
+ */
+ plat->clk_csr = STMMAC_CSR_20_35M;
+ plat->tx_coe = 1;
+ plat->rx_coe = 1;
+ plat->clk_ref_rate = 125000000;
+ plat->core_type = DWMAC_CORE_GMAC4;
+ plat->suspend = stmmac_pci_plat_suspend;
+ plat->resume = motorcomm_resume;
+ plat->flags = STMMAC_FLAG_TSO_EN |
+ STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP;
+
+ return plat;
+}
+
+static void motorcomm_free_irq(void *data)
+{
+ struct pci_dev *pdev = data;
+
+ pci_free_irq_vectors(pdev);
+}
+
+static int motorcomm_setup_irq(struct pci_dev *pdev,
+ struct stmmac_resources *res,
+ struct plat_stmmacenet_data *plat)
+{
+ int ret;
+
+ ret = pci_alloc_irq_vectors(pdev, 6, 6, PCI_IRQ_MSIX);
+ if (ret > 0) {
+ res->rx_irq[0] = pci_irq_vector(pdev, 0);
+ res->tx_irq[0] = pci_irq_vector(pdev, 4);
+ res->irq = pci_irq_vector(pdev, 5);
+
+ plat->flags |= STMMAC_FLAG_MULTI_MSI_EN;
+ } else {
+ dev_info(&pdev->dev, "failed to allocate MSI-X vector: %d\n",
+ ret);
+ dev_info(&pdev->dev, "try MSI instead\n");
+
+ ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
+ if (ret < 0)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to allocate MSI\n");
+
+ res->irq = pci_irq_vector(pdev, 0);
+ }
+
+ return devm_add_action_or_reset(&pdev->dev, motorcomm_free_irq, pdev);
+}
+
+static int motorcomm_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+ struct plat_stmmacenet_data *plat;
+ struct dwmac_motorcomm_priv *priv;
+ struct stmmac_resources res = {};
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = &pdev->dev;
+
+ plat = motorcomm_default_plat_data(pdev);
+ if (!plat)
+ return -ENOMEM;
+
+ plat->bsp_priv = priv;
+
+ ret = pcim_enable_device(pdev);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to enable device\n");
+
+ priv->base = pcim_iomap_region(pdev, 0, DRIVER_NAME);
+ if (IS_ERR(priv->base))
+ return dev_err_probe(&pdev->dev, PTR_ERR(priv->base),
+ "failed to map IO region\n");
+
+ pci_set_master(pdev);
+
+ motorcomm_reset(priv);
+
+ ret = motorcomm_efuse_read_mac(priv, res.mac);
+ if (ret == -ENOENT) {
+ dev_warn(&pdev->dev, "eFuse contains no valid MAC address\n");
+ dev_warn(&pdev->dev, "fallback to random MAC address\n");
+
+ memset(res.mac, 0, sizeof(res.mac));
+ } else if (ret) {
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to read MAC address from eFuse\n");
+ }
+
+ ret = motorcomm_setup_irq(pdev, &res, plat);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret, "failed to setup IRQ\n");
+
+ motorcomm_init(priv);
+
+ res.addr = priv->base + GMAC_OFFSET;
+
+ return stmmac_dvr_probe(&pdev->dev, plat, &res);
+}
+
+static void motorcomm_remove(struct pci_dev *pdev)
+{
+ stmmac_dvr_remove(&pdev->dev);
+}
+
+static const struct pci_device_id dwmac_motorcomm_pci_id_table[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_MOTORCOMM, 0x6801) },
+ { },
+};
+MODULE_DEVICE_TABLE(pci, dwmac_motorcomm_pci_id_table);
+
+static struct pci_driver dwmac_motorcomm_pci_driver = {
+ .name = DRIVER_NAME,
+ .id_table = dwmac_motorcomm_pci_id_table,
+ .probe = motorcomm_probe,
+ .remove = motorcomm_remove,
+ .driver = {
+ .pm = &stmmac_simple_pm_ops,
+ },
+};
+
+module_pci_driver(dwmac_motorcomm_pci_driver);
+
+MODULE_DESCRIPTION("DWMAC glue driver for Motorcomm PCI Ethernet controllers");
+MODULE_AUTHOR("Yao Zi <me@ziyao.cc>");
+MODULE_LICENSE("GPL");
--
2.51.2