[PATCH net-next 2/2] net: stmmac: Add Siflower SF19A2890 glue
Joseph Telaak via B4 Relay
devnull+joseph.telaak.dev at kernel.org
Tue Nov 3 23:22:25 PST 2026
From: Joseph Telaak <joseph at telaak.dev>
Add the glue for the DesignWare GMAC of the Siflower SF19A2890. The
interface type is set in the GMAC's configuration block through the
set_phy_intf_sel hook, and so are the RGMII clock delays, which the
MAC adds only where rx-internal-delay-ps or tx-internal-delay-ps is
present.
The delay line's step is not documented. Sweeping each delay over its
whole range with the link at 1000 Mb/s, the working windows repeat every
145 steps, one 8 ns clock period, so a step is about 55 ps; the driver
rounds to the nearest step.
Based on Chuanhong Guo's driver from OpenWrt and his siflower-7.1
branch, which read the delays from a factory flash cell in the delay
line's own units and always applied them. That driver also set
STMMAC_FLAG_HAS_INTEGRATED_PCS, because the core reports a PCS that
does not work in RGMII mode; stmmac now uses the integrated PCS only
for SGMII, and the flag is gone.
Signed-off-by: Joseph Telaak <joseph at telaak.dev>
---
drivers/net/ethernet/stmicro/stmmac/Kconfig | 11 ++
drivers/net/ethernet/stmicro/stmmac/Makefile | 1 +
.../net/ethernet/stmicro/stmmac/dwmac-sf19a2890.c | 158 +++++++++++++++++++++
3 files changed, 170 insertions(+)
diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index c6559e749..78efe7859 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
@@ -201,6 +201,17 @@ config DWMAC_S32
SOCs GMAC ethernet controller, ie. S32G2xx, S32G3xx and
S32R45.
+config DWMAC_SF19A2890
+ tristate "Siflower SF19A2890 GMAC support"
+ default MACH_SIFLOWER_MIPS
+ depends on OF && (MACH_SIFLOWER_MIPS || COMPILE_TEST)
+ help
+ Support for the Ethernet controller of the Siflower SF19A2890 SoC.
+
+ This selects the SF19A2890 glue layer support for the stmmac
+ device driver. It sets the interface type and the RGMII clock
+ delays in the GMAC's configuration block.
+
config DWMAC_SOCFPGA
tristate "SOCFPGA dwmac support"
default ARCH_INTEL_SOCFPGA
diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
index b16a456b7..9330de094 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Makefile
+++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_DWMAC_RENESAS_GBETH) += dwmac-renesas-gbeth.o
obj-$(CONFIG_DWMAC_ROCKCHIP) += dwmac-rk.o
obj-$(CONFIG_DWMAC_RZN1) += dwmac-rzn1.o
obj-$(CONFIG_DWMAC_S32) += dwmac-s32.o
+obj-$(CONFIG_DWMAC_SF19A2890) += dwmac-sf19a2890.o
obj-$(CONFIG_DWMAC_SOCFPGA) += dwmac-altr-socfpga.o
obj-$(CONFIG_DWMAC_SOPHGO) += dwmac-sophgo.o
obj-$(CONFIG_DWMAC_SPACEMIT) += dwmac-spacemit.o
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sf19a2890.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sf19a2890.c
new file mode 100644
index 000000000..41bfe7a4a
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sf19a2890.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Siflower SF19A2890 GMAC glue
+ *
+ * The SF19A2890 has a DWMAC 3.73a. Its interface type and RGMII clock
+ * delays are set in a register block of their own.
+ *
+ * Based on the driver by Chuanhong Guo <gch981213 at gmail.com>.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/stmmac.h>
+
+#include "stmmac_platform.h"
+
+/* GMAC configuration block */
+#define SF19A2890_GMAC_MISC 0x0
+#define SF19A2890_PHY_INTF_SEL GENMASK(2, 0)
+#define SF19A2890_GMAC_TX_DELAY 0x4
+#define SF19A2890_GMAC_RX_DELAY 0x8
+#define SF19A2890_GMAC_RX_DELAY_EN 0xc
+#define SF19A2890_DELAY_MAX 0xff
+
+/*
+ * The delay line's step is not documented. Sweeping a full 8 ns RGMII clock
+ * period at 1000 Mb/s takes 145 steps, so one step is about 55 ps.
+ */
+#define SF19A2890_DELAY_STEP_PS 55
+
+struct sf19a2890_gmac {
+ struct device *dev;
+ void __iomem *cfg;
+};
+
+static int sf19a2890_gmac_set_phy_intf_sel(void *bsp_priv, u8 phy_intf_sel)
+{
+ struct sf19a2890_gmac *gmac = bsp_priv;
+ u32 val;
+
+ if (phy_intf_sel != PHY_INTF_SEL_GMII_MII &&
+ phy_intf_sel != PHY_INTF_SEL_RGMII &&
+ phy_intf_sel != PHY_INTF_SEL_RMII)
+ return -EINVAL;
+
+ val = readl(gmac->cfg + SF19A2890_GMAC_MISC);
+ val &= ~SF19A2890_PHY_INTF_SEL;
+ val |= FIELD_PREP(SF19A2890_PHY_INTF_SEL, phy_intf_sel);
+ writel(val, gmac->cfg + SF19A2890_GMAC_MISC);
+
+ return 0;
+}
+
+static int sf19a2890_gmac_get_delay(struct sf19a2890_gmac *gmac,
+ const char *prop, u32 *steps)
+{
+ u32 ps;
+
+ *steps = 0;
+ if (of_property_read_u32(gmac->dev->of_node, prop, &ps))
+ return 0;
+
+ *steps = DIV_ROUND_CLOSEST(ps, SF19A2890_DELAY_STEP_PS);
+ if (*steps > SF19A2890_DELAY_MAX)
+ return dev_err_probe(gmac->dev, -EINVAL,
+ "%s too large: %u\n", prop, ps);
+
+ return 0;
+}
+
+/* The MAC adds an RGMII delay only where the device tree asks for one */
+static int sf19a2890_gmac_set_delays(struct sf19a2890_gmac *gmac)
+{
+ u32 tx, rx;
+ int ret;
+
+ ret = sf19a2890_gmac_get_delay(gmac, "tx-internal-delay-ps", &tx);
+ if (ret)
+ return ret;
+
+ ret = sf19a2890_gmac_get_delay(gmac, "rx-internal-delay-ps", &rx);
+ if (ret)
+ return ret;
+
+ writel(tx, gmac->cfg + SF19A2890_GMAC_TX_DELAY);
+ writel(rx, gmac->cfg + SF19A2890_GMAC_RX_DELAY);
+ writel(!!rx, gmac->cfg + SF19A2890_GMAC_RX_DELAY_EN);
+
+ return 0;
+}
+
+static int sf19a2890_gmac_probe(struct platform_device *pdev)
+{
+ struct plat_stmmacenet_data *plat_dat;
+ struct stmmac_resources stmmac_res;
+ struct device *dev = &pdev->dev;
+ struct sf19a2890_gmac *gmac;
+ struct clk *clk;
+ int ret;
+
+ gmac = devm_kzalloc(dev, sizeof(*gmac), GFP_KERNEL);
+ if (!gmac)
+ return -ENOMEM;
+
+ gmac->dev = dev;
+
+ gmac->cfg = devm_platform_ioremap_resource(pdev, 1);
+ if (IS_ERR(gmac->cfg))
+ return dev_err_probe(dev, PTR_ERR(gmac->cfg),
+ "failed to map the configuration block\n");
+
+ clk = devm_clk_get_enabled(dev, "byp_ref");
+ if (IS_ERR(clk))
+ return dev_err_probe(dev, PTR_ERR(clk),
+ "failed to enable the byp_ref clock\n");
+
+ ret = sf19a2890_gmac_set_delays(gmac);
+ if (ret)
+ return ret;
+
+ ret = stmmac_get_platform_resources(pdev, &stmmac_res);
+ if (ret)
+ return ret;
+
+ plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
+ if (IS_ERR(plat_dat))
+ return PTR_ERR(plat_dat);
+
+ plat_dat->bsp_priv = gmac;
+ plat_dat->set_phy_intf_sel = sf19a2890_gmac_set_phy_intf_sel;
+
+ return stmmac_dvr_probe(dev, plat_dat, &stmmac_res);
+}
+
+static const struct of_device_id sf19a2890_gmac_match[] = {
+ { .compatible = "siflower,sf19a2890-gmac" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, sf19a2890_gmac_match);
+
+static struct platform_driver sf19a2890_gmac_driver = {
+ .probe = sf19a2890_gmac_probe,
+ .remove = stmmac_pltfr_remove,
+ .driver = {
+ .name = "sf19a2890-gmac",
+ .pm = &stmmac_pltfr_pm_ops,
+ .of_match_table = sf19a2890_gmac_match,
+ },
+};
+module_platform_driver(sf19a2890_gmac_driver);
+
+MODULE_DESCRIPTION("Siflower SF19A2890 GMAC glue");
+MODULE_LICENSE("GPL");
--
Git-155)
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