[PATCH net-next v11 2/7] phy: qcom: add the SGMII SerDes PHY driver for SCMI systems

[Bartosz Golaszewski]

Implement support for the firmware-managed SGMII/SerDes PHY present on
Qualcomm platforms. Do this as a separate driver from the HLOS-managed
variant as they don't share almost any code.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
 drivers/phy/qualcomm/Kconfig                   |  10 ++
 drivers/phy/qualcomm/Makefile                  |   1 +
 drivers/phy/qualcomm/phy-qcom-sgmii-eth-scmi.c | 161 +++++++++++++++++++++++++
 3 files changed, 172 insertions(+)

diff --git a/drivers/phy/qualcomm/Kconfig b/drivers/phy/qualcomm/Kconfig
index 60a0ead127fa9f08749e1bc686e15cc5eb341c28..bd7d3fe411d7f3ea333e9e32e54f926a3bdead01 100644
--- a/drivers/phy/qualcomm/Kconfig
+++ b/drivers/phy/qualcomm/Kconfig
@@ -232,3 +232,13 @@ config PHY_QCOM_SGMII_ETH
 	help
 	  Enable this to support the internal SerDes/SGMII PHY on various
 	  Qualcomm chipsets.
+
+config PHY_QCOM_SGMII_ETH_SCMI
+	tristate "Qualcomm DWMAC SGMII SerDes/PHY driver (firmware managed)"
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	select PM_GENERIC_DOMAINS
+	help
+	  Enable this to support the internal SerDes/SGMII PHY on Qualcomm
+	  chipsets where the SerDes hardware (clocks and registers) is owned
+	  by the firmware.
diff --git a/drivers/phy/qualcomm/Makefile b/drivers/phy/qualcomm/Makefile
index b71a6a0bed3f1489b1d07664ecd728f1db145986..032e582f2e1af96687484ce28aaba0c2ef73e754 100644
--- a/drivers/phy/qualcomm/Makefile
+++ b/drivers/phy/qualcomm/Makefile
@@ -25,3 +25,4 @@ obj-$(CONFIG_PHY_QCOM_USB_SS)		+= phy-qcom-usb-ss.o
 obj-$(CONFIG_PHY_QCOM_USB_SNPS_FEMTO_V2)+= phy-qcom-snps-femto-v2.o
 obj-$(CONFIG_PHY_QCOM_IPQ806X_USB)	+= phy-qcom-ipq806x-usb.o
 obj-$(CONFIG_PHY_QCOM_SGMII_ETH)	+= phy-qcom-sgmii-eth.o
+obj-$(CONFIG_PHY_QCOM_SGMII_ETH_SCMI)	+= phy-qcom-sgmii-eth-scmi.o
diff --git a/drivers/phy/qualcomm/phy-qcom-sgmii-eth-scmi.c b/drivers/phy/qualcomm/phy-qcom-sgmii-eth-scmi.c
new file mode 100644
index 0000000000000000000000000000000000000000..8ee62189556fe4ff0d8aa2f8b105175e08000b7c
--- /dev/null
+++ b/drivers/phy/qualcomm/phy-qcom-sgmii-eth-scmi.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ *
+ * Firmware-managed variant of the Qualcomm DWMAC SGMII SerDes/PHY driver.
+ */
+
+#include <linux/delay.h>
+#include <linux/ethtool.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
+
+struct qcom_dwmac_sgmii_phy_scmi {
+	unsigned int perf_state;
+};
+
+static int qcom_dwmac_sgmii_phy_scmi_power_on(struct phy *phy)
+{
+	struct qcom_dwmac_sgmii_phy_scmi *priv = phy_get_drvdata(phy);
+	struct device *dev = phy->dev.parent;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret)
+		return ret;
+
+	ret = dev_pm_genpd_set_performance_state(dev, priv->perf_state);
+	if (ret) {
+		pm_runtime_put(dev);
+		return ret;
+	}
+
+	usleep_range(5000, 10000);
+
+	return 0;
+}
+
+static int qcom_dwmac_sgmii_phy_scmi_power_off(struct phy *phy)
+{
+	struct device *dev = phy->dev.parent;
+
+	dev_pm_genpd_set_performance_state(dev, 0);
+	pm_runtime_put(dev);
+
+	return 0;
+}
+
+static int qcom_dwmac_sgmii_phy_scmi_validate(struct phy *phy, enum phy_mode mode,
+					      int submode,
+					      union phy_configure_opts *opts)
+{
+	if (mode != PHY_MODE_ETHERNET)
+		return -EINVAL;
+
+	switch (submode) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_1000BASEX:
+	case PHY_INTERFACE_MODE_2500BASEX:
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int qcom_dwmac_sgmii_phy_scmi_set_mode(struct phy *phy, enum phy_mode mode,
+					      int submode)
+{
+	struct qcom_dwmac_sgmii_phy_scmi *priv = phy_get_drvdata(phy);
+	int ret;
+
+	ret = qcom_dwmac_sgmii_phy_scmi_validate(phy, mode, submode, NULL);
+	if (ret)
+		return ret;
+
+	priv->perf_state = (submode == PHY_INTERFACE_MODE_2500BASEX) ?
+			   SPEED_2500 : SPEED_1000;
+
+	return 0;
+}
+
+static const struct phy_ops qcom_dwmac_sgmii_phy_scmi_ops = {
+	.power_on	= qcom_dwmac_sgmii_phy_scmi_power_on,
+	.power_off	= qcom_dwmac_sgmii_phy_scmi_power_off,
+	.set_mode	= qcom_dwmac_sgmii_phy_scmi_set_mode,
+	.validate	= qcom_dwmac_sgmii_phy_scmi_validate,
+	.owner		= THIS_MODULE,
+};
+
+static void qcom_dwmac_sgmii_phy_scmi_runtime_disable(void *data)
+{
+	struct device *dev = data;
+
+	pm_runtime_disable(dev);
+}
+
+static int qcom_dwmac_sgmii_phy_scmi_probe(struct platform_device *pdev)
+{
+	struct qcom_dwmac_sgmii_phy_scmi *priv;
+	struct device *dev = &pdev->dev;
+	struct phy_provider *provider;
+	struct phy *phy;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->perf_state = SPEED_1000;
+
+	/*
+	 * Enable runtime PM on the provider before creating the PHY so that the
+	 * PHY core enables runtime PM on the PHY device too. The single SCMI
+	 * power domain has already been attached to this device by the driver
+	 * core, so runtime PM votes propagate to firmware through the genpd
+	 * device link. No register or clock access is done here - firmware owns
+	 * the SerDes.
+	 */
+	pm_runtime_enable(dev);
+
+	ret = devm_add_action_or_reset(dev, qcom_dwmac_sgmii_phy_scmi_runtime_disable, dev);
+	if (ret)
+		return ret;
+
+	phy = devm_phy_create(dev, NULL, &qcom_dwmac_sgmii_phy_scmi_ops);
+	if (IS_ERR(phy))
+		return dev_err_probe(dev, PTR_ERR(phy), "failed to create the phy\n");
+
+	phy_set_drvdata(phy, priv);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(provider))
+		return dev_err_probe(dev, PTR_ERR(provider),
+				     "failed to register the PHY provider\n");
+
+	return 0;
+}
+
+static const struct of_device_id qcom_dwmac_sgmii_phy_scmi_of_match[] = {
+	{ .compatible = "qcom,sa8255p-dwmac-sgmii-phy" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_dwmac_sgmii_phy_scmi_of_match);
+
+static struct platform_driver qcom_dwmac_sgmii_phy_scmi_driver = {
+	.probe	= qcom_dwmac_sgmii_phy_scmi_probe,
+	.driver = {
+		.name = "qcom-dwmac-sgmii-phy-scmi",
+		.of_match_table = qcom_dwmac_sgmii_phy_scmi_of_match,
+	},
+};
+module_platform_driver(qcom_dwmac_sgmii_phy_scmi_driver);
+
+MODULE_DESCRIPTION("Qualcomm DWMAC SGMII PHY driver (firmware managed)");
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");

-- 
2.47.3