phy: bcm-sr-pcie: Add Stingray PCIe PHY driver

Add Stingray PCIe PHY driver for both PAXB and PAXC root complex
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/broadcom/Kconfig

@@ -80,3 +80,13 @@ config PHY_BRCM_USB
 	  This driver is required by the USB XHCI, EHCI and OHCI
 	  drivers.
 	  If unsure, say N.
+
+config PHY_BCM_SR_PCIE
+	tristate "Broadcom Stingray PCIe PHY driver"
+	depends on OF && (ARCH_BCM_IPROC || COMPILE_TEST)
+	select GENERIC_PHY
+	select MFD_SYSCON
+	default ARCH_BCM_IPROC
+	help
+	  Enable this to support the Broadcom Stingray PCIe PHY
+	  If unsure, say N.

drivers/phy/broadcom/Makefile

@@ -9,3 +9,5 @@ obj-$(CONFIG_PHY_BRCM_SATA)		+= phy-brcm-sata.o
 obj-$(CONFIG_PHY_BRCM_USB)		+= phy-brcm-usb-dvr.o
 
 phy-brcm-usb-dvr-objs := phy-brcm-usb.o phy-brcm-usb-init.o
+
+obj-$(CONFIG_PHY_BCM_SR_PCIE)		+= phy-bcm-sr-pcie.o

drivers/phy/broadcom/phy-bcm-sr-pcie.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2016-2018 Broadcom
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* we have up to 8 PAXB based RC. The 9th one is always PAXC */
+#define SR_NR_PCIE_PHYS               9
+#define SR_PAXC_PHY_IDX               (SR_NR_PCIE_PHYS - 1)
+
+#define PCIE_PIPEMUX_CFG_OFFSET       0x10c
+#define PCIE_PIPEMUX_SELECT_STRAP     0xf
+
+#define CDRU_STRAP_DATA_LSW_OFFSET    0x5c
+#define PCIE_PIPEMUX_SHIFT            19
+#define PCIE_PIPEMUX_MASK             0xf
+
+#define MHB_MEM_PW_PAXC_OFFSET        0x1c0
+#define MHB_PWR_ARR_POWERON           0x8
+#define MHB_PWR_ARR_POWEROK           0x4
+#define MHB_PWR_POWERON               0x2
+#define MHB_PWR_POWEROK               0x1
+#define MHB_PWR_STATUS_MASK           (MHB_PWR_ARR_POWERON | \
+				       MHB_PWR_ARR_POWEROK | \
+				       MHB_PWR_POWERON | \
+				       MHB_PWR_POWEROK)
+
+struct sr_pcie_phy_core;
+
+/**
+ * struct sr_pcie_phy - Stingray PCIe PHY
+ *
+ * @core: pointer to the Stingray PCIe PHY core control
+ * @index: PHY index
+ * @phy: pointer to the kernel PHY device
+ */
+struct sr_pcie_phy {
+	struct sr_pcie_phy_core *core;
+	unsigned int index;
+	struct phy *phy;
+};
+
+/**
+ * struct sr_pcie_phy_core - Stingray PCIe PHY core control
+ *
+ * @dev: pointer to device
+ * @base: base register of PCIe SS
+ * @cdru: regmap to the CDRU device
+ * @mhb: regmap to the MHB device
+ * @pipemux: pipemuex strap
+ * @phys: array of PCIe PHYs
+ */
+struct sr_pcie_phy_core {
+	struct device *dev;
+	void __iomem *base;
+	struct regmap *cdru;
+	struct regmap *mhb;
+	u32 pipemux;
+	struct sr_pcie_phy phys[SR_NR_PCIE_PHYS];
+};
+
+/*
+ * PCIe PIPEMUX lookup table
+ *
+ * Each array index represents a PIPEMUX strap setting
+ * The array element represents a bitmap where a set bit means the PCIe
+ * core and associated serdes has been enabled as RC and is available for use
+ */
+static const u8 pipemux_table[] = {
+	/* PIPEMUX = 0, EP 1x16 */
+	0x00,
+	/* PIPEMUX = 1, EP 2x8 */
+	0x00,
+	/* PIPEMUX = 2, EP 4x4 */
+	0x00,
+	/* PIPEMUX = 3, RC 2x8, cores 0, 7 */
+	0x81,
+	/* PIPEMUX = 4, RC 4x4, cores 0, 1, 6, 7 */
+	0xc3,
+	/* PIPEMUX = 5, RC 8x2, all 8 cores */
+	0xff,
+	/* PIPEMUX = 6, RC 3x4 + 2x2, cores 0, 2, 3, 6, 7 */
+	0xcd,
+	/* PIPEMUX = 7, RC 1x4 + 6x2, cores 0, 2, 3, 4, 5, 6, 7 */
+	0xfd,
+	/* PIPEMUX = 8, EP 1x8 + RC 4x2, cores 4, 5, 6, 7 */
+	0xf0,
+	/* PIPEMUX = 9, EP 1x8 + RC 2x4, cores 6, 7 */
+	0xc0,
+	/* PIPEMUX = 10, EP 2x4 + RC 2x4, cores 1, 6 */
+	0x42,
+	/* PIPEMUX = 11, EP 2x4 + RC 4x2, cores 2, 3, 4, 5 */
+	0x3c,
+	/* PIPEMUX = 12, EP 1x4 + RC 6x2, cores 2, 3, 4, 5, 6, 7 */
+	0xfc,
+	/* PIPEMUX = 13, RC 2x4 + RC 1x4 + 2x2, cores 2, 3, 6 */
+	0x4c,
+};
+
+/*
+ * Return true if the strap setting is valid
+ */
+static bool pipemux_strap_is_valid(u32 pipemux)
+{
+	return !!(pipemux < ARRAY_SIZE(pipemux_table));
+}
+
+/*
+ * Read the PCIe PIPEMUX from strap
+ */
+static u32 pipemux_strap_read(struct sr_pcie_phy_core *core)
+{
+	u32 pipemux;
+
+	/*
+	 * Read PIPEMUX configuration register to determine the pipemux setting
+	 *
+	 * In the case when the value indicates using HW strap, fall back to
+	 * use HW strap
+	 */
+	pipemux = readl(core->base + PCIE_PIPEMUX_CFG_OFFSET);
+	pipemux &= PCIE_PIPEMUX_MASK;
+	if (pipemux == PCIE_PIPEMUX_SELECT_STRAP) {
+		regmap_read(core->cdru, CDRU_STRAP_DATA_LSW_OFFSET, &pipemux);
+		pipemux >>= PCIE_PIPEMUX_SHIFT;
+		pipemux &= PCIE_PIPEMUX_MASK;
+	}
+
+	return pipemux;
+}
+
+/*
+ * Given a PIPEMUX strap and PCIe core index, this function returns true if the
+ * PCIe core needs to be enabled
+ */
+static bool pcie_core_is_for_rc(struct sr_pcie_phy *phy)
+{
+	struct sr_pcie_phy_core *core = phy->core;
+	unsigned int core_idx = phy->index;
+
+	return !!((pipemux_table[core->pipemux] >> core_idx) & 0x1);
+}
+
+static int sr_pcie_phy_init(struct phy *p)
+{
+	struct sr_pcie_phy *phy = phy_get_drvdata(p);
+
+	/*
+	 * Check whether this PHY is for root complex or not. If yes, return
+	 * zero so the host driver can proceed to enumeration. If not, return
+	 * an error and that will force the host driver to bail out
+	 */
+	if (pcie_core_is_for_rc(phy))
+		return 0;
+
+	return -ENODEV;
+}
+
+static int sr_paxc_phy_init(struct phy *p)
+{
+	struct sr_pcie_phy *phy = phy_get_drvdata(p);
+	struct sr_pcie_phy_core *core = phy->core;
+	unsigned int core_idx = phy->index;
+	u32 val;
+
+	if (core_idx != SR_PAXC_PHY_IDX)
+		return -EINVAL;
+
+	regmap_read(core->mhb, MHB_MEM_PW_PAXC_OFFSET, &val);
+	if ((val & MHB_PWR_STATUS_MASK) != MHB_PWR_STATUS_MASK) {
+		dev_err(core->dev, "PAXC is not powered up\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static const struct phy_ops sr_pcie_phy_ops = {
+	.init = sr_pcie_phy_init,
+	.owner = THIS_MODULE,
+};
+
+static const struct phy_ops sr_paxc_phy_ops = {
+	.init = sr_paxc_phy_init,
+	.owner = THIS_MODULE,
+};
+
+static struct phy *sr_pcie_phy_xlate(struct device *dev,
+				     struct of_phandle_args *args)
+{
+	struct sr_pcie_phy_core *core;
+	int phy_idx;
+
+	core = dev_get_drvdata(dev);
+	if (!core)
+		return ERR_PTR(-EINVAL);
+
+	phy_idx = args->args[0];
+
+	if (WARN_ON(phy_idx >= SR_NR_PCIE_PHYS))
+		return ERR_PTR(-ENODEV);
+
+	return core->phys[phy_idx].phy;
+}
+
+static int sr_pcie_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct sr_pcie_phy_core *core;
+	struct resource *res;
+	struct phy_provider *provider;
+	unsigned int phy_idx = 0;
+
+	core = devm_kzalloc(dev, sizeof(*core), GFP_KERNEL);
+	if (!core)
+		return -ENOMEM;
+
+	core->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	core->base = devm_ioremap_resource(core->dev, res);
+	if (IS_ERR(core->base))
+		return PTR_ERR(core->base);
+
+	core->cdru = syscon_regmap_lookup_by_phandle(node, "brcm,sr-cdru");
+	if (IS_ERR(core->cdru)) {
+		dev_err(core->dev, "unable to find CDRU device\n");
+		return PTR_ERR(core->cdru);
+	}
+
+	core->mhb = syscon_regmap_lookup_by_phandle(node, "brcm,sr-mhb");
+	if (IS_ERR(core->mhb)) {
+		dev_err(core->dev, "unable to find MHB device\n");
+		return PTR_ERR(core->mhb);
+	}
+
+	/* read the PCIe PIPEMUX strap setting */
+	core->pipemux = pipemux_strap_read(core);
+	if (!pipemux_strap_is_valid(core->pipemux)) {
+		dev_err(core->dev, "invalid PCIe PIPEMUX strap %u\n",
+			core->pipemux);
+		return -EIO;
+	}
+
+	for (phy_idx = 0; phy_idx < SR_NR_PCIE_PHYS; phy_idx++) {
+		struct sr_pcie_phy *p = &core->phys[phy_idx];
+		const struct phy_ops *ops;
+
+		if (phy_idx == SR_PAXC_PHY_IDX)
+			ops = &sr_paxc_phy_ops;
+		else
+			ops = &sr_pcie_phy_ops;
+
+		p->phy = devm_phy_create(dev, NULL, ops);
+		if (IS_ERR(p->phy)) {
+			dev_err(dev, "failed to create PCIe PHY\n");
+			return PTR_ERR(p->phy);
+		}
+
+		p->core = core;
+		p->index = phy_idx;
+		phy_set_drvdata(p->phy, p);
+	}
+
+	dev_set_drvdata(dev, core);
+
+	provider = devm_of_phy_provider_register(dev, sr_pcie_phy_xlate);
+	if (IS_ERR(provider)) {
+		dev_err(dev, "failed to register PHY provider\n");
+		return PTR_ERR(provider);
+	}
+
+	dev_info(dev, "Stingray PCIe PHY driver initialized\n");
+
+	return 0;
+}
+
+static const struct of_device_id sr_pcie_phy_match_table[] = {
+	{ .compatible = "brcm,sr-pcie-phy" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sr_pcie_phy_match_table);
+
+static struct platform_driver sr_pcie_phy_driver = {
+	.driver = {
+		.name		= "sr-pcie-phy",
+		.of_match_table	= sr_pcie_phy_match_table,
+	},
+	.probe	= sr_pcie_phy_probe,
+};
+module_platform_driver(sr_pcie_phy_driver);
+
+MODULE_AUTHOR("Ray Jui <ray.jui@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom Stingray PCIe PHY driver");
+MODULE_LICENSE("GPL v2");