PCI: qcom: Add Qualcomm PCIe controller driver

The PCIe driver reuses the Designware common code for host and MSI
initialization, and also programs the Qualcomm application specific
registers.

[bhelgaas: remove COMPILE_TEST Kconfig dependency]
Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

3 files changed, 627 insertions, 0 deletions

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index f131ba9..de18298 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -172,4 +172,14 @@ config PCI_HISI
 	help
 	  Say Y here if you want PCIe controller support on HiSilicon HIP05 SoC
 
+config PCIE_QCOM
+	bool "Qualcomm PCIe controller"
+	depends on ARCH_QCOM && OF
+	select PCIE_DW
+	select PCIEPORTBUS
+	help
+	  Say Y here to enable PCIe controller support on Qualcomm SoCs. The
+	  PCIe controller uses the Designware core plus Qualcomm-specific
+	  hardware wrappers.
+
 endmenu
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 9d4d3c6..e523c17 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -20,3 +20,4 @@ obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
 obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
 obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
 obj-$(CONFIG_PCI_HISI) += pcie-hisi.o
+obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
diff --git a/drivers/pci/host/pcie-qcom.c b/drivers/pci/host/pcie-qcom.c
new file mode 100644
index 0000000..e845fba
--- /dev/null
+++ b/drivers/pci/host/pcie-qcom.c
@@ -0,0 +1,616 @@
+/*
+ * Copyright (c) 2014-2015, The Linux Foundation. All rights reserved.
+ * Copyright 2015 Linaro Limited.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/phy/phy.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "pcie-designware.h"
+
+#define PCIE20_PARF_PHY_CTRL			0x40
+#define PCIE20_PARF_PHY_REFCLK			0x4C
+#define PCIE20_PARF_DBI_BASE_ADDR		0x168
+#define PCIE20_PARF_SLV_ADDR_SPACE_SIZE		0x16c
+#define PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT	0x178
+
+#define PCIE20_ELBI_SYS_CTRL			0x04
+#define PCIE20_ELBI_SYS_CTRL_LT_ENABLE		BIT(0)
+
+#define PCIE20_CAP				0x70
+
+#define PERST_DELAY_US				1000
+
+struct qcom_pcie_resources_v0 {
+	struct clk *iface_clk;
+	struct clk *core_clk;
+	struct clk *phy_clk;
+	struct reset_control *pci_reset;
+	struct reset_control *axi_reset;
+	struct reset_control *ahb_reset;
+	struct reset_control *por_reset;
+	struct reset_control *phy_reset;
+	struct regulator *vdda;
+	struct regulator *vdda_phy;
+	struct regulator *vdda_refclk;
+};
+
+struct qcom_pcie_resources_v1 {
+	struct clk *iface;
+	struct clk *aux;
+	struct clk *master_bus;
+	struct clk *slave_bus;
+	struct reset_control *core;
+	struct regulator *vdda;
+};
+
+union qcom_pcie_resources {
+	struct qcom_pcie_resources_v0 v0;
+	struct qcom_pcie_resources_v1 v1;
+};
+
+struct qcom_pcie;
+
+struct qcom_pcie_ops {
+	int (*get_resources)(struct qcom_pcie *pcie);
+	int (*init)(struct qcom_pcie *pcie);
+	void (*deinit)(struct qcom_pcie *pcie);
+};
+
+struct qcom_pcie {
+	struct pcie_port pp;
+	struct device *dev;
+	union qcom_pcie_resources res;
+	void __iomem *parf;
+	void __iomem *dbi;
+	void __iomem *elbi;
+	struct phy *phy;
+	struct gpio_desc *reset;
+	struct qcom_pcie_ops *ops;
+};
+
+#define to_qcom_pcie(x)		container_of(x, struct qcom_pcie, pp)
+
+static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
+{
+	gpiod_set_value(pcie->reset, 1);
+	usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500);
+}
+
+static void qcom_ep_reset_deassert(struct qcom_pcie *pcie)
+{
+	gpiod_set_value(pcie->reset, 0);
+	usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500);
+}
+
+static irqreturn_t qcom_pcie_msi_irq_handler(int irq, void *arg)
+{
+	struct pcie_port *pp = arg;
+
+	return dw_handle_msi_irq(pp);
+}
+
+static int qcom_pcie_establish_link(struct qcom_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	unsigned int retries = 0;
+	u32 val;
+
+	if (dw_pcie_link_up(&pcie->pp))
+		return 0;
+
+	/* enable link training */
+	val = readl(pcie->elbi + PCIE20_ELBI_SYS_CTRL);
+	val |= PCIE20_ELBI_SYS_CTRL_LT_ENABLE;
+	writel(val, pcie->elbi + PCIE20_ELBI_SYS_CTRL);
+
+	do {
+		if (dw_pcie_link_up(&pcie->pp))
+			return 0;
+		usleep_range(250, 1000);
+	} while (retries < 200);
+
+	dev_warn(dev, "phy link never came up\n");
+
+	return -ETIMEDOUT;
+}
+
+static int qcom_pcie_get_resources_v0(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_resources_v0 *res = &pcie->res.v0;
+	struct device *dev = pcie->dev;
+
+	res->vdda = devm_regulator_get(dev, "vdda");
+	if (IS_ERR(res->vdda))
+		return PTR_ERR(res->vdda);
+
+	res->vdda_phy = devm_regulator_get(dev, "vdda_phy");
+	if (IS_ERR(res->vdda_phy))
+		return PTR_ERR(res->vdda_phy);
+
+	res->vdda_refclk = devm_regulator_get(dev, "vdda_refclk");
+	if (IS_ERR(res->vdda_refclk))
+		return PTR_ERR(res->vdda_refclk);
+
+	res->iface_clk = devm_clk_get(dev, "iface");
+	if (IS_ERR(res->iface_clk))
+		return PTR_ERR(res->iface_clk);
+
+	res->core_clk = devm_clk_get(dev, "core");
+	if (IS_ERR(res->core_clk))
+		return PTR_ERR(res->core_clk);
+
+	res->phy_clk = devm_clk_get(dev, "phy");
+	if (IS_ERR(res->phy_clk))
+		return PTR_ERR(res->phy_clk);
+
+	res->pci_reset = devm_reset_control_get(dev, "pci");
+	if (IS_ERR(res->pci_reset))
+		return PTR_ERR(res->pci_reset);
+
+	res->axi_reset = devm_reset_control_get(dev, "axi");
+	if (IS_ERR(res->axi_reset))
+		return PTR_ERR(res->axi_reset);
+
+	res->ahb_reset = devm_reset_control_get(dev, "ahb");
+	if (IS_ERR(res->ahb_reset))
+		return PTR_ERR(res->ahb_reset);
+
+	res->por_reset = devm_reset_control_get(dev, "por");
+	if (IS_ERR(res->por_reset))
+		return PTR_ERR(res->por_reset);
+
+	res->phy_reset = devm_reset_control_get(dev, "phy");
+	if (IS_ERR(res->phy_reset))
+		return PTR_ERR(res->phy_reset);
+
+	return 0;
+}
+
+static int qcom_pcie_get_resources_v1(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_resources_v1 *res = &pcie->res.v1;
+	struct device *dev = pcie->dev;
+
+	res->vdda = devm_regulator_get(dev, "vdda");
+	if (IS_ERR(res->vdda))
+		return PTR_ERR(res->vdda);
+
+	res->iface = devm_clk_get(dev, "iface");
+	if (IS_ERR(res->iface))
+		return PTR_ERR(res->iface);
+
+	res->aux = devm_clk_get(dev, "aux");
+	if (IS_ERR(res->aux))
+		return PTR_ERR(res->aux);
+
+	res->master_bus = devm_clk_get(dev, "master_bus");
+	if (IS_ERR(res->master_bus))
+		return PTR_ERR(res->master_bus);
+
+	res->slave_bus = devm_clk_get(dev, "slave_bus");
+	if (IS_ERR(res->slave_bus))
+		return PTR_ERR(res->slave_bus);
+
+	res->core = devm_reset_control_get(dev, "core");
+	if (IS_ERR(res->core))
+		return PTR_ERR(res->core);
+
+	return 0;
+}
+
+static void qcom_pcie_deinit_v0(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_resources_v0 *res = &pcie->res.v0;
+
+	reset_control_assert(res->pci_reset);
+	reset_control_assert(res->axi_reset);
+	reset_control_assert(res->ahb_reset);
+	reset_control_assert(res->por_reset);
+	reset_control_assert(res->pci_reset);
+	clk_disable_unprepare(res->iface_clk);
+	clk_disable_unprepare(res->core_clk);
+	clk_disable_unprepare(res->phy_clk);
+	regulator_disable(res->vdda);
+	regulator_disable(res->vdda_phy);
+	regulator_disable(res->vdda_refclk);
+}
+
+static int qcom_pcie_init_v0(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_resources_v0 *res = &pcie->res.v0;
+	struct device *dev = pcie->dev;
+	u32 val;
+	int ret;
+
+	ret = regulator_enable(res->vdda);
+	if (ret) {
+		dev_err(dev, "cannot enable vdda regulator\n");
+		return ret;
+	}
+
+	ret = regulator_enable(res->vdda_refclk);
+	if (ret) {
+		dev_err(dev, "cannot enable vdda_refclk regulator\n");
+		goto err_refclk;
+	}
+
+	ret = regulator_enable(res->vdda_phy);
+	if (ret) {
+		dev_err(dev, "cannot enable vdda_phy regulator\n");
+		goto err_vdda_phy;
+	}
+
+	ret = reset_control_assert(res->ahb_reset);
+	if (ret) {
+		dev_err(dev, "cannot assert ahb reset\n");
+		goto err_assert_ahb;
+	}
+
+	ret = clk_prepare_enable(res->iface_clk);
+	if (ret) {
+		dev_err(dev, "cannot prepare/enable iface clock\n");
+		goto err_assert_ahb;
+	}
+
+	ret = clk_prepare_enable(res->phy_clk);
+	if (ret) {
+		dev_err(dev, "cannot prepare/enable phy clock\n");
+		goto err_clk_phy;
+	}
+
+	ret = clk_prepare_enable(res->core_clk);
+	if (ret) {
+		dev_err(dev, "cannot prepare/enable core clock\n");
+		goto err_clk_core;
+	}
+
+	ret = reset_control_deassert(res->ahb_reset);
+	if (ret) {
+		dev_err(dev, "cannot deassert ahb reset\n");
+		goto err_deassert_ahb;
+	}
+
+	/* enable PCIe clocks and resets */
+	val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
+	val &= ~BIT(0);
+	writel(val, pcie->parf + PCIE20_PARF_PHY_CTRL);
+
+	/* enable external reference clock */
+	val = readl(pcie->parf + PCIE20_PARF_PHY_REFCLK);
+	val |= BIT(16);
+	writel(val, pcie->parf + PCIE20_PARF_PHY_REFCLK);
+
+	ret = reset_control_deassert(res->phy_reset);
+	if (ret) {
+		dev_err(dev, "cannot deassert phy reset\n");
+		return ret;
+	}
+
+	ret = reset_control_deassert(res->pci_reset);
+	if (ret) {
+		dev_err(dev, "cannot deassert pci reset\n");
+		return ret;
+	}
+
+	ret = reset_control_deassert(res->por_reset);
+	if (ret) {
+		dev_err(dev, "cannot deassert por reset\n");
+		return ret;
+	}
+
+	ret = reset_control_deassert(res->axi_reset);
+	if (ret) {
+		dev_err(dev, "cannot deassert axi reset\n");
+		return ret;
+	}
+
+	/* wait for clock acquisition */
+	usleep_range(1000, 1500);
+
+	return 0;
+
+err_deassert_ahb:
+	clk_disable_unprepare(res->core_clk);
+err_clk_core:
+	clk_disable_unprepare(res->phy_clk);
+err_clk_phy:
+	clk_disable_unprepare(res->iface_clk);
+err_assert_ahb:
+	regulator_disable(res->vdda_phy);
+err_vdda_phy:
+	regulator_disable(res->vdda_refclk);
+err_refclk:
+	regulator_disable(res->vdda);
+
+	return ret;
+}
+
+static void qcom_pcie_deinit_v1(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_resources_v1 *res = &pcie->res.v1;
+
+	reset_control_assert(res->core);
+	clk_disable_unprepare(res->slave_bus);
+	clk_disable_unprepare(res->master_bus);
+	clk_disable_unprepare(res->iface);
+	clk_disable_unprepare(res->aux);
+	regulator_disable(res->vdda);
+}
+
+static int qcom_pcie_init_v1(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_resources_v1 *res = &pcie->res.v1;
+	struct device *dev = pcie->dev;
+	int ret;
+
+	ret = reset_control_deassert(res->core);
+	if (ret) {
+		dev_err(dev, "cannot deassert core reset\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(res->aux);
+	if (ret) {
+		dev_err(dev, "cannot prepare/enable aux clock\n");
+		goto err_res;
+	}
+
+	ret = clk_prepare_enable(res->iface);
+	if (ret) {
+		dev_err(dev, "cannot prepare/enable iface clock\n");
+		goto err_aux;
+	}
+
+	ret = clk_prepare_enable(res->master_bus);
+	if (ret) {
+		dev_err(dev, "cannot prepare/enable master_bus clock\n");
+		goto err_iface;
+	}
+
+	ret = clk_prepare_enable(res->slave_bus);
+	if (ret) {
+		dev_err(dev, "cannot prepare/enable slave_bus clock\n");
+		goto err_master;
+	}
+
+	ret = regulator_enable(res->vdda);
+	if (ret) {
+		dev_err(dev, "cannot enable vdda regulator\n");
+		goto err_slave;
+	}
+
+	/* change DBI base address */
+	writel(0, pcie->parf + PCIE20_PARF_DBI_BASE_ADDR);
+
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		u32 val = readl(pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT);
+
+		val |= BIT(31);
+		writel(val, pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT);
+	}
+
+	return 0;
+err_slave:
+	clk_disable_unprepare(res->slave_bus);
+err_master:
+	clk_disable_unprepare(res->master_bus);
+err_iface:
+	clk_disable_unprepare(res->iface);
+err_aux:
+	clk_disable_unprepare(res->aux);
+err_res:
+	reset_control_assert(res->core);
+
+	return ret;
+}
+
+static int qcom_pcie_link_up(struct pcie_port *pp)
+{
+	struct qcom_pcie *pcie = to_qcom_pcie(pp);
+	u16 val = readw(pcie->dbi + PCIE20_CAP + PCI_EXP_LNKSTA);
+
+	return !!(val & PCI_EXP_LNKSTA_DLLLA);
+}
+
+static void qcom_pcie_host_init(struct pcie_port *pp)
+{
+	struct qcom_pcie *pcie = to_qcom_pcie(pp);
+	int ret;
+
+	qcom_ep_reset_assert(pcie);
+
+	ret = pcie->ops->init(pcie);
+	if (ret)
+		goto err_deinit;
+
+	ret = phy_power_on(pcie->phy);
+	if (ret)
+		goto err_deinit;
+
+	dw_pcie_setup_rc(pp);
+
+	if (IS_ENABLED(CONFIG_PCI_MSI))
+		dw_pcie_msi_init(pp);
+
+	qcom_ep_reset_deassert(pcie);
+
+	ret = qcom_pcie_establish_link(pcie);
+	if (ret)
+		goto err;
+
+	return;
+err:
+	qcom_ep_reset_assert(pcie);
+	phy_power_off(pcie->phy);
+err_deinit:
+	pcie->ops->deinit(pcie);
+}
+
+static int qcom_pcie_rd_own_conf(struct pcie_port *pp, int where, int size,
+				 u32 *val)
+{
+	/* the device class is not reported correctly from the register */
+	if (where == PCI_CLASS_REVISION && size == 4) {
+		*val = readl(pp->dbi_base + PCI_CLASS_REVISION);
+		*val &= 0xff;	/* keep revision id */
+		*val |= PCI_CLASS_BRIDGE_PCI << 16;
+		return PCIBIOS_SUCCESSFUL;
+	}
+
+	return dw_pcie_cfg_read(pp->dbi_base + where, size, val);
+}
+
+static struct pcie_host_ops qcom_pcie_dw_ops = {
+	.link_up = qcom_pcie_link_up,
+	.host_init = qcom_pcie_host_init,
+	.rd_own_conf = qcom_pcie_rd_own_conf,
+};
+
+static const struct qcom_pcie_ops ops_v0 = {
+	.get_resources = qcom_pcie_get_resources_v0,
+	.init = qcom_pcie_init_v0,
+	.deinit = qcom_pcie_deinit_v0,
+};
+
+static const struct qcom_pcie_ops ops_v1 = {
+	.get_resources = qcom_pcie_get_resources_v1,
+	.init = qcom_pcie_init_v1,
+	.deinit = qcom_pcie_deinit_v1,
+};
+
+static int qcom_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	struct qcom_pcie *pcie;
+	struct pcie_port *pp;
+	int ret;
+
+	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
+	if (!pcie)
+		return -ENOMEM;
+
+	pcie->ops = (struct qcom_pcie_ops *)of_device_get_match_data(dev);
+	pcie->dev = dev;
+
+	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_LOW);
+	if (IS_ERR(pcie->reset))
+		return PTR_ERR(pcie->reset);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "parf");
+	pcie->parf = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pcie->parf))
+		return PTR_ERR(pcie->parf);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
+	pcie->dbi = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pcie->dbi))
+		return PTR_ERR(pcie->dbi);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "elbi");
+	pcie->elbi = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pcie->elbi))
+		return PTR_ERR(pcie->elbi);
+
+	pcie->phy = devm_phy_optional_get(dev, "pciephy");
+	if (IS_ERR(pcie->phy))
+		return PTR_ERR(pcie->phy);
+
+	ret = pcie->ops->get_resources(pcie);
+	if (ret)
+		return ret;
+
+	pp = &pcie->pp;
+	pp->dev = dev;
+	pp->dbi_base = pcie->dbi;
+	pp->root_bus_nr = -1;
+	pp->ops = &qcom_pcie_dw_ops;
+
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		pp->msi_irq = platform_get_irq_byname(pdev, "msi");
+		if (pp->msi_irq < 0)
+			return pp->msi_irq;
+
+		ret = devm_request_irq(dev, pp->msi_irq,
+				       qcom_pcie_msi_irq_handler,
+				       IRQF_SHARED, "qcom-pcie-msi", pp);
+		if (ret) {
+			dev_err(dev, "cannot request msi irq\n");
+			return ret;
+		}
+	}
+
+	ret = phy_init(pcie->phy);
+	if (ret)
+		return ret;
+
+	ret = dw_pcie_host_init(pp);
+	if (ret) {
+		dev_err(dev, "cannot initialize host\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pcie);
+
+	return 0;
+}
+
+static int qcom_pcie_remove(struct platform_device *pdev)
+{
+	struct qcom_pcie *pcie = platform_get_drvdata(pdev);
+
+	qcom_ep_reset_assert(pcie);
+	phy_power_off(pcie->phy);
+	phy_exit(pcie->phy);
+	pcie->ops->deinit(pcie);
+
+	return 0;
+}
+
+static const struct of_device_id qcom_pcie_match[] = {
+	{ .compatible = "qcom,pcie-ipq8064", .data = &ops_v0 },
+	{ .compatible = "qcom,pcie-apq8064", .data = &ops_v0 },
+	{ .compatible = "qcom,pcie-apq8084", .data = &ops_v1 },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_pcie_match);
+
+static struct platform_driver qcom_pcie_driver = {
+	.probe = qcom_pcie_probe,
+	.remove = qcom_pcie_remove,
+	.driver = {
+		.name = "qcom-pcie",
+		.of_match_table = qcom_pcie_match,
+	},
+};
+
+module_platform_driver(qcom_pcie_driver);
+
+MODULE_AUTHOR("Stanimir Varbanov <svarbanov@mm-sol.com>");
+MODULE_DESCRIPTION("Qualcomm PCIe root complex driver");
+MODULE_LICENSE("GPL v2");