root/drivers/pci/controller/dwc/pcie-uniphier.c
// SPDX-License-Identifier: GPL-2.0
/*
 * PCIe host controller driver for UniPhier SoCs
 * Copyright 2018 Socionext Inc.
 * Author: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
 */

#include <linux/bitops.h>
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/of_irq.h>
#include <linux/pci.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/reset.h>

#include "pcie-designware.h"

#define PCL_PINCTRL0                    0x002c
#define PCL_PERST_PLDN_REGEN            BIT(12)
#define PCL_PERST_NOE_REGEN             BIT(11)
#define PCL_PERST_OUT_REGEN             BIT(8)
#define PCL_PERST_PLDN_REGVAL           BIT(4)
#define PCL_PERST_NOE_REGVAL            BIT(3)
#define PCL_PERST_OUT_REGVAL            BIT(0)

#define PCL_PIPEMON                     0x0044
#define PCL_PCLK_ALIVE                  BIT(15)

#define PCL_MODE                        0x8000
#define PCL_MODE_REGEN                  BIT(8)
#define PCL_MODE_REGVAL                 BIT(0)

#define PCL_APP_READY_CTRL              0x8008
#define PCL_APP_LTSSM_ENABLE            BIT(0)

#define PCL_APP_PM0                     0x8078
#define PCL_SYS_AUX_PWR_DET             BIT(8)

#define PCL_RCV_INT                     0x8108
#define PCL_RCV_INT_ALL_ENABLE          GENMASK(20, 17)
#define PCL_CFG_BW_MGT_STATUS           BIT(4)
#define PCL_CFG_LINK_AUTO_BW_STATUS     BIT(3)
#define PCL_CFG_AER_RC_ERR_MSI_STATUS   BIT(2)
#define PCL_CFG_PME_MSI_STATUS          BIT(1)

#define PCL_RCV_INTX                    0x810c
#define PCL_RCV_INTX_ALL_ENABLE         GENMASK(19, 16)
#define PCL_RCV_INTX_ALL_MASK           GENMASK(11, 8)
#define PCL_RCV_INTX_MASK_SHIFT         8
#define PCL_RCV_INTX_ALL_STATUS         GENMASK(3, 0)
#define PCL_RCV_INTX_STATUS_SHIFT       0

#define PCL_STATUS_LINK                 0x8140
#define PCL_RDLH_LINK_UP                BIT(1)
#define PCL_XMLH_LINK_UP                BIT(0)

struct uniphier_pcie {
        struct dw_pcie pci;
        void __iomem *base;
        struct clk *clk;
        struct reset_control *rst;
        struct phy *phy;
        struct irq_domain *intx_irq_domain;
};

#define to_uniphier_pcie(x)     dev_get_drvdata((x)->dev)

static void uniphier_pcie_ltssm_enable(struct uniphier_pcie *pcie,
                                       bool enable)
{
        u32 val;

        val = readl(pcie->base + PCL_APP_READY_CTRL);
        if (enable)
                val |= PCL_APP_LTSSM_ENABLE;
        else
                val &= ~PCL_APP_LTSSM_ENABLE;
        writel(val, pcie->base + PCL_APP_READY_CTRL);
}

static void uniphier_pcie_init_rc(struct uniphier_pcie *pcie)
{
        u32 val;

        /* set RC MODE */
        val = readl(pcie->base + PCL_MODE);
        val |= PCL_MODE_REGEN;
        val &= ~PCL_MODE_REGVAL;
        writel(val, pcie->base + PCL_MODE);

        /* use auxiliary power detection */
        val = readl(pcie->base + PCL_APP_PM0);
        val |= PCL_SYS_AUX_PWR_DET;
        writel(val, pcie->base + PCL_APP_PM0);

        /* assert PERST# */
        val = readl(pcie->base + PCL_PINCTRL0);
        val &= ~(PCL_PERST_NOE_REGVAL | PCL_PERST_OUT_REGVAL
                 | PCL_PERST_PLDN_REGVAL);
        val |= PCL_PERST_NOE_REGEN | PCL_PERST_OUT_REGEN
                | PCL_PERST_PLDN_REGEN;
        writel(val, pcie->base + PCL_PINCTRL0);

        uniphier_pcie_ltssm_enable(pcie, false);

        usleep_range(100000, 200000);

        /* deassert PERST# */
        val = readl(pcie->base + PCL_PINCTRL0);
        val |= PCL_PERST_OUT_REGVAL | PCL_PERST_OUT_REGEN;
        writel(val, pcie->base + PCL_PINCTRL0);
}

static int uniphier_pcie_wait_rc(struct uniphier_pcie *pcie)
{
        u32 status;
        int ret;

        /* wait PIPE clock */
        ret = readl_poll_timeout(pcie->base + PCL_PIPEMON, status,
                                 status & PCL_PCLK_ALIVE, 100000, 1000000);
        if (ret) {
                dev_err(pcie->pci.dev,
                        "Failed to initialize controller in RC mode\n");
                return ret;
        }

        return 0;
}

static bool uniphier_pcie_link_up(struct dw_pcie *pci)
{
        struct uniphier_pcie *pcie = to_uniphier_pcie(pci);
        u32 val, mask;

        val = readl(pcie->base + PCL_STATUS_LINK);
        mask = PCL_RDLH_LINK_UP | PCL_XMLH_LINK_UP;

        return (val & mask) == mask;
}

static int uniphier_pcie_start_link(struct dw_pcie *pci)
{
        struct uniphier_pcie *pcie = to_uniphier_pcie(pci);

        uniphier_pcie_ltssm_enable(pcie, true);

        return 0;
}

static void uniphier_pcie_stop_link(struct dw_pcie *pci)
{
        struct uniphier_pcie *pcie = to_uniphier_pcie(pci);

        uniphier_pcie_ltssm_enable(pcie, false);
}

static void uniphier_pcie_irq_enable(struct uniphier_pcie *pcie)
{
        writel(PCL_RCV_INT_ALL_ENABLE, pcie->base + PCL_RCV_INT);
        writel(PCL_RCV_INTX_ALL_ENABLE, pcie->base + PCL_RCV_INTX);
}


static void uniphier_pcie_irq_mask(struct irq_data *d)
{
        struct dw_pcie_rp *pp = irq_data_get_irq_chip_data(d);
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct uniphier_pcie *pcie = to_uniphier_pcie(pci);
        unsigned long flags;
        u32 val;

        raw_spin_lock_irqsave(&pp->lock, flags);

        val = readl(pcie->base + PCL_RCV_INTX);
        val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT);
        writel(val, pcie->base + PCL_RCV_INTX);

        raw_spin_unlock_irqrestore(&pp->lock, flags);
}

static void uniphier_pcie_irq_unmask(struct irq_data *d)
{
        struct dw_pcie_rp *pp = irq_data_get_irq_chip_data(d);
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct uniphier_pcie *pcie = to_uniphier_pcie(pci);
        unsigned long flags;
        u32 val;

        raw_spin_lock_irqsave(&pp->lock, flags);

        val = readl(pcie->base + PCL_RCV_INTX);
        val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT);
        writel(val, pcie->base + PCL_RCV_INTX);

        raw_spin_unlock_irqrestore(&pp->lock, flags);
}

static struct irq_chip uniphier_pcie_irq_chip = {
        .name = "PCI",
        .irq_mask = uniphier_pcie_irq_mask,
        .irq_unmask = uniphier_pcie_irq_unmask,
};

static int uniphier_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
                                  irq_hw_number_t hwirq)
{
        irq_set_chip_and_handler(irq, &uniphier_pcie_irq_chip,
                                 handle_level_irq);
        irq_set_chip_data(irq, domain->host_data);

        return 0;
}

static const struct irq_domain_ops uniphier_intx_domain_ops = {
        .map = uniphier_pcie_intx_map,
};

static void uniphier_pcie_irq_handler(struct irq_desc *desc)
{
        struct dw_pcie_rp *pp = irq_desc_get_handler_data(desc);
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct uniphier_pcie *pcie = to_uniphier_pcie(pci);
        struct irq_chip *chip = irq_desc_get_chip(desc);
        unsigned long reg;
        u32 val, bit;

        /* INT for debug */
        val = readl(pcie->base + PCL_RCV_INT);

        if (val & PCL_CFG_BW_MGT_STATUS)
                dev_dbg(pci->dev, "Link Bandwidth Management Event\n");
        if (val & PCL_CFG_LINK_AUTO_BW_STATUS)
                dev_dbg(pci->dev, "Link Autonomous Bandwidth Event\n");
        if (val & PCL_CFG_AER_RC_ERR_MSI_STATUS)
                dev_dbg(pci->dev, "Root Error\n");
        if (val & PCL_CFG_PME_MSI_STATUS)
                dev_dbg(pci->dev, "PME Interrupt\n");

        writel(val, pcie->base + PCL_RCV_INT);

        /* INTx */
        chained_irq_enter(chip, desc);

        val = readl(pcie->base + PCL_RCV_INTX);
        reg = FIELD_GET(PCL_RCV_INTX_ALL_STATUS, val);

        for_each_set_bit(bit, &reg, PCI_NUM_INTX)
                generic_handle_domain_irq(pcie->intx_irq_domain, bit);

        chained_irq_exit(chip, desc);
}

static int uniphier_pcie_config_intx_irq(struct dw_pcie_rp *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct uniphier_pcie *pcie = to_uniphier_pcie(pci);
        struct device_node *np = pci->dev->of_node;
        struct device_node *np_intc;
        int ret = 0;

        np_intc = of_get_child_by_name(np, "legacy-interrupt-controller");
        if (!np_intc) {
                dev_err(pci->dev, "Failed to get legacy-interrupt-controller node\n");
                return -EINVAL;
        }

        pp->irq = irq_of_parse_and_map(np_intc, 0);
        if (!pp->irq) {
                dev_err(pci->dev, "Failed to get an IRQ entry in legacy-interrupt-controller\n");
                ret = -EINVAL;
                goto out_put_node;
        }

        pcie->intx_irq_domain = irq_domain_create_linear(of_fwnode_handle(np_intc), PCI_NUM_INTX,
                                                &uniphier_intx_domain_ops, pp);
        if (!pcie->intx_irq_domain) {
                dev_err(pci->dev, "Failed to get INTx domain\n");
                ret = -ENODEV;
                goto out_put_node;
        }

        irq_set_chained_handler_and_data(pp->irq, uniphier_pcie_irq_handler,
                                         pp);

out_put_node:
        of_node_put(np_intc);
        return ret;
}

static int uniphier_pcie_host_init(struct dw_pcie_rp *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct uniphier_pcie *pcie = to_uniphier_pcie(pci);
        int ret;

        ret = uniphier_pcie_config_intx_irq(pp);
        if (ret)
                return ret;

        uniphier_pcie_irq_enable(pcie);

        return 0;
}

static const struct dw_pcie_host_ops uniphier_pcie_host_ops = {
        .init = uniphier_pcie_host_init,
};

static int uniphier_pcie_host_enable(struct uniphier_pcie *pcie)
{
        int ret;

        ret = clk_prepare_enable(pcie->clk);
        if (ret)
                return ret;

        ret = reset_control_deassert(pcie->rst);
        if (ret)
                goto out_clk_disable;

        uniphier_pcie_init_rc(pcie);

        ret = phy_init(pcie->phy);
        if (ret)
                goto out_rst_assert;

        ret = uniphier_pcie_wait_rc(pcie);
        if (ret)
                goto out_phy_exit;

        return 0;

out_phy_exit:
        phy_exit(pcie->phy);
out_rst_assert:
        reset_control_assert(pcie->rst);
out_clk_disable:
        clk_disable_unprepare(pcie->clk);

        return ret;
}

static const struct dw_pcie_ops dw_pcie_ops = {
        .start_link = uniphier_pcie_start_link,
        .stop_link = uniphier_pcie_stop_link,
        .link_up = uniphier_pcie_link_up,
};

static int uniphier_pcie_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct uniphier_pcie *pcie;
        int ret;

        pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
        if (!pcie)
                return -ENOMEM;

        pcie->pci.dev = dev;
        pcie->pci.ops = &dw_pcie_ops;

        pcie->base = devm_platform_ioremap_resource_byname(pdev, "link");
        if (IS_ERR(pcie->base))
                return PTR_ERR(pcie->base);

        pcie->clk = devm_clk_get(dev, NULL);
        if (IS_ERR(pcie->clk))
                return PTR_ERR(pcie->clk);

        pcie->rst = devm_reset_control_get_shared(dev, NULL);
        if (IS_ERR(pcie->rst))
                return PTR_ERR(pcie->rst);

        pcie->phy = devm_phy_optional_get(dev, "pcie-phy");
        if (IS_ERR(pcie->phy))
                return PTR_ERR(pcie->phy);

        platform_set_drvdata(pdev, pcie);

        ret = uniphier_pcie_host_enable(pcie);
        if (ret)
                return ret;

        pcie->pci.pp.ops = &uniphier_pcie_host_ops;

        return dw_pcie_host_init(&pcie->pci.pp);
}

static const struct of_device_id uniphier_pcie_match[] = {
        { .compatible = "socionext,uniphier-pcie", },
        { /* sentinel */ },
};

static struct platform_driver uniphier_pcie_driver = {
        .probe  = uniphier_pcie_probe,
        .driver = {
                .name = "uniphier-pcie",
                .of_match_table = uniphier_pcie_match,
        },
};
builtin_platform_driver(uniphier_pcie_driver);