root/drivers/reset/reset-npcm.c
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Nuvoton Technology corporation.

#include <linux/auxiliary_bus.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/reboot.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/of_address.h>

#include <soc/nuvoton/clock-npcm8xx.h>

/* NPCM7xx GCR registers */
#define NPCM_MDLR_OFFSET        0x7C
#define NPCM7XX_MDLR_USBD0      BIT(9)
#define NPCM7XX_MDLR_USBD1      BIT(8)
#define NPCM7XX_MDLR_USBD2_4    BIT(21)
#define NPCM7XX_MDLR_USBD5_9    BIT(22)

/* NPCM8xx MDLR bits */
#define NPCM8XX_MDLR_USBD0_3    BIT(9)
#define NPCM8XX_MDLR_USBD4_7    BIT(22)
#define NPCM8XX_MDLR_USBD8      BIT(24)
#define NPCM8XX_MDLR_USBD9      BIT(21)

#define NPCM_USB1PHYCTL_OFFSET  0x140
#define NPCM_USB2PHYCTL_OFFSET  0x144
#define NPCM_USB3PHYCTL_OFFSET  0x148
#define NPCM_USBXPHYCTL_RS      BIT(28)

/* NPCM7xx Reset registers */
#define NPCM_SWRSTR             0x14
#define NPCM_SWRST              BIT(2)

#define NPCM_IPSRST1            0x20
#define NPCM_IPSRST1_USBD1      BIT(5)
#define NPCM_IPSRST1_USBD2      BIT(8)
#define NPCM_IPSRST1_USBD3      BIT(25)
#define NPCM_IPSRST1_USBD4      BIT(22)
#define NPCM_IPSRST1_USBD5      BIT(23)
#define NPCM_IPSRST1_USBD6      BIT(24)

#define NPCM_IPSRST2            0x24
#define NPCM_IPSRST2_USB_HOST   BIT(26)

#define NPCM_IPSRST3            0x34
#define NPCM_IPSRST3_USBD0      BIT(4)
#define NPCM_IPSRST3_USBD7      BIT(5)
#define NPCM_IPSRST3_USBD8      BIT(6)
#define NPCM_IPSRST3_USBD9      BIT(7)
#define NPCM_IPSRST3_USBPHY1    BIT(24)
#define NPCM_IPSRST3_USBPHY2    BIT(25)

#define NPCM_IPSRST4            0x74
#define NPCM_IPSRST4_USBPHY3    BIT(25)
#define NPCM_IPSRST4_USB_HOST2  BIT(31)

#define NPCM_RC_RESETS_PER_REG  32
#define NPCM_MASK_RESETS        GENMASK(4, 0)

enum {
        BMC_NPCM7XX = 0,
        BMC_NPCM8XX,
};

static const u32 npxm7xx_ipsrst[] = {NPCM_IPSRST1, NPCM_IPSRST2, NPCM_IPSRST3};
static const u32 npxm8xx_ipsrst[] = {NPCM_IPSRST1, NPCM_IPSRST2, NPCM_IPSRST3,
        NPCM_IPSRST4};

struct npcm_reset_info {
        u32 bmc_id;
        u32 num_ipsrst;
        const u32 *ipsrst;
};

static const struct npcm_reset_info npxm7xx_reset_info[] = {
        {.bmc_id = BMC_NPCM7XX, .num_ipsrst = 3, .ipsrst = npxm7xx_ipsrst}};
static const struct npcm_reset_info npxm8xx_reset_info[] = {
        {.bmc_id = BMC_NPCM8XX, .num_ipsrst = 4, .ipsrst = npxm8xx_ipsrst}};

struct npcm_rc_data {
        struct reset_controller_dev rcdev;
        struct notifier_block restart_nb;
        const struct npcm_reset_info *info;
        struct regmap *gcr_regmap;
        u32 sw_reset_number;
        struct device *dev;
        void __iomem *base;
        spinlock_t lock;
};

#define to_rc_data(p) container_of(p, struct npcm_rc_data, rcdev)

static int npcm_rc_restart(struct notifier_block *nb, unsigned long mode,
                           void *cmd)
{
        struct npcm_rc_data *rc = container_of(nb, struct npcm_rc_data,
                                               restart_nb);

        writel(NPCM_SWRST << rc->sw_reset_number, rc->base + NPCM_SWRSTR);
        mdelay(1000);

        pr_emerg("%s: unable to restart system\n", __func__);

        return NOTIFY_DONE;
}

static int npcm_rc_setclear_reset(struct reset_controller_dev *rcdev,
                                  unsigned long id, bool set)
{
        struct npcm_rc_data *rc = to_rc_data(rcdev);
        unsigned int rst_bit = BIT(id & NPCM_MASK_RESETS);
        unsigned int ctrl_offset = id >> 8;
        unsigned long flags;
        u32 stat;

        spin_lock_irqsave(&rc->lock, flags);
        stat = readl(rc->base + ctrl_offset);
        if (set)
                writel(stat | rst_bit, rc->base + ctrl_offset);
        else
                writel(stat & ~rst_bit, rc->base + ctrl_offset);
        spin_unlock_irqrestore(&rc->lock, flags);

        return 0;
}

static int npcm_rc_assert(struct reset_controller_dev *rcdev, unsigned long id)
{
        return npcm_rc_setclear_reset(rcdev, id, true);
}

static int npcm_rc_deassert(struct reset_controller_dev *rcdev,
                            unsigned long id)
{
        return npcm_rc_setclear_reset(rcdev, id, false);
}

static int npcm_rc_status(struct reset_controller_dev *rcdev,
                          unsigned long id)
{
        struct npcm_rc_data *rc = to_rc_data(rcdev);
        unsigned int rst_bit = BIT(id & NPCM_MASK_RESETS);
        unsigned int ctrl_offset = id >> 8;

        return (readl(rc->base + ctrl_offset) & rst_bit);
}

static int npcm_reset_xlate(struct reset_controller_dev *rcdev,
                            const struct of_phandle_args *reset_spec)
{
        struct npcm_rc_data *rc = to_rc_data(rcdev);
        unsigned int offset, bit;
        bool offset_found = false;
        int off_num;

        offset = reset_spec->args[0];
        for (off_num = 0 ; off_num < rc->info->num_ipsrst ; off_num++) {
                if (offset == rc->info->ipsrst[off_num]) {
                        offset_found = true;
                        break;
                }
        }

        if (!offset_found) {
                dev_err(rcdev->dev, "Error reset register (0x%x)\n", offset);
                return -EINVAL;
        }

        bit = reset_spec->args[1];
        if (bit >= NPCM_RC_RESETS_PER_REG) {
                dev_err(rcdev->dev, "Error reset number (%d)\n", bit);
                return -EINVAL;
        }

        return (offset << 8) | bit;
}

static const struct of_device_id npcm_rc_match[] = {
        { .compatible = "nuvoton,npcm750-reset", .data = &npxm7xx_reset_info},
        { .compatible = "nuvoton,npcm845-reset", .data = &npxm8xx_reset_info},
        { }
};

static void npcm_usb_reset_npcm7xx(struct npcm_rc_data *rc)
{
        u32 mdlr, iprst1, iprst2, iprst3;
        u32 ipsrst1_bits = 0;
        u32 ipsrst2_bits = NPCM_IPSRST2_USB_HOST;
        u32 ipsrst3_bits = 0;

        /* checking which USB device is enabled */
        regmap_read(rc->gcr_regmap, NPCM_MDLR_OFFSET, &mdlr);
        if (!(mdlr & NPCM7XX_MDLR_USBD0))
                ipsrst3_bits |= NPCM_IPSRST3_USBD0;
        if (!(mdlr & NPCM7XX_MDLR_USBD1))
                ipsrst1_bits |= NPCM_IPSRST1_USBD1;
        if (!(mdlr & NPCM7XX_MDLR_USBD2_4))
                ipsrst1_bits |= (NPCM_IPSRST1_USBD2 |
                                 NPCM_IPSRST1_USBD3 |
                                 NPCM_IPSRST1_USBD4);
        if (!(mdlr & NPCM7XX_MDLR_USBD0)) {
                ipsrst1_bits |= (NPCM_IPSRST1_USBD5 |
                                 NPCM_IPSRST1_USBD6);
                ipsrst3_bits |= (NPCM_IPSRST3_USBD7 |
                                 NPCM_IPSRST3_USBD8 |
                                 NPCM_IPSRST3_USBD9);
        }

        /* assert reset USB PHY and USB devices */
        iprst1 = readl(rc->base + NPCM_IPSRST1);
        iprst2 = readl(rc->base + NPCM_IPSRST2);
        iprst3 = readl(rc->base + NPCM_IPSRST3);

        iprst1 |= ipsrst1_bits;
        iprst2 |= ipsrst2_bits;
        iprst3 |= (ipsrst3_bits | NPCM_IPSRST3_USBPHY1 |
                   NPCM_IPSRST3_USBPHY2);

        writel(iprst1, rc->base + NPCM_IPSRST1);
        writel(iprst2, rc->base + NPCM_IPSRST2);
        writel(iprst3, rc->base + NPCM_IPSRST3);

        /* clear USB PHY RS bit */
        regmap_update_bits(rc->gcr_regmap, NPCM_USB1PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, 0);
        regmap_update_bits(rc->gcr_regmap, NPCM_USB2PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, 0);

        /* deassert reset USB PHY */
        iprst3 &= ~(NPCM_IPSRST3_USBPHY1 | NPCM_IPSRST3_USBPHY2);
        writel(iprst3, rc->base + NPCM_IPSRST3);

        udelay(50);

        /* set USB PHY RS bit */
        regmap_update_bits(rc->gcr_regmap, NPCM_USB1PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);
        regmap_update_bits(rc->gcr_regmap, NPCM_USB2PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);

        /* deassert reset USB devices*/
        iprst1 &= ~ipsrst1_bits;
        iprst2 &= ~ipsrst2_bits;
        iprst3 &= ~ipsrst3_bits;

        writel(iprst1, rc->base + NPCM_IPSRST1);
        writel(iprst2, rc->base + NPCM_IPSRST2);
        writel(iprst3, rc->base + NPCM_IPSRST3);
}

static void npcm_usb_reset_npcm8xx(struct npcm_rc_data *rc)
{
        u32 mdlr, iprst1, iprst2, iprst3, iprst4;
        u32 ipsrst1_bits = 0;
        u32 ipsrst2_bits = NPCM_IPSRST2_USB_HOST;
        u32 ipsrst3_bits = 0;
        u32 ipsrst4_bits = NPCM_IPSRST4_USB_HOST2 | NPCM_IPSRST4_USBPHY3;

        /* checking which USB device is enabled */
        regmap_read(rc->gcr_regmap, NPCM_MDLR_OFFSET, &mdlr);
        if (!(mdlr & NPCM8XX_MDLR_USBD0_3)) {
                ipsrst3_bits |= NPCM_IPSRST3_USBD0;
                ipsrst1_bits |= (NPCM_IPSRST1_USBD1 |
                                 NPCM_IPSRST1_USBD2 |
                                 NPCM_IPSRST1_USBD3);
        }
        if (!(mdlr & NPCM8XX_MDLR_USBD4_7)) {
                ipsrst1_bits |= (NPCM_IPSRST1_USBD4 |
                                 NPCM_IPSRST1_USBD5 |
                                 NPCM_IPSRST1_USBD6);
                ipsrst3_bits |= NPCM_IPSRST3_USBD7;
        }

        if (!(mdlr & NPCM8XX_MDLR_USBD8))
                ipsrst3_bits |= NPCM_IPSRST3_USBD8;
        if (!(mdlr & NPCM8XX_MDLR_USBD9))
                ipsrst3_bits |= NPCM_IPSRST3_USBD9;

        /* assert reset USB PHY and USB devices */
        iprst1 = readl(rc->base + NPCM_IPSRST1);
        iprst2 = readl(rc->base + NPCM_IPSRST2);
        iprst3 = readl(rc->base + NPCM_IPSRST3);
        iprst4 = readl(rc->base + NPCM_IPSRST4);

        iprst1 |= ipsrst1_bits;
        iprst2 |= ipsrst2_bits;
        iprst3 |= (ipsrst3_bits | NPCM_IPSRST3_USBPHY1 |
                   NPCM_IPSRST3_USBPHY2);
        iprst4 |= ipsrst4_bits;

        writel(iprst1, rc->base + NPCM_IPSRST1);
        writel(iprst2, rc->base + NPCM_IPSRST2);
        writel(iprst3, rc->base + NPCM_IPSRST3);
        writel(iprst4, rc->base + NPCM_IPSRST4);

        /* clear USB PHY RS bit */
        regmap_update_bits(rc->gcr_regmap, NPCM_USB1PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, 0);
        regmap_update_bits(rc->gcr_regmap, NPCM_USB2PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, 0);
        regmap_update_bits(rc->gcr_regmap, NPCM_USB3PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, 0);

        /* deassert reset USB PHY */
        iprst3 &= ~(NPCM_IPSRST3_USBPHY1 | NPCM_IPSRST3_USBPHY2);
        writel(iprst3, rc->base + NPCM_IPSRST3);
        iprst4 &= ~NPCM_IPSRST4_USBPHY3;
        writel(iprst4, rc->base + NPCM_IPSRST4);

        /* set USB PHY RS bit */
        regmap_update_bits(rc->gcr_regmap, NPCM_USB1PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);
        regmap_update_bits(rc->gcr_regmap, NPCM_USB2PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);
        regmap_update_bits(rc->gcr_regmap, NPCM_USB3PHYCTL_OFFSET,
                           NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);

        /* deassert reset USB devices*/
        iprst1 &= ~ipsrst1_bits;
        iprst2 &= ~ipsrst2_bits;
        iprst3 &= ~ipsrst3_bits;
        iprst4 &= ~ipsrst4_bits;

        writel(iprst1, rc->base + NPCM_IPSRST1);
        writel(iprst2, rc->base + NPCM_IPSRST2);
        writel(iprst3, rc->base + NPCM_IPSRST3);
        writel(iprst4, rc->base + NPCM_IPSRST4);
}

/*
 *  The following procedure should be observed in USB PHY, USB device and
 *  USB host initialization at BMC boot
 */
static int npcm_usb_reset(struct platform_device *pdev, struct npcm_rc_data *rc)
{
        struct device *dev = &pdev->dev;

        rc->gcr_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "nuvoton,sysgcr");
        if (IS_ERR(rc->gcr_regmap)) {
                dev_warn(&pdev->dev, "Failed to find nuvoton,sysgcr property, please update the device tree\n");
                dev_info(&pdev->dev, "Using nuvoton,npcm750-gcr for Poleg backward compatibility\n");
                rc->gcr_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-gcr");
                if (IS_ERR(rc->gcr_regmap)) {
                        dev_err(&pdev->dev, "Failed to find nuvoton,npcm750-gcr");
                        return PTR_ERR(rc->gcr_regmap);
                }
        }

        rc->info = device_get_match_data(dev);
        switch (rc->info->bmc_id) {
        case BMC_NPCM7XX:
                npcm_usb_reset_npcm7xx(rc);
                break;
        case BMC_NPCM8XX:
                npcm_usb_reset_npcm8xx(rc);
                break;
        default:
                return -ENODEV;
        }

        return 0;
}

static const struct reset_control_ops npcm_rc_ops = {
        .assert         = npcm_rc_assert,
        .deassert       = npcm_rc_deassert,
        .status         = npcm_rc_status,
};

static void npcm_clock_unregister_adev(void *_adev)
{
        struct auxiliary_device *adev = _adev;

        auxiliary_device_delete(adev);
        auxiliary_device_uninit(adev);
}

static void npcm_clock_adev_release(struct device *dev)
{
        struct auxiliary_device *adev = to_auxiliary_dev(dev);
        struct npcm_clock_adev *rdev = to_npcm_clock_adev(adev);

        kfree(rdev);
}

static struct auxiliary_device *npcm_clock_adev_alloc(struct npcm_rc_data *rst_data, char *clk_name)
{
        struct npcm_clock_adev *rdev;
        struct auxiliary_device *adev;
        int ret;

        rdev = kzalloc_obj(*rdev);
        if (!rdev)
                return ERR_PTR(-ENOMEM);

        rdev->base = rst_data->base;

        adev = &rdev->adev;
        adev->name = clk_name;
        adev->dev.parent = rst_data->dev;
        adev->dev.release = npcm_clock_adev_release;
        adev->id = 555u;

        ret = auxiliary_device_init(adev);
        if (ret) {
                kfree(rdev);
                return ERR_PTR(ret);
        }

        return adev;
}

static int npcm8xx_clock_controller_register(struct npcm_rc_data *rst_data, char *clk_name)
{
        struct auxiliary_device *adev;
        int ret;

        adev = npcm_clock_adev_alloc(rst_data, clk_name);
        if (IS_ERR(adev))
                return PTR_ERR(adev);

        ret = auxiliary_device_add(adev);
        if (ret) {
                auxiliary_device_uninit(adev);
                return ret;
        }

        return devm_add_action_or_reset(rst_data->dev, npcm_clock_unregister_adev, adev);
}

static int npcm_rc_probe(struct platform_device *pdev)
{
        struct npcm_rc_data *rc;
        int ret;

        rc = devm_kzalloc(&pdev->dev, sizeof(*rc), GFP_KERNEL);
        if (!rc)
                return -ENOMEM;

        rc->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(rc->base))
                return PTR_ERR(rc->base);

        spin_lock_init(&rc->lock);

        rc->rcdev.owner = THIS_MODULE;
        rc->rcdev.ops = &npcm_rc_ops;
        rc->rcdev.of_node = pdev->dev.of_node;
        rc->rcdev.of_reset_n_cells = 2;
        rc->rcdev.of_xlate = npcm_reset_xlate;
        rc->dev = &pdev->dev;

        ret = devm_reset_controller_register(&pdev->dev, &rc->rcdev);
        if (ret) {
                dev_err(&pdev->dev, "unable to register device\n");
                return ret;
        }

        if (npcm_usb_reset(pdev, rc))
                dev_warn(&pdev->dev, "NPCM USB reset failed, can cause issues with UDC and USB host\n");

        if (!of_property_read_u32(pdev->dev.of_node, "nuvoton,sw-reset-number",
                                  &rc->sw_reset_number)) {
                if (rc->sw_reset_number && rc->sw_reset_number < 5) {
                        rc->restart_nb.priority = 192;
                        rc->restart_nb.notifier_call = npcm_rc_restart;
                        ret = register_restart_handler(&rc->restart_nb);
                        if (ret) {
                                dev_warn(&pdev->dev, "failed to register restart handler\n");
                                return ret;
                        }
                }
        }

        switch (rc->info->bmc_id) {
        case BMC_NPCM8XX:
                return npcm8xx_clock_controller_register(rc, "clk-npcm8xx");
        default:
                return 0;
        }
}

static struct platform_driver npcm_rc_driver = {
        .probe  = npcm_rc_probe,
        .driver = {
                .name                   = "npcm-reset",
                .of_match_table         = npcm_rc_match,
                .suppress_bind_attrs    = true,
        },
};
builtin_platform_driver(npcm_rc_driver);