// SPDX-License-Identifier: GPL-2.0
/*
 * MUSB OTG driver virtual root hub support
 *
 * Copyright 2005 Mentor Graphics Corporation
 * Copyright (C) 2005-2006 by Texas Instruments
 * Copyright (C) 2006-2007 Nokia Corporation
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/timer.h>

#include <linux/unaligned.h>

#include "musb_core.h"

void musb_host_finish_resume(struct work_struct *work)
{
        struct musb *musb;
        unsigned long flags;
        u8 power;

        musb = container_of(work, struct musb, finish_resume_work.work);

        spin_lock_irqsave(&musb->lock, flags);

        power = musb_readb(musb->mregs, MUSB_POWER);
        power &= ~MUSB_POWER_RESUME;
        musb_dbg(musb, "root port resume stopped, power %02x", power);
        musb_writeb(musb->mregs, MUSB_POWER, power);

        /*
         * ISSUE:  DaVinci (RTL 1.300) disconnects after
         * resume of high speed peripherals (but not full
         * speed ones).
         */
        musb->is_active = 1;
        musb->port1_status &= ~(USB_PORT_STAT_SUSPEND | MUSB_PORT_STAT_RESUME);
        musb->port1_status |= USB_PORT_STAT_C_SUSPEND << 16;
        usb_hcd_poll_rh_status(musb->hcd);
        /* NOTE: it might really be A_WAIT_BCON ... */
        musb_set_state(musb, OTG_STATE_A_HOST);

        spin_unlock_irqrestore(&musb->lock, flags);
}

int musb_port_suspend(struct musb *musb, bool do_suspend)
{
        u8              power;
        void __iomem    *mbase = musb->mregs;

        if (!is_host_active(musb))
                return 0;

        /* NOTE:  this doesn't necessarily put PHY into low power mode,
         * turning off its clock; that's a function of PHY integration and
         * MUSB_POWER_ENSUSPEND.  PHY may need a clock (sigh) to detect
         * SE0 changing to connect (J) or wakeup (K) states.
         */
        power = musb_readb(mbase, MUSB_POWER);
        if (do_suspend) {
                int retries = 10000;

                if (power & MUSB_POWER_RESUME)
                        return -EBUSY;

                if (!(power & MUSB_POWER_SUSPENDM)) {
                        power |= MUSB_POWER_SUSPENDM;
                        musb_writeb(mbase, MUSB_POWER, power);

                        /* Needed for OPT A tests */
                        power = musb_readb(mbase, MUSB_POWER);
                        while (power & MUSB_POWER_SUSPENDM) {
                                power = musb_readb(mbase, MUSB_POWER);
                                if (retries-- < 1)
                                        break;
                        }
                }

                musb_dbg(musb, "Root port suspended, power %02x", power);

                musb->port1_status |= USB_PORT_STAT_SUSPEND;
                switch (musb_get_state(musb)) {
                case OTG_STATE_A_HOST:
                        musb_set_state(musb, OTG_STATE_A_SUSPEND);
                        musb->is_active = musb->xceiv &&
                                musb->xceiv->otg->host->b_hnp_enable;
                        if (musb->is_active)
                                mod_timer(&musb->otg_timer, jiffies
                                        + msecs_to_jiffies(
                                                OTG_TIME_A_AIDL_BDIS));
                        musb_platform_try_idle(musb, 0);
                        break;
                case OTG_STATE_B_HOST:
                        musb_set_state(musb, OTG_STATE_B_WAIT_ACON);
                        musb->is_active = musb->xceiv &&
                                musb->xceiv->otg->host->b_hnp_enable;
                        musb_platform_try_idle(musb, 0);
                        break;
                default:
                        musb_dbg(musb, "bogus rh suspend? %s",
                                 musb_otg_state_string(musb));
                }
        } else if (power & MUSB_POWER_SUSPENDM) {
                power &= ~MUSB_POWER_SUSPENDM;
                power |= MUSB_POWER_RESUME;
                musb_writeb(mbase, MUSB_POWER, power);

                musb_dbg(musb, "Root port resuming, power %02x", power);

                musb->port1_status |= MUSB_PORT_STAT_RESUME;
                schedule_delayed_work(&musb->finish_resume_work,
                                      msecs_to_jiffies(USB_RESUME_TIMEOUT));
        }
        return 0;
}

void musb_port_reset(struct musb *musb, bool do_reset)
{
        u8              power;
        void __iomem    *mbase = musb->mregs;

        if (musb_get_state(musb) == OTG_STATE_B_IDLE) {
                musb_dbg(musb, "HNP: Returning from HNP; no hub reset from b_idle");
                musb->port1_status &= ~USB_PORT_STAT_RESET;
                return;
        }

        if (!is_host_active(musb))
                return;

        /* NOTE:  caller guarantees it will turn off the reset when
         * the appropriate amount of time has passed
         */
        power = musb_readb(mbase, MUSB_POWER);
        if (do_reset) {
                /*
                 * If RESUME is set, we must make sure it stays minimum 20 ms.
                 * Then we must clear RESUME and wait a bit to let musb start
                 * generating SOFs. If we don't do this, OPT HS A 6.8 tests
                 * fail with "Error! Did not receive an SOF before suspend
                 * detected".
                 */
                if (power &  MUSB_POWER_RESUME) {
                        long remain = (unsigned long) musb->rh_timer - jiffies;

                        if (musb->rh_timer > 0 && remain > 0) {
                                /* take into account the minimum delay after resume */
                                schedule_delayed_work(
                                        &musb->deassert_reset_work, remain);
                                return;
                        }

                        musb_writeb(mbase, MUSB_POWER,
                                    power & ~MUSB_POWER_RESUME);

                        /* Give the core 1 ms to clear MUSB_POWER_RESUME */
                        schedule_delayed_work(&musb->deassert_reset_work,
                                              msecs_to_jiffies(1));
                        return;
                }

                power &= 0xf0;
                musb_writeb(mbase, MUSB_POWER,
                                power | MUSB_POWER_RESET);

                musb->port1_status |= USB_PORT_STAT_RESET;
                musb->port1_status &= ~USB_PORT_STAT_ENABLE;
                schedule_delayed_work(&musb->deassert_reset_work,
                                      msecs_to_jiffies(50));
        } else {
                musb_dbg(musb, "root port reset stopped");
                musb_platform_pre_root_reset_end(musb);
                musb_writeb(mbase, MUSB_POWER,
                                power & ~MUSB_POWER_RESET);
                musb_platform_post_root_reset_end(musb);

                power = musb_readb(mbase, MUSB_POWER);
                if (power & MUSB_POWER_HSMODE) {
                        musb_dbg(musb, "high-speed device connected");
                        musb->port1_status |= USB_PORT_STAT_HIGH_SPEED;
                }

                musb->port1_status &= ~USB_PORT_STAT_RESET;
                musb->port1_status |= USB_PORT_STAT_ENABLE
                                        | (USB_PORT_STAT_C_RESET << 16)
                                        | (USB_PORT_STAT_C_ENABLE << 16);
                usb_hcd_poll_rh_status(musb->hcd);

                musb->vbuserr_retry = VBUSERR_RETRY_COUNT;
        }
}

void musb_root_disconnect(struct musb *musb)
{
        musb->port1_status = USB_PORT_STAT_POWER
                        | (USB_PORT_STAT_C_CONNECTION << 16);

        usb_hcd_poll_rh_status(musb->hcd);
        musb->is_active = 0;

        switch (musb_get_state(musb)) {
        case OTG_STATE_A_SUSPEND:
                if (musb->xceiv && musb->xceiv->otg->host->b_hnp_enable) {
                        musb_set_state(musb, OTG_STATE_A_PERIPHERAL);
                        musb->g.is_a_peripheral = 1;
                        break;
                }
                fallthrough;
        case OTG_STATE_A_HOST:
                musb_set_state(musb, OTG_STATE_A_WAIT_BCON);
                musb->is_active = 0;
                break;
        case OTG_STATE_A_WAIT_VFALL:
                musb_set_state(musb, OTG_STATE_B_IDLE);
                break;
        default:
                musb_dbg(musb, "host disconnect (%s)",
                         musb_otg_state_string(musb));
        }
}
EXPORT_SYMBOL_GPL(musb_root_disconnect);


/*---------------------------------------------------------------------*/

/* Caller may or may not hold musb->lock */
int musb_hub_status_data(struct usb_hcd *hcd, char *buf)
{
        struct musb     *musb = hcd_to_musb(hcd);
        int             retval = 0;

        /* called in_irq() via usb_hcd_poll_rh_status() */
        if (musb->port1_status & 0xffff0000) {
                *buf = 0x02;
                retval = 1;
        }
        return retval;
}

static int musb_has_gadget(struct musb *musb)
{
        /*
         * In host-only mode we start a connection right away. In OTG mode
         * we have to wait until we loaded a gadget. We don't really need a
         * gadget if we operate as a host but we should not start a session
         * as a device without a gadget or else we explode.
         */
#ifdef CONFIG_USB_MUSB_HOST
        return 1;
#else
        return musb->port_mode == MUSB_HOST;
#endif
}

int musb_hub_control(
        struct usb_hcd  *hcd,
        u16             typeReq,
        u16             wValue,
        u16             wIndex,
        char            *buf,
        u16             wLength)
{
        struct musb     *musb = hcd_to_musb(hcd);
        u32             temp;
        int             retval = 0;
        unsigned long   flags;
        bool            start_musb = false;

        spin_lock_irqsave(&musb->lock, flags);

        if (unlikely(!HCD_HW_ACCESSIBLE(hcd))) {
                spin_unlock_irqrestore(&musb->lock, flags);
                return -ESHUTDOWN;
        }

        /* hub features:  always zero, setting is a NOP
         * port features: reported, sometimes updated when host is active
         * no indicators
         */
        switch (typeReq) {
        case ClearHubFeature:
        case SetHubFeature:
                switch (wValue) {
                case C_HUB_OVER_CURRENT:
                case C_HUB_LOCAL_POWER:
                        break;
                default:
                        goto error;
                }
                break;
        case ClearPortFeature:
                if ((wIndex & 0xff) != 1)
                        goto error;

                switch (wValue) {
                case USB_PORT_FEAT_ENABLE:
                        break;
                case USB_PORT_FEAT_SUSPEND:
                        musb_port_suspend(musb, false);
                        break;
                case USB_PORT_FEAT_POWER:
                        if (!hcd->self.is_b_host)
                                musb_platform_set_vbus(musb, 0);
                        break;
                case USB_PORT_FEAT_C_CONNECTION:
                case USB_PORT_FEAT_C_ENABLE:
                case USB_PORT_FEAT_C_OVER_CURRENT:
                case USB_PORT_FEAT_C_RESET:
                case USB_PORT_FEAT_C_SUSPEND:
                        break;
                default:
                        goto error;
                }
                musb_dbg(musb, "clear feature %d", wValue);
                musb->port1_status &= ~(1 << wValue);
                break;
        case GetHubDescriptor:
                {
                struct usb_hub_descriptor *desc = (void *)buf;

                desc->bDescLength = 9;
                desc->bDescriptorType = USB_DT_HUB;
                desc->bNbrPorts = 1;
                desc->wHubCharacteristics = cpu_to_le16(
                        HUB_CHAR_INDV_PORT_LPSM /* per-port power switching */
                        | HUB_CHAR_NO_OCPM      /* no overcurrent reporting */
                        );
                desc->bPwrOn2PwrGood = 5;       /* msec/2 */
                desc->bHubContrCurrent = 0;

                /* workaround bogus struct definition */
                desc->u.hs.DeviceRemovable[0] = 0x02;   /* port 1 */
                desc->u.hs.DeviceRemovable[1] = 0xff;
                }
                break;
        case GetHubStatus:
                temp = 0;
                *(__le32 *) buf = cpu_to_le32(temp);
                break;
        case GetPortStatus:
                if (wIndex != 1)
                        goto error;

                put_unaligned(cpu_to_le32(musb->port1_status
                                        & ~MUSB_PORT_STAT_RESUME),
                                (__le32 *) buf);

                /* port change status is more interesting */
                musb_dbg(musb, "port status %08x", musb->port1_status);
                break;
        case SetPortFeature:
                if ((wIndex & 0xff) != 1)
                        goto error;

                switch (wValue) {
                case USB_PORT_FEAT_POWER:
                        /* NOTE: this controller has a strange state machine
                         * that involves "requesting sessions" according to
                         * magic side effects from incompletely-described
                         * rules about startup...
                         *
                         * This call is what really starts the host mode; be
                         * very careful about side effects if you reorder any
                         * initialization logic, e.g. for OTG, or change any
                         * logic relating to VBUS power-up.
                         */
                        if (!hcd->self.is_b_host && musb_has_gadget(musb))
                                start_musb = true;
                        break;
                case USB_PORT_FEAT_RESET:
                        musb_port_reset(musb, true);
                        break;
                case USB_PORT_FEAT_SUSPEND:
                        musb_port_suspend(musb, true);
                        break;
                case USB_PORT_FEAT_TEST:
                        if (unlikely(is_host_active(musb)))
                                goto error;

                        wIndex >>= 8;
                        switch (wIndex) {
                        case USB_TEST_J:
                                pr_debug("USB_TEST_J\n");
                                temp = MUSB_TEST_J;
                                break;
                        case USB_TEST_K:
                                pr_debug("USB_TEST_K\n");
                                temp = MUSB_TEST_K;
                                break;
                        case USB_TEST_SE0_NAK:
                                pr_debug("USB_TEST_SE0_NAK\n");
                                temp = MUSB_TEST_SE0_NAK;
                                break;
                        case USB_TEST_PACKET:
                                pr_debug("USB_TEST_PACKET\n");
                                temp = MUSB_TEST_PACKET;
                                musb_load_testpacket(musb);
                                break;
                        case USB_TEST_FORCE_ENABLE:
                                pr_debug("USB_TEST_FORCE_ENABLE\n");
                                temp = MUSB_TEST_FORCE_HOST
                                        | MUSB_TEST_FORCE_HS;

                                musb_writeb(musb->mregs, MUSB_DEVCTL,
                                                MUSB_DEVCTL_SESSION);
                                break;
                        case 6:
                                pr_debug("TEST_FIFO_ACCESS\n");
                                temp = MUSB_TEST_FIFO_ACCESS;
                                break;
                        default:
                                goto error;
                        }
                        musb_writeb(musb->mregs, MUSB_TESTMODE, temp);
                        break;
                default:
                        goto error;
                }
                musb_dbg(musb, "set feature %d", wValue);
                musb->port1_status |= 1 << wValue;
                break;

        default:
error:
                /* "protocol stall" on error */
                retval = -EPIPE;
        }
        spin_unlock_irqrestore(&musb->lock, flags);

        if (start_musb)
                musb_start(musb);

        return retval;
}