// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
 *
 */

#include <linux/device.h>
#include <linux/dma-direction.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/mhi.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include "internal.h"

int __must_check mhi_read_reg(struct mhi_controller *mhi_cntrl,
			      void __iomem *base, u32 offset, u32 *out)
{
	u32 tmp = readl(base + offset);

	/* If there is any unexpected value, query the link status */
	if (PCI_INVALID_READ(tmp) &&
	    mhi_cntrl->link_status(mhi_cntrl))
		return -EIO;

	*out = tmp;

	return 0;
}

int __must_check mhi_read_reg_field(struct mhi_controller *mhi_cntrl,
				    void __iomem *base, u32 offset,
				    u32 mask, u32 shift, u32 *out)
{
	u32 tmp;
	int ret;

	ret = mhi_read_reg(mhi_cntrl, base, offset, &tmp);
	if (ret)
		return ret;

	*out = (tmp & mask) >> shift;

	return 0;
}

void mhi_write_reg(struct mhi_controller *mhi_cntrl, void __iomem *base,
		   u32 offset, u32 val)
{
	writel(val, base + offset);
}

void mhi_write_reg_field(struct mhi_controller *mhi_cntrl, void __iomem *base,
			 u32 offset, u32 mask, u32 shift, u32 val)
{
	int ret;
	u32 tmp;

	ret = mhi_read_reg(mhi_cntrl, base, offset, &tmp);
	if (ret)
		return;

	tmp &= ~mask;
	tmp |= (val << shift);
	mhi_write_reg(mhi_cntrl, base, offset, tmp);
}

void mhi_write_db(struct mhi_controller *mhi_cntrl, void __iomem *db_addr,
		  dma_addr_t db_val)
{
	mhi_write_reg(mhi_cntrl, db_addr, 4, upper_32_bits(db_val));
	mhi_write_reg(mhi_cntrl, db_addr, 0, lower_32_bits(db_val));
}

void mhi_db_brstmode(struct mhi_controller *mhi_cntrl,
		     struct db_cfg *db_cfg,
		     void __iomem *db_addr,
		     dma_addr_t db_val)
{
	if (db_cfg->db_mode) {
		db_cfg->db_val = db_val;
		mhi_write_db(mhi_cntrl, db_addr, db_val);
		db_cfg->db_mode = 0;
	}
}

void mhi_db_brstmode_disable(struct mhi_controller *mhi_cntrl,
			     struct db_cfg *db_cfg,
			     void __iomem *db_addr,
			     dma_addr_t db_val)
{
	db_cfg->db_val = db_val;
	mhi_write_db(mhi_cntrl, db_addr, db_val);
}

void mhi_ring_er_db(struct mhi_event *mhi_event)
{
	struct mhi_ring *ring = &mhi_event->ring;

	mhi_event->db_cfg.process_db(mhi_event->mhi_cntrl, &mhi_event->db_cfg,
				     ring->db_addr, *ring->ctxt_wp);
}

void mhi_ring_cmd_db(struct mhi_controller *mhi_cntrl, struct mhi_cmd *mhi_cmd)
{
	dma_addr_t db;
	struct mhi_ring *ring = &mhi_cmd->ring;

	db = ring->iommu_base + (ring->wp - ring->base);
	*ring->ctxt_wp = db;
	mhi_write_db(mhi_cntrl, ring->db_addr, db);
}

void mhi_ring_chan_db(struct mhi_controller *mhi_cntrl,
		      struct mhi_chan *mhi_chan)
{
	struct mhi_ring *ring = &mhi_chan->tre_ring;
	dma_addr_t db;

	db = ring->iommu_base + (ring->wp - ring->base);
	*ring->ctxt_wp = db;
	mhi_chan->db_cfg.process_db(mhi_cntrl, &mhi_chan->db_cfg,
				    ring->db_addr, db);
}

enum mhi_ee_type mhi_get_exec_env(struct mhi_controller *mhi_cntrl)
{
	u32 exec;
	int ret = mhi_read_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_EXECENV, &exec);

	return (ret) ? MHI_EE_MAX : exec;
}

enum mhi_state mhi_get_mhi_state(struct mhi_controller *mhi_cntrl)
{
	u32 state;
	int ret = mhi_read_reg_field(mhi_cntrl, mhi_cntrl->regs, MHISTATUS,
				     MHISTATUS_MHISTATE_MASK,
				     MHISTATUS_MHISTATE_SHIFT, &state);
	return ret ? MHI_STATE_MAX : state;
}

static void *mhi_to_virtual(struct mhi_ring *ring, dma_addr_t addr)
{
	return (addr - ring->iommu_base) + ring->base;
}

int mhi_destroy_device(struct device *dev, void *data)
{
	struct mhi_device *mhi_dev;
	struct mhi_controller *mhi_cntrl;

	if (dev->bus != &mhi_bus_type)
		return 0;

	mhi_dev = to_mhi_device(dev);
	mhi_cntrl = mhi_dev->mhi_cntrl;

	/* Only destroy virtual devices thats attached to bus */
	if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
		return 0;

	dev_dbg(&mhi_cntrl->mhi_dev->dev, "destroy device for chan:%s\n",
		 mhi_dev->chan_name);

	/* Notify the client and remove the device from MHI bus */
	device_del(dev);
	put_device(dev);

	return 0;
}

static void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
	struct mhi_driver *mhi_drv;

	if (!mhi_dev->dev.driver)
		return;

	mhi_drv = to_mhi_driver(mhi_dev->dev.driver);

	if (mhi_drv->status_cb)
		mhi_drv->status_cb(mhi_dev, cb_reason);
}

/* Bind MHI channels to MHI devices */
void mhi_create_devices(struct mhi_controller *mhi_cntrl)
{
	struct mhi_chan *mhi_chan;
	struct mhi_device *mhi_dev;
	struct device *dev = &mhi_cntrl->mhi_dev->dev;
	int i, ret;

	mhi_chan = mhi_cntrl->mhi_chan;
	for (i = 0; i < mhi_cntrl->max_chan; i++, mhi_chan++) {
		if (!mhi_chan->configured || mhi_chan->mhi_dev ||
		    !(mhi_chan->ee_mask & BIT(mhi_cntrl->ee)))
			continue;
		mhi_dev = mhi_alloc_device(mhi_cntrl);
		if (!mhi_dev)
			return;

		mhi_dev->dev_type = MHI_DEVICE_XFER;
		switch (mhi_chan->dir) {
		case DMA_TO_DEVICE:
			mhi_dev->ul_chan = mhi_chan;
			mhi_dev->ul_chan_id = mhi_chan->chan;
			break;
		case DMA_FROM_DEVICE:
			/* We use dl_chan as offload channels */
			mhi_dev->dl_chan = mhi_chan;
			mhi_dev->dl_chan_id = mhi_chan->chan;
			break;
		default:
			dev_err(dev, "Direction not supported\n");
			put_device(&mhi_dev->dev);
			return;
		}

		get_device(&mhi_dev->dev);
		mhi_chan->mhi_dev = mhi_dev;

		/* Check next channel if it matches */
		if ((i + 1) < mhi_cntrl->max_chan && mhi_chan[1].configured) {
			if (!strcmp(mhi_chan[1].name, mhi_chan->name)) {
				i++;
				mhi_chan++;
				if (mhi_chan->dir == DMA_TO_DEVICE) {
					mhi_dev->ul_chan = mhi_chan;
					mhi_dev->ul_chan_id = mhi_chan->chan;
				} else {
					mhi_dev->dl_chan = mhi_chan;
					mhi_dev->dl_chan_id = mhi_chan->chan;
				}
				get_device(&mhi_dev->dev);
				mhi_chan->mhi_dev = mhi_dev;
			}
		}

		/* Channel name is same for both UL and DL */
		mhi_dev->chan_name = mhi_chan->name;
		dev_set_name(&mhi_dev->dev, "%04x_%s", mhi_chan->chan,
			     mhi_dev->chan_name);

		/* Init wakeup source if available */
		if (mhi_dev->dl_chan && mhi_dev->dl_chan->wake_capable)
			device_init_wakeup(&mhi_dev->dev, true);

		ret = device_add(&mhi_dev->dev);
		if (ret)
			put_device(&mhi_dev->dev);
	}
}

irqreturn_t mhi_irq_handler(int irq_number, void *dev)
{
	struct mhi_event *mhi_event = dev;
	struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl;
	struct mhi_event_ctxt *er_ctxt =
		&mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index];
	struct mhi_ring *ev_ring = &mhi_event->ring;
	void *dev_rp = mhi_to_virtual(ev_ring, er_ctxt->rp);

	/* Only proceed if event ring has pending events */
	if (ev_ring->rp == dev_rp)
		return IRQ_HANDLED;

	/* For client managed event ring, notify pending data */
	if (mhi_event->cl_manage) {
		struct mhi_chan *mhi_chan = mhi_event->mhi_chan;
		struct mhi_device *mhi_dev = mhi_chan->mhi_dev;

		if (mhi_dev)
			mhi_notify(mhi_dev, MHI_CB_PENDING_DATA);
	} else {
		tasklet_schedule(&mhi_event->task);
	}

	return IRQ_HANDLED;
}

irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *dev)
{
	struct mhi_controller *mhi_cntrl = dev;
	enum mhi_state state = MHI_STATE_MAX;
	enum mhi_pm_state pm_state = 0;
	enum mhi_ee_type ee = 0;

	write_lock_irq(&mhi_cntrl->pm_lock);
	if (MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state)) {
		state = mhi_get_mhi_state(mhi_cntrl);
		ee = mhi_cntrl->ee;
		mhi_cntrl->ee = mhi_get_exec_env(mhi_cntrl);
	}

	if (state == MHI_STATE_SYS_ERR) {
		dev_dbg(&mhi_cntrl->mhi_dev->dev, "System error detected\n");
		pm_state = mhi_tryset_pm_state(mhi_cntrl,
					       MHI_PM_SYS_ERR_DETECT);
	}
	write_unlock_irq(&mhi_cntrl->pm_lock);

	/* If device in RDDM don't bother processing SYS error */
	if (mhi_cntrl->ee == MHI_EE_RDDM) {
		if (mhi_cntrl->ee != ee) {
			mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_EE_RDDM);
			wake_up_all(&mhi_cntrl->state_event);
		}
		goto exit_intvec;
	}

	if (pm_state == MHI_PM_SYS_ERR_DETECT) {
		wake_up_all(&mhi_cntrl->state_event);

		/* For fatal errors, we let controller decide next step */
		if (MHI_IN_PBL(ee))
			mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_FATAL_ERROR);
		else
			schedule_work(&mhi_cntrl->syserr_worker);
	}

exit_intvec:

	return IRQ_HANDLED;
}

irqreturn_t mhi_intvec_handler(int irq_number, void *dev)
{
	struct mhi_controller *mhi_cntrl = dev;

	/* Wake up events waiting for state change */
	wake_up_all(&mhi_cntrl->state_event);

	return IRQ_WAKE_THREAD;
}