// SPDX-License-Identifier: GPL-2.0-only
/*
 * arch/arm/plat-spear/pl080.c
 *
 * DMAC pl080 definitions for SPEAr platform
 *
 * Copyright (C) 2012 ST Microelectronics
 * Viresh Kumar <vireshk@kernel.org>
 */

#include <linux/amba/pl08x.h>
#include <linux/amba/bus.h>
#include <linux/bug.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spinlock_types.h>
#include "spear.h"
#include "misc_regs.h"
#include "pl080.h"

static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x);

struct {
        unsigned char busy;
        unsigned char val;
} signals[16] = {{0, 0}, };

int pl080_get_signal(const struct pl08x_channel_data *cd)
{
        unsigned int signal = cd->min_signal, val;
        unsigned long flags;

        spin_lock_irqsave(&lock, flags);

        /* Return if signal is already acquired by somebody else */
        if (signals[signal].busy &&
                        (signals[signal].val != cd->muxval)) {
                spin_unlock_irqrestore(&lock, flags);
                return -EBUSY;
        }

        /* If acquiring for the first time, configure it */
        if (!signals[signal].busy) {
                val = readl(DMA_CHN_CFG);

                /*
                 * Each request line has two bits in DMA_CHN_CFG register. To
                 * goto the bits of current request line, do left shift of
                 * value by 2 * signal number.
                 */
                val &= ~(0x3 << (signal * 2));
                val |= cd->muxval << (signal * 2);
                writel(val, DMA_CHN_CFG);
        }

        signals[signal].busy++;
        signals[signal].val = cd->muxval;
        spin_unlock_irqrestore(&lock, flags);

        return signal;
}

void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
{
        unsigned long flags;

        spin_lock_irqsave(&lock, flags);

        /* if signal is not used */
        if (!signals[signal].busy)
                BUG();

        signals[signal].busy--;

        spin_unlock_irqrestore(&lock, flags);
}