linux-imx

/*

 * DMA Router driver for LPC18xx/43xx DMA MUX

 *

 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>

 *

 * Based on TI DMA Crossbar driver by:

 *   Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com

 *   Author: Peter Ujfalusi <peter.ujfalusi@ti.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 */

​

#include <linux/err.h>

#include <linux/init.h>

#include <linux/mfd/syscon.h>

#include <linux/of_device.h>

#include <linux/of_dma.h>

#include <linux/regmap.h>

#include <linux/spinlock.h>

​

/* CREG register offset and macros for mux manipulation */

#define LPC18XX_CREG_DMAMUX     0x11c

#define LPC18XX_DMAMUX_VAL(v, n)    ((v) << (n * 2))

#define LPC18XX_DMAMUX_MASK(n)      (0x3 << (n * 2))

#define LPC18XX_DMAMUX_MAX_VAL      0x3

​

struct lpc18xx_dmamux {

    u32 value;

    bool busy;

};

​

struct lpc18xx_dmamux_data {

    struct dma_router dmarouter;

    struct lpc18xx_dmamux *muxes;

    u32 dma_master_requests;

    u32 dma_mux_requests;

    struct regmap *reg;

    spinlock_t lock;

};

​

static void lpc18xx_dmamux_free(struct device *dev, void *route_data)

{

    struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev);

    struct lpc18xx_dmamux *mux = route_data;

    unsigned long flags;

​

    spin_lock_irqsave(&dmamux->lock, flags);

    mux->busy = false;

    spin_unlock_irqrestore(&dmamux->lock, flags);

}

​

static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,

                    struct of_dma *ofdma)

{

    struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);

    struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev);

    unsigned long flags;

    unsigned mux;

​

    if (dma_spec->args_count != 3) {