emif.c

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/*
 *  External Memory Interface
 *
 *  Copyright (C) 2011 Texas Instruments Incorporated
 *  Author: Mark Salter <[email protected]>
 *
 *  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/of.h>
#include <linux/of_address.h>
#include <linux/io.h>
#include <asm/soc.h>
#include <asm/dscr.h>

#define NUM_EMIFA_CHIP_ENABLES 4

struct emifa_regs {
    u32 midr;
    u32 stat;
    u32 reserved1[6];
    u32 bprio;
    u32 reserved2[23];
    u32 cecfg[NUM_EMIFA_CHIP_ENABLES];
    u32 reserved3[4];
    u32 awcc;
    u32 reserved4[7];
    u32 intraw;
    u32 intmsk;
    u32 intmskset;
    u32 intmskclr;
};

static struct of_device_id emifa_match[] __initdata = {
    { .compatible = "ti,c64x+emifa" },
    {}
};

/*
 * Parse device tree for existence of an EMIF (External Memory Interface)
 * and initialize it if found.
 */
static int __init c6x_emifa_init(void)
{
    struct emifa_regs __iomem *regs;
    struct device_node *node;
    const __be32 *p;
    u32 val;
    int i, len, err;

    node = of_find_matching_node(NULL, emifa_match);
    if (!node)
        return 0;

    regs = of_iomap(node, 0);
    if (!regs)
        return 0;

    /* look for a dscr-based enable for emifa pin buffers */
    err = of_property_read_u32_array(node, "ti,dscr-dev-enable", &val, 1);
    if (!err)
        dscr_set_devstate(val, DSCR_DEVSTATE_ENABLED);

    /* set up the chip enables */
    p = of_get_property(node, "ti,emifa-ce-config", &len);
    if (p) {
        len /= sizeof(u32);
        if (len > NUM_EMIFA_CHIP_ENABLES)
            len = NUM_EMIFA_CHIP_ENABLES;
        for (i = 0; i <= len; i++)
            soc_writel(be32_to_cpup(&p[i]), &regs->cecfg[i]);
    }

    err = of_property_read_u32_array(node, "ti,emifa-burst-priority", &val, 1);
    if (!err)
        soc_writel(val, &regs->bprio);

    err = of_property_read_u32_array(node, "ti,emifa-async-wait-control", &val, 1);
    if (!err)
        soc_writel(val, &regs->awcc);

    iounmap(regs);
    of_node_put(node);
    return 0;
}
pure_initcall(c6x_emifa_init);