C6X: EMIF - External Memory Interface

/*

 *  External Memory Interface

 *

 *  Copyright (C) 2011 Texas Instruments Incorporated

 *  Author: Mark Salter <msalter@redhat.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/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	ce_config;

	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);