fpga.c

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/*
 * SDK7786 FPGA Support.
 *
 * Copyright (C) 2010  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/io.h>
#include <linux/bcd.h>
#include <mach/fpga.h>
#include <asm/sizes.h>

#define FPGA_REGS_OFFSET    0x03fff800
#define FPGA_REGS_SIZE      0x490

/*
 * The FPGA can be mapped in any of the generally available areas,
 * so we attempt to scan for it using the fixed SRSTR read magic.
 *
 * Once the FPGA is located, the rest of the mapping data for the other
 * components can be determined dynamically from its section mapping
 * registers.
 */
static void __iomem *sdk7786_fpga_probe(void)
{
    unsigned long area;
    void __iomem *base;

    /*
     * Iterate over all of the areas where the FPGA could be mapped.
     * The possible range is anywhere from area 0 through 6, area 7
     * is reserved.
     */
    for (area = PA_AREA0; area < PA_AREA7; area += SZ_64M) {
        base = ioremap_nocache(area + FPGA_REGS_OFFSET, FPGA_REGS_SIZE);
        if (!base) {
            /* Failed to remap this area, move along. */
            continue;
        }

        if (ioread16(base + SRSTR) == SRSTR_MAGIC)
            return base;    /* Found it! */

        iounmap(base);
    }

    return NULL;
}

void __iomem *sdk7786_fpga_base;

void __init sdk7786_fpga_init(void)
{
    u16 version, date;

    sdk7786_fpga_base = sdk7786_fpga_probe();
    if (unlikely(!sdk7786_fpga_base)) {
        panic("FPGA detection failed.\n");
        return;
    }

    version = fpga_read_reg(FPGAVR);
    date = fpga_read_reg(FPGADR);

    pr_info("\tFPGA version:\t%d.%d (built on %d/%d/%d)\n",
        bcd2bin(version >> 8) & 0xf, bcd2bin(version & 0xf),
        ((date >> 12) & 0xf) + 2000,
        (date >> 8) & 0xf, bcd2bin(date & 0xff));
}