LXR linux/arch/sh/boards/mach-sdk7786/sram.c

   1/*
   2 * SDK7786 FPGA SRAM Support.
   3 *
   4 * Copyright (C) 2010  Paul Mundt
   5 *
   6 * This file is subject to the terms and conditions of the GNU General Public
   7 * License.  See the file "COPYING" in the main directory of this archive
   8 * for more details.
   9 */
  10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12#include <linux/init.h>
  13#include <linux/kernel.h>
  14#include <linux/types.h>
  15#include <linux/io.h>
  16#include <linux/string.h>
  17#include <mach/fpga.h>
  18#include <asm/sram.h>
  19#include <asm/sizes.h>
  20
  21static int __init fpga_sram_init(void)
  22{
  23        unsigned long phys;
  24        unsigned int area;
  25        void __iomem *vaddr;
  26        int ret;
  27        u16 data;
  28
  29        /* Enable FPGA SRAM */
  30        data = fpga_read_reg(LCLASR);
  31        data |= LCLASR_FRAMEN;
  32        fpga_write_reg(data, LCLASR);
  33
  34        /*
  35         * FPGA_SEL determines the area mapping
  36         */
  37        area = (data & LCLASR_FPGA_SEL_MASK) >> LCLASR_FPGA_SEL_SHIFT;
  38        if (unlikely(area == LCLASR_AREA_MASK)) {
  39                pr_err("FPGA memory unmapped.\n");
  40                return -ENXIO;
  41        }
  42
  43        /*
  44         * The memory itself occupies a 2KiB range at the top of the area
  45         * immediately below the system registers.
  46         */
  47        phys = (area << 26) + SZ_64M - SZ_4K;
  48
  49        /*
  50         * The FPGA SRAM resides in translatable physical space, so set
  51         * up a mapping prior to inserting it in to the pool.
  52         */
  53        vaddr = ioremap(phys, SZ_2K);
  54        if (unlikely(!vaddr)) {
  55                pr_err("Failed remapping FPGA memory.\n");
  56                return -ENXIO;
  57        }
  58
  59        pr_info("Adding %dKiB of FPGA memory at 0x%08lx-0x%08lx "
  60                "(area %d) to pool.\n",
  61                SZ_2K >> 10, phys, phys + SZ_2K - 1, area);
  62
  63        ret = gen_pool_add(sram_pool, (unsigned long)vaddr, SZ_2K, -1);
  64        if (unlikely(ret < 0)) {
  65                pr_err("Failed adding memory\n");
  66                iounmap(vaddr);
  67                return ret;
  68        }
  69
  70        return 0;
  71}
  72postcore_initcall(fpga_sram_init);
  73