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
  21 static 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 }
  72 postcore_initcall(fpga_sram_init);