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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SDK7786 FPGA SRAM Support.
   4  *
   5  * Copyright (C) 2010  Paul Mundt
   6  */
   7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   8
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/types.h>
  12 #include <linux/io.h>
  13 #include <linux/string.h>
  14 #include <mach/fpga.h>
  15 #include <asm/sram.h>
  16 #include <linux/sizes.h>
  17
  18 static int __init fpga_sram_init(void)
  19 {
  20         unsigned long phys;
  21         unsigned int area;
  22         void __iomem *vaddr;
  23         int ret;
  24         u16 data;
  25
  26         /* Enable FPGA SRAM */
  27         data = fpga_read_reg(LCLASR);
  28         data |= LCLASR_FRAMEN;
  29         fpga_write_reg(data, LCLASR);
  30
  31         /*
  32          * FPGA_SEL determines the area mapping
  33          */
  34         area = (data & LCLASR_FPGA_SEL_MASK) >> LCLASR_FPGA_SEL_SHIFT;
  35         if (unlikely(area == LCLASR_AREA_MASK)) {
  36                 pr_err("FPGA memory unmapped.\n");
  37                 return -ENXIO;
  38         }
  39
  40         /*
  41          * The memory itself occupies a 2KiB range at the top of the area
  42          * immediately below the system registers.
  43          */
  44         phys = (area << 26) + SZ_64M - SZ_4K;
  45
  46         /*
  47          * The FPGA SRAM resides in translatable physical space, so set
  48          * up a mapping prior to inserting it in to the pool.
  49          */
  50         vaddr = ioremap(phys, SZ_2K);
  51         if (unlikely(!vaddr)) {
  52                 pr_err("Failed remapping FPGA memory.\n");
  53                 return -ENXIO;
  54         }
  55
  56         pr_info("Adding %dKiB of FPGA memory at 0x%08lx-0x%08lx "
  57                 "(area %d) to pool.\n",
  58                 SZ_2K >> 10, phys, phys + SZ_2K - 1, area);
  59
  60         ret = gen_pool_add(sram_pool, (unsigned long)vaddr, SZ_2K, -1);
  61         if (unlikely(ret < 0)) {
  62                 pr_err("Failed adding memory\n");
  63                 iounmap(vaddr);
  64                 return ret;
  65         }
  66
  67         return 0;
  68 }
  69 postcore_initcall(fpga_sram_init);