target/linux/adm5120/files/arch/mips/adm5120/memory.c

   1 /*
   2  *  $Id$
   3  *
   4  *  Copyright (C) 2007 OpenWrt.org
   5  *  Copyright (C) 2007 Gabor Juhos <juhosg at openwrt.org>
   6  *
   7  *  This program is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU General Public License
   9  *  as published by the Free Software Foundation; either version 2
  10  *  of the License, or (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the
  19  *  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20  *  Boston, MA  02110-1301, USA.
  21  *
  22  */
  23
  24 #include <linux/init.h>
  25 #include <linux/types.h>
  26 #include <linux/kernel.h>
  27
  28 #include <asm/bootinfo.h>
  29 #include <asm/addrspace.h>
  30
  31 #include <asm/mach-adm5120/adm5120_info.h>
  32 #include <asm/mach-adm5120/adm5120_defs.h>
  33 #include <asm/mach-adm5120/adm5120_switch.h>
  34 #include <asm/mach-adm5120/adm5120_mpmc.h>
  35
  36 #define SWITCH_READ(r) *(u32 *)(KSEG1ADDR(ADM5120_SWITCH_BASE)+(r))
  37 #define SWITCH_WRITE(r,v) *(u32 *)(KSEG1ADDR(ADM5120_SWITCH_BASE)+(r))=(v)
  38
  39 #define MPMC_READ(r) *(u32 *)(KSEG1ADDR(ADM5120_SWITCH_BASE)+(r))
  40 #define MPMC_WRITE(r,v) *(u32 *)(KSEG1ADDR(ADM5120_SWITCH_BASE)+(r))=(v)
  41
  42 #if 1
  43 #  define mem_dbg(f, a...)      printk("mem_detect: " f, ## a)
  44 #else
  45 #  define mem_dbg(f, a...)
  46 #endif
  47
  48 #define MEM_WR_DELAY    10000 /* 0.01 usec */
  49
  50 unsigned long adm5120_memsize;
  51
  52 static int __init mem_check_pattern(u8 *addr, unsigned long offs)
  53 {
  54         volatile u32 *p1 = (volatile u32 *)addr;
  55         volatile u32 *p2 = (volatile u32 *)(addr+offs);
  56         u32 t,u,v;
  57
  58         /* save original value */
  59         t = *p1;
  60         u = *p2;
  61
  62         if (t != u)
  63                 return 0;
  64
  65         v = 0x55555555;
  66         if (u == v)
  67                 v = 0xAAAAAAAA;
  68
  69         mem_dbg("write 0x%08X to 0x%08lX\n", v, (unsigned long)p1);
  70
  71         *p1 = v;
  72         mem_dbg("delay %d ns\n", MEM_WR_DELAY);
  73         adm5120_ndelay(MEM_WR_DELAY);
  74         u = *p2;
  75
  76         mem_dbg("pattern at 0x%08lX is 0x%08X\n", (unsigned long)p2, u);
  77
  78         /* restore original value */
  79         *p1 = t;
  80
  81         return (v == u);
  82 }
  83
  84 static void __init adm5120_detect_memsize(void)
  85 {
  86         u32     memctrl;
  87         u32     size, maxsize;
  88         u8      *p;
  89
  90         memctrl = SWITCH_READ(SWITCH_REG_MEMCTRL);
  91         switch (memctrl & MEMCTRL_SDRS_MASK) {
  92         case MEMCTRL_SDRS_4M:
  93                 maxsize = 4 << 20;
  94                 break;
  95         case MEMCTRL_SDRS_8M:
  96                 maxsize = 8 << 20;
  97                 break;
  98         case MEMCTRL_SDRS_16M:
  99                 maxsize = 16 << 20;
 100                 break;
 101         default:
 102                 maxsize = 64 << 20;
 103                 break;
 104         }
 105
 106         /* disable buffers for both SDRAM banks */
 107         mem_dbg("disable buffers for both banks\n");
 108         MPMC_WRITE(MPMC_REG_DC0, MPMC_READ(MPMC_REG_DC0) & ~DC_BE);
 109         MPMC_WRITE(MPMC_REG_DC1, MPMC_READ(MPMC_REG_DC1) & ~DC_BE);
 110
 111         mem_dbg("checking for %uMB chip in 1st bank\n", maxsize >> 20);
 112
 113         /* detect size of the 1st SDRAM bank */
 114         p = (u8 *)KSEG1ADDR(0);
 115         for (size = 2<<20; size <= (maxsize >> 1); size <<= 1) {
 116                 if (mem_check_pattern(p, size)) {
 117                         /* mirrored address */
 118                         mem_dbg("mirrored data found at offset 0x%08X\n", size);
 119                         break;
 120                 }
 121         }
 122
 123         mem_dbg("chip size in 1st bank is %uMB\n", size >> 20);
 124         adm5120_memsize = size;
 125
 126         if (size != maxsize)
 127                 /* 2nd bank is not supported */
 128                 goto out;
 129
 130         if ((memctrl & MEMCTRL_SDR1_ENABLE) == 0)
 131                 /* 2nd bank is disabled */
 132                 goto out;
 133
 134         /*
 135          * some bootloaders enable 2nd bank, even if the 2nd SDRAM chip
 136          * are missing.
 137          */
 138         mem_dbg("check presence of 2nd bank\n");
 139
 140         p = (u8 *)KSEG1ADDR(maxsize+size-4);
 141         if (mem_check_pattern(p, 0)) {
 142                 adm5120_memsize += size;
 143         }
 144
 145         if (maxsize != size) {
 146                 /* adjusting MECTRL register */
 147                 memctrl &= ~(MEMCTRL_SDRS_MASK);
 148                 switch (size>>20) {
 149                 case 4:
 150                         memctrl |= MEMCTRL_SDRS_4M;
 151                         break;
 152                 case 8:
 153                         memctrl |= MEMCTRL_SDRS_8M;
 154                         break;
 155                 case 16:
 156                         memctrl |= MEMCTRL_SDRS_16M;
 157                         break;
 158                 default:
 159                         memctrl |= MEMCTRL_SDRS_64M;
 160                         break;
 161                 }
 162                 SWITCH_WRITE(SWITCH_REG_MEMCTRL, memctrl);
 163         }
 164
 165 out:
 166         /* reenable buffer for both SDRAM banks */
 167         mem_dbg("enable buffers for both banks\n");
 168         MPMC_WRITE(MPMC_REG_DC0, MPMC_READ(MPMC_REG_DC0) | DC_BE);
 169         MPMC_WRITE(MPMC_REG_DC1, MPMC_READ(MPMC_REG_DC1) | DC_BE);
 170
 171         mem_dbg("%dx%uMB memory found\n", (adm5120_memsize == size) ? 1 : 2 ,
 172                 size >>20);
 173 }
 174
 175 void __init adm5120_mem_init(void)
 176 {
 177         adm5120_detect_memsize();
 178         add_memory_region(0, adm5120_memsize, BOOT_MEM_RAM);
 179 }