arch/arm/plat-omap/sram.c

   1 /*
   2  * linux/arch/arm/plat-omap/sram.c
   3  *
   4  * OMAP SRAM detection and management
   5  *
   6  * Copyright (C) 2005 Nokia Corporation
   7  * Written by Tony Lindgren <tony@atomide.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/init.h>
  18
  19 #include <asm/mach/map.h>
  20 #include <asm/io.h>
  21 #include <asm/cacheflush.h>
  22
  23 #include "sram.h"
  24
  25 #define OMAP1_SRAM_BASE         0xd0000000
  26 #define OMAP1_SRAM_START        0x20000000
  27 #define SRAM_BOOTLOADER_SZ      0x80
  28
  29 static unsigned long omap_sram_base;
  30 static unsigned long omap_sram_size;
  31 static unsigned long omap_sram_ceil;
  32
  33 /*
  34  * The amount of SRAM depends on the core type:
  35  * 730 = 200K, 1510 = 512K, 5912 = 256K, 1610 = 16K, 1710 = 16K
  36  * Note that we cannot try to test for SRAM here because writes
  37  * to secure SRAM will hang the system. Also the SRAM is not
  38  * yet mapped at this point.
  39  */
  40 void __init omap_detect_sram(void)
  41 {
  42         omap_sram_base = OMAP1_SRAM_BASE;
  43
  44         if (cpu_is_omap730())
  45                 omap_sram_size = 0x32000;
  46         else if (cpu_is_omap1510())
  47                 omap_sram_size = 0x80000;
  48         else if (cpu_is_omap1610() || cpu_is_omap1621() || cpu_is_omap1710())
  49                 omap_sram_size = 0x4000;
  50         else if (cpu_is_omap1611())
  51                 omap_sram_size = 0x3e800;
  52         else {
  53                 printk(KERN_ERR "Could not detect SRAM size\n");
  54                 omap_sram_size = 0x4000;
  55         }
  56
  57         printk(KERN_INFO "SRAM size: 0x%lx\n", omap_sram_size);
  58         omap_sram_ceil = omap_sram_base + omap_sram_size;
  59 }
  60
  61 static struct map_desc omap_sram_io_desc[] __initdata = {
  62         {       /* .length gets filled in at runtime */
  63                 .virtual        = OMAP1_SRAM_BASE,
  64                 .pfn            = __phys_to_pfn(OMAP1_SRAM_START),
  65                 .type           = MT_DEVICE
  66         }
  67 };
  68
  69 /*
  70  * In order to use last 2kB of SRAM on 1611b, we must round the size
  71  * up to multiple of PAGE_SIZE. We cannot use ioremap for SRAM, as
  72  * clock init needs SRAM early.
  73  */
  74 void __init omap_map_sram(void)
  75 {
  76         if (omap_sram_size == 0)
  77                 return;
  78
  79         omap_sram_io_desc[0].length = (omap_sram_size + PAGE_SIZE-1)/PAGE_SIZE;
  80         omap_sram_io_desc[0].length *= PAGE_SIZE;
  81         iotable_init(omap_sram_io_desc, ARRAY_SIZE(omap_sram_io_desc));
  82
  83         /*
  84          * Looks like we need to preserve some bootloader code at the
  85          * beginning of SRAM for jumping to flash for reboot to work...
  86          */
  87         memset((void *)omap_sram_base + SRAM_BOOTLOADER_SZ, 0,
  88                omap_sram_size - SRAM_BOOTLOADER_SZ);
  89 }
  90
  91 static void (*_omap_sram_reprogram_clock)(u32 dpllctl, u32 ckctl) = NULL;
  92
  93 void omap_sram_reprogram_clock(u32 dpllctl, u32 ckctl)
  94 {
  95         if (_omap_sram_reprogram_clock == NULL)
  96                 panic("Cannot use SRAM");
  97
  98         return _omap_sram_reprogram_clock(dpllctl, ckctl);
  99 }
 100
 101 void * omap_sram_push(void * start, unsigned long size)
 102 {
 103         if (size > (omap_sram_ceil - (omap_sram_base + SRAM_BOOTLOADER_SZ))) {
 104                 printk(KERN_ERR "Not enough space in SRAM\n");
 105                 return NULL;
 106         }
 107         omap_sram_ceil -= size;
 108         omap_sram_ceil &= ~0x3;
 109         memcpy((void *)omap_sram_ceil, start, size);
 110
 111         return (void *)omap_sram_ceil;
 112 }
 113
 114 void __init omap_sram_init(void)
 115 {
 116         omap_detect_sram();
 117         omap_map_sram();
 118         _omap_sram_reprogram_clock = omap_sram_push(sram_reprogram_clock,
 119                                                     sram_reprogram_clock_sz);
 120 }