arch/arm/mach-davinci/id.c

   1 /*
   2  * Davinci CPU identification code
   3  *
   4  * Copyright (C) 2006 Komal Shah <komal_shah802003@yahoo.com>
   5  *
   6  * Derived from OMAP1 CPU identification code.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16
  17 #include <asm/io.h>
  18
  19 #define JTAG_ID_BASE            0x01c40028
  20
  21 struct davinci_id {
  22         u8      variant;        /* JTAG ID bits 31:28 */
  23         u16     part_no;        /* JTAG ID bits 27:12 */
  24         u32     manufacturer;   /* JTAG ID bits 11:1 */
  25         u32     type;           /* Cpu id bits [31:8], cpu class bits [7:0] */
  26 };
  27
  28 /* Register values to detect the DaVinci version */
  29 static struct davinci_id davinci_ids[] __initdata = {
  30         {
  31                 /* DM6446 */
  32                 .part_no      = 0xb700,
  33                 .variant      = 0x0,
  34                 .manufacturer = 0x017,
  35                 .type         = 0x64460000,
  36         },
  37 };
  38
  39 /*
  40  * Get Device Part No. from JTAG ID register
  41  */
  42 static u16 __init davinci_get_part_no(void)
  43 {
  44         u32 dev_id, part_no;
  45
  46         dev_id = davinci_readl(JTAG_ID_BASE);
  47
  48         part_no = ((dev_id >> 12) & 0xffff);
  49
  50         return part_no;
  51 }
  52
  53 /*
  54  * Get Device Revision from JTAG ID register
  55  */
  56 static u8 __init davinci_get_variant(void)
  57 {
  58         u32 variant;
  59
  60         variant = davinci_readl(JTAG_ID_BASE);
  61
  62         variant = (variant >> 28) & 0xf;
  63
  64         return variant;
  65 }
  66
  67 void __init davinci_check_revision(void)
  68 {
  69         int i;
  70         u16 part_no;
  71         u8 variant;
  72
  73         part_no = davinci_get_part_no();
  74         variant = davinci_get_variant();
  75
  76         /* First check only the major version in a safe way */
  77         for (i = 0; i < ARRAY_SIZE(davinci_ids); i++) {
  78                 if (part_no == (davinci_ids[i].part_no)) {
  79                         system_rev = davinci_ids[i].type;
  80                         break;
  81                 }
  82         }
  83
  84         /* Check if we can find the dev revision */
  85         for (i = 0; i < ARRAY_SIZE(davinci_ids); i++) {
  86                 if (part_no == davinci_ids[i].part_no &&
  87                     variant == davinci_ids[i].variant) {
  88                         system_rev = davinci_ids[i].type;
  89                         break;
  90                 }
  91         }
  92
  93         printk("DaVinci DM%04x variant 0x%x\n", system_rev >> 16, variant);
  94 }