arch/mips/bcm47xx/prom.c

   1 /*
   2  *  Copyright (C) 2004 Florian Schirmer <jolt@tuxbox.org>
   3  *  Copyright (C) 2007 Aurelien Jarno <aurelien@aurel32.net>
   4  *  Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
   5  *
   6  *  This program is free software; you can redistribute  it and/or modify it
   7  *  under  the terms of  the GNU General  Public License as published by the
   8  *  Free Software Foundation;  either version 2 of the  License, or (at your
   9  *  option) any later version.
  10  *
  11  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  12  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  13  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  14  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  15  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  16  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  17  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  18  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  19  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  20  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  21  *
  22  *  You should have received a copy of the  GNU General Public License along
  23  *  with this program; if not, write  to the Free Software Foundation, Inc.,
  24  *  675 Mass Ave, Cambridge, MA 02139, USA.
  25  */
  26
  27 #include <linux/init.h>
  28 #include <linux/types.h>
  29 #include <linux/kernel.h>
  30 #include <linux/memblock.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/ssb/ssb_driver_chipcommon.h>
  33 #include <linux/ssb/ssb_regs.h>
  34 #include <linux/smp.h>
  35 #include <asm/bmips.h>
  36 #include <asm/bootinfo.h>
  37 #include <bcm47xx.h>
  38 #include <bcm47xx_board.h>
  39 #include "bcm47xx_private.h"
  40
  41 static char bcm47xx_system_type[20] = "Broadcom BCM47XX";
  42
  43 const char *get_system_type(void)
  44 {
  45         return bcm47xx_system_type;
  46 }
  47
  48 __init void bcm47xx_set_system_type(u16 chip_id)
  49 {
  50         snprintf(bcm47xx_system_type, sizeof(bcm47xx_system_type),
  51                  (chip_id > 0x9999) ? "Broadcom BCM%d" :
  52                                       "Broadcom BCM%04X",
  53                  chip_id);
  54 }
  55
  56 static unsigned long lowmem __initdata;
  57
  58 static __init void prom_init_mem(void)
  59 {
  60         unsigned long mem;
  61         unsigned long max;
  62         unsigned long off;
  63         struct cpuinfo_mips *c = &current_cpu_data;
  64
  65         /* Figure out memory size by finding aliases.
  66          *
  67          * We should theoretically use the mapping from CFE using cfe_enummem().
  68          * However as the BCM47XX is mostly used on low-memory systems, we
  69          * want to reuse the memory used by CFE (around 4MB). That means cfe_*
  70          * functions stop to work at some point during the boot, we should only
  71          * call them at the beginning of the boot.
  72          *
  73          * BCM47XX uses 128MB for addressing the ram, if the system contains
  74          * less than that amount of ram it remaps the ram more often into the
  75          * available space.
  76          */
  77
  78         /* Physical address, without mapping to any kernel segment */
  79         off = CPHYSADDR((unsigned long)prom_init);
  80
  81         /* Accessing memory after 128 MiB will cause an exception */
  82         max = 128 << 20;
  83
  84         for (mem = 1 << 20; mem < max; mem += 1 << 20) {
  85                 /* Loop condition may be not enough, off may be over 1 MiB */
  86                 if (off + mem >= max) {
  87                         mem = max;
  88                         pr_debug("Assume 128MB RAM\n");
  89                         break;
  90                 }
  91                 if (!memcmp((void *)prom_init, (void *)prom_init + mem, 32))
  92                         break;
  93         }
  94         lowmem = mem;
  95
  96         /* Ignoring the last page when ddr size is 128M. Cached
  97          * accesses to last page is causing the processor to prefetch
  98          * using address above 128M stepping out of the ddr address
  99          * space.
 100          */
 101         if (c->cputype == CPU_74K && (mem == (128  << 20)))
 102                 mem -= 0x1000;
 103         memblock_add(0, mem);
 104 }
 105
 106 /*
 107  * This is the first serial on the chip common core, it is at this position
 108  * for sb (ssb) and ai (bcma) bus.
 109  */
 110 #define BCM47XX_SERIAL_ADDR (SSB_ENUM_BASE + SSB_CHIPCO_UART0_DATA)
 111
 112 void __init prom_init(void)
 113 {
 114         /* Cache CBR addr before CPU/DMA setup */
 115         bmips_cbr_addr = BMIPS_GET_CBR();
 116         prom_init_mem();
 117         setup_8250_early_printk_port(CKSEG1ADDR(BCM47XX_SERIAL_ADDR), 0, 0);
 118 }
 119
 120 #if defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM)
 121
 122 #define EXTVBASE        0xc0000000
 123 #define ENTRYLO(x)      ((pte_val(pfn_pte((x) >> PFN_PTE_SHIFT, PAGE_KERNEL_UNCACHED)) >> 6) | 1)
 124
 125 #include <asm/tlbflush.h>
 126
 127 /* Stripped version of tlb_init, with the call to build_tlb_refill_handler
 128  * dropped. Calling it at this stage causes a hang.
 129  */
 130 static void early_tlb_init(void)
 131 {
 132         write_c0_pagemask(PM_DEFAULT_MASK);
 133         write_c0_wired(0);
 134         temp_tlb_entry = current_cpu_data.tlbsize - 1;
 135         local_flush_tlb_all();
 136 }
 137
 138 void __init bcm47xx_prom_highmem_init(void)
 139 {
 140         unsigned long off = (unsigned long)prom_init;
 141         unsigned long extmem = 0;
 142         bool highmem_region = false;
 143
 144         if (WARN_ON(bcm47xx_bus_type != BCM47XX_BUS_TYPE_BCMA))
 145                 return;
 146
 147         if (bcm47xx_bus.bcma.bus.chipinfo.id == BCMA_CHIP_ID_BCM4706)
 148                 highmem_region = true;
 149
 150         if (lowmem != 128 << 20 || !highmem_region)
 151                 return;
 152
 153         early_tlb_init();
 154
 155         /* Add one temporary TLB entry to map SDRAM Region 2.
 156          *      Physical        Virtual
 157          *      0x80000000      0xc0000000      (1st: 256MB)
 158          *      0x90000000      0xd0000000      (2nd: 256MB)
 159          */
 160         add_temporary_entry(ENTRYLO(0x80000000),
 161                             ENTRYLO(0x80000000 + (256 << 20)),
 162                             EXTVBASE, PM_256M);
 163
 164         off = EXTVBASE + __pa(off);
 165         for (extmem = 128 << 20; extmem < 512 << 20; extmem <<= 1) {
 166                 if (!memcmp((void *)prom_init, (void *)(off + extmem), 16))
 167                         break;
 168         }
 169         extmem -= lowmem;
 170
 171         early_tlb_init();
 172
 173         if (!extmem)
 174                 return;
 175
 176         pr_warn("Found %lu MiB of extra memory, but highmem is unsupported yet!\n",
 177                 extmem >> 20);
 178
 179         /* TODO: Register extra memory */
 180 }
 181
 182 #endif /* defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM) */