mips/bcm47xx/prom.c

0001 /*
0002  *  Copyright (C) 2004 Florian Schirmer <jolt@tuxbox.org>
0003  *  Copyright (C) 2007 Aurelien Jarno <aurelien@aurel32.net>
0004  *  Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
0005  *
0006  *  This program is free software; you can redistribute  it and/or modify it
0007  *  under  the terms of  the GNU General  Public License as published by the
0008  *  Free Software Foundation;  either version 2 of the  License, or (at your
0009  *  option) any later version.
0010  *
0011  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
0012  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
0013  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
0014  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
0015  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
0016  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
0017  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
0018  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
0019  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
0020  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
0021  *
0022  *  You should have received a copy of the  GNU General Public License along
0023  *  with this program; if not, write  to the Free Software Foundation, Inc.,
0024  *  675 Mass Ave, Cambridge, MA 02139, USA.
0025  */
0026
0027 #include <linux/init.h>
0028 #include <linux/types.h>
0029 #include <linux/kernel.h>
0030 #include <linux/memblock.h>
0031 #include <linux/spinlock.h>
0032 #include <linux/ssb/ssb_driver_chipcommon.h>
0033 #include <linux/ssb/ssb_regs.h>
0034 #include <linux/smp.h>
0035 #include <asm/bootinfo.h>
0036 #include <bcm47xx.h>
0037 #include <bcm47xx_board.h>
0038
0039 static char bcm47xx_system_type[20] = "Broadcom BCM47XX";
0040
0041 const char *get_system_type(void)
0042 {
0043     return bcm47xx_system_type;
0044 }
0045
0046 __init void bcm47xx_set_system_type(u16 chip_id)
0047 {
0048     snprintf(bcm47xx_system_type, sizeof(bcm47xx_system_type),
0049          (chip_id > 0x9999) ? "Broadcom BCM%d" :
0050                       "Broadcom BCM%04X",
0051          chip_id);
0052 }
0053
0054 static unsigned long lowmem __initdata;
0055
0056 static __init void prom_init_mem(void)
0057 {
0058     unsigned long mem;
0059     unsigned long max;
0060     unsigned long off;
0061     struct cpuinfo_mips *c = &current_cpu_data;
0062
0063     /* Figure out memory size by finding aliases.
0064      *
0065      * We should theoretically use the mapping from CFE using cfe_enummem().
0066      * However as the BCM47XX is mostly used on low-memory systems, we
0067      * want to reuse the memory used by CFE (around 4MB). That means cfe_*
0068      * functions stop to work at some point during the boot, we should only
0069      * call them at the beginning of the boot.
0070      *
0071      * BCM47XX uses 128MB for addressing the ram, if the system contains
0072      * less than that amount of ram it remaps the ram more often into the
0073      * available space.
0074      */
0075
0076     /* Physical address, without mapping to any kernel segment */
0077     off = CPHYSADDR((unsigned long)prom_init);
0078
0079     /* Accessing memory after 128 MiB will cause an exception */
0080     max = 128 << 20;
0081
0082     for (mem = 1 << 20; mem < max; mem += 1 << 20) {
0083         /* Loop condition may be not enough, off may be over 1 MiB */
0084         if (off + mem >= max) {
0085             mem = max;
0086             pr_debug("Assume 128MB RAM\n");
0087             break;
0088         }
0089         if (!memcmp(prom_init, prom_init + mem, 32))
0090             break;
0091     }
0092     lowmem = mem;
0093
0094     /* Ignoring the last page when ddr size is 128M. Cached
0095      * accesses to last page is causing the processor to prefetch
0096      * using address above 128M stepping out of the ddr address
0097      * space.
0098      */
0099     if (c->cputype == CPU_74K && (mem == (128  << 20)))
0100         mem -= 0x1000;
0101     memblock_add(0, mem);
0102 }
0103
0104 /*
0105  * This is the first serial on the chip common core, it is at this position
0106  * for sb (ssb) and ai (bcma) bus.
0107  */
0108 #define BCM47XX_SERIAL_ADDR (SSB_ENUM_BASE + SSB_CHIPCO_UART0_DATA)
0109
0110 void __init prom_init(void)
0111 {
0112     prom_init_mem();
0113     setup_8250_early_printk_port(CKSEG1ADDR(BCM47XX_SERIAL_ADDR), 0, 0);
0114 }
0115
0116 #if defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM)
0117
0118 #define EXTVBASE    0xc0000000
0119 #define ENTRYLO(x)  ((pte_val(pfn_pte((x) >> _PFN_SHIFT, PAGE_KERNEL_UNCACHED)) >> 6) | 1)
0120
0121 #include <asm/tlbflush.h>
0122
0123 /* Stripped version of tlb_init, with the call to build_tlb_refill_handler
0124  * dropped. Calling it at this stage causes a hang.
0125  */
0126 void early_tlb_init(void)
0127 {
0128     write_c0_pagemask(PM_DEFAULT_MASK);
0129     write_c0_wired(0);
0130     temp_tlb_entry = current_cpu_data.tlbsize - 1;
0131     local_flush_tlb_all();
0132 }
0133
0134 void __init bcm47xx_prom_highmem_init(void)
0135 {
0136     unsigned long off = (unsigned long)prom_init;
0137     unsigned long extmem = 0;
0138     bool highmem_region = false;
0139
0140     if (WARN_ON(bcm47xx_bus_type != BCM47XX_BUS_TYPE_BCMA))
0141         return;
0142
0143     if (bcm47xx_bus.bcma.bus.chipinfo.id == BCMA_CHIP_ID_BCM4706)
0144         highmem_region = true;
0145
0146     if (lowmem != 128 << 20 || !highmem_region)
0147         return;
0148
0149     early_tlb_init();
0150
0151     /* Add one temporary TLB entry to map SDRAM Region 2.
0152      *      Physical        Virtual
0153      *      0x80000000      0xc0000000      (1st: 256MB)
0154      *      0x90000000      0xd0000000      (2nd: 256MB)
0155      */
0156     add_temporary_entry(ENTRYLO(0x80000000),
0157                 ENTRYLO(0x80000000 + (256 << 20)),
0158                 EXTVBASE, PM_256M);
0159
0160     off = EXTVBASE + __pa(off);
0161     for (extmem = 128 << 20; extmem < 512 << 20; extmem <<= 1) {
0162         if (!memcmp(prom_init, (void *)(off + extmem), 16))
0163             break;
0164     }
0165     extmem -= lowmem;
0166
0167     early_tlb_init();
0168
0169     if (!extmem)
0170         return;
0171
0172     pr_warn("Found %lu MiB of extra memory, but highmem is unsupported yet!\n",
0173         extmem >> 20);
0174
0175     /* TODO: Register extra memory */
0176 }
0177
0178 #endif /* defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM) */