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/spinlock.h>
  31 #include <linux/smp.h>
  32 #include <asm/bootinfo.h>
  33 #include <asm/fw/cfe/cfe_api.h>
  34 #include <asm/fw/cfe/cfe_error.h>
  35
  36 static int cfe_cons_handle;
  37
  38 const char *get_system_type(void)
  39 {
  40         return "Broadcom BCM47XX";
  41 }
  42
  43 void prom_putchar(char c)
  44 {
  45         while (cfe_write(cfe_cons_handle, &c, 1) == 0)
  46                 ;
  47 }
  48
  49 static __init void prom_init_cfe(void)
  50 {
  51         uint32_t cfe_ept;
  52         uint32_t cfe_handle;
  53         uint32_t cfe_eptseal;
  54         int argc = fw_arg0;
  55         char **envp = (char **) fw_arg2;
  56         int *prom_vec = (int *) fw_arg3;
  57
  58         /*
  59          * Check if a loader was used; if NOT, the 4 arguments are
  60          * what CFE gives us (handle, 0, EPT and EPTSEAL)
  61          */
  62         if (argc < 0) {
  63                 cfe_handle = (uint32_t)argc;
  64                 cfe_ept = (uint32_t)envp;
  65                 cfe_eptseal = (uint32_t)prom_vec;
  66         } else {
  67                 if ((int)prom_vec < 0) {
  68                         /*
  69                          * Old loader; all it gives us is the handle,
  70                          * so use the "known" entrypoint and assume
  71                          * the seal.
  72                          */
  73                         cfe_handle = (uint32_t)prom_vec;
  74                         cfe_ept = 0xBFC00500;
  75                         cfe_eptseal = CFE_EPTSEAL;
  76                 } else {
  77                         /*
  78                          * Newer loaders bundle the handle/ept/eptseal
  79                          * Note: prom_vec is in the loader's useg
  80                          * which is still alive in the TLB.
  81                          */
  82                         cfe_handle = prom_vec[0];
  83                         cfe_ept = prom_vec[2];
  84                         cfe_eptseal = prom_vec[3];
  85                 }
  86         }
  87
  88         if (cfe_eptseal != CFE_EPTSEAL) {
  89                 /* too early for panic to do any good */
  90                 printk(KERN_ERR "CFE's entrypoint seal doesn't match.");
  91                 while (1) ;
  92         }
  93
  94         cfe_init(cfe_handle, cfe_ept);
  95 }
  96
  97 static __init void prom_init_console(void)
  98 {
  99         /* Initialize CFE console */
 100         cfe_cons_handle = cfe_getstdhandle(CFE_STDHANDLE_CONSOLE);
 101 }
 102
 103 static __init void prom_init_cmdline(void)
 104 {
 105         static char buf[COMMAND_LINE_SIZE] __initdata;
 106
 107         /* Get the kernel command line from CFE */
 108         if (cfe_getenv("LINUX_CMDLINE", buf, COMMAND_LINE_SIZE) >= 0) {
 109                 buf[COMMAND_LINE_SIZE - 1] = 0;
 110                 strcpy(arcs_cmdline, buf);
 111         }
 112
 113         /* Force a console handover by adding a console= argument if needed,
 114          * as CFE is not available anymore later in the boot process. */
 115         if ((strstr(arcs_cmdline, "console=")) == NULL) {
 116                 /* Try to read the default serial port used by CFE */
 117                 if ((cfe_getenv("BOOT_CONSOLE", buf, COMMAND_LINE_SIZE) < 0)
 118                     || (strncmp("uart", buf, 4)))
 119                         /* Default to uart0 */
 120                         strcpy(buf, "uart0");
 121
 122                 /* Compute the new command line */
 123                 snprintf(arcs_cmdline, COMMAND_LINE_SIZE, "%s console=ttyS%c,115200",
 124                          arcs_cmdline, buf[4]);
 125         }
 126 }
 127
 128 static __init void prom_init_mem(void)
 129 {
 130         unsigned long mem;
 131         unsigned long max;
 132         unsigned long off;
 133         struct cpuinfo_mips *c = &current_cpu_data;
 134
 135         /* Figure out memory size by finding aliases.
 136          *
 137          * We should theoretically use the mapping from CFE using cfe_enummem().
 138          * However as the BCM47XX is mostly used on low-memory systems, we
 139          * want to reuse the memory used by CFE (around 4MB). That means cfe_*
 140          * functions stop to work at some point during the boot, we should only
 141          * call them at the beginning of the boot.
 142          *
 143          * BCM47XX uses 128MB for addressing the ram, if the system contains
 144          * less that that amount of ram it remaps the ram more often into the
 145          * available space.
 146          * Accessing memory after 128MB will cause an exception.
 147          * max contains the biggest possible address supported by the platform.
 148          * If the method wants to try something above we assume 128MB ram.
 149          */
 150         off = (unsigned long)prom_init;
 151         max = off | ((128 << 20) - 1);
 152         for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) {
 153                 if ((off + mem) > max) {
 154                         mem = (128 << 20);
 155                         printk(KERN_DEBUG "assume 128MB RAM\n");
 156                         break;
 157                 }
 158                 if (!memcmp(prom_init, prom_init + mem, 32))
 159                         break;
 160         }
 161
 162         /* Ignoring the last page when ddr size is 128M. Cached
 163          * accesses to last page is causing the processor to prefetch
 164          * using address above 128M stepping out of the ddr address
 165          * space.
 166          */
 167         if (c->cputype == CPU_74K && (mem == (128  << 20)))
 168                 mem -= 0x1000;
 169
 170         add_memory_region(0, mem, BOOT_MEM_RAM);
 171 }
 172
 173 void __init prom_init(void)
 174 {
 175         prom_init_cfe();
 176         prom_init_console();
 177         prom_init_cmdline();
 178         prom_init_mem();
 179 }
 180
 181 void __init prom_free_prom_memory(void)
 182 {
 183 }