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  *
   5  *  This program is free software; you can redistribute  it and/or modify it
   6  *  under  the terms of  the GNU General  Public License as published by the
   7  *  Free Software Foundation;  either version 2 of the  License, or (at your
   8  *  option) any later version.
   9  *
  10  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  11  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  12  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  13  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  14  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  15  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  16  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  17  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  18  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  19  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  20  *
  21  *  You should have received a copy of the  GNU General Public License along
  22  *  with this program; if not, write  to the Free Software Foundation, Inc.,
  23  *  675 Mass Ave, Cambridge, MA 02139, USA.
  24  */
  25
  26 #include <linux/init.h>
  27 #include <linux/types.h>
  28 #include <linux/kernel.h>
  29 #include <linux/spinlock.h>
  30 #include <asm/bootinfo.h>
  31 #include <asm/fw/cfe/cfe_api.h>
  32 #include <asm/fw/cfe/cfe_error.h>
  33
  34 static int cfe_cons_handle;
  35
  36 const char *get_system_type(void)
  37 {
  38         return "Broadcom BCM47XX";
  39 }
  40
  41 void prom_putchar(char c)
  42 {
  43         while (cfe_write(cfe_cons_handle, &c, 1) == 0)
  44                 ;
  45 }
  46
  47 static __init void prom_init_cfe(void)
  48 {
  49         uint32_t cfe_ept;
  50         uint32_t cfe_handle;
  51         uint32_t cfe_eptseal;
  52         int argc = fw_arg0;
  53         char **envp = (char **) fw_arg2;
  54         int *prom_vec = (int *) fw_arg3;
  55
  56         /*
  57          * Check if a loader was used; if NOT, the 4 arguments are
  58          * what CFE gives us (handle, 0, EPT and EPTSEAL)
  59          */
  60         if (argc < 0) {
  61                 cfe_handle = (uint32_t)argc;
  62                 cfe_ept = (uint32_t)envp;
  63                 cfe_eptseal = (uint32_t)prom_vec;
  64         } else {
  65                 if ((int)prom_vec < 0) {
  66                         /*
  67                          * Old loader; all it gives us is the handle,
  68                          * so use the "known" entrypoint and assume
  69                          * the seal.
  70                          */
  71                         cfe_handle = (uint32_t)prom_vec;
  72                         cfe_ept = 0xBFC00500;
  73                         cfe_eptseal = CFE_EPTSEAL;
  74                 } else {
  75                         /*
  76                          * Newer loaders bundle the handle/ept/eptseal
  77                          * Note: prom_vec is in the loader's useg
  78                          * which is still alive in the TLB.
  79                          */
  80                         cfe_handle = prom_vec[0];
  81                         cfe_ept = prom_vec[2];
  82                         cfe_eptseal = prom_vec[3];
  83                 }
  84         }
  85
  86         if (cfe_eptseal != CFE_EPTSEAL) {
  87                 /* too early for panic to do any good */
  88                 printk(KERN_ERR "CFE's entrypoint seal doesn't match.");
  89                 while (1) ;
  90         }
  91
  92         cfe_init(cfe_handle, cfe_ept);
  93 }
  94
  95 static __init void prom_init_console(void)
  96 {
  97         /* Initialize CFE console */
  98         cfe_cons_handle = cfe_getstdhandle(CFE_STDHANDLE_CONSOLE);
  99 }
 100
 101 static __init void prom_init_cmdline(void)
 102 {
 103         static char buf[COMMAND_LINE_SIZE] __initdata;
 104
 105         /* Get the kernel command line from CFE */
 106         if (cfe_getenv("LINUX_CMDLINE", buf, COMMAND_LINE_SIZE) >= 0) {
 107                 buf[COMMAND_LINE_SIZE - 1] = 0;
 108                 strcpy(arcs_cmdline, buf);
 109         }
 110
 111         /* Force a console handover by adding a console= argument if needed,
 112          * as CFE is not available anymore later in the boot process. */
 113         if ((strstr(arcs_cmdline, "console=")) == NULL) {
 114                 /* Try to read the default serial port used by CFE */
 115                 if ((cfe_getenv("BOOT_CONSOLE", buf, COMMAND_LINE_SIZE) < 0)
 116                     || (strncmp("uart", buf, 4)))
 117                         /* Default to uart0 */
 118                         strcpy(buf, "uart0");
 119
 120                 /* Compute the new command line */
 121                 snprintf(arcs_cmdline, COMMAND_LINE_SIZE, "%s console=ttyS%c,115200",
 122                          arcs_cmdline, buf[4]);
 123         }
 124 }
 125
 126 static __init void prom_init_mem(void)
 127 {
 128         unsigned long mem;
 129         unsigned long max;
 130
 131         /* Figure out memory size by finding aliases.
 132          *
 133          * We should theoretically use the mapping from CFE using cfe_enummem().
 134          * However as the BCM47XX is mostly used on low-memory systems, we
 135          * want to reuse the memory used by CFE (around 4MB). That means cfe_*
 136          * functions stop to work at some point during the boot, we should only
 137          * call them at the beginning of the boot.
 138          *
 139          * BCM47XX uses 128MB for addressing the ram, if the system contains
 140          * less that that amount of ram it remaps the ram more often into the
 141          * available space.
 142          * Accessing memory after 128MB will cause an exception.
 143          * max contains the biggest possible address supported by the platform.
 144          * If the method wants to try something above we assume 128MB ram.
 145          */
 146         max = ((unsigned long)(prom_init) | ((128 << 20) - 1));
 147         for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) {
 148                 if (((unsigned long)(prom_init) + mem) > max) {
 149                         mem = (128 << 20);
 150                         printk(KERN_DEBUG "assume 128MB RAM\n");
 151                         break;
 152                 }
 153                 if (*(unsigned long *)((unsigned long)(prom_init) + mem) ==
 154                     *(unsigned long *)(prom_init))
 155                         break;
 156         }
 157
 158         add_memory_region(0, mem, BOOT_MEM_RAM);
 159 }
 160
 161 void __init prom_init(void)
 162 {
 163         prom_init_cfe();
 164         prom_init_console();
 165         prom_init_cmdline();
 166         prom_init_mem();
 167 }
 168
 169 void __init prom_free_prom_memory(void)
 170 {
 171 }