linux/arch/mips/bcm47xx/prom.c
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   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
  36static int cfe_cons_handle;
  37
  38const char *get_system_type(void)
  39{
  40        return "Broadcom BCM47XX";
  41}
  42
  43void prom_putchar(char c)
  44{
  45        while (cfe_write(cfe_cons_handle, &c, 1) == 0)
  46                ;
  47}
  48
  49static __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
  97static __init void prom_init_console(void)
  98{
  99        /* Initialize CFE console */
 100        cfe_cons_handle = cfe_getstdhandle(CFE_STDHANDLE_CONSOLE);
 101}
 102
 103static __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
 128static __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
 173void __init prom_init(void)
 174{
 175        prom_init_cfe();
 176        prom_init_console();
 177        prom_init_cmdline();
 178        prom_init_mem();
 179}
 180
 181void __init prom_free_prom_memory(void)
 182{
 183}
 184