prom.c

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/*
 *  Copyright (C) 2004 Florian Schirmer <[email protected]>
 *  Copyright (C) 2007 Aurelien Jarno <[email protected]>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  You should have received a copy of the  GNU General Public License along
 *  with this program; if not, write  to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/init.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <asm/bootinfo.h>
#include <asm/fw/cfe/cfe_api.h>
#include <asm/fw/cfe/cfe_error.h>

static int cfe_cons_handle;

const char *get_system_type(void)
{
    return "Broadcom BCM47XX";
}

void prom_putchar(char c)
{
    while (cfe_write(cfe_cons_handle, &c, 1) == 0)
        ;
}

static __init void prom_init_cfe(void)
{
    uint32_t cfe_ept;
    uint32_t cfe_handle;
    uint32_t cfe_eptseal;
    int argc = fw_arg0;
    char **envp = (char **) fw_arg2;
    int *prom_vec = (int *) fw_arg3;

    /*
     * Check if a loader was used; if NOT, the 4 arguments are
     * what CFE gives us (handle, 0, EPT and EPTSEAL)
     */
    if (argc < 0) {
        cfe_handle = (uint32_t)argc;
        cfe_ept = (uint32_t)envp;
        cfe_eptseal = (uint32_t)prom_vec;
    } else {
        if ((int)prom_vec < 0) {
            /*
             * Old loader; all it gives us is the handle,
             * so use the "known" entrypoint and assume
             * the seal.
             */
            cfe_handle = (uint32_t)prom_vec;
            cfe_ept = 0xBFC00500;
            cfe_eptseal = CFE_EPTSEAL;
        } else {
            /*
             * Newer loaders bundle the handle/ept/eptseal
             * Note: prom_vec is in the loader's useg
             * which is still alive in the TLB.
             */
            cfe_handle = prom_vec[0];
            cfe_ept = prom_vec[2];
            cfe_eptseal = prom_vec[3];
        }
    }

    if (cfe_eptseal != CFE_EPTSEAL) {
        /* too early for panic to do any good */
        printk(KERN_ERR "CFE's entrypoint seal doesn't match.");
        while (1) ;
    }

    cfe_init(cfe_handle, cfe_ept);
}

static __init void prom_init_console(void)
{
    /* Initialize CFE console */
    cfe_cons_handle = cfe_getstdhandle(CFE_STDHANDLE_CONSOLE);
}

static __init void prom_init_cmdline(void)
{
    static char buf[COMMAND_LINE_SIZE] __initdata;

    /* Get the kernel command line from CFE */
    if (cfe_getenv("LINUX_CMDLINE", buf, COMMAND_LINE_SIZE) >= 0) {
        buf[COMMAND_LINE_SIZE - 1] = 0;
        strcpy(arcs_cmdline, buf);
    }

    /* Force a console handover by adding a console= argument if needed,
     * as CFE is not available anymore later in the boot process. */
    if ((strstr(arcs_cmdline, "console=")) == NULL) {
        /* Try to read the default serial port used by CFE */
        if ((cfe_getenv("BOOT_CONSOLE", buf, COMMAND_LINE_SIZE) < 0)
            || (strncmp("uart", buf, 4)))
            /* Default to uart0 */
            strcpy(buf, "uart0");

        /* Compute the new command line */
        snprintf(arcs_cmdline, COMMAND_LINE_SIZE, "%s console=ttyS%c,115200",
             arcs_cmdline, buf[4]);
    }
}

static __init void prom_init_mem(void)
{
    unsigned long mem;
    unsigned long max;

    /* Figure out memory size by finding aliases.
     *
     * We should theoretically use the mapping from CFE using cfe_enummem().
     * However as the BCM47XX is mostly used on low-memory systems, we
     * want to reuse the memory used by CFE (around 4MB). That means cfe_*
     * functions stop to work at some point during the boot, we should only
     * call them at the beginning of the boot.
     *
     * BCM47XX uses 128MB for addressing the ram, if the system contains
     * less that that amount of ram it remaps the ram more often into the
     * available space.
     * Accessing memory after 128MB will cause an exception.
     * max contains the biggest possible address supported by the platform.
     * If the method wants to try something above we assume 128MB ram.
     */
    max = ((unsigned long)(prom_init) | ((128 << 20) - 1));
    for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) {
        if (((unsigned long)(prom_init) + mem) > max) {
            mem = (128 << 20);
            printk(KERN_DEBUG "assume 128MB RAM\n");
            break;
        }
        if (*(unsigned long *)((unsigned long)(prom_init) + mem) ==
            *(unsigned long *)(prom_init))
            break;
    }

    add_memory_region(0, mem, BOOT_MEM_RAM);
}

void __init prom_init(void)
{
    prom_init_cfe();
    prom_init_console();
    prom_init_cmdline();
    prom_init_mem();
}

void __init prom_free_prom_memory(void)
{
}