linux/arch/mips/bcm47xx/prom.c
Hauke Mehrtens c47cc20ca5 MIPS: BCM47XX: improve memory size detection
The memory size is detected by finding a place where it repeats in
memory. Currently we are just checking when the function prom_init is
seen again, but it is better to check for a bigger part of the memory
to decrease the chance of wrong results.

This should fix a problem we saw in OpenWrt, where the detected
available memory decreed on some devices when doing a soft reboot.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: http://patchwork.linux-mips.org/patch/4362
Signed-off-by: John Crispin <blogic@openwrt.org>
2012-11-09 11:37:17 +01:00

184 lines
5.4 KiB
C

/*
* Copyright (C) 2004 Florian Schirmer <jolt@tuxbox.org>
* Copyright (C) 2007 Aurelien Jarno <aurelien@aurel32.net>
* Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
*
* 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 <linux/smp.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;
unsigned long off;
struct cpuinfo_mips *c = &current_cpu_data;
/* 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.
*/
off = (unsigned long)prom_init;
max = off | ((128 << 20) - 1);
for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) {
if ((off + mem) > max) {
mem = (128 << 20);
printk(KERN_DEBUG "assume 128MB RAM\n");
break;
}
if (!memcmp(prom_init, prom_init + mem, 32))
break;
}
/* Ignoring the last page when ddr size is 128M. Cached
* accesses to last page is causing the processor to prefetch
* using address above 128M stepping out of the ddr address
* space.
*/
if (c->cputype == CPU_74K && (mem == (128 << 20)))
mem -= 0x1000;
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)
{
}