brcm47xx: fix commit r18413 "128MB ram problem"

[openwrt-10.03/.git] / target / linux / brcm47xx / patches-2.6.30 / 170-128MB_ram_bugfix.patch

diff --git a/target/linux/brcm47xx/patches-2.6.30/170-128MB_ram_bugfix.patch b/target/linux/brcm47xx/patches-2.6.30/170-128MB_ram_bugfix.patch
index e54e3de4098d92e531c30f34cd4da27cc9c867ee..93f4b1f101fa6a9ecb13ad980a07f86296167323 100644 (file)
--- a/target/linux/brcm47xx/patches-2.6.30/170-128MB_ram_bugfix.patch
+++ b/target/linux/brcm47xx/patches-2.6.30/170-128MB_ram_bugfix.patch
@@ -1,17 +1,32 @@
 --- a/arch/mips/bcm47xx/prom.c
 +++ b/arch/mips/bcm47xx/prom.c
-@@ -141,6 +141,14 @@ static __init void prom_init_mem(void)
-                       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 (mem == 0x8000000)
-+              mem -= 0x1000;
-+
-       add_memory_region(0, mem, BOOT_MEM_RAM);
- }
+@@ -126,6 +126,7 @@ static __init void prom_init_cmdline(voi
+ static __init void prom_init_mem(void)
+ {
+       unsigned long mem;
++      unsigned long max;
  
+       /* Figure out memory size by finding aliases.
+        *
+@@ -134,8 +135,21 @@ static __init void prom_init_mem(void)
+        * 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("assume 128MB RAM\n");
++                      break;
++              }
+               if (*(unsigned long *)((unsigned long)(prom_init) + mem) ==
+                   *(unsigned long *)(prom_init))
+                       break;