5 files changed, 86 insertions, 2 deletions

diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
index 060a75e99263..0406cb3f1af7 100644
--- a/arch/arm/include/asm/mach/arch.h
+++ b/arch/arm/include/asm/mach/arch.h
@@ -50,6 +50,7 @@ struct machine_desc {
         struct smp_operations   *smp;           /* SMP operations       */
         bool                    (*smp_init)(void);
         void                    (*fixup)(struct tag *, char **);
+        void                    (*dt_fixup)(void);
         void                    (*init_meminfo)(void);
         void                    (*reserve)(void);/* reserve mem blocks  */
         void                    (*map_io)(void);/* IO mapping function  */
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index e94a157ddff1..11c54de9f8cf 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -212,7 +212,7 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
         mdesc_best = &__mach_desc_GENERIC_DT;
 #endif
 
-        if (!dt_phys || !early_init_dt_scan(phys_to_virt(dt_phys)))
+        if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys)))
                 return NULL;
 
         mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
@@ -237,6 +237,12 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
                 dump_machine_table(); /* does not return */
         }
 
+        /* We really don't want to do this, but sometimes firmware provides buggy data */
+        if (mdesc->dt_fixup)
+                mdesc->dt_fixup();
+
+        early_init_dt_scan_nodes();
+
         /* Change machine number to match the mdesc we're using */
         __machine_arch_type = mdesc->nr;
 
diff --git a/arch/arm/mach-exynos/exynos.c b/arch/arm/mach-exynos/exynos.c
index 46d893fcbe85..66c9b9614f3c 100644
--- a/arch/arm/mach-exynos/exynos.c
+++ b/arch/arm/mach-exynos/exynos.c
@@ -335,6 +335,15 @@ static void __init exynos_reserve(void)
 #endif
 }
 
+static void __init exynos_dt_fixup(void)
+{
+        /*
+         * Some versions of uboot pass garbage entries in the memory node,
+         * use the old CONFIG_ARM_NR_BANKS
+         */
+        of_fdt_limit_memory(8);
+}
+
 DT_MACHINE_START(EXYNOS_DT, "SAMSUNG EXYNOS (Flattened Device Tree)")
         /* Maintainer: Thomas Abraham <thomas.abraham@linaro.org> */
         /* Maintainer: Kukjin Kim <kgene.kim@samsung.com> */
@@ -348,4 +357,5 @@ DT_MACHINE_START(EXYNOS_DT, "SAMSUNG EXYNOS (Flattened Device Tree)")
         .dt_compat      = exynos_dt_compat,
         .restart        = exynos_restart,
         .reserve        = exynos_reserve,
+        .dt_fixup       = exynos_dt_fixup,
 MACHINE_END
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index b777d8f46bd5..9aa012e6ea0a 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -26,6 +26,54 @@
 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
 #include <asm/page.h>
 
+/*
+ * of_fdt_limit_memory - limit the number of regions in the /memory node
+ * @limit: maximum entries
+ *
+ * Adjust the flattened device tree to have at most 'limit' number of
+ * memory entries in the /memory node. This function may be called
+ * any time after initial_boot_param is set.
+ */
+void of_fdt_limit_memory(int limit)
+{
+        int memory;
+        int len;
+        const void *val;
+        int nr_address_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
+        int nr_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
+        const uint32_t *addr_prop;
+        const uint32_t *size_prop;
+        int root_offset;
+        int cell_size;
+
+        root_offset = fdt_path_offset(initial_boot_params, "/");
+        if (root_offset < 0)
+                return;
+
+        addr_prop = fdt_getprop(initial_boot_params, root_offset,
+                                "#address-cells", NULL);
+        if (addr_prop)
+                nr_address_cells = fdt32_to_cpu(*addr_prop);
+
+        size_prop = fdt_getprop(initial_boot_params, root_offset,
+                                "#size-cells", NULL);
+        if (size_prop)
+                nr_size_cells = fdt32_to_cpu(*size_prop);
+
+        cell_size = sizeof(uint32_t)*(nr_address_cells + nr_size_cells);
+
+        memory = fdt_path_offset(initial_boot_params, "/memory");
+        if (memory > 0) {
+                val = fdt_getprop(initial_boot_params, memory, "reg", &len);
+                if (len > limit*cell_size) {
+                        len = limit*cell_size;
+                        pr_debug("Limiting number of entries to %d\n", limit);
+                        fdt_setprop(initial_boot_params, memory, "reg", val,
+                                        len);
+                }
+        }
+}
+
 /**
  * of_fdt_is_compatible - Return true if given node from the given blob has
  * compat in its compatible list
@@ -937,7 +985,7 @@ int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,
 }
 #endif
 
-bool __init early_init_dt_scan(void *params)
+bool __init early_init_dt_verify(void *params)
 {
         if (!params)
                 return false;
@@ -951,6 +999,12 @@ bool __init early_init_dt_scan(void *params)
                 return false;
         }
 
+        return true;
+}
+
+
+void __init early_init_dt_scan_nodes(void)
+{
         /* Retrieve various information from the /chosen node */
         of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
 
@@ -959,7 +1013,17 @@ bool __init early_init_dt_scan(void *params)
 
         /* Setup memory, calling early_init_dt_add_memory_arch */
         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
+}
+
+bool __init early_init_dt_scan(void *params)
+{
+        bool status;
+
+        status = early_init_dt_verify(params);
+        if (!status)
+                return false;
 
+        early_init_dt_scan_nodes();
         return true;
 }
 
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 05117899fcb4..0ff360d5b3b3 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -73,6 +73,8 @@ extern int early_init_dt_scan_root(unsigned long node, const char *uname,
                                    int depth, void *data);
 
 extern bool early_init_dt_scan(void *params);
+extern bool early_init_dt_verify(void *params);
+extern void early_init_dt_scan_nodes(void);
 
 extern const char *of_flat_dt_get_machine_name(void);
 extern const void *of_flat_dt_match_machine(const void *default_match,
@@ -84,6 +86,7 @@ extern void unflatten_and_copy_device_tree(void);
 extern void early_init_devtree(void *);
 extern void early_get_first_memblock_info(void *, phys_addr_t *);
 extern u64 fdt_translate_address(const void *blob, int node_offset);
+extern void of_fdt_limit_memory(int limit);
 #else /* CONFIG_OF_FLATTREE */
 static inline void early_init_fdt_scan_reserved_mem(void) {}
 static inline const char *of_flat_dt_get_machine_name(void) { return NULL; }