xtensa: handle memmap kernel option

This option is useful for reserving memory regions for secondary cores
in AMP configurations.

Implement the following memmap variants:
- memmap=nn[KMG]@ss[KMG]: force usage of a specific region of memory;
- memmap=nn[KMG]$ss[KMG]: mark specified memory as reserved;
- memmap=nn[KMG]: set end of memory.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index 017c06a..9757bb7 100644 (file)
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -507,6 +507,7 @@ void __init setup_arch(char **cmdline_p)
                    __pa(&_Level6InterruptVector_text_end), 0);
 #endif
 
+       parse_early_param();
        bootmem_init();
 
        unflatten_and_copy_device_tree();

diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index 5d23697..d70ba93 100644 (file)
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -332,3 +332,53 @@ void free_initmem(void)
 {
        free_initmem_default(-1);
 }
+
+static void __init parse_memmap_one(char *p)
+{
+       char *oldp;
+       unsigned long start_at, mem_size;
+
+       if (!p)
+               return;
+
+       oldp = p;
+       mem_size = memparse(p, &p);
+       if (p == oldp)
+               return;
+
+       switch (*p) {
+       case '@':
+               start_at = memparse(p + 1, &p);
+               add_sysmem_bank(start_at, start_at + mem_size);
+               break;
+
+       case '$':
+               start_at = memparse(p + 1, &p);
+               mem_reserve(start_at, start_at + mem_size, 0);
+               break;
+
+       case 0:
+               mem_reserve(mem_size, 0, 0);
+               break;
+
+       default:
+               pr_warn("Unrecognized memmap syntax: %s\n", p);
+               break;
+       }
+}
+
+static int __init parse_memmap_opt(char *str)
+{
+       while (str) {
+               char *k = strchr(str, ',');
+
+               if (k)
+                       *k++ = 0;
+
+               parse_memmap_one(str);
+               str = k;
+       }
+
+       return 0;
+}
+early_param("memmap", parse_memmap_opt);