1 files changed, 37 insertions, 0 deletions

diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index f38badeb7747..7d12af1317f1 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -212,6 +212,42 @@ static int __init parse_bootparam(const bp_tag_t* tag)
 #ifdef CONFIG_OF
 bool __initdata dt_memory_scan = false;
 
+#if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY
+unsigned long xtensa_kio_paddr = XCHAL_KIO_DEFAULT_PADDR;
+EXPORT_SYMBOL(xtensa_kio_paddr);
+
+static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
+                int depth, void *data)
+{
+        const __be32 *ranges;
+        unsigned long len;
+
+        if (depth > 1)
+                return 0;
+
+        if (!of_flat_dt_is_compatible(node, "simple-bus"))
+                return 0;
+
+        ranges = of_get_flat_dt_prop(node, "ranges", &len);
+        if (!ranges)
+                return 1;
+        if (len == 0)
+                return 1;
+
+        xtensa_kio_paddr = of_read_ulong(ranges+1, 1);
+        /* round down to nearest 256MB boundary */
+        xtensa_kio_paddr &= 0xf0000000;
+
+        return 1;
+}
+#else
+static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
+                int depth, void *data)
+{
+        return 1;
+}
+#endif
+
 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
 {
         if (!dt_memory_scan)
@@ -232,6 +268,7 @@ void __init early_init_devtree(void *params)
                 dt_memory_scan = true;
 
         early_init_dt_scan(params);
+        of_scan_flat_dt(xtensa_dt_io_area, NULL);
 
         if (!command_line[0])
                 strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);