1 files changed, 19 insertions, 3 deletions

diff --git a/arch/arm/kernel/tcm.c b/arch/arm/kernel/tcm.c
index 30e302d33e0a..01ec453bb924 100644
--- a/arch/arm/kernel/tcm.c
+++ b/arch/arm/kernel/tcm.c
@@ -180,9 +180,9 @@ static int __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
  */
 void __init tcm_init(void)
 {
-        u32 tcm_status = read_cpuid_tcmstatus();
-        u8 dtcm_banks = (tcm_status >> 16) & 0x03;
-        u8 itcm_banks = (tcm_status & 0x03);
+        u32 tcm_status;
+        u8 dtcm_banks;
+        u8 itcm_banks;
         size_t dtcm_code_sz = &__edtcm_data - &__sdtcm_data;
         size_t itcm_code_sz = &__eitcm_text - &__sitcm_text;
         char *start;
@@ -191,6 +191,22 @@ void __init tcm_init(void)
         int ret;
         int i;
 
+        /*
+         * Prior to ARMv5 there is no TCM, and trying to read the status
+         * register will hang the processor.
+         */
+        if (cpu_architecture() < CPU_ARCH_ARMv5) {
+                if (dtcm_code_sz || itcm_code_sz)
+                        pr_info("CPU TCM: %u bytes of DTCM and %u bytes of "
+                                "ITCM code compiled in, but no TCM present "
+                                "in pre-v5 CPU\n", dtcm_code_sz, itcm_code_sz);
+                return;
+        }
+
+        tcm_status = read_cpuid_tcmstatus();
+        dtcm_banks = (tcm_status >> 16) & 0x03;
+        itcm_banks = (tcm_status & 0x03);
+
         /* Values greater than 2 for D/ITCM banks are "reserved" */
         if (dtcm_banks > 2)
                 dtcm_banks = 0;