armv7m: detect floating point feature

[fw/openocd] / src / target / cortex_m.c

diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c
index 76e197c116d904fe8c2fb046138b818363986f12..488899cbe9430ac814db859efb9219bc2d0d38d5 100644 (file)
--- a/src/target/cortex_m.c
+++ b/src/target/cortex_m.c
@@ -1756,13 +1756,20 @@ fail1:
         */
 }
 
+#define MVFR0 0xe000ef40
+#define MVFR1 0xe000ef44
+
+#define MVFR0_DEFAULT_M4 0x10110021
+#define MVFR1_DEFAULT_M4 0x11000011
+
 int cortex_m3_examine(struct target *target)
 {
        int retval;
-       uint32_t cpuid, fpcr;
+       uint32_t cpuid, fpcr, mvfr0, mvfr1;
        int i;
        struct cortex_m3_common *cortex_m3 = target_to_cm3(target);
        struct adiv5_dap *swjdp = &cortex_m3->armv7m.dap;
+       struct armv7m_common *armv7m = target_to_armv7m(target);
 
        retval = ahbap_debugport_init(swjdp);
        if (retval != ERROR_OK)
@@ -1783,6 +1790,17 @@ int cortex_m3_examine(struct target *target)
                                i, (uint8_t)((cpuid >> 20) & 0xf), (uint8_t)((cpuid >> 0) & 0xf));
                LOG_DEBUG("cpuid: 0x%8.8" PRIx32 "", cpuid);
 
+               /* test for floating point feature on cortex-m4 */
+               if (i == 4) {
+                       target_read_u32(target, MVFR0, &mvfr0);
+                       target_read_u32(target, MVFR1, &mvfr1);
+
+                       if ((mvfr0 == MVFR0_DEFAULT_M4) && (mvfr1 == MVFR1_DEFAULT_M4)) {
+                               LOG_DEBUG("Cortex-M%d floating point feature FPv4_SP found", i);
+                               armv7m->fp_feature = FPv4_SP;
+                       }
+               }
+
                /* NOTE: FPB and DWT are both optional. */
 
                /* Setup FPB */