From 861df4574d351731b8651ff5cd71a6d51e491d3f Mon Sep 17 00:00:00 2001
From: Mathias K <kesmtp@freenet.de>
Date: Thu, 15 Mar 2012 14:58:32 +0100
Subject: [PATCH] armv7m: detect floating point feature

This patch add fp feature detection on cortex-m4.

Change-Id: I99e9d1bf5534630a22b8ad9c878165683db2d0ba
Signed-off-by: Mathias K <kesmtp@freenet.de>
Reviewed-on: http://openocd.zylin.com/524
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
---
 src/target/armv7m.c   |  1 +
 src/target/armv7m.h   |  7 +++++++
 src/target/cortex_m.c | 20 +++++++++++++++++++-
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/target/armv7m.c b/src/target/armv7m.c
index 258653eb..780e81b5 100644
--- a/src/target/armv7m.c
+++ b/src/target/armv7m.c
@@ -578,6 +578,7 @@ int armv7m_init_arch_info(struct target *target, struct armv7m_common *armv7m)
 	struct arm *arm = &armv7m->arm;
 
 	armv7m->common_magic = ARMV7M_COMMON_MAGIC;
+	armv7m->fp_feature = FP_NONE;
 
 	arm->core_type = ARM_MODE_THREAD;
 	arm->arch_info = armv7m;
diff --git a/src/target/armv7m.h b/src/target/armv7m.h
index 35bd62a6..827a8799 100644
--- a/src/target/armv7m.h
+++ b/src/target/armv7m.h
@@ -97,6 +97,11 @@ enum {
 	ARMV7M_LAST_REG,
 };
 
+enum {
+	FP_NONE = 0,
+	FPv4_SP,
+};
+
 #define ARMV7M_COMMON_MAGIC 0x2A452A45
 
 struct armv7m_common {
@@ -108,6 +113,8 @@ struct armv7m_common {
 	int exception_number;
 	struct adiv5_dap dap;
 
+	int fp_feature;
+
 	uint32_t demcr;
 
 	/* Direct processor core register read and writes */
diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c
index 76e197c1..488899cb 100644
--- 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 */
-- 
2.39.5