ARM DPM: make DSCR bit defs sharable

Move the symbols for these bits from "armv7a.h" to "arm_dpm.h",
where they can be seen and used not just by Cortex-A but also
by the ARM11 (armv6) code.

Change them from bit numbers to bit masks ... this matches the
usage in ARM11 code, and also makes it easier to read.

Rename DSCR_EXT_INT_EN as DSCR_ITR_EN to match the docs; it's
enabling ITR functionality, not external interrupts, so this
changes the name to be less misleading.  (There *IS* a bit
affecting interrupts, and this isn't it.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

3 files changed, 43 insertions, 33 deletions

diff --git a/src/target/arm_dpm.h b/src/target/arm_dpm.h
index c284144a..1f32e8bc 100644
--- a/src/target/arm_dpm.h
+++ b/src/target/arm_dpm.h
@@ -136,4 +136,18 @@ int arm_dpm_write_dirty_registers(struct arm_dpm *, bool bpwp);
 
 void arm_dpm_report_wfar(struct arm_dpm *, uint32_t wfar);
 
+/* Subset of DSCR bits; see ARMv7a arch spec section C10.3.1.
+ * Not all v7 bits are valid in v6.
+ */
+#define DSCR_CORE_HALTED	(1 << 0)
+#define DSCR_CORE_RESTARTED	(1 << 1)
+#define DSCR_ITR_EN		(1 << 13)
+#define DSCR_HALT_DBG_MODE	(1 << 14)
+#define DSCR_MON_DBG_MODE	(1 << 15)
+#define DSCR_INSTR_COMP		(1 << 24)
+#define DSCR_DTR_TX_FULL	(1 << 29)
+#define DSCR_DTR_RX_FULL	(1 << 30)
+
+#define DSCR_ENTRY(dscr) (((dscr) >> 2) & 0xf)
+
 #endif /* __ARM_DPM_H */
diff --git a/src/target/armv7a.h b/src/target/armv7a.h
index 0d5da86f..f089c5c5 100644
--- a/src/target/armv7a.h
+++ b/src/target/armv7a.h
@@ -114,16 +114,6 @@ target_to_armv7a(struct target *target)
 /* See ARMv7a arch spec section C10.8 */
 #define CPUDBG_AUTHSTATUS	0xFB8
 
-/* DSCR bit numbers (See ARMv7a arch spec section 12.4.5) */
-#define DSCR_CORE_HALTED	0
-#define DSCR_CORE_RESTARTED	1
-#define DSCR_EXT_INT_EN		13
-#define DSCR_HALT_DBG_MODE	14
-#define DSCR_MON_DBG_MODE	15
-#define DSCR_INSTR_COMP		24
-#define DSCR_DTR_TX_FULL	29
-#define DSCR_DTR_RX_FULL	30
-
 struct armv7a_algorithm
 {
 	int common_magic;
diff --git a/src/target/cortex_a8.c b/src/target/cortex_a8.c
index 9ca072e0..14cbb9d7 100644
--- a/src/target/cortex_a8.c
+++ b/src/target/cortex_a8.c
@@ -91,8 +91,8 @@ static int cortex_a8_init_debug_access(struct target *target)
 
 /* To reduce needless round-trips, pass in a pointer to the current
  * DSCR value.  Initialize it to zero if you just need to know the
- * value on return from this function; or (1 << DSCR_INSTR_COMP) if
- * you happen to know that no instruction is pending.
+ * value on return from this function; or DSCR_INSTR_COMP if you
+ * happen to know that no instruction is pending.
  */
 static int cortex_a8_exec_opcode(struct target *target,
 		uint32_t opcode, uint32_t *dscr_p)
@@ -107,7 +107,7 @@ static int cortex_a8_exec_opcode(struct target *target,
 	LOG_DEBUG("exec opcode 0x%08" PRIx32, opcode);
 
 	/* Wait for InstrCompl bit to be set */
-	while ((dscr & (1 << DSCR_INSTR_COMP)) == 0)
+	while ((dscr & DSCR_INSTR_COMP) == 0)
 	{
 		retval = mem_ap_read_atomic_u32(swjdp,
 				armv7a->debug_base + CPUDBG_DSCR, &dscr);
@@ -130,7 +130,7 @@ static int cortex_a8_exec_opcode(struct target *target,
 			return retval;
 		}
 	}
-	while ((dscr & (1 << DSCR_INSTR_COMP)) == 0); /* Wait for InstrCompl bit to be set */
+	while ((dscr & DSCR_INSTR_COMP) == 0); /* Wait for InstrCompl bit to be set */
 
 	if (dscr_p)
 		*dscr_p = dscr;
@@ -198,7 +198,7 @@ static int cortex_a8_dap_read_coreregister_u32(struct target *target,
 	}
 
 	/* Wait for DTRRXfull then read DTRRTX */
-	while ((dscr & (1 << DSCR_DTR_TX_FULL)) == 0)
+	while ((dscr & DSCR_DTR_TX_FULL) == 0)
 	{
 		retval = mem_ap_read_atomic_u32(swjdp,
 				armv7a->debug_base + CPUDBG_DSCR, &dscr);
@@ -225,7 +225,7 @@ static int cortex_a8_dap_write_coreregister_u32(struct target *target,
 	/* Check that DCCRX is not full */
 	retval = mem_ap_read_atomic_u32(swjdp,
 				armv7a->debug_base + CPUDBG_DSCR, &dscr);
-	if (dscr & (1 << DSCR_DTR_RX_FULL))
+	if (dscr & DSCR_DTR_RX_FULL)
 	{
 		LOG_ERROR("DSCR_DTR_RX_FULL, dscr 0x%08" PRIx32, dscr);
 		/* Clear DCCRX with MCR(p14, 0, Rd, c0, c5, 0), opcode  0xEE000E15 */
@@ -315,14 +315,14 @@ static int cortex_a8_read_dcc(struct cortex_a8_common *a8, uint32_t *data,
 		uint32_t *dscr_p)
 {
 	struct swjdp_common *swjdp = &a8->armv7a_common.swjdp_info;
-	uint32_t dscr = 1 << DSCR_INSTR_COMP;
+	uint32_t dscr = DSCR_INSTR_COMP;
 	int retval;
 
 	if (dscr_p)
 		dscr = *dscr_p;
 
 	/* Wait for DTRRXfull */
-	while ((dscr & (1 << DSCR_DTR_TX_FULL)) == 0) {
+	while ((dscr & DSCR_DTR_TX_FULL) == 0) {
 		retval = mem_ap_read_atomic_u32(swjdp,
 				a8->armv7a_common.debug_base + CPUDBG_DSCR,
 				&dscr);
@@ -350,10 +350,10 @@ static int cortex_a8_dpm_prepare(struct arm_dpm *dpm)
 		retval = mem_ap_read_atomic_u32(swjdp,
 				a8->armv7a_common.debug_base + CPUDBG_DSCR,
 				&dscr);
-	} while ((dscr & (1 << DSCR_INSTR_COMP)) == 0);
+	} while ((dscr & DSCR_INSTR_COMP) == 0);
 
 	/* this "should never happen" ... */
-	if (dscr & (1 << DSCR_DTR_RX_FULL)) {
+	if (dscr & DSCR_DTR_RX_FULL) {
 		LOG_ERROR("DSCR_DTR_RX_FULL, dscr 0x%08" PRIx32, dscr);
 		/* Clear DCCRX */
 		retval = cortex_a8_exec_opcode(
@@ -376,7 +376,7 @@ static int cortex_a8_instr_write_data_dcc(struct arm_dpm *dpm,
 {
 	struct cortex_a8_common *a8 = dpm_to_a8(dpm);
 	int retval;
-	uint32_t dscr = 1 << DSCR_INSTR_COMP;
+	uint32_t dscr = DSCR_INSTR_COMP;
 
 	retval = cortex_a8_write_dcc(a8, data);
 
@@ -390,7 +390,7 @@ static int cortex_a8_instr_write_data_r0(struct arm_dpm *dpm,
 		uint32_t opcode, uint32_t data)
 {
 	struct cortex_a8_common *a8 = dpm_to_a8(dpm);
-	uint32_t dscr = 1 << DSCR_INSTR_COMP;
+	uint32_t dscr = DSCR_INSTR_COMP;
 	int retval;
 
 	retval = cortex_a8_write_dcc(a8, data);
@@ -413,7 +413,7 @@ static int cortex_a8_instr_write_data_r0(struct arm_dpm *dpm,
 static int cortex_a8_instr_cpsr_sync(struct arm_dpm *dpm)
 {
 	struct target *target = dpm->arm->target;
-	uint32_t dscr = 1 << DSCR_INSTR_COMP;
+	uint32_t dscr = DSCR_INSTR_COMP;
 
 	/* "Prefetch flush" after modifying execution status in CPSR */
 	return cortex_a8_exec_opcode(target,
@@ -426,7 +426,7 @@ static int cortex_a8_instr_read_data_dcc(struct arm_dpm *dpm,
 {
 	struct cortex_a8_common *a8 = dpm_to_a8(dpm);
 	int retval;
-	uint32_t dscr = 1 << DSCR_INSTR_COMP;
+	uint32_t dscr = DSCR_INSTR_COMP;
 
 	/* the opcode, writing data to DCC */
 	retval = cortex_a8_exec_opcode(
@@ -442,7 +442,7 @@ static int cortex_a8_instr_read_data_r0(struct arm_dpm *dpm,
 		uint32_t opcode, uint32_t *data)
 {
 	struct cortex_a8_common *a8 = dpm_to_a8(dpm);
-	uint32_t dscr = 1 << DSCR_INSTR_COMP;
+	uint32_t dscr = DSCR_INSTR_COMP;
 	int retval;
 
 	/* the opcode, writing data to R0 */
@@ -639,7 +639,7 @@ static int cortex_a8_halt(struct target *target)
 	 */
 	mem_ap_read_atomic_u32(swjdp, armv7a->debug_base + CPUDBG_DSCR, &dscr);
 	retval = mem_ap_write_atomic_u32(swjdp,
-		armv7a->debug_base + CPUDBG_DSCR, dscr | (1 << DSCR_HALT_DBG_MODE));
+		armv7a->debug_base + CPUDBG_DSCR, dscr | DSCR_HALT_DBG_MODE);
 
 	if (retval != ERROR_OK)
 		goto out;
@@ -647,7 +647,7 @@ static int cortex_a8_halt(struct target *target)
 	do {
 		mem_ap_read_atomic_u32(swjdp,
 			armv7a->debug_base + CPUDBG_DSCR, &dscr);
-	} while ((dscr & (1 << DSCR_CORE_HALTED)) == 0);
+	} while ((dscr & DSCR_CORE_HALTED) == 0);
 
 	target->debug_reason = DBG_REASON_DBGRQ;
 
@@ -742,13 +742,18 @@ static int cortex_a8_resume(struct target *target, int current,
 	}
 
 #endif
-	/* Restart core and wait for it to be started */
+	/* Restart core and wait for it to be started
+	 * NOTE: this clears DSCR_ITR_EN and other bits.
+	 *
+	 * REVISIT: for single stepping, we probably want to
+	 * disable IRQs by default, with optional override...
+	 */
 	mem_ap_write_atomic_u32(swjdp, armv7a->debug_base + CPUDBG_DRCR, 0x2);
 
 	do {
 		mem_ap_read_atomic_u32(swjdp,
 			armv7a->debug_base + CPUDBG_DSCR, &dscr);
-	} while ((dscr & (1 << DSCR_CORE_RESTARTED)) == 0);
+	} while ((dscr & DSCR_CORE_RESTARTED) == 0);
 
 	target->debug_reason = DBG_REASON_NOTHALTED;
 	target->state = TARGET_RUNNING;
@@ -788,7 +793,6 @@ static int cortex_a8_debug_entry(struct target *target)
 
 	LOG_DEBUG("dscr = 0x%08" PRIx32, cortex_a8->cpudbg_dscr);
 
-	/* Enable the ITR execution once we are in debug mode */
 	mem_ap_read_atomic_u32(swjdp,
 				armv7a->debug_base + CPUDBG_DSCR, &dscr);
 
@@ -797,12 +801,13 @@ static int cortex_a8_debug_entry(struct target *target)
 	 * Synchronization Barrier:  ARMV4_5_MCR(15, 0, 0, 7, 10, 4).
 	 */
 
-	dscr |= (1 << DSCR_EXT_INT_EN);
+	/* Enable the ITR execution once we are in debug mode */
+	dscr |= DSCR_ITR_EN;
 	retval = mem_ap_write_atomic_u32(swjdp,
 			armv7a->debug_base + CPUDBG_DSCR, dscr);
 
 	/* Examine debug reason */
-	switch ((cortex_a8->cpudbg_dscr >> 2)&0xF)
+	switch (DSCR_ENTRY(cortex_a8->cpudbg_dscr))
 	{
 		case 0:		/* DRCR[0] write */
 		case 4:		/* EDBGRQ */
@@ -1005,7 +1010,8 @@ static int cortex_a8_step(struct target *target, int current, uint32_t address,
 	}
 
 	cortex_a8_unset_breakpoint(target, &stepbreakpoint);
-	if (timeout > 0) target->debug_reason = DBG_REASON_BREAKPOINT;
+	if (timeout > 0)
+		target->debug_reason = DBG_REASON_BREAKPOINT;
 
 	if (breakpoint)
 		cortex_a8_set_breakpoint(target, breakpoint, 0);