htm: Toggle debug bit so trace actually starts

Without this the trace doesn't actually run.

In the past, it was only running once the user did another htm command
which toggled this bit during the probe.

Signed-off-by: Michael Neuling <mikey@neuling.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/libpdbg/htm.c b/libpdbg/htm.c
index 790ca4f..4003ac3 100644
--- a/libpdbg/htm.c
+++ b/libpdbg/htm.c
@@ -720,6 +720,31 @@ static int do_htm_reset(struct htm *htm)
 	return 1;
 }
 
+/* Stolen from p8chip.c */
+#define RAS_MODE_REG			0x1
+#define  MR_THREAD_IN_DEBUG		PPC_BIT(43)
+static int htm_toggle_debug_bit(struct htm *htm)
+{
+	struct pdbg_target *target;
+	uint64_t reg;
+
+	/* FIXME: this is a hack for P8 */
+	if (!dt_node_is_compatible(htm->target.parent, "ibm,power8-core")) {
+		PR_ERROR("HTM is POWER8 only currently\n");
+		return -1;
+	}
+
+	pdbg_for_each_target("thread", htm->target.parent, target) {
+		if (pdbg_target_index(target) == 0) {
+			/* Need to set this bit to ensure HTM starts */
+			pib_read (target, RAS_MODE_REG, &reg);
+			pib_write(target, RAS_MODE_REG, reg | MR_THREAD_IN_DEBUG);
+			pib_write(target, RAS_MODE_REG, reg);
+		}
+	}
+	return 0;
+}
+
 static int do_htm_start(struct htm *htm)
 {
 	struct htm_status status;
@@ -742,6 +767,9 @@ static int do_htm_start(struct htm *htm)
 	if (HTM_ERR(pib_write(&htm->target, HTM_SCOM_TRIGGER, HTM_TRIG_START)))
 		return -1;
 
+	if (htm_toggle_debug_bit(htm))
+		return -1;
+
 	/*
 	 * Instead of the HTM_TRIG_START, this is where you might want
 	 * to call do_adu_magic()