intel_l3_parity: Support a daemonic mode

v2: Add a comment explaining the dangers of directly accessing the DFT
register (Daniel)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>

tools/intel_l3_parity.h

@@ -0,0 +1,31 @@
+#ifndef INTEL_L3_PARITY_H_
+#define INTEL_L3_PARITY_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+
+struct l3_parity {
+	struct udev *udev;
+	struct udev_monitor *uevent_monitor;
+	int fd;
+	fd_set fdset;
+};
+
+struct l3_location {
+	uint8_t slice;
+	uint16_t row;
+	uint8_t bank;
+	uint8_t subbank;
+};
+
+#if HAVE_UDEV
+int l3_uevent_setup(struct l3_parity *par);
+/* Listens (blocks) for an l3 parity event. Returns the location of the error. */
+int l3_listen(struct l3_parity *par, bool daemon, struct l3_location *loc);
+#define l3_uevent_teardown(par) {}
+#else
+#define l3_uevent_setup(par, daemon, loc) -1
+#define l3_listen(par) -1
+#endif
+
+#endif