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>

1 files changed, 108 insertions, 0 deletions

diff --git a/tools/intel_l3_udev_listener.c b/tools/intel_l3_udev_listener.c
new file mode 100644
index 00000000..c50820ca
--- /dev/null
+++ b/tools/intel_l3_udev_listener.c
@@ -0,0 +1,108 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#if HAVE_UDEV
+#include <libudev.h>
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#include <syslog.h>
+#include "i915_drm.h"
+#include "intel_l3_parity.h"
+
+#ifndef I915_L3_PARITY_UEVENT
+#define I915_L3_PARITY_UEVENT "L3_PARITY_ERROR"
+#endif
+
+int l3_uevent_setup(struct l3_parity *par)
+{
+	struct udev *udev;
+	struct udev_monitor *uevent_monitor;
+	fd_set fdset;
+	int fd, ret = -1;
+
+	udev = udev_new();
+	if (!udev) {
+		return -1;
+	}
+
+	uevent_monitor = udev_monitor_new_from_netlink(udev, "udev");
+	if (!uevent_monitor)
+		goto err_out;
+
+	ret = udev_monitor_filter_add_match_subsystem_devtype(uevent_monitor, "drm", "drm_minor");
+	if (ret < 0)
+		goto err_out;
+
+	ret = udev_monitor_enable_receiving(uevent_monitor);
+	if (ret < 0)
+		goto err_out;
+
+	fd = udev_monitor_get_fd(uevent_monitor);
+	FD_ZERO(&fdset);
+	FD_SET(fd, &fdset);
+
+	par->udev = udev;
+	par->fd = fd;
+	par->fdset = fdset;
+	par->uevent_monitor = uevent_monitor;
+	return 0;
+
+err_out:
+	udev_unref(udev);
+	return ret;
+}
+
+int l3_listen(struct l3_parity *par, bool daemon, struct l3_location *loc)
+{
+	struct udev_device *udev_dev;
+	const char *parity_status;
+	char *err_msg;
+	int ret;
+
+again:
+	ret = select(par->fd + 1, &par->fdset, NULL, NULL, NULL);
+	/* Number of bits set is returned, must be >= 1 */
+	if (ret <= 0) {
+		return ret;
+	}
+
+	assert(FD_ISSET(par->fd, &par->fdset));
+
+	udev_dev = udev_monitor_receive_device(par->uevent_monitor);
+	if (!udev_dev)
+		return -1;
+
+	parity_status = udev_device_get_property_value(udev_dev, I915_L3_PARITY_UEVENT);
+	if (strncmp(parity_status, "1", 1))
+		goto again;
+
+	loc->slice = atoi(udev_device_get_property_value(udev_dev, "SLICE"));
+	loc->row = atoi(udev_device_get_property_value(udev_dev, "ROW"));
+	loc->bank = atoi(udev_device_get_property_value(udev_dev, "BANK"));
+	loc->subbank = atoi(udev_device_get_property_value(udev_dev, "SUBBANK"));
+
+	udev_device_unref(udev_dev);
+
+	asprintf(&err_msg, "Parity error detected on: %d,%d,%d,%d. "
+			"Try to run intel_l3_parity -r %d -b %d -s %d -w %d -d",
+			loc->slice, loc->row, loc->bank, loc->subbank,
+			loc->row, loc->bank, loc->subbank, loc->slice);
+	if (daemon) {
+		syslog(LOG_INFO, "%s\n", err_msg);
+		goto again;
+	}
+
+	fprintf(stderr, "%s\n", err_msg);
+
+	free(err_msg);
+
+	return 0;
+}
+#endif