remoteproc: add IPA notification to q6v5 driver

Set up a subdev in the q6v5 modem remoteproc driver that generates
event notifications for the IPA driver to use for initialization and
recovery following a modem shutdown or crash.

A pair of new functions provides a way for the IPA driver to register
and deregister a notification callback function that will be called
whenever modem events (about to boot, running, about to shut down,
etc.) occur.  A void pointer value (provided by the IPA driver at
registration time) and an event type are supplied to the callback
function.

One event, MODEM_REMOVING, is signaled whenever the q6v5 driver is
about to remove the notification subdevice.  It requires the IPA
driver de-register its callback.

This sub-device is only used by the modem subsystem (MSS) driver,
so the code that adds the new subdev and allows registration and
deregistration of the notifier is found in "qcom_q6v6_mss.c".

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 85 insertions, 0 deletions

diff --git a/drivers/remoteproc/qcom_q6v5_ipa_notify.c b/drivers/remoteproc/qcom_q6v5_ipa_notify.c
new file mode 100644
index 000000000000..e1c10a128bfd
--- /dev/null
+++ b/drivers/remoteproc/qcom_q6v5_ipa_notify.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Qualcomm IPA notification subdev support
+ *
+ * Copyright (C) 2019 Linaro Ltd.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/remoteproc.h>
+#include <linux/remoteproc/qcom_q6v5_ipa_notify.h>
+
+static void
+ipa_notify_common(struct rproc_subdev *subdev, enum qcom_rproc_event event)
+{
+	struct qcom_rproc_ipa_notify *ipa_notify;
+	qcom_ipa_notify_t notify;
+
+	ipa_notify = container_of(subdev, struct qcom_rproc_ipa_notify, subdev);
+	notify = ipa_notify->notify;
+	if (notify)
+		notify(ipa_notify->data, event);
+}
+
+static int ipa_notify_prepare(struct rproc_subdev *subdev)
+{
+	ipa_notify_common(subdev, MODEM_STARTING);
+
+	return 0;
+}
+
+static int ipa_notify_start(struct rproc_subdev *subdev)
+{
+	ipa_notify_common(subdev, MODEM_RUNNING);
+
+	return 0;
+}
+
+static void ipa_notify_stop(struct rproc_subdev *subdev, bool crashed)
+
+{
+	ipa_notify_common(subdev, crashed ? MODEM_CRASHED : MODEM_STOPPING);
+}
+
+static void ipa_notify_unprepare(struct rproc_subdev *subdev)
+{
+	ipa_notify_common(subdev, MODEM_OFFLINE);
+}
+
+static void ipa_notify_removing(struct rproc_subdev *subdev)
+{
+	ipa_notify_common(subdev, MODEM_REMOVING);
+}
+
+/* Register the IPA notification subdevice with the Q6V5 MSS remoteproc */
+void qcom_add_ipa_notify_subdev(struct rproc *rproc,
+		struct qcom_rproc_ipa_notify *ipa_notify)
+{
+	ipa_notify->notify = NULL;
+	ipa_notify->data = NULL;
+	ipa_notify->subdev.prepare = ipa_notify_prepare;
+	ipa_notify->subdev.start = ipa_notify_start;
+	ipa_notify->subdev.stop = ipa_notify_stop;
+	ipa_notify->subdev.unprepare = ipa_notify_unprepare;
+
+	rproc_add_subdev(rproc, &ipa_notify->subdev);
+}
+EXPORT_SYMBOL_GPL(qcom_add_ipa_notify_subdev);
+
+/* Remove the IPA notification subdevice */
+void qcom_remove_ipa_notify_subdev(struct rproc *rproc,
+		struct qcom_rproc_ipa_notify *ipa_notify)
+{
+	struct rproc_subdev *subdev = &ipa_notify->subdev;
+
+	ipa_notify_removing(subdev);
+
+	rproc_remove_subdev(rproc, subdev);
+	ipa_notify->notify = NULL;	/* Make it obvious */
+}
+EXPORT_SYMBOL_GPL(qcom_remove_ipa_notify_subdev);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Qualcomm IPA notification remoteproc subdev");