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>

drivers/remoteproc/Kconfig

@@ -167,6 +167,12 @@ config QCOM_Q6V5_WCSS
 	  Say y here to support the Qualcomm Peripheral Image Loader for the
 	  Hexagon V5 based WCSS remote processors.
 
+config QCOM_Q6V5_IPA_NOTIFY
+	tristate
+	depends on QCOM_IPA
+	depends on QCOM_Q6V5_MSS
+	default QCOM_IPA
+
 config QCOM_SYSMON
 	tristate "Qualcomm sysmon driver"
 	depends on RPMSG

drivers/remoteproc/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_QCOM_Q6V5_ADSP)		+= qcom_q6v5_adsp.o
 obj-$(CONFIG_QCOM_Q6V5_MSS)		+= qcom_q6v5_mss.o
 obj-$(CONFIG_QCOM_Q6V5_PAS)		+= qcom_q6v5_pas.o
 obj-$(CONFIG_QCOM_Q6V5_WCSS)		+= qcom_q6v5_wcss.o
+obj-$(CONFIG_QCOM_Q6V5_IPA_NOTIFY)	+= qcom_q6v5_ipa_notify.o
 obj-$(CONFIG_QCOM_SYSMON)		+= qcom_sysmon.o
 obj-$(CONFIG_QCOM_WCNSS_PIL)		+= qcom_wcnss_pil.o
 qcom_wcnss_pil-y			+= qcom_wcnss.o

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");

drivers/remoteproc/qcom_q6v5_mss.c

@@ -22,6 +22,7 @@
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/remoteproc.h>
+#include "linux/remoteproc/qcom_q6v5_ipa_notify.h"
 #include <linux/reset.h>
 #include <linux/soc/qcom/mdt_loader.h>
 #include <linux/iopoll.h>
@@ -201,6 +202,7 @@ struct q6v5 {
 	struct qcom_rproc_glink glink_subdev;
 	struct qcom_rproc_subdev smd_subdev;
 	struct qcom_rproc_ssr ssr_subdev;
+	struct qcom_rproc_ipa_notify ipa_notify_subdev;
 	struct qcom_sysmon *sysmon;
 	bool need_mem_protection;
 	bool has_alt_reset;
@@ -1540,6 +1542,39 @@ static int q6v5_alloc_memory_region(struct q6v5 *qproc)
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_QCOM_Q6V5_IPA_NOTIFY)
+
+/* Register IPA notification function */
+int qcom_register_ipa_notify(struct rproc *rproc, qcom_ipa_notify_t notify,
+			     void *data)
+{
+	struct qcom_rproc_ipa_notify *ipa_notify;
+	struct q6v5 *qproc = rproc->priv;
+
+	if (!notify)
+		return -EINVAL;
+
+	ipa_notify = &qproc->ipa_notify_subdev;
+	if (ipa_notify->notify)
+		return -EBUSY;
+
+	ipa_notify->notify = notify;
+	ipa_notify->data = data;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qcom_register_ipa_notify);
+
+/* Deregister IPA notification function */
+void qcom_deregister_ipa_notify(struct rproc *rproc)
+{
+	struct q6v5 *qproc = rproc->priv;
+
+	qproc->ipa_notify_subdev.notify = NULL;
+}
+EXPORT_SYMBOL_GPL(qcom_deregister_ipa_notify);
+#endif /* !IS_ENABLED(CONFIG_QCOM_Q6V5_IPA_NOTIFY) */
+
 static int q6v5_probe(struct platform_device *pdev)
 {
 	const struct rproc_hexagon_res *desc;
@@ -1664,6 +1699,7 @@ static int q6v5_probe(struct platform_device *pdev)
 	qcom_add_glink_subdev(rproc, &qproc->glink_subdev);
 	qcom_add_smd_subdev(rproc, &qproc->smd_subdev);
 	qcom_add_ssr_subdev(rproc, &qproc->ssr_subdev, "mpss");
+	qcom_add_ipa_notify_subdev(rproc, &qproc->ipa_notify_subdev);
 	qproc->sysmon = qcom_add_sysmon_subdev(rproc, "modem", 0x12);
 	if (IS_ERR(qproc->sysmon)) {
 		ret = PTR_ERR(qproc->sysmon);
@@ -1677,6 +1713,7 @@ static int q6v5_probe(struct platform_device *pdev)
 	return 0;
 
 detach_proxy_pds:
+	qcom_remove_ipa_notify_subdev(qproc->rproc, &qproc->ipa_notify_subdev);
 	q6v5_pds_detach(qproc, qproc->proxy_pds, qproc->proxy_pd_count);
 detach_active_pds:
 	q6v5_pds_detach(qproc, qproc->active_pds, qproc->active_pd_count);
@@ -1693,6 +1730,7 @@ static int q6v5_remove(struct platform_device *pdev)
 	rproc_del(qproc->rproc);
 
 	qcom_remove_sysmon_subdev(qproc->sysmon);
+	qcom_remove_ipa_notify_subdev(qproc->rproc, &qproc->ipa_notify_subdev);
 	qcom_remove_glink_subdev(qproc->rproc, &qproc->glink_subdev);
 	qcom_remove_smd_subdev(qproc->rproc, &qproc->smd_subdev);
 	qcom_remove_ssr_subdev(qproc->rproc, &qproc->ssr_subdev);

include/linux/remoteproc/qcom_q6v5_ipa_notify.h

@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Copyright (C) 2019 Linaro Ltd. */
+
+#ifndef __QCOM_Q6V5_IPA_NOTIFY_H__
+#define __QCOM_Q6V5_IPA_NOTIFY_H__
+
+#if IS_ENABLED(CONFIG_QCOM_Q6V5_IPA_NOTIFY)
+
+#include <linux/remoteproc.h>
+
+enum qcom_rproc_event {
+	MODEM_STARTING	= 0,	/* Modem is about to be started */
+	MODEM_RUNNING	= 1,	/* Startup complete; modem is operational */
+	MODEM_STOPPING	= 2,	/* Modem is about to shut down */
+	MODEM_CRASHED	= 3,	/* Modem has crashed (implies stopping) */
+	MODEM_OFFLINE	= 4,	/* Modem is now offline */
+	MODEM_REMOVING	= 5,	/* Modem is about to be removed */
+};
+
+typedef void (*qcom_ipa_notify_t)(void *data, enum qcom_rproc_event event);
+
+struct qcom_rproc_ipa_notify {
+	struct rproc_subdev subdev;
+
+	qcom_ipa_notify_t notify;
+	void *data;
+};
+
+/**
+ * qcom_add_ipa_notify_subdev() - Register IPA notification subdevice
+ * @rproc:	rproc handle
+ * @ipa_notify:	IPA notification subdevice handle
+ *
+ * Register the @ipa_notify subdevice with the @rproc so modem events
+ * can be sent to IPA when they occur.
+ *
+ * This is defined in "qcom_q6v5_ipa_notify.c".
+ */
+void qcom_add_ipa_notify_subdev(struct rproc *rproc,
+		struct qcom_rproc_ipa_notify *ipa_notify);
+
+/**
+ * qcom_remove_ipa_notify_subdev() - Remove IPA SSR subdevice
+ * @rproc:	rproc handle
+ * @ipa_notify:	IPA notification subdevice handle
+ *
+ * This is defined in "qcom_q6v5_ipa_notify.c".
+ */
+void qcom_remove_ipa_notify_subdev(struct rproc *rproc,
+		struct qcom_rproc_ipa_notify *ipa_notify);
+
+/**
+ * qcom_register_ipa_notify() - Register IPA notification function
+ * @rproc:	Remote processor handle
+ * @notify:	Non-null IPA notification callback function pointer
+ * @data:	Data supplied to IPA notification callback function
+ *
+ * @Return: 0 if successful, or a negative error code otherwise
+ *
+ * This is defined in "qcom_q6v5_mss.c".
+ */
+int qcom_register_ipa_notify(struct rproc *rproc, qcom_ipa_notify_t notify,
+			     void *data);
+/**
+ * qcom_deregister_ipa_notify() - Deregister IPA notification function
+ * @rproc:	Remote processor handle
+ *
+ * This is defined in "qcom_q6v5_mss.c".
+ */
+void qcom_deregister_ipa_notify(struct rproc *rproc);
+
+#else /* !IS_ENABLED(CONFIG_QCOM_Q6V5_IPA_NOTIFY) */
+
+struct qcom_rproc_ipa_notify { /* empty */ };
+
+#define qcom_add_ipa_notify_subdev(rproc, ipa_notify)		/* no-op */
+#define qcom_remove_ipa_notify_subdev(rproc, ipa_notify)	/* no-op */
+
+#endif /* !IS_ENABLED(CONFIG_QCOM_Q6V5_IPA_NOTIFY) */
+
+#endif /* !__QCOM_Q6V5_IPA_NOTIFY_H__ */