icnss2: Register early SSR notification for WPSS

Consider a scenario where WPSS watchdog happens RPROC driver
gets interrupt and notified to GLINK layer(underlying layer
within QMI) now if ICNSS driver tries to send any QMI message
it will fail and ASSERTS. If ICNSS would have received legacy
SSR notifier it could have ignore ASSERT. But there is a race
where ICNSS sends QMI message between GLINK layer received
WPSS down and ICNSS receives WPSS down and ASSERT of QMI
failure cannot be avoided. To resolve this register early
SSR notifier from ICNSS which notifies about WPSS down to
ICNSS before GLINK. Based on that ICNSS can either avoid
sending QMI message or can ignore ASSERT.

Change-Id: Iada85a1bfff6ae420123afc5f86a738b662171fc

icnss2/main.c

@@ -1910,6 +1910,24 @@ static char *icnss_qcom_ssr_notify_state_to_str(enum qcom_ssr_notify_type code)
 	}
 };
 
+static int icnss_wpss_early_notifier_nb(struct notifier_block *nb,
+					unsigned long code,
+					void *data)
+{
+	struct icnss_priv *priv = container_of(nb, struct icnss_priv,
+					       wpss_early_ssr_nb);
+
+	icnss_pr_vdbg("WPSS-EARLY-Notify: event %s(%lu)\n",
+		      icnss_qcom_ssr_notify_state_to_str(code), code);
+
+	if (code == QCOM_SSR_BEFORE_SHUTDOWN) {
+		set_bit(ICNSS_FW_DOWN, &priv->state);
+		icnss_ignore_fw_timeout(true);
+	}
+
+	return NOTIFY_DONE;
+}
+
 static int icnss_wpss_notifier_nb(struct notifier_block *nb,
 				  unsigned long code,
 				  void *data)
@@ -2045,6 +2063,24 @@ out:
 	return NOTIFY_OK;
 }
 
+static int icnss_wpss_early_ssr_register_notifier(struct icnss_priv *priv)
+{
+	int ret = 0;
+
+	priv->wpss_early_ssr_nb.notifier_call = icnss_wpss_early_notifier_nb;
+
+	priv->wpss_early_notify_handler =
+		qcom_register_early_ssr_notifier("wpss",
+						 &priv->wpss_early_ssr_nb);
+
+	if (IS_ERR(priv->wpss_early_notify_handler)) {
+		ret = PTR_ERR(priv->wpss_early_notify_handler);
+		icnss_pr_err("WPSS register early notifier failed: %d\n", ret);
+	}
+
+	return ret;
+}
+
 static int icnss_wpss_ssr_register_notifier(struct icnss_priv *priv)
 {
 	int ret = 0;
@@ -2093,6 +2129,16 @@ static int icnss_modem_ssr_register_notifier(struct icnss_priv *priv)
 	return ret;
 }
 
+static void icnss_wpss_early_ssr_unregister_notifier(struct icnss_priv *priv)
+{
+	if (IS_ERR(priv->wpss_early_notify_handler))
+		return;
+
+	qcom_unregister_early_ssr_notifier(priv->wpss_early_notify_handler,
+					   &priv->wpss_early_ssr_nb);
+	priv->wpss_early_notify_handler = NULL;
+}
+
 static int icnss_wpss_ssr_unregister_notifier(struct icnss_priv *priv)
 {
 	if (!test_and_clear_bit(ICNSS_SSR_REGISTERED, &priv->state))
@@ -2367,6 +2413,7 @@ static int icnss_enable_recovery(struct icnss_priv *priv)
 		return ret;
 
 	if (priv->device_id == WCN6750_DEVICE_ID) {
+		icnss_wpss_early_ssr_register_notifier(priv);
 		icnss_wpss_ssr_register_notifier(priv);
 		return 0;
 	}
@@ -4286,6 +4333,7 @@ static int icnss_remove(struct platform_device *pdev)
 	icnss_destroy_ramdump_device(priv->msa0_dump_dev);
 
 	if (priv->device_id == WCN6750_DEVICE_ID) {
+		icnss_wpss_early_ssr_unregister_notifier(priv);
 		icnss_wpss_ssr_unregister_notifier(priv);
 		rproc_put(priv->rproc);
 		icnss_destroy_ramdump_device(priv->m3_dump_phyareg);

icnss2/main.h

@@ -419,8 +419,10 @@ struct icnss_priv {
 	struct icnss_stats stats;
 	void *modem_notify_handler;
 	void *wpss_notify_handler;
+	void *wpss_early_notify_handler;
 	struct notifier_block modem_ssr_nb;
 	struct notifier_block wpss_ssr_nb;
+	struct notifier_block wpss_early_ssr_nb;
 	uint32_t diag_reg_read_addr;
 	uint32_t diag_reg_read_mem_type;
 	uint32_t diag_reg_read_len;