From: Anson Huang

The System Controller Firmware (SCFW) controls RTC, thermal and WDOG etc.,
these resources' interrupt function are managed by SCU. When any IRQ
pending, SCU will notify Linux via MU general interrupt channel #3, and Linux
kernel needs to call SCU APIs to get IRQ status and notify each module to
handle the interrupt.

Since there is no data transmission for SCU IRQ notification, so doorbell mode
is used for this MU channel, and SCU driver will use notifier mechanism to
broadcast to every module which registers the SCU block notifier.

Signed-off-by: Anson Huang <redacted>
---
Changes since V3:
	- use alias to get general MU interrupt channel id and then get resource
ID,
	  this is to support different MU instance;
	- add return value check for imx_scu_enable_general_irq_channel().
---
 drivers/firmware/imx/imx-scu.c   | 116
+++++++++++++++++++++++++++++++++++++++

Generally I would suggest to put scu irq support into another separate file under
The same folder to make code clean from function point of view.

I feel it a bit strange to put this mu id in struct imx_sc_ipc.

No packed needed for this one

+	} data;
+};
+
 static struct imx_sc_ipc *imx_sc_ipc_handle;
+static struct work_struct imx_sc_general_irq_work; static
+BLOCKING_NOTIFIER_HEAD(imx_scu_notifier_chain);

Imx_scu_irq_xxx

 static inline int imx_sc_to_linux_errno(int errno)  { @@ -194,9 +214,90 @@
int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)  }
EXPORT_SYMBOL(imx_scu_call_rpc);

+int imx_scu_register_notifier(struct notifier_block *nb) {
+	return blocking_notifier_chain_register(&imx_scu_notifier_chain, nb);
+} EXPORT_SYMBOL(imx_scu_register_notifier);
+
+int imx_scu_unregister_notifier(struct notifier_block *nb) {
+	return blocking_notifier_chain_unregister(&imx_scu_notifier_chain,
+nb); } EXPORT_SYMBOL(imx_scu_unregister_notifier);
+
+static int imx_scu_notifier_call_chain(unsigned long status, u8 *group)
+{
+	return blocking_notifier_call_chain(&imx_scu_notifier_chain,
+					    status, (void *)group);
+}
+
+static void imx_scu_general_irq_work_handler(struct work_struct *work)
+{
+	struct imx_sc_msg_irq_get_status msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+	u32 irq_status;
+	int ret;
+	u8 i;
+
+	for (i = 0; i < IMX_SC_IRQ_NUM_GROUP; i++) {

Do we need to support all irq group?

+		hdr->ver = IMX_SC_RPC_VERSION;
+		hdr->svc = IMX_SC_RPC_SVC_IRQ;
+		hdr->func = IMX_SC_IRQ_FUNC_STATUS;
+		hdr->size = 2;
+
+		msg.data.req.resource = imx_sc_ipc_handle->mu_resource_id;
+		msg.data.req.group = i;
+
+		ret = imx_scu_call_rpc(imx_sc_ipc_handle, &msg, true);
+		if (ret) {
+			pr_err("get irq status failed, ret %d\n", ret);

Can the error output more useful information?

+			return;
+		}
+
+		irq_status = msg.data.resp.status;
+		if (!irq_status)
+			continue;
+
+		imx_scu_notifier_call_chain(irq_status, &i);
+	}
+}
+
+static void imx_scu_rxdb_callback(struct mbox_client *c, void *msg) {

Imx_scu_irq_callback

It does not make sense to parse again if failed. Pls put them into one function.

+	if (!of_parse_phandle_with_args(dev->of_node, "mboxes",
+				       "#mbox-cells", 0, &spec))
+		i = of_alias_get_id(spec.np, "mu");

This needs a binding doc for mailbox (mu).

imx_scu_irq_xxx

Regards
Dong Aisheng

 #endif /* _SC_SCI_H */
--
2.7.4