[v3,15/22] firmware: arm_scmi: abstract mailbox interface

diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index f9dee5ad0aa0..733157c5b4e2 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -1,2 +1,2 @@ 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL)	= arm_scmi.o
-arm_scmi-y = base.o clock.o driver.o perf.o power.o sensors.o
+arm_scmi-y = base.o clock.o driver.o mbox_if.o perf.o power.o sensors.o
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 92ef21d6aa5a..97285a22dfaa 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -30,7 +30,6 @@ 
 #include <linux/export.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
-#include <linux/mailbox_client.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
@@ -38,6 +37,7 @@ 
 #include <linux/slab.h>
 
 #include "common.h"
+#include "mbox_if.h"
 
 #define MSG_ID_SHIFT		0
 #define MSG_ID_MASK		0xff
@@ -90,36 +90,6 @@  struct scmi_xfers_info {
 };
 
 /**
- * struct scmi_desc - Description of SoC integration
- *
- * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
- * @max_msg: Maximum number of messages that can be pending
- *	simultaneously in the system
- * @max_msg_size: Maximum size of data per message that can be handled.
- */
-struct scmi_desc {
-	int max_rx_timeout_ms;
-	int max_msg;
-	int max_msg_size;
-};
-
-/**
- * struct scmi_chan_info - Structure representing a SCMI channel informfation
- *
- * @cl: Mailbox Client
- * @chan: Transmit/Receive mailbox channel
- * @payload: Transmit/Receive mailbox channel payload area
- * @dev: Reference to device in the SCMI hierarchy corresponding to this
- *	 channel
- */
-struct scmi_chan_info {
-	struct mbox_client cl;
-	struct mbox_chan *chan;
-	void __iomem *payload;
-	struct device *dev;
-};
-
-/**
  * struct scmi_info - Structure representing a  SCMI instance
  *
  * @dev: Device pointer
@@ -137,6 +107,7 @@  struct scmi_chan_info {
 struct scmi_info {
 	struct device *dev;
 	const struct scmi_desc *desc;
+	struct scmi_mbox_ops *mbox_ops;
 	struct scmi_revision_info version;
 	struct scmi_handle handle;
 	struct scmi_xfers_info minfo;
@@ -146,7 +117,6 @@  struct scmi_info {
 	int users;
 };
 
-#define client_to_scmi_chan_info(c) container_of(c, struct scmi_chan_info, cl)
 #define handle_to_scmi_info(h)	container_of(h, struct scmi_info, handle)
 
 /*
@@ -221,10 +191,10 @@  static void scmi_fetch_response(struct scmi_xfer *xfer,
 }
 
 /**
- * scmi_rx_callback() - mailbox client callback for receive messages
+ * scmi_generic_rx_callback() -generic mailbox client callback for receive
+ * messages
  *
- * @cl: client pointer
- * @m: mailbox message
+ * @cinfo: pointer to structure with SCMI mailbox channels information
  *
  * Processes one received message to appropriate transfer information and
  * signals completion of the transfer.
@@ -232,11 +202,10 @@  static void scmi_fetch_response(struct scmi_xfer *xfer,
  * NOTE: This function will be invoked in IRQ context, hence should be
  * as optimal as possible.
  */
-static void scmi_rx_callback(struct mbox_client *cl, void *m)
+void scmi_generic_rx_callback(struct scmi_chan_info *cinfo)
 {
 	u16 xfer_id;
 	struct scmi_xfer *xfer;
-	struct scmi_chan_info *cinfo = client_to_scmi_chan_info(cl);
 	struct device *dev = cinfo->dev;
 	struct scmi_info *info = dev_get_drvdata(dev);
 	struct scmi_xfers_info *minfo = &info->minfo;
@@ -280,18 +249,18 @@  static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
 }
 
 /**
- * scmi_tx_prepare() - mailbox client callback to prepare for the transfer
+ * scmi_generic_tx_prepare() - generic mailbox client callback to prepare for
+ * the transfer
  *
- * @cl: client pointer
+ * @cinfo: pointer to structure with SCMI mailbox channels information
  * @m: mailbox message
  *
  * This function prepares the shared memory which contains the header and the
  * payload.
  */
-static void scmi_tx_prepare(struct mbox_client *cl, void *m)
+void scmi_generic_tx_prepare(struct scmi_chan_info *cinfo, void *m)
 {
 	struct scmi_xfer *t = m;
-	struct scmi_chan_info *cinfo = client_to_scmi_chan_info(cl);
 	struct scmi_shared_mem *mem = cinfo->payload;
 
 	mem->channel_status = 0x0; /* Mark channel busy + clear error */
@@ -384,9 +353,8 @@  void scmi_one_xfer_put(const struct scmi_handle *handle, struct scmi_xfer *xfer)
 }
 
 static bool
-scmi_xfer_poll_done(const struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
+scmi_xfer_poll_done(struct scmi_shared_mem *mem, struct scmi_xfer *xfer)
 {
-	struct scmi_shared_mem *mem = cinfo->payload;
 	u16 xfer_id = MSG_XTRACT_TOKEN(le32_to_cpu(mem->msg_header));
 
 	if (xfer->hdr.seq != xfer_id)
@@ -419,7 +387,7 @@  int scmi_do_xfer(const struct scmi_handle *handle, struct scmi_xfer *xfer)
 	if (unlikely(!cinfo))
 		return -EINVAL;
 
-	ret = mbox_send_message(cinfo->chan, xfer);
+	ret = info->mbox_ops->send_message(cinfo, xfer);
 	if (ret < 0) {
 		dev_dbg(dev, "mbox send fail %d\n", ret);
 		return ret;
@@ -430,7 +398,8 @@  int scmi_do_xfer(const struct scmi_handle *handle, struct scmi_xfer *xfer)
 
 	if (xfer->hdr.poll_completion) {
 		timeout = info->desc->max_rx_timeout_ms * 100;
-		while (!scmi_xfer_poll_done(cinfo, xfer) && timeout--)
+		while (!scmi_xfer_poll_done(cinfo->payload, xfer) &&
+		       timeout--)
 			udelay(10);
 		if (timeout)
 			scmi_fetch_response(xfer, cinfo->payload);
@@ -676,12 +645,6 @@  const struct scmi_handle *devm_scmi_handle_get(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(devm_scmi_handle_get);
 
-static const struct scmi_desc scmi_generic_desc = {
-	.max_rx_timeout_ms = 30,	/* we may increase this if required */
-	.max_msg = 20,		/* Limited by MBOX_TX_QUEUE_LEN */
-	.max_msg_size = 128,
-};
-
 /* Each compatible listed below must have descriptor associated with it */
 static const struct of_device_id scmi_of_match[] = {
 	{ .compatible = "arm,scmi", .data = &scmi_generic_desc },
@@ -775,13 +738,14 @@  static int scmi_mailbox_check(struct device_node *np)
 	return of_parse_phandle_with_args(np, "mboxes", "#mbox-cells", 0, &arg);
 }
 
-static int scmi_mbox_free_channel(int id, void *p, void *data)
+static int scmi_free_channel(int id, void *p, void *data)
 {
-	struct scmi_chan_info *cinfo = p;
 	struct idr *idr = data;
+	struct scmi_chan_info *cinfo = p;
+	struct scmi_info *info = dev_get_drvdata(cinfo->dev);
 
 	if (!IS_ERR_OR_NULL(cinfo->chan)) {
-		mbox_free_channel(cinfo->chan);
+		info->mbox_ops->free_channel(cinfo);
 		cinfo->chan = NULL;
 	}
 
@@ -807,7 +771,7 @@  static int scmi_remove(struct platform_device *pdev)
 
 	if (!ret) {
 		/* Safe to free channels since no more users */
-		ret = idr_for_each(idr, scmi_mbox_free_channel, idr);
+		ret = idr_for_each(idr, scmi_free_channel, idr);
 		idr_destroy(&info->tx_idr);
 	}
 
@@ -834,11 +798,8 @@  scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id)
 		return -ENOMEM;
 
 	cinfo->dev = dev;
-
 	cl = &cinfo->cl;
 	cl->dev = dev;
-	cl->rx_callback = scmi_rx_callback;
-	cl->tx_prepare = scmi_tx_prepare;
 	cl->tx_block = false;
 	cl->knows_txdone = true;
 
@@ -858,9 +819,8 @@  scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id)
 	}
 
 	/* Transmit channel is first entry i.e. index 0 */
-	cinfo->chan = mbox_request_channel(cl, 0);
-	if (IS_ERR(cinfo->chan)) {
-		ret = PTR_ERR(cinfo->chan);
+	ret = info->mbox_ops->request_channel(cinfo, 0);
+	if (ret) {
 		if (ret != -EPROBE_DEFER)
 			dev_err(dev, "failed to request SCMI Tx mailbox\n");
 		return ret;
@@ -924,6 +884,8 @@  static int scmi_probe(struct platform_device *pdev)
 
 	info->dev = dev;
 	info->desc = desc;
+	/* set up mailbox operations */
+	info->mbox_ops = desc->mbox_ops;
 	INIT_LIST_HEAD(&info->node);
 
 	ret = scmi_xfer_info_init(info);
diff --git a/drivers/firmware/arm_scmi/mbox_if.c b/drivers/firmware/arm_scmi/mbox_if.c
new file mode 100644
index 000000000000..dc2bcc060f30
--- /dev/null
+++ b/drivers/firmware/arm_scmi/mbox_if.c
@@ -0,0 +1,80 @@ 
+/*
+ * System Control and Management Interface (SCMI) default mailbox interface
+ *
+ * Copyright (C) 2017 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#include "mbox_if.h"
+
+static void scmi_tx_prepare(struct mbox_client *cl, void *m)
+{
+	struct scmi_chan_info *cinfo = client_to_scmi_chan_info(cl);
+
+	scmi_generic_tx_prepare(cinfo, m);
+}
+
+static void scmi_rx_callback(struct mbox_client *cl, void *m)
+{
+	struct scmi_chan_info *cinfo = client_to_scmi_chan_info(cl);
+
+	scmi_generic_rx_callback(cinfo);
+}
+
+static int scmi_mbox_request_channel(struct scmi_chan_info *cinfo, int index)
+{
+	int ret = 0;
+	struct mbox_client *cl = &cinfo->cl;
+
+	cl->rx_callback = scmi_rx_callback;
+	cl->tx_prepare = scmi_tx_prepare;
+
+	cinfo->chan = mbox_request_channel(cl, index);
+	if (IS_ERR(cinfo->chan))
+		ret = PTR_ERR(cinfo->chan);
+
+	return ret;
+}
+
+static int scmi_mbox_send_message(struct scmi_chan_info *cinfo, void *msg)
+{
+	return mbox_send_message(cinfo->chan, msg);
+}
+
+static void scmi_mbox_client_txdone(struct scmi_chan_info *cinfo, int r)
+{
+	mbox_client_txdone(cinfo->chan, r);
+}
+
+static void scmi_mbox_free_channel(struct scmi_chan_info *cinfo)
+{
+	mbox_free_channel(cinfo->chan);
+}
+
+static struct scmi_mbox_ops scmi_default_mbox_ops = {
+	.request_channel = scmi_mbox_request_channel,
+	.send_message = scmi_mbox_send_message,
+	.client_txdone = scmi_mbox_client_txdone,
+	.free_channel = scmi_mbox_free_channel,
+};
+
+const struct scmi_desc scmi_generic_desc = {
+	.max_rx_timeout_ms = 30,	/* we may increase this if required */
+	.max_msg = 20,		/* Limited by MBOX_TX_QUEUE_LEN */
+	.max_msg_size = 128,
+	.mbox_ops = &scmi_default_mbox_ops,
+};
diff --git a/drivers/firmware/arm_scmi/mbox_if.h b/drivers/firmware/arm_scmi/mbox_if.h
new file mode 100644
index 000000000000..02baa73e8613
--- /dev/null
+++ b/drivers/firmware/arm_scmi/mbox_if.h
@@ -0,0 +1,68 @@ 
+/*
+ * System Control and Management Interface (SCMI) mailbox interface header
+ *
+ * Copyright (C) 2017 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/mailbox_client.h>
+
+/**
+ * struct scmi_chan_info - Structure representing a SCMI channel informfation
+ *
+ * @cl: Mailbox Client
+ * @tx_chan: Transmit mailbox channel
+ * @rx_chan: Receive mailbox channel
+ * @tx_payload: Transmit mailbox channel payload area
+ * @rx_payload: Receive mailbox channel payload area
+ * @dev: Reference to device in the SCMI hierarchy corresponding to this
+ *	 channel
+ */
+struct scmi_chan_info {
+	struct mbox_client cl;
+	struct mbox_chan *chan;
+	void __iomem *payload;
+	struct device *dev;
+	void *priv;
+};
+
+#define client_to_scmi_chan_info(c) container_of(c, struct scmi_chan_info, cl)
+
+struct scmi_mbox_ops {
+	int (*request_channel)(struct scmi_chan_info *cinfo, int index);
+	int (*send_message)(struct scmi_chan_info *cinfo, void *msg);
+	void (*client_txdone)(struct scmi_chan_info *cinfo, int r);
+	void (*free_channel)(struct scmi_chan_info *cinfo);
+};
+
+/**
+ * struct scmi_desc - Description of SoC integration
+ *
+ * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
+ * @max_msg: Maximum number of messages that can be pending
+ *	simultaneously in the system
+ * @max_msg_size: Maximum size of data per message that can be handled.
+ * @mbox_ops: Function to initialise the mailbox operations
+ */
+struct scmi_desc {
+	int max_rx_timeout_ms;
+	int max_msg;
+	int max_msg_size;
+	struct scmi_mbox_ops *mbox_ops;
+};
+
+void scmi_generic_rx_callback(struct scmi_chan_info *cinfo);
+void scmi_generic_tx_prepare(struct scmi_chan_info *cinfo, void *m);
+
+extern const struct scmi_desc scmi_generic_desc;