[PATCH 2/2] firmware: arm_scmi: add smc/hvc transports

[peng . fan]

From: Peng Fan <peng.fan@xxxxxxx>

Add SCMI smc/hvc transports support.

Each protocol could have its own smc/hvc id, or share the same id.
There is no Rx, only Tx because of smc/hvc not support Rx.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
 drivers/firmware/arm_scmi/Makefile |   2 +-
 drivers/firmware/arm_scmi/common.h |   1 +
 drivers/firmware/arm_scmi/driver.c |   1 +
 drivers/firmware/arm_scmi/smc.c    | 177 +++++++++++++++++++++++++++++++++++++
 4 files changed, 180 insertions(+), 1 deletion(-)
 create mode 100644 drivers/firmware/arm_scmi/smc.c

diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index 6694d0d908d6..6b1b0d6c6d0e 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -2,6 +2,6 @@
 obj-y	= scmi-bus.o scmi-driver.o scmi-protocols.o scmi-transport.o
 scmi-bus-y = bus.o
 scmi-driver-y = driver.o
-scmi-transport-y = mailbox.o shmem.o
+scmi-transport-y = mailbox.o shmem.o smc.o
 scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o
 obj-$(CONFIG_ARM_SCMI_POWER_DOMAIN) += scmi_pm_domain.o
diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 5df262a564a4..f9ff5cdb68be 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -207,6 +207,7 @@ struct scmi_desc {
 };
 
 extern const struct scmi_desc scmi_mailbox_desc;
+extern const struct scmi_desc scmi_smc_desc;
 
 void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr);
 void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id);
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index dbec767222e9..c759dd094374 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -827,6 +827,7 @@ ATTRIBUTE_GROUPS(versions);
 /* Each compatible listed below must have descriptor associated with it */
 static const struct of_device_id scmi_of_match[] = {
 	{ .compatible = "arm,scmi", .data = &scmi_mailbox_desc },
+	{ .compatible = "arm,scmi-smc", .data = &scmi_smc_desc },
 	{ /* Sentinel */ },
 };
 
diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c
new file mode 100644
index 000000000000..4af0bbc4c827
--- /dev/null
+++ b/drivers/firmware/arm_scmi/smc.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) Message SMC/HVC
+ * Transport driver
+ *
+ * Copyright 2020 NXP
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+
+#include "common.h"
+
+/**
+ * struct scmi_smc - Structure representing a SCMI smc transport
+ *
+ * @cinfo: SCMI channel info
+ * @shmem: Transmit/Receive shared memory area
+ * @func_id: smc/hvc call function id
+ * @smc: Indicate it is smc channel or hvc channel
+ */
+
+struct scmi_smc {
+	struct scmi_chan_info *cinfo;
+	struct scmi_shared_mem __iomem *shmem;
+	u32 func_id;
+	bool smc;
+};
+
+#define client_to_scmi_smc(c) container_of(c, struct scmi_smc, cl)
+
+static bool smc_chan_available(struct device *dev, int idx)
+{
+	return true;
+}
+
+static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
+			  bool tx)
+{
+	struct device *cdev = cinfo->dev;
+	struct scmi_smc *scmi_info;
+	struct device_node *shmem;
+	resource_size_t size;
+	struct resource res;
+	u32 func_id;
+	int ret;
+
+	if (!tx)
+		return -ENODEV;
+
+	scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
+	if (!scmi_info)
+		return -ENOMEM;
+
+	shmem = of_parse_phandle(cdev->of_node, "shmem", 0);
+	if (!shmem)
+		shmem = of_parse_phandle(dev->of_node, "shmem", 0);
+	ret = of_address_to_resource(shmem, 0, &res);
+	of_node_put(shmem);
+	if (ret) {
+		dev_err(cdev, "failed to get SCMI Tx shared memory\n");
+		return ret;
+	}
+
+	size = resource_size(&res);
+	scmi_info->shmem = devm_ioremap(dev, res.start, size);
+	if (!scmi_info->shmem) {
+		dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
+		return -EADDRNOTAVAIL;
+	}
+
+	ret = of_property_read_u32(cdev->of_node, "arm,smc-id", &func_id);
+	if (ret)
+		ret = of_property_read_u32(dev->of_node, "arm,smc-id",
+					   &func_id);
+	if (!ret) {
+		scmi_info->smc = true;
+	} else {
+		ret = of_property_read_u32(cdev->of_node, "arm,hvc-id",
+					   &func_id);
+		if (ret)
+			ret = of_property_read_u32(dev->of_node,
+						   "arm,hvc-id",
+						   &func_id);
+
+		if (ret) {
+			dev_err(dev, "failed to get SCMI arm,smc/hvc_id\n");
+			return ret;
+		}
+		scmi_info->smc = false;
+	}
+
+	scmi_info->func_id = func_id;
+	scmi_info->cinfo = cinfo;
+	cinfo->transport_info = scmi_info;
+
+	iowrite32(BIT(0), &scmi_info->shmem->channel_status);
+
+	return 0;
+}
+
+static int smc_chan_free(int id, void *p, void *data)
+{
+	struct scmi_chan_info *cinfo = p;
+	struct scmi_smc *scmi_info = cinfo->transport_info;
+
+	cinfo->transport_info = NULL;
+	scmi_info->cinfo = NULL;
+
+	scmi_free_channel(cinfo, data, id);
+
+	return 0;
+}
+
+static int smc_send_message(struct scmi_chan_info *cinfo,
+			    struct scmi_xfer *xfer)
+{
+	struct scmi_smc *scmi_info = cinfo->transport_info;
+	struct arm_smccc_res res;
+	int ret;
+
+	shmem_tx_prepare(scmi_info->shmem, xfer);
+
+	if (scmi_info->smc)
+		arm_smccc_smc(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
+	else
+		arm_smccc_hvc(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
+
+	ret = res.a0;
+	if (ret > 0)
+		ret = 0;
+
+	scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem));
+
+	return ret;
+}
+
+static void smc_mark_txdone(struct scmi_chan_info *cinfo, int ret)
+{
+}
+
+static void smc_fetch_response(struct scmi_chan_info *cinfo,
+			       struct scmi_xfer *xfer)
+{
+	struct scmi_smc *scmi_info = cinfo->transport_info;
+
+	shmem_fetch_response(scmi_info->shmem, xfer);
+}
+
+static bool
+smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
+{
+	struct scmi_smc *scmi_info = cinfo->transport_info;
+
+	return shmem_poll_done(scmi_info->shmem, xfer);
+}
+
+static struct scmi_transport_ops scmi_smc_ops = {
+	.chan_available = smc_chan_available,
+	.chan_setup = smc_chan_setup,
+	.chan_free = smc_chan_free,
+	.send_message = smc_send_message,
+	.mark_txdone = smc_mark_txdone,
+	.fetch_response = smc_fetch_response,
+	.poll_done = smc_poll_done,
+};
+
+const struct scmi_desc scmi_smc_desc = {
+	.ops = &scmi_smc_ops,
+	.max_rx_timeout_ms = 30,
+	.max_msg = 1,
+	.max_msg_size = 128,
+};
-- 
2.16.4