1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c
new file mode 100644
index 000000000..82a82a5dc
--- /dev/null
+++ b/drivers/firmware/arm_scmi/smc.c
@@ -0,0 +1,154 @@
+// 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/mutex.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
+ * @shmem_lock: Lock to protect access to Tx/Rx shared memory area
+ * @func_id: smc/hvc call function id
+ */
+
+struct scmi_smc {
+	struct scmi_chan_info *cinfo;
+	struct scmi_shared_mem __iomem *shmem;
+	struct mutex shmem_lock;
+	u32 func_id;
+};
+
+static bool smc_chan_available(struct device *dev, int idx)
+{
+	struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0);
+	if (!np)
+		return false;
+
+	of_node_put(np);
+	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;
+	resource_size_t size;
+	struct resource res;
+	struct device_node *np;
+	u32 func_id;
+	int ret;
+
+	if (!tx)
+		return -ENODEV;
+
+	scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
+	if (!scmi_info)
+		return -ENOMEM;
+
+	np = of_parse_phandle(cdev->of_node, "shmem", 0);
+	ret = of_address_to_resource(np, 0, &res);
+	of_node_put(np);
+	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(dev->of_node, "arm,smc-id", &func_id);
+	if (ret < 0)
+		return ret;
+
+	scmi_info->func_id = func_id;
+	scmi_info->cinfo = cinfo;
+	mutex_init(&scmi_info->shmem_lock);
+	cinfo->transport_info = scmi_info;
+
+	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;
+
+	mutex_lock(&scmi_info->shmem_lock);
+
+	shmem_tx_prepare(scmi_info->shmem, xfer);
+
+	arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
+	scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem));
+
+	mutex_unlock(&scmi_info->shmem_lock);
+
+	/* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
+	if (res.a0)
+		return -EOPNOTSUPP;
+	return 0;
+}
+
+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 const 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,
+	.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 = 20,
+	.max_msg_size = 128,
+};