1 // SPDX-License-Identifier: GPL-2.0
3 * System Control and Management Interface (SCMI) Message SMC/HVC
9 #include <linux/arm-smccc.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/interrupt.h>
13 #include <linux/mutex.h>
15 #include <linux/of_address.h>
16 #include <linux/of_irq.h>
17 #include <linux/slab.h>
22 * struct scmi_smc - Structure representing a SCMI smc transport
24 * @cinfo: SCMI channel info
25 * @shmem: Transmit/Receive shared memory area
26 * @shmem_lock: Lock to protect access to Tx/Rx shared memory area
27 * @func_id: smc/hvc call function id
28 * @irq: Optional; employed when platforms indicates msg completion by intr.
29 * @tx_complete: Optional, employed only when irq is valid.
33 struct scmi_chan_info *cinfo;
34 struct scmi_shared_mem __iomem *shmem;
35 struct mutex shmem_lock;
38 struct completion tx_complete;
41 static irqreturn_t smc_msg_done_isr(int irq, void *data)
43 struct scmi_smc *scmi_info = data;
45 complete(&scmi_info->tx_complete);
50 static bool smc_chan_available(struct device *dev, int idx)
52 struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0);
60 static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
63 struct device *cdev = cinfo->dev;
64 struct scmi_smc *scmi_info;
67 struct device_node *np;
74 scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
78 np = of_parse_phandle(cdev->of_node, "shmem", 0);
79 if (!of_device_is_compatible(np, "arm,scmi-shmem"))
82 ret = of_address_to_resource(np, 0, &res);
85 dev_err(cdev, "failed to get SCMI Tx shared memory\n");
89 size = resource_size(&res);
90 scmi_info->shmem = devm_ioremap(dev, res.start, size);
91 if (!scmi_info->shmem) {
92 dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
93 return -EADDRNOTAVAIL;
96 ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
101 * If there is an interrupt named "a2p", then the service and
102 * completion of a message is signaled by an interrupt rather than by
103 * the return of the SMC call.
105 irq = of_irq_get_byname(cdev->of_node, "a2p");
107 ret = devm_request_irq(dev, irq, smc_msg_done_isr,
109 dev_name(dev), scmi_info);
111 dev_err(dev, "failed to setup SCMI smc irq\n");
114 init_completion(&scmi_info->tx_complete);
115 scmi_info->irq = irq;
118 scmi_info->func_id = func_id;
119 scmi_info->cinfo = cinfo;
120 mutex_init(&scmi_info->shmem_lock);
121 cinfo->transport_info = scmi_info;
126 static int smc_chan_free(int id, void *p, void *data)
128 struct scmi_chan_info *cinfo = p;
129 struct scmi_smc *scmi_info = cinfo->transport_info;
131 cinfo->transport_info = NULL;
132 scmi_info->cinfo = NULL;
134 scmi_free_channel(cinfo, data, id);
139 static int smc_send_message(struct scmi_chan_info *cinfo,
140 struct scmi_xfer *xfer)
142 struct scmi_smc *scmi_info = cinfo->transport_info;
143 struct arm_smccc_res res;
145 mutex_lock(&scmi_info->shmem_lock);
147 shmem_tx_prepare(scmi_info->shmem, xfer);
150 reinit_completion(&scmi_info->tx_complete);
152 arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
155 wait_for_completion(&scmi_info->tx_complete);
157 scmi_rx_callback(scmi_info->cinfo,
158 shmem_read_header(scmi_info->shmem), NULL);
160 mutex_unlock(&scmi_info->shmem_lock);
162 /* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
168 static void smc_fetch_response(struct scmi_chan_info *cinfo,
169 struct scmi_xfer *xfer)
171 struct scmi_smc *scmi_info = cinfo->transport_info;
173 shmem_fetch_response(scmi_info->shmem, xfer);
177 smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
179 struct scmi_smc *scmi_info = cinfo->transport_info;
181 return shmem_poll_done(scmi_info->shmem, xfer);
184 static const struct scmi_transport_ops scmi_smc_ops = {
185 .chan_available = smc_chan_available,
186 .chan_setup = smc_chan_setup,
187 .chan_free = smc_chan_free,
188 .send_message = smc_send_message,
189 .fetch_response = smc_fetch_response,
190 .poll_done = smc_poll_done,
193 const struct scmi_desc scmi_smc_desc = {
194 .ops = &scmi_smc_ops,
195 .max_rx_timeout_ms = 30,