1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * System Control and Management Interface (SCMI) Message SMC/HVC 4 * Transport driver 5 * 6 * Copyright 2020 NXP 7 */ 8 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> 14 #include <linux/of.h> 15 #include <linux/of_address.h> 16 #include <linux/of_irq.h> 17 #include <linux/slab.h> 18 19 #include "common.h" 20 21 /** 22 * struct scmi_smc - Structure representing a SCMI smc transport 23 * 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. 30 */ 31 32 struct scmi_smc { 33 struct scmi_chan_info *cinfo; 34 struct scmi_shared_mem __iomem *shmem; 35 struct mutex shmem_lock; 36 u32 func_id; 37 int irq; 38 struct completion tx_complete; 39 }; 40 41 static irqreturn_t smc_msg_done_isr(int irq, void *data) 42 { 43 struct scmi_smc *scmi_info = data; 44 45 complete(&scmi_info->tx_complete); 46 47 return IRQ_HANDLED; 48 } 49 50 static bool smc_chan_available(struct device *dev, int idx) 51 { 52 struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0); 53 if (!np) 54 return false; 55 56 of_node_put(np); 57 return true; 58 } 59 60 static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, 61 bool tx) 62 { 63 struct device *cdev = cinfo->dev; 64 struct scmi_smc *scmi_info; 65 resource_size_t size; 66 struct resource res; 67 struct device_node *np; 68 u32 func_id; 69 int ret, irq; 70 71 if (!tx) 72 return -ENODEV; 73 74 scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL); 75 if (!scmi_info) 76 return -ENOMEM; 77 78 np = of_parse_phandle(cdev->of_node, "shmem", 0); 79 if (!of_device_is_compatible(np, "arm,scmi-shmem")) 80 return -ENXIO; 81 82 ret = of_address_to_resource(np, 0, &res); 83 of_node_put(np); 84 if (ret) { 85 dev_err(cdev, "failed to get SCMI Tx shared memory\n"); 86 return ret; 87 } 88 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; 94 } 95 96 ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id); 97 if (ret < 0) 98 return ret; 99 100 /* 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. 104 */ 105 irq = of_irq_get_byname(cdev->of_node, "a2p"); 106 if (irq > 0) { 107 ret = devm_request_irq(dev, irq, smc_msg_done_isr, 108 IRQF_NO_SUSPEND, 109 dev_name(dev), scmi_info); 110 if (ret) { 111 dev_err(dev, "failed to setup SCMI smc irq\n"); 112 return ret; 113 } 114 init_completion(&scmi_info->tx_complete); 115 scmi_info->irq = irq; 116 } 117 118 scmi_info->func_id = func_id; 119 scmi_info->cinfo = cinfo; 120 mutex_init(&scmi_info->shmem_lock); 121 cinfo->transport_info = scmi_info; 122 123 return 0; 124 } 125 126 static int smc_chan_free(int id, void *p, void *data) 127 { 128 struct scmi_chan_info *cinfo = p; 129 struct scmi_smc *scmi_info = cinfo->transport_info; 130 131 cinfo->transport_info = NULL; 132 scmi_info->cinfo = NULL; 133 134 scmi_free_channel(cinfo, data, id); 135 136 return 0; 137 } 138 139 static int smc_send_message(struct scmi_chan_info *cinfo, 140 struct scmi_xfer *xfer) 141 { 142 struct scmi_smc *scmi_info = cinfo->transport_info; 143 struct arm_smccc_res res; 144 145 mutex_lock(&scmi_info->shmem_lock); 146 147 shmem_tx_prepare(scmi_info->shmem, xfer); 148 149 if (scmi_info->irq) 150 reinit_completion(&scmi_info->tx_complete); 151 152 arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res); 153 154 if (scmi_info->irq) 155 wait_for_completion(&scmi_info->tx_complete); 156 157 scmi_rx_callback(scmi_info->cinfo, 158 shmem_read_header(scmi_info->shmem), NULL); 159 160 mutex_unlock(&scmi_info->shmem_lock); 161 162 /* Only SMCCC_RET_NOT_SUPPORTED is valid error code */ 163 if (res.a0) 164 return -EOPNOTSUPP; 165 return 0; 166 } 167 168 static void smc_fetch_response(struct scmi_chan_info *cinfo, 169 struct scmi_xfer *xfer) 170 { 171 struct scmi_smc *scmi_info = cinfo->transport_info; 172 173 shmem_fetch_response(scmi_info->shmem, xfer); 174 } 175 176 static bool 177 smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer) 178 { 179 struct scmi_smc *scmi_info = cinfo->transport_info; 180 181 return shmem_poll_done(scmi_info->shmem, xfer); 182 } 183 184 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, 191 }; 192 193 const struct scmi_desc scmi_smc_desc = { 194 .ops = &scmi_smc_ops, 195 .max_rx_timeout_ms = 30, 196 .max_msg = 20, 197 .max_msg_size = 128, 198 }; 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