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/mutex.h> 13 #include <linux/of.h> 14 #include <linux/of_address.h> 15 #include <linux/slab.h> 16 17 #include "common.h" 18 19 /** 20 * struct scmi_smc - Structure representing a SCMI smc transport 21 * 22 * @cinfo: SCMI channel info 23 * @shmem: Transmit/Receive shared memory area 24 * @func_id: smc/hvc call function id 25 */ 26 27 struct scmi_smc { 28 struct scmi_chan_info *cinfo; 29 struct scmi_shared_mem __iomem *shmem; 30 struct mutex shmem_lock; 31 u32 func_id; 32 }; 33 34 static bool smc_chan_available(struct device *dev, int idx) 35 { 36 struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0); 37 if (!np) 38 return false; 39 40 of_node_put(np); 41 return true; 42 } 43 44 static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, 45 bool tx) 46 { 47 struct device *cdev = cinfo->dev; 48 struct scmi_smc *scmi_info; 49 resource_size_t size; 50 struct resource res; 51 struct device_node *np; 52 u32 func_id; 53 int ret; 54 55 if (!tx) 56 return -ENODEV; 57 58 scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL); 59 if (!scmi_info) 60 return -ENOMEM; 61 62 np = of_parse_phandle(cdev->of_node, "shmem", 0); 63 ret = of_address_to_resource(np, 0, &res); 64 of_node_put(np); 65 if (ret) { 66 dev_err(cdev, "failed to get SCMI Tx shared memory\n"); 67 return ret; 68 } 69 70 size = resource_size(&res); 71 scmi_info->shmem = devm_ioremap(dev, res.start, size); 72 if (!scmi_info->shmem) { 73 dev_err(dev, "failed to ioremap SCMI Tx shared memory\n"); 74 return -EADDRNOTAVAIL; 75 } 76 77 ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id); 78 if (ret < 0) 79 return ret; 80 81 scmi_info->func_id = func_id; 82 scmi_info->cinfo = cinfo; 83 mutex_init(&scmi_info->shmem_lock); 84 cinfo->transport_info = scmi_info; 85 86 return 0; 87 } 88 89 static int smc_chan_free(int id, void *p, void *data) 90 { 91 struct scmi_chan_info *cinfo = p; 92 struct scmi_smc *scmi_info = cinfo->transport_info; 93 94 cinfo->transport_info = NULL; 95 scmi_info->cinfo = NULL; 96 97 scmi_free_channel(cinfo, data, id); 98 99 return 0; 100 } 101 102 static int smc_send_message(struct scmi_chan_info *cinfo, 103 struct scmi_xfer *xfer) 104 { 105 struct scmi_smc *scmi_info = cinfo->transport_info; 106 struct arm_smccc_res res; 107 108 mutex_lock(&scmi_info->shmem_lock); 109 110 shmem_tx_prepare(scmi_info->shmem, xfer); 111 112 arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res); 113 scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem)); 114 115 mutex_unlock(&scmi_info->shmem_lock); 116 117 /* Only SMCCC_RET_NOT_SUPPORTED is valid error code */ 118 if (res.a0) 119 return -EOPNOTSUPP; 120 return 0; 121 } 122 123 static void smc_fetch_response(struct scmi_chan_info *cinfo, 124 struct scmi_xfer *xfer) 125 { 126 struct scmi_smc *scmi_info = cinfo->transport_info; 127 128 shmem_fetch_response(scmi_info->shmem, xfer); 129 } 130 131 static bool 132 smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer) 133 { 134 struct scmi_smc *scmi_info = cinfo->transport_info; 135 136 return shmem_poll_done(scmi_info->shmem, xfer); 137 } 138 139 static struct scmi_transport_ops scmi_smc_ops = { 140 .chan_available = smc_chan_available, 141 .chan_setup = smc_chan_setup, 142 .chan_free = smc_chan_free, 143 .send_message = smc_send_message, 144 .fetch_response = smc_fetch_response, 145 .poll_done = smc_poll_done, 146 }; 147 148 const struct scmi_desc scmi_smc_desc = { 149 .ops = &scmi_smc_ops, 150 .max_rx_timeout_ms = 30, 151 .max_msg = 1, 152 .max_msg_size = 128, 153 }; 154