1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2020 Linaro Limited. 4 */ 5 6 #include <common.h> 7 #include <dm.h> 8 #include <errno.h> 9 #include <scmi_agent.h> 10 #include <scmi_agent-uclass.h> 11 #include <dm/devres.h> 12 #include <dm/device-internal.h> 13 #include <linux/arm-smccc.h> 14 #include <linux/compat.h> 15 16 #include "smt.h" 17 18 #define SMCCC_RET_NOT_SUPPORTED ((unsigned long)-1) 19 20 /** 21 * struct scmi_smccc_channel - Description of an SCMI SMCCC transport 22 * @func_id: SMCCC function ID used by the SCMI transport 23 * @smt: Shared memory buffer 24 */ 25 struct scmi_smccc_channel { 26 ulong func_id; 27 struct scmi_smt smt; 28 }; 29 30 static int scmi_smccc_process_msg(struct udevice *dev, struct scmi_msg *msg) 31 { 32 struct scmi_smccc_channel *chan = dev_get_priv(dev); 33 struct arm_smccc_res res; 34 int ret; 35 36 ret = scmi_write_msg_to_smt(dev, &chan->smt, msg); 37 if (ret) 38 return ret; 39 40 arm_smccc_smc(chan->func_id, 0, 0, 0, 0, 0, 0, 0, &res); 41 if (res.a0 == SMCCC_RET_NOT_SUPPORTED) 42 ret = -ENXIO; 43 else 44 ret = scmi_read_resp_from_smt(dev, &chan->smt, msg); 45 46 scmi_clear_smt_channel(&chan->smt); 47 48 return ret; 49 } 50 51 static int scmi_smccc_probe(struct udevice *dev) 52 { 53 struct scmi_smccc_channel *chan = dev_get_priv(dev); 54 u32 func_id; 55 int ret; 56 57 if (dev_read_u32(dev, "arm,smc-id", &func_id)) { 58 dev_err(dev, "Missing property func-id\n"); 59 return -EINVAL; 60 } 61 62 chan->func_id = func_id; 63 64 ret = scmi_dt_get_smt_buffer(dev, &chan->smt); 65 if (ret) { 66 dev_err(dev, "Failed to get smt resources: %d\n", ret); 67 return ret; 68 } 69 70 return 0; 71 } 72 73 static const struct udevice_id scmi_smccc_ids[] = { 74 { .compatible = "arm,scmi-smc" }, 75 { } 76 }; 77 78 static const struct scmi_agent_ops scmi_smccc_ops = { 79 .process_msg = scmi_smccc_process_msg, 80 }; 81 82 U_BOOT_DRIVER(scmi_smccc) = { 83 .name = "scmi-over-smccc", 84 .id = UCLASS_SCMI_AGENT, 85 .of_match = scmi_smccc_ids, 86 .priv_auto_alloc_size = sizeof(struct scmi_smccc_channel), 87 .probe = scmi_smccc_probe, 88 .ops = &scmi_smccc_ops, 89 }; 90