1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved. 4 * Copyright (C) 2019-2020 Linaro Limited. 5 */ 6 7 #include <common.h> 8 #include <cpu_func.h> 9 #include <dm.h> 10 #include <dm/device_compat.h> 11 #include <errno.h> 12 #include <scmi_agent.h> 13 #include <asm/cache.h> 14 #include <asm/system.h> 15 #include <dm/ofnode.h> 16 #include <linux/compat.h> 17 #include <linux/io.h> 18 #include <linux/ioport.h> 19 20 #include "smt.h" 21 22 /** 23 * Get shared memory configuration defined by the referred DT phandle 24 * Return with a errno compliant value. 25 */ 26 int scmi_dt_get_smt_buffer(struct udevice *dev, struct scmi_smt *smt) 27 { 28 int ret; 29 struct ofnode_phandle_args args; 30 struct resource resource; 31 fdt32_t faddr; 32 phys_addr_t paddr; 33 34 ret = dev_read_phandle_with_args(dev, "shmem", NULL, 0, 0, &args); 35 if (ret) 36 return ret; 37 38 ret = ofnode_read_resource(args.node, 0, &resource); 39 if (ret) 40 return ret; 41 42 faddr = cpu_to_fdt32(resource.start); 43 paddr = ofnode_translate_address(args.node, &faddr); 44 45 smt->size = resource_size(&resource); 46 if (smt->size < sizeof(struct scmi_smt_header)) { 47 dev_err(dev, "Shared memory buffer too small\n"); 48 return -EINVAL; 49 } 50 51 smt->buf = devm_ioremap(dev, paddr, smt->size); 52 if (!smt->buf) 53 return -ENOMEM; 54 55 #ifdef CONFIG_ARM 56 if (dcache_status()) 57 mmu_set_region_dcache_behaviour((uintptr_t)smt->buf, 58 smt->size, DCACHE_OFF); 59 #endif 60 61 return 0; 62 } 63 64 /** 65 * Write SCMI message @msg into a SMT shared buffer @smt. 66 * Return 0 on success and with a negative errno in case of error. 67 */ 68 int scmi_write_msg_to_smt(struct udevice *dev, struct scmi_smt *smt, 69 struct scmi_msg *msg) 70 { 71 struct scmi_smt_header *hdr = (void *)smt->buf; 72 73 if ((!msg->in_msg && msg->in_msg_sz) || 74 (!msg->out_msg && msg->out_msg_sz)) 75 return -EINVAL; 76 77 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { 78 dev_dbg(dev, "Channel busy\n"); 79 return -EBUSY; 80 } 81 82 if (smt->size < (sizeof(*hdr) + msg->in_msg_sz) || 83 smt->size < (sizeof(*hdr) + msg->out_msg_sz)) { 84 dev_dbg(dev, "Buffer too small\n"); 85 return -ETOOSMALL; 86 } 87 88 /* Load message in shared memory */ 89 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE; 90 hdr->length = msg->in_msg_sz + sizeof(hdr->msg_header); 91 hdr->msg_header = SMT_HEADER_TOKEN(0) | 92 SMT_HEADER_MESSAGE_TYPE(0) | 93 SMT_HEADER_PROTOCOL_ID(msg->protocol_id) | 94 SMT_HEADER_MESSAGE_ID(msg->message_id); 95 96 memcpy_toio(hdr->msg_payload, msg->in_msg, msg->in_msg_sz); 97 98 return 0; 99 } 100 101 /** 102 * Read SCMI message from a SMT shared buffer @smt and copy it into @msg. 103 * Return 0 on success and with a negative errno in case of error. 104 */ 105 int scmi_read_resp_from_smt(struct udevice *dev, struct scmi_smt *smt, 106 struct scmi_msg *msg) 107 { 108 struct scmi_smt_header *hdr = (void *)smt->buf; 109 110 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { 111 dev_err(dev, "Channel unexpectedly busy\n"); 112 return -EBUSY; 113 } 114 115 if (hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR) { 116 dev_err(dev, "Channel error reported, reset channel\n"); 117 return -ECOMM; 118 } 119 120 if (hdr->length > msg->out_msg_sz + sizeof(hdr->msg_header)) { 121 dev_err(dev, "Buffer to small\n"); 122 return -ETOOSMALL; 123 } 124 125 /* Get the data */ 126 msg->out_msg_sz = hdr->length - sizeof(hdr->msg_header); 127 memcpy_fromio(msg->out_msg, hdr->msg_payload, msg->out_msg_sz); 128 129 return 0; 130 } 131 132 /** 133 * Clear SMT flags in shared buffer to allow further message exchange 134 */ 135 void scmi_clear_smt_channel(struct scmi_smt *smt) 136 { 137 struct scmi_smt_header *hdr = (void *)smt->buf; 138 139 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR; 140 } 141