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