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 30 ret = dev_read_phandle_with_args(dev, "shmem", NULL, 0, 0, &args); 31 if (ret) 32 return ret; 33 34 ret = ofnode_read_resource(args.node, 0, &resource); 35 if (ret) 36 return ret; 37 38 smt->size = resource_size(&resource); 39 if (smt->size < sizeof(struct scmi_smt_header)) { 40 dev_err(dev, "Shared memory buffer too small\n"); 41 return -EINVAL; 42 } 43 44 smt->buf = devm_ioremap(dev, resource.start, smt->size); 45 if (!smt->buf) 46 return -ENOMEM; 47 48 #ifdef CONFIG_ARM 49 if (dcache_status()) 50 mmu_set_region_dcache_behaviour(round_down((ulong)smt->buf, SZ_4K), 51 round_up((ulong)smt->size, SZ_4K), 52 DCACHE_OFF); 53 #endif 54 55 return 0; 56 } 57 58 /** 59 * Write SCMI message @msg into a SMT shared buffer @smt. 60 * Return 0 on success and with a negative errno in case of error. 61 */ 62 int scmi_write_msg_to_smt(struct udevice *dev, struct scmi_smt *smt, 63 struct scmi_msg *msg) 64 { 65 struct scmi_smt_header *hdr = (void *)smt->buf; 66 67 if ((!msg->in_msg && msg->in_msg_sz) || 68 (!msg->out_msg && msg->out_msg_sz)) 69 return -EINVAL; 70 71 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { 72 dev_dbg(dev, "Channel busy\n"); 73 return -EBUSY; 74 } 75 76 if (smt->size < (sizeof(*hdr) + msg->in_msg_sz) || 77 smt->size < (sizeof(*hdr) + msg->out_msg_sz)) { 78 dev_dbg(dev, "Buffer too small\n"); 79 return -ETOOSMALL; 80 } 81 82 /* Load message in shared memory */ 83 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE; 84 hdr->length = msg->in_msg_sz + sizeof(hdr->msg_header); 85 hdr->msg_header = SMT_HEADER_TOKEN(0) | 86 SMT_HEADER_MESSAGE_TYPE(0) | 87 SMT_HEADER_PROTOCOL_ID(msg->protocol_id) | 88 SMT_HEADER_MESSAGE_ID(msg->message_id); 89 90 memcpy_toio(hdr->msg_payload, msg->in_msg, msg->in_msg_sz); 91 92 return 0; 93 } 94 95 /** 96 * Read SCMI message from a SMT shared buffer @smt and copy it into @msg. 97 * Return 0 on success and with a negative errno in case of error. 98 */ 99 int scmi_read_resp_from_smt(struct udevice *dev, struct scmi_smt *smt, 100 struct scmi_msg *msg) 101 { 102 struct scmi_smt_header *hdr = (void *)smt->buf; 103 104 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { 105 dev_err(dev, "Channel unexpectedly busy\n"); 106 return -EBUSY; 107 } 108 109 if (hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR) { 110 dev_err(dev, "Channel error reported, reset channel\n"); 111 return -ECOMM; 112 } 113 114 if (hdr->length > msg->out_msg_sz + sizeof(hdr->msg_header)) { 115 dev_err(dev, "Buffer to small\n"); 116 return -ETOOSMALL; 117 } 118 119 /* Get the data */ 120 msg->out_msg_sz = hdr->length - sizeof(hdr->msg_header); 121 memcpy_fromio(msg->out_msg, hdr->msg_payload, msg->out_msg_sz); 122 123 return 0; 124 } 125 126 /** 127 * Clear SMT flags in shared buffer to allow further message exchange 128 */ 129 void scmi_clear_smt_channel(struct scmi_smt *smt) 130 { 131 struct scmi_smt_header *hdr = (void *)smt->buf; 132 133 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR; 134 } 135