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 phys_addr_t paddr; 30 31 ret = dev_read_phandle_with_args(dev, "shmem", NULL, 0, 0, &args); 32 if (ret) 33 return ret; 34 35 ret = ofnode_read_resource(args.node, 0, &resource); 36 if (ret) 37 return ret; 38 39 paddr = resource.start; 40 smt->size = resource_size(&resource); 41 if (smt->size < sizeof(struct scmi_smt_header)) { 42 dev_err(dev, "Shared memory buffer too small\n"); 43 return -EINVAL; 44 } 45 46 smt->buf = devm_ioremap(dev, paddr, smt->size); 47 if (!smt->buf) 48 return -ENOMEM; 49 50 #ifdef CONFIG_ARM 51 if (dcache_status()) 52 mmu_set_region_dcache_behaviour(round_down((ulong)smt->buf, SZ_4K), 53 round_up((ulong)smt->size, SZ_4K), 54 DCACHE_OFF); 55 #endif 56 57 return 0; 58 } 59 60 /** 61 * Write SCMI message @msg into a SMT shared buffer @smt. 62 * Return 0 on success and with a negative errno in case of error. 63 */ 64 int scmi_write_msg_to_smt(struct udevice *dev, struct scmi_smt *smt, 65 struct scmi_msg *msg) 66 { 67 struct scmi_smt_header *hdr = (void *)smt->buf; 68 69 if ((!msg->in_msg && msg->in_msg_sz) || 70 (!msg->out_msg && msg->out_msg_sz)) 71 return -EINVAL; 72 73 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { 74 dev_dbg(dev, "Channel busy\n"); 75 return -EBUSY; 76 } 77 78 if (smt->size < (sizeof(*hdr) + msg->in_msg_sz) || 79 smt->size < (sizeof(*hdr) + msg->out_msg_sz)) { 80 dev_dbg(dev, "Buffer too small\n"); 81 return -ETOOSMALL; 82 } 83 84 /* Load message in shared memory */ 85 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE; 86 hdr->length = msg->in_msg_sz + sizeof(hdr->msg_header); 87 hdr->msg_header = SMT_HEADER_TOKEN(0) | 88 SMT_HEADER_MESSAGE_TYPE(0) | 89 SMT_HEADER_PROTOCOL_ID(msg->protocol_id) | 90 SMT_HEADER_MESSAGE_ID(msg->message_id); 91 92 memcpy_toio(hdr->msg_payload, msg->in_msg, msg->in_msg_sz); 93 94 return 0; 95 } 96 97 /** 98 * Read SCMI message from a SMT shared buffer @smt and copy it into @msg. 99 * Return 0 on success and with a negative errno in case of error. 100 */ 101 int scmi_read_resp_from_smt(struct udevice *dev, struct scmi_smt *smt, 102 struct scmi_msg *msg) 103 { 104 struct scmi_smt_header *hdr = (void *)smt->buf; 105 106 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { 107 dev_err(dev, "Channel unexpectedly busy\n"); 108 return -EBUSY; 109 } 110 111 if (hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR) { 112 dev_err(dev, "Channel error reported, reset channel\n"); 113 return -ECOMM; 114 } 115 116 if (hdr->length > msg->out_msg_sz + sizeof(hdr->msg_header)) { 117 dev_err(dev, "Buffer to small\n"); 118 return -ETOOSMALL; 119 } 120 121 /* Get the data */ 122 msg->out_msg_sz = hdr->length - sizeof(hdr->msg_header); 123 memcpy_fromio(msg->out_msg, hdr->msg_payload, msg->out_msg_sz); 124 125 return 0; 126 } 127 128 /** 129 * Clear SMT flags in shared buffer to allow further message exchange 130 */ 131 void scmi_clear_smt_channel(struct scmi_smt *smt) 132 { 133 struct scmi_smt_header *hdr = (void *)smt->buf; 134 135 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR; 136 } 137