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 #define LOG_CATEGORY UCLASS_SCMI_AGENT
8
9 #include <common.h>
10 #include <cpu_func.h>
11 #include <dm.h>
12 #include <dm/device_compat.h>
13 #include <errno.h>
14 #include <scmi_agent.h>
15 #include <asm/cache.h>
16 #include <asm/system.h>
17 #include <dm/ofnode.h>
18 #include <linux/compat.h>
19 #include <linux/io.h>
20 #include <linux/ioport.h>
21
22 #include "smt.h"
23
24 /**
25 * Get shared memory configuration defined by the referred DT phandle
26 * Return with a errno compliant value.
27 */
scmi_dt_get_smt_buffer(struct udevice * dev,struct scmi_smt * smt)28 int scmi_dt_get_smt_buffer(struct udevice *dev, struct scmi_smt *smt)
29 {
30 int ret;
31 struct ofnode_phandle_args args;
32 struct resource resource;
33 fdt32_t faddr;
34 phys_addr_t paddr;
35
36 ret = dev_read_phandle_with_args(dev, "shmem", NULL, 0, 0, &args);
37 if (ret)
38 return ret;
39
40 ret = ofnode_read_resource(args.node, 0, &resource);
41 if (ret)
42 return ret;
43
44 faddr = cpu_to_fdt32(resource.start);
45 paddr = ofnode_translate_address(args.node, &faddr);
46
47 smt->size = resource_size(&resource);
48 if (smt->size < sizeof(struct scmi_smt_header)) {
49 dev_err(dev, "Shared memory buffer too small\n");
50 return -EINVAL;
51 }
52
53 smt->buf = devm_ioremap(dev, paddr, smt->size);
54 if (!smt->buf)
55 return -ENOMEM;
56
57 #ifdef CONFIG_ARM
58 if (dcache_status())
59 mmu_set_region_dcache_behaviour((uintptr_t)smt->buf,
60 smt->size, DCACHE_OFF);
61 #endif
62
63 return 0;
64 }
65
66 /**
67 * Write SCMI message @msg into a SMT shared buffer @smt.
68 * Return 0 on success and with a negative errno in case of error.
69 */
scmi_write_msg_to_smt(struct udevice * dev,struct scmi_smt * smt,struct scmi_msg * msg)70 int scmi_write_msg_to_smt(struct udevice *dev, struct scmi_smt *smt,
71 struct scmi_msg *msg)
72 {
73 struct scmi_smt_header *hdr = (void *)smt->buf;
74
75 if ((!msg->in_msg && msg->in_msg_sz) ||
76 (!msg->out_msg && msg->out_msg_sz))
77 return -EINVAL;
78
79 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) {
80 dev_dbg(dev, "Channel busy\n");
81 return -EBUSY;
82 }
83
84 if (smt->size < (sizeof(*hdr) + msg->in_msg_sz) ||
85 smt->size < (sizeof(*hdr) + msg->out_msg_sz)) {
86 dev_dbg(dev, "Buffer too small\n");
87 return -ETOOSMALL;
88 }
89
90 /* Load message in shared memory */
91 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE;
92 hdr->length = msg->in_msg_sz + sizeof(hdr->msg_header);
93 hdr->msg_header = SMT_HEADER_TOKEN(0) |
94 SMT_HEADER_MESSAGE_TYPE(0) |
95 SMT_HEADER_PROTOCOL_ID(msg->protocol_id) |
96 SMT_HEADER_MESSAGE_ID(msg->message_id);
97
98 memcpy_toio(hdr->msg_payload, msg->in_msg, msg->in_msg_sz);
99
100 return 0;
101 }
102
103 /**
104 * Read SCMI message from a SMT shared buffer @smt and copy it into @msg.
105 * Return 0 on success and with a negative errno in case of error.
106 */
scmi_read_resp_from_smt(struct udevice * dev,struct scmi_smt * smt,struct scmi_msg * msg)107 int scmi_read_resp_from_smt(struct udevice *dev, struct scmi_smt *smt,
108 struct scmi_msg *msg)
109 {
110 struct scmi_smt_header *hdr = (void *)smt->buf;
111
112 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) {
113 dev_err(dev, "Channel unexpectedly busy\n");
114 return -EBUSY;
115 }
116
117 if (hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR) {
118 dev_err(dev, "Channel error reported, reset channel\n");
119 return -ECOMM;
120 }
121
122 if (hdr->length > msg->out_msg_sz + sizeof(hdr->msg_header)) {
123 dev_err(dev, "Buffer to small\n");
124 return -ETOOSMALL;
125 }
126
127 /* Get the data */
128 msg->out_msg_sz = hdr->length - sizeof(hdr->msg_header);
129 memcpy_fromio(msg->out_msg, hdr->msg_payload, msg->out_msg_sz);
130
131 return 0;
132 }
133
134 /**
135 * Clear SMT flags in shared buffer to allow further message exchange
136 */
scmi_clear_smt_channel(struct scmi_smt * smt)137 void scmi_clear_smt_channel(struct scmi_smt *smt)
138 {
139 struct scmi_smt_header *hdr = (void *)smt->buf;
140
141 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR;
142 }
143