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
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 smt->size = resource_size(&resource);
43 if (smt->size < sizeof(struct scmi_smt_header)) {
44 dev_err(dev, "Shared memory buffer too small\n");
45 return -EINVAL;
46 }
47
48 smt->buf = devm_ioremap(dev, resource.start, smt->size);
49 if (!smt->buf)
50 return -ENOMEM;
51
52 #ifdef CONFIG_ARM
53 if (dcache_status())
54 mmu_set_region_dcache_behaviour(ALIGN_DOWN((uintptr_t)smt->buf, MMU_SECTION_SIZE),
55 ALIGN(smt->size, MMU_SECTION_SIZE),
56 DCACHE_OFF);
57
58 #endif
59
60 return 0;
61 }
62
63 /**
64 * Write SCMI message @msg into a SMT shared buffer @smt.
65 * Return 0 on success and with a negative errno in case of error.
66 */
scmi_write_msg_to_smt(struct udevice * dev,struct scmi_smt * smt,struct scmi_msg * msg)67 int scmi_write_msg_to_smt(struct udevice *dev, struct scmi_smt *smt,
68 struct scmi_msg *msg)
69 {
70 struct scmi_smt_header *hdr = (void *)smt->buf;
71
72 if ((!msg->in_msg && msg->in_msg_sz) ||
73 (!msg->out_msg && msg->out_msg_sz))
74 return -EINVAL;
75
76 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) {
77 dev_dbg(dev, "Channel busy\n");
78 return -EBUSY;
79 }
80
81 if (smt->size < (sizeof(*hdr) + msg->in_msg_sz) ||
82 smt->size < (sizeof(*hdr) + msg->out_msg_sz)) {
83 dev_dbg(dev, "Buffer too small\n");
84 return -ETOOSMALL;
85 }
86
87 /* Load message in shared memory */
88 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE;
89 hdr->length = msg->in_msg_sz + sizeof(hdr->msg_header);
90 hdr->msg_header = SMT_HEADER_TOKEN(0) |
91 SMT_HEADER_MESSAGE_TYPE(0) |
92 SMT_HEADER_PROTOCOL_ID(msg->protocol_id) |
93 SMT_HEADER_MESSAGE_ID(msg->message_id);
94
95 memcpy_toio(hdr->msg_payload, msg->in_msg, msg->in_msg_sz);
96
97 return 0;
98 }
99
100 /**
101 * Read SCMI message from a SMT shared buffer @smt and copy it into @msg.
102 * Return 0 on success and with a negative errno in case of error.
103 */
scmi_read_resp_from_smt(struct udevice * dev,struct scmi_smt * smt,struct scmi_msg * msg)104 int scmi_read_resp_from_smt(struct udevice *dev, struct scmi_smt *smt,
105 struct scmi_msg *msg)
106 {
107 struct scmi_smt_header *hdr = (void *)smt->buf;
108
109 if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) {
110 dev_err(dev, "Channel unexpectedly busy\n");
111 return -EBUSY;
112 }
113
114 if (hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR) {
115 dev_err(dev, "Channel error reported, reset channel\n");
116 return -ECOMM;
117 }
118
119 if (hdr->length > msg->out_msg_sz + sizeof(hdr->msg_header)) {
120 dev_err(dev, "Buffer to small\n");
121 return -ETOOSMALL;
122 }
123
124 /* Get the data */
125 msg->out_msg_sz = hdr->length - sizeof(hdr->msg_header);
126 memcpy_fromio(msg->out_msg, hdr->msg_payload, msg->out_msg_sz);
127
128 return 0;
129 }
130
131 /**
132 * Clear SMT flags in shared buffer to allow further message exchange
133 */
scmi_clear_smt_channel(struct scmi_smt * smt)134 void scmi_clear_smt_channel(struct scmi_smt *smt)
135 {
136 struct scmi_smt_header *hdr = (void *)smt->buf;
137
138 hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR;
139 }
140