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 */
scmi_dt_get_smt_buffer(struct udevice * dev,struct scmi_smt * smt)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 */
scmi_write_msg_to_smt(struct udevice * dev,struct scmi_smt * smt,struct scmi_msg * msg)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 */
scmi_read_resp_from_smt(struct udevice * dev,struct scmi_smt * smt,struct scmi_msg * msg)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 */
scmi_clear_smt_channel(struct scmi_smt * smt)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