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1dc65580 PF |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * System Control and Management Interface (SCMI) Message SMC/HVC | |
4 | * Transport driver | |
5 | * | |
6 | * Copyright 2020 NXP | |
7 | */ | |
8 | ||
9 | #include <linux/arm-smccc.h> | |
0bfdca8a | 10 | #include <linux/atomic.h> |
1dc65580 PF |
11 | #include <linux/device.h> |
12 | #include <linux/err.h> | |
dd820ee2 | 13 | #include <linux/interrupt.h> |
1dc65580 PF |
14 | #include <linux/mutex.h> |
15 | #include <linux/of.h> | |
16 | #include <linux/of_address.h> | |
dd820ee2 | 17 | #include <linux/of_irq.h> |
0bfdca8a | 18 | #include <linux/processor.h> |
1dc65580 PF |
19 | #include <linux/slab.h> |
20 | ||
21 | #include "common.h" | |
22 | ||
23 | /** | |
24 | * struct scmi_smc - Structure representing a SCMI smc transport | |
25 | * | |
26 | * @cinfo: SCMI channel info | |
27 | * @shmem: Transmit/Receive shared memory area | |
0bfdca8a CM |
28 | * @shmem_lock: Lock to protect access to Tx/Rx shared memory area. |
29 | * Used when NOT operating in atomic mode. | |
30 | * @inflight: Atomic flag to protect access to Tx/Rx shared memory area. | |
31 | * Used when operating in atomic mode. | |
1dc65580 PF |
32 | * @func_id: smc/hvc call function id |
33 | */ | |
34 | ||
35 | struct scmi_smc { | |
36 | struct scmi_chan_info *cinfo; | |
37 | struct scmi_shared_mem __iomem *shmem; | |
0bfdca8a | 38 | /* Protect access to shmem area */ |
18988265 | 39 | struct mutex shmem_lock; |
0bfdca8a CM |
40 | #define INFLIGHT_NONE MSG_TOKEN_MAX |
41 | atomic_t inflight; | |
1dc65580 PF |
42 | u32 func_id; |
43 | }; | |
44 | ||
dd820ee2 JQ |
45 | static irqreturn_t smc_msg_done_isr(int irq, void *data) |
46 | { | |
47 | struct scmi_smc *scmi_info = data; | |
48 | ||
f716cbd3 CM |
49 | scmi_rx_callback(scmi_info->cinfo, |
50 | shmem_read_header(scmi_info->shmem), NULL); | |
dd820ee2 JQ |
51 | |
52 | return IRQ_HANDLED; | |
53 | } | |
54 | ||
7a75b7af | 55 | static bool smc_chan_available(struct device_node *of_node, int idx) |
1dc65580 | 56 | { |
7a75b7af | 57 | struct device_node *np = of_parse_phandle(of_node, "shmem", 0); |
8aa6e12b SH |
58 | if (!np) |
59 | return false; | |
60 | ||
61 | of_node_put(np); | |
1dc65580 PF |
62 | return true; |
63 | } | |
64 | ||
0bfdca8a CM |
65 | static inline void smc_channel_lock_init(struct scmi_smc *scmi_info) |
66 | { | |
67 | if (IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE)) | |
68 | atomic_set(&scmi_info->inflight, INFLIGHT_NONE); | |
69 | else | |
70 | mutex_init(&scmi_info->shmem_lock); | |
71 | } | |
72 | ||
73 | static bool smc_xfer_inflight(struct scmi_xfer *xfer, atomic_t *inflight) | |
74 | { | |
75 | int ret; | |
76 | ||
77 | ret = atomic_cmpxchg(inflight, INFLIGHT_NONE, xfer->hdr.seq); | |
78 | ||
79 | return ret == INFLIGHT_NONE; | |
80 | } | |
81 | ||
82 | static inline void | |
83 | smc_channel_lock_acquire(struct scmi_smc *scmi_info, | |
84 | struct scmi_xfer *xfer __maybe_unused) | |
85 | { | |
86 | if (IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE)) | |
87 | spin_until_cond(smc_xfer_inflight(xfer, &scmi_info->inflight)); | |
88 | else | |
89 | mutex_lock(&scmi_info->shmem_lock); | |
90 | } | |
91 | ||
92 | static inline void smc_channel_lock_release(struct scmi_smc *scmi_info) | |
93 | { | |
94 | if (IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE)) | |
95 | atomic_set(&scmi_info->inflight, INFLIGHT_NONE); | |
96 | else | |
97 | mutex_unlock(&scmi_info->shmem_lock); | |
98 | } | |
99 | ||
1dc65580 PF |
100 | static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, |
101 | bool tx) | |
102 | { | |
103 | struct device *cdev = cinfo->dev; | |
104 | struct scmi_smc *scmi_info; | |
105 | resource_size_t size; | |
106 | struct resource res; | |
107 | struct device_node *np; | |
108 | u32 func_id; | |
dd820ee2 | 109 | int ret, irq; |
1dc65580 PF |
110 | |
111 | if (!tx) | |
112 | return -ENODEV; | |
113 | ||
114 | scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL); | |
115 | if (!scmi_info) | |
116 | return -ENOMEM; | |
117 | ||
118 | np = of_parse_phandle(cdev->of_node, "shmem", 0); | |
507cd4d2 SH |
119 | if (!of_device_is_compatible(np, "arm,scmi-shmem")) |
120 | return -ENXIO; | |
121 | ||
1dc65580 PF |
122 | ret = of_address_to_resource(np, 0, &res); |
123 | of_node_put(np); | |
124 | if (ret) { | |
125 | dev_err(cdev, "failed to get SCMI Tx shared memory\n"); | |
126 | return ret; | |
127 | } | |
128 | ||
129 | size = resource_size(&res); | |
130 | scmi_info->shmem = devm_ioremap(dev, res.start, size); | |
131 | if (!scmi_info->shmem) { | |
132 | dev_err(dev, "failed to ioremap SCMI Tx shared memory\n"); | |
133 | return -EADDRNOTAVAIL; | |
134 | } | |
135 | ||
136 | ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id); | |
137 | if (ret < 0) | |
138 | return ret; | |
139 | ||
dd820ee2 JQ |
140 | /* |
141 | * If there is an interrupt named "a2p", then the service and | |
142 | * completion of a message is signaled by an interrupt rather than by | |
143 | * the return of the SMC call. | |
144 | */ | |
145 | irq = of_irq_get_byname(cdev->of_node, "a2p"); | |
146 | if (irq > 0) { | |
147 | ret = devm_request_irq(dev, irq, smc_msg_done_isr, | |
148 | IRQF_NO_SUSPEND, | |
149 | dev_name(dev), scmi_info); | |
150 | if (ret) { | |
151 | dev_err(dev, "failed to setup SCMI smc irq\n"); | |
152 | return ret; | |
153 | } | |
f716cbd3 CM |
154 | } else { |
155 | cinfo->no_completion_irq = true; | |
dd820ee2 JQ |
156 | } |
157 | ||
1dc65580 PF |
158 | scmi_info->func_id = func_id; |
159 | scmi_info->cinfo = cinfo; | |
0bfdca8a | 160 | smc_channel_lock_init(scmi_info); |
1dc65580 PF |
161 | cinfo->transport_info = scmi_info; |
162 | ||
163 | return 0; | |
164 | } | |
165 | ||
166 | static int smc_chan_free(int id, void *p, void *data) | |
167 | { | |
168 | struct scmi_chan_info *cinfo = p; | |
169 | struct scmi_smc *scmi_info = cinfo->transport_info; | |
170 | ||
171 | cinfo->transport_info = NULL; | |
172 | scmi_info->cinfo = NULL; | |
173 | ||
1dc65580 PF |
174 | return 0; |
175 | } | |
176 | ||
177 | static int smc_send_message(struct scmi_chan_info *cinfo, | |
178 | struct scmi_xfer *xfer) | |
179 | { | |
180 | struct scmi_smc *scmi_info = cinfo->transport_info; | |
181 | struct arm_smccc_res res; | |
182 | ||
f716cbd3 | 183 | /* |
0bfdca8a | 184 | * Channel will be released only once response has been |
f716cbd3 CM |
185 | * surely fully retrieved, so after .mark_txdone() |
186 | */ | |
0bfdca8a | 187 | smc_channel_lock_acquire(scmi_info, xfer); |
1dc65580 | 188 | |
59172b21 | 189 | shmem_tx_prepare(scmi_info->shmem, xfer, cinfo); |
1dc65580 PF |
190 | |
191 | arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res); | |
dd820ee2 | 192 | |
f7199cf4 | 193 | /* Only SMCCC_RET_NOT_SUPPORTED is valid error code */ |
f716cbd3 | 194 | if (res.a0) { |
0bfdca8a | 195 | smc_channel_lock_release(scmi_info); |
f7199cf4 | 196 | return -EOPNOTSUPP; |
f716cbd3 CM |
197 | } |
198 | ||
f7199cf4 | 199 | return 0; |
1dc65580 PF |
200 | } |
201 | ||
1dc65580 PF |
202 | static void smc_fetch_response(struct scmi_chan_info *cinfo, |
203 | struct scmi_xfer *xfer) | |
204 | { | |
205 | struct scmi_smc *scmi_info = cinfo->transport_info; | |
206 | ||
207 | shmem_fetch_response(scmi_info->shmem, xfer); | |
208 | } | |
209 | ||
94d0cd1d CM |
210 | static void smc_mark_txdone(struct scmi_chan_info *cinfo, int ret, |
211 | struct scmi_xfer *__unused) | |
f716cbd3 CM |
212 | { |
213 | struct scmi_smc *scmi_info = cinfo->transport_info; | |
214 | ||
0bfdca8a | 215 | smc_channel_lock_release(scmi_info); |
f716cbd3 CM |
216 | } |
217 | ||
3de7b830 | 218 | static const struct scmi_transport_ops scmi_smc_ops = { |
1dc65580 PF |
219 | .chan_available = smc_chan_available, |
220 | .chan_setup = smc_chan_setup, | |
221 | .chan_free = smc_chan_free, | |
222 | .send_message = smc_send_message, | |
f716cbd3 | 223 | .mark_txdone = smc_mark_txdone, |
1dc65580 | 224 | .fetch_response = smc_fetch_response, |
1dc65580 PF |
225 | }; |
226 | ||
227 | const struct scmi_desc scmi_smc_desc = { | |
228 | .ops = &scmi_smc_ops, | |
229 | .max_rx_timeout_ms = 30, | |
7adb2c8a | 230 | .max_msg = 20, |
1dc65580 | 231 | .max_msg_size = 128, |
117542b8 CM |
232 | /* |
233 | * Setting .sync_cmds_atomic_replies to true for SMC assumes that, | |
234 | * once the SMC instruction has completed successfully, the issued | |
235 | * SCMI command would have been already fully processed by the SCMI | |
236 | * platform firmware and so any possible response value expected | |
237 | * for the issued command will be immmediately ready to be fetched | |
238 | * from the shared memory area. | |
239 | */ | |
240 | .sync_cmds_completed_on_ret = true, | |
0bfdca8a | 241 | .atomic_enabled = IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE), |
1dc65580 | 242 | }; |