1 /*
2 * Copyright 2020 Google LLC
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 *
6 * This driver creates fake SPI buses which can contain emulated devices,
7 * implemented by a separate emulation driver. The API between this driver and
8 * its emulators is defined by struct spi_emul_driver_api.
9 */
10
11 #define DT_DRV_COMPAT zephyr_spi_emul_controller
12
13 #define LOG_LEVEL CONFIG_SPI_LOG_LEVEL
14 #include <zephyr/logging/log.h>
15 LOG_MODULE_REGISTER(spi_emul_ctlr);
16
17 #include <zephyr/device.h>
18 #include <zephyr/drivers/emul.h>
19 #include <zephyr/drivers/spi.h>
20 #include <zephyr/drivers/spi/rtio.h>
21 #include <zephyr/drivers/spi_emul.h>
22
23 /** Working data for the device */
24 struct spi_emul_data {
25 /* List of struct spi_emul associated with the device */
26 sys_slist_t emuls;
27 /* SPI host configuration */
28 uint32_t config;
29 };
30
spi_emul_get_config(const struct device * dev)31 uint32_t spi_emul_get_config(const struct device *dev)
32 {
33 struct spi_emul_data *data = dev->data;
34
35 return data->config;
36 }
37
38 /**
39 * Find an emulator for a SPI bus
40 *
41 * At present only a single emulator is supported on the bus, since we do not
42 * support chip selects, despite there being a chipsel field. It cannot be
43 * implemented until we have a GPIO emulator.
44 *
45 * @param dev SPI emulation controller device
46 * @param chipsel Chip-select value
47 * @return emulator to use
48 * @return NULL if not found
49 */
spi_emul_find(const struct device * dev,unsigned int chipsel)50 static struct spi_emul *spi_emul_find(const struct device *dev, unsigned int chipsel)
51 {
52 struct spi_emul_data *data = dev->data;
53 sys_snode_t *node;
54
55 SYS_SLIST_FOR_EACH_NODE(&data->emuls, node) {
56 struct spi_emul *emul;
57
58 emul = CONTAINER_OF(node, struct spi_emul, node);
59 if (emul->chipsel == chipsel) {
60 return emul;
61 }
62 }
63
64 return NULL;
65 }
66
spi_emul_io(const struct device * dev,const struct spi_config * config,const struct spi_buf_set * tx_bufs,const struct spi_buf_set * rx_bufs)67 static int spi_emul_io(const struct device *dev, const struct spi_config *config,
68 const struct spi_buf_set *tx_bufs, const struct spi_buf_set *rx_bufs)
69 {
70 struct spi_emul *emul;
71 const struct spi_emul_api *api;
72 int ret;
73
74 emul = spi_emul_find(dev, config->slave);
75 if (!emul) {
76 return -EIO;
77 }
78
79 api = emul->api;
80 __ASSERT_NO_MSG(emul->api);
81 __ASSERT_NO_MSG(emul->api->io);
82
83 if (emul->mock_api != NULL && emul->mock_api->io != NULL) {
84 ret = emul->mock_api->io(emul->target, config, tx_bufs, rx_bufs);
85 if (ret != -ENOSYS) {
86 return ret;
87 }
88 }
89
90 return api->io(emul->target, config, tx_bufs, rx_bufs);
91 }
92
93 /**
94 * @brief This is a no-op stub of the SPI API's `release` method to protect drivers under test
95 * from hitting a segmentation fault when using SPI_LOCK_ON plus spi_release()
96 */
spi_emul_release(const struct device * dev,const struct spi_config * config)97 static int spi_emul_release(const struct device *dev, const struct spi_config *config)
98 {
99 ARG_UNUSED(dev);
100 ARG_UNUSED(config);
101
102 return 0;
103 }
104
105 /**
106 * Set up a new emulator and add it to the list
107 *
108 * @param dev SPI emulation controller device
109 */
spi_emul_init(const struct device * dev)110 static int spi_emul_init(const struct device *dev)
111 {
112 struct spi_emul_data *data = dev->data;
113
114 sys_slist_init(&data->emuls);
115
116 return emul_init_for_bus(dev);
117 }
118
spi_emul_register(const struct device * dev,struct spi_emul * emul)119 int spi_emul_register(const struct device *dev, struct spi_emul *emul)
120 {
121 struct spi_emul_data *data = dev->data;
122 const char *name = emul->target->dev->name;
123
124 sys_slist_append(&data->emuls, &emul->node);
125
126 LOG_INF("Register emulator '%s' at cs %u\n", name, emul->chipsel);
127
128 return 0;
129 }
130
131 /* Device instantiation */
132
133 static DEVICE_API(spi, spi_emul_api) = {
134 .transceive = spi_emul_io,
135 #ifdef CONFIG_SPI_RTIO
136 .iodev_submit = spi_rtio_iodev_default_submit,
137 #endif
138 .release = spi_emul_release,
139 };
140
141 #define EMUL_LINK_AND_COMMA(node_id) \
142 { \
143 .dev = DEVICE_DT_GET(node_id), \
144 },
145
146 #define SPI_EMUL_INIT(n) \
147 static const struct emul_link_for_bus emuls_##n[] = { \
148 DT_FOREACH_CHILD_STATUS_OKAY(DT_DRV_INST(n), EMUL_LINK_AND_COMMA)}; \
149 static struct emul_list_for_bus spi_emul_cfg_##n = { \
150 .children = emuls_##n, \
151 .num_children = ARRAY_SIZE(emuls_##n), \
152 }; \
153 static struct spi_emul_data spi_emul_data_##n; \
154 SPI_DEVICE_DT_INST_DEFINE(n, spi_emul_init, NULL, &spi_emul_data_##n, &spi_emul_cfg_##n, \
155 POST_KERNEL, CONFIG_SPI_INIT_PRIORITY, &spi_emul_api);
156
157 DT_INST_FOREACH_STATUS_OKAY(SPI_EMUL_INIT)
158
