1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2016
4 * Dirk Eibach, Guntermann & Drunck GmbH, dirk.eibach@gdsys.cc
5 *
6 * (C) Copyright 2017, 2018
7 * Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
8 */
9
10 #include <common.h>
11 #include <axi.h>
12 #include <dm.h>
13 #include <regmap.h>
14
15 /**
16 * struct ihs_axi_regs - Structure for the register map of a IHS AXI device
17 * @interrupt_status: Status register to indicate certain events (e.g.
18 * error during transfer, transfer complete, etc.)
19 * @interrupt_enable_control: Register to both control which statuses will be
20 * indicated in the interrupt_status register, and
21 * to change bus settings
22 * @address_lsb: Least significant 16-bit word of the address of a
23 * device to transfer data from/to
24 * @address_msb: Most significant 16-bit word of the address of a
25 * device to transfer data from/to
26 * @write_data_lsb: Least significant 16-bit word of the data to be
27 * written to a device
28 * @write_data_msb: Most significant 16-bit word of the data to be
29 * written to a device
30 * @read_data_lsb: Least significant 16-bit word of the data read
31 * from a device
32 * @read_data_msb: Most significant 16-bit word of the data read
33 * from a device
34 */
35 struct ihs_axi_regs {
36 u16 interrupt_status;
37 u16 interrupt_enable_control;
38 u16 address_lsb;
39 u16 address_msb;
40 u16 write_data_lsb;
41 u16 write_data_msb;
42 u16 read_data_lsb;
43 u16 read_data_msb;
44 };
45
46 /**
47 * ihs_axi_set() - Convenience macro to set values in register map
48 * @map: The register map to write to
49 * @member: The member of the ihs_axi_regs structure to write
50 * @val: The value to write to the register map
51 */
52 #define ihs_axi_set(map, member, val) \
53 regmap_set(map, struct ihs_axi_regs, member, val)
54
55 /**
56 * ihs_axi_get() - Convenience macro to read values from register map
57 * @map: The register map to read from
58 * @member: The member of the ihs_axi_regs structure to read
59 * @valp: Pointer to a buffer to receive the value read
60 */
61 #define ihs_axi_get(map, member, valp) \
62 regmap_get(map, struct ihs_axi_regs, member, valp)
63
64 /**
65 * struct ihs_axi_priv - Private data structure of IHS AXI devices
66 * @map: Register map for the IHS AXI device
67 */
68 struct ihs_axi_priv {
69 struct regmap *map;
70 };
71
72 /**
73 * enum status_reg - Description of bits in the interrupt_status register
74 * @STATUS_READ_COMPLETE_EVENT: A read transfer was completed
75 * @STATUS_WRITE_COMPLETE_EVENT: A write transfer was completed
76 * @STATUS_TIMEOUT_EVENT: A timeout has occurred during the transfer
77 * @STATUS_ERROR_EVENT: A error has occurred during the transfer
78 * @STATUS_AXI_INT: A AXI interrupt has occurred
79 * @STATUS_READ_DATA_AVAILABLE: Data is available to be read
80 * @STATUS_BUSY: The bus is busy
81 * @STATUS_INIT_DONE: The bus has finished initializing
82 */
83 enum status_reg {
84 STATUS_READ_COMPLETE_EVENT = BIT(15),
85 STATUS_WRITE_COMPLETE_EVENT = BIT(14),
86 STATUS_TIMEOUT_EVENT = BIT(13),
87 STATUS_ERROR_EVENT = BIT(12),
88 STATUS_AXI_INT = BIT(11),
89 STATUS_READ_DATA_AVAILABLE = BIT(7),
90 STATUS_BUSY = BIT(6),
91 STATUS_INIT_DONE = BIT(5),
92 };
93
94 /**
95 * enum control_reg - Description of bit fields in the interrupt_enable_control
96 * register
97 * @CONTROL_READ_COMPLETE_EVENT_ENABLE: STATUS_READ_COMPLETE_EVENT will be
98 * raised in the interrupt_status register
99 * @CONTROL_WRITE_COMPLETE_EVENT_ENABLE: STATUS_WRITE_COMPLETE_EVENT will be
100 * raised in the interrupt_status register
101 * @CONTROL_TIMEOUT_EVENT_ENABLE: STATUS_TIMEOUT_EVENT will be raised in
102 * the interrupt_status register
103 * @CONTROL_ERROR_EVENT_ENABLE: STATUS_ERROR_EVENT will be raised in
104 * the interrupt_status register
105 * @CONTROL_AXI_INT_ENABLE: STATUS_AXI_INT will be raised in the
106 * interrupt_status register
107 * @CONTROL_CMD_NOP: Configure bus to send a NOP command
108 * for the next transfer
109 * @CONTROL_CMD_WRITE: Configure bus to do a write transfer
110 * @CONTROL_CMD_WRITE_POST_INC: Auto-increment address after write
111 * transfer
112 * @CONTROL_CMD_READ: Configure bus to do a read transfer
113 * @CONTROL_CMD_READ_POST_INC: Auto-increment address after read
114 * transfer
115 */
116 enum control_reg {
117 CONTROL_READ_COMPLETE_EVENT_ENABLE = BIT(15),
118 CONTROL_WRITE_COMPLETE_EVENT_ENABLE = BIT(14),
119 CONTROL_TIMEOUT_EVENT_ENABLE = BIT(13),
120 CONTROL_ERROR_EVENT_ENABLE = BIT(12),
121 CONTROL_AXI_INT_ENABLE = BIT(11),
122
123 CONTROL_CMD_NOP = 0x0,
124 CONTROL_CMD_WRITE = 0x8,
125 CONTROL_CMD_WRITE_POST_INC = 0x9,
126 CONTROL_CMD_READ = 0xa,
127 CONTROL_CMD_READ_POST_INC = 0xb,
128 };
129
130 /**
131 * enum axi_cmd - Determine if transfer is read or write transfer
132 * @AXI_CMD_READ: The transfer should be a read transfer
133 * @AXI_CMD_WRITE: The transfer should be a write transfer
134 */
135 enum axi_cmd {
136 AXI_CMD_READ,
137 AXI_CMD_WRITE,
138 };
139
140 /**
141 * ihs_axi_transfer() - Run transfer on the AXI bus
142 * @bus: The AXI bus device on which to run the transfer on
143 * @address: The address to use in the transfer (i.e. which address to
144 * read/write from/to)
145 * @cmd: Should the transfer be a read or write transfer?
146 *
147 * Return: 0 if OK, -ve on error
148 */
ihs_axi_transfer(struct udevice * bus,ulong address,enum axi_cmd cmd)149 static int ihs_axi_transfer(struct udevice *bus, ulong address,
150 enum axi_cmd cmd)
151 {
152 struct ihs_axi_priv *priv = dev_get_priv(bus);
153 /* Try waiting for events up to 10 times */
154 const uint WAIT_TRIES = 10;
155 u16 wait_mask = STATUS_TIMEOUT_EVENT |
156 STATUS_ERROR_EVENT;
157 u16 complete_flag;
158 u16 status;
159 uint k;
160
161 if (cmd == AXI_CMD_READ) {
162 complete_flag = STATUS_READ_COMPLETE_EVENT;
163 cmd = CONTROL_CMD_READ;
164 } else {
165 complete_flag = STATUS_WRITE_COMPLETE_EVENT;
166 cmd = CONTROL_CMD_WRITE;
167 }
168
169 wait_mask |= complete_flag;
170
171 /* Lower 16 bit */
172 ihs_axi_set(priv->map, address_lsb, address & 0xffff);
173 /* Upper 16 bit */
174 ihs_axi_set(priv->map, address_msb, (address >> 16) & 0xffff);
175
176 ihs_axi_set(priv->map, interrupt_status, wait_mask);
177 ihs_axi_set(priv->map, interrupt_enable_control, cmd);
178
179 for (k = WAIT_TRIES; k > 0; --k) {
180 ihs_axi_get(priv->map, interrupt_status, &status);
181 if (status & wait_mask)
182 break;
183 udelay(1);
184 }
185
186 /*
187 * k == 0 -> Tries ran out with no event we were waiting for actually
188 * occurring.
189 */
190 if (!k)
191 ihs_axi_get(priv->map, interrupt_status, &status);
192
193 if (status & complete_flag)
194 return 0;
195
196 if (status & STATUS_ERROR_EVENT) {
197 debug("%s: Error occurred during transfer\n", bus->name);
198 return -EIO;
199 }
200
201 debug("%s: Transfer timed out\n", bus->name);
202 return -ETIMEDOUT;
203 }
204
205 /*
206 * API
207 */
208
ihs_axi_read(struct udevice * dev,ulong address,void * data,enum axi_size_t size)209 static int ihs_axi_read(struct udevice *dev, ulong address, void *data,
210 enum axi_size_t size)
211 {
212 struct ihs_axi_priv *priv = dev_get_priv(dev);
213 int ret;
214 u16 data_lsb, data_msb;
215 u32 *p = data;
216
217 if (size != AXI_SIZE_32) {
218 debug("%s: transfer size '%d' not supported\n",
219 dev->name, size);
220 return -ENOSYS;
221 }
222
223 ret = ihs_axi_transfer(dev, address, AXI_CMD_READ);
224 if (ret < 0) {
225 debug("%s: Error during AXI transfer (err = %d)\n",
226 dev->name, ret);
227 return ret;
228 }
229
230 ihs_axi_get(priv->map, read_data_lsb, &data_lsb);
231 ihs_axi_get(priv->map, read_data_msb, &data_msb);
232
233 /* Assemble data from two 16-bit words */
234 *p = (data_msb << 16) | data_lsb;
235
236 return 0;
237 }
238
ihs_axi_write(struct udevice * dev,ulong address,void * data,enum axi_size_t size)239 static int ihs_axi_write(struct udevice *dev, ulong address, void *data,
240 enum axi_size_t size)
241 {
242 struct ihs_axi_priv *priv = dev_get_priv(dev);
243 int ret;
244 u32 *p = data;
245
246 if (size != AXI_SIZE_32) {
247 debug("%s: transfer size '%d' not supported\n",
248 dev->name, size);
249 return -ENOSYS;
250 }
251
252 /* Lower 16 bit */
253 ihs_axi_set(priv->map, write_data_lsb, *p & 0xffff);
254 /* Upper 16 bit */
255 ihs_axi_set(priv->map, write_data_msb, (*p >> 16) & 0xffff);
256
257 ret = ihs_axi_transfer(dev, address, AXI_CMD_WRITE);
258 if (ret < 0) {
259 debug("%s: Error during AXI transfer (err = %d)\n",
260 dev->name, ret);
261 return ret;
262 }
263
264 return 0;
265 }
266
267 static const struct udevice_id ihs_axi_ids[] = {
268 { .compatible = "gdsys,ihs_axi" },
269 { /* sentinel */ }
270 };
271
272 static const struct axi_ops ihs_axi_ops = {
273 .read = ihs_axi_read,
274 .write = ihs_axi_write,
275 };
276
ihs_axi_probe(struct udevice * dev)277 static int ihs_axi_probe(struct udevice *dev)
278 {
279 struct ihs_axi_priv *priv = dev_get_priv(dev);
280
281 regmap_init_mem(dev_ofnode(dev), &priv->map);
282
283 return 0;
284 }
285
286 U_BOOT_DRIVER(ihs_axi_bus) = {
287 .name = "ihs_axi_bus",
288 .id = UCLASS_AXI,
289 .of_match = ihs_axi_ids,
290 .ops = &ihs_axi_ops,
291 .priv_auto_alloc_size = sizeof(struct ihs_axi_priv),
292 .probe = ihs_axi_probe,
293 };
294