xref: /dpdk/drivers/net/axgbe/axgbe_i2c.c (revision 25d11a86c56d50947af33d0b79ede622809bd8b9)
1 /*   SPDX-License-Identifier: BSD-3-Clause
2  *   Copyright(c) 2018 Advanced Micro Devices, Inc. All rights reserved.
3  *   Copyright(c) 2018 Synopsys, Inc. All rights reserved.
4  */
5 
6 #include "axgbe_ethdev.h"
7 #include "axgbe_common.h"
8 
9 #define AXGBE_ABORT_COUNT	500
10 #define AXGBE_DISABLE_COUNT	1000
11 
12 #define AXGBE_STD_SPEED		1
13 
14 #define AXGBE_INTR_RX_FULL	BIT(IC_RAW_INTR_STAT_RX_FULL_INDEX)
15 #define AXGBE_INTR_TX_EMPTY	BIT(IC_RAW_INTR_STAT_TX_EMPTY_INDEX)
16 #define AXGBE_INTR_TX_ABRT	BIT(IC_RAW_INTR_STAT_TX_ABRT_INDEX)
17 #define AXGBE_INTR_STOP_DET	BIT(IC_RAW_INTR_STAT_STOP_DET_INDEX)
18 #define AXGBE_DEFAULT_INT_MASK	(AXGBE_INTR_RX_FULL  |	\
19 				 AXGBE_INTR_TX_EMPTY |	\
20 				 AXGBE_INTR_TX_ABRT  |	\
21 				 AXGBE_INTR_STOP_DET)
22 
23 #define AXGBE_I2C_READ		BIT(8)
24 #define AXGBE_I2C_STOP		BIT(9)
25 
26 static int axgbe_i2c_abort(struct axgbe_port *pdata)
27 {
28 	unsigned int wait = AXGBE_ABORT_COUNT;
29 
30 	/* Must be enabled to recognize the abort request */
31 	XI2C_IOWRITE_BITS(pdata, IC_ENABLE, EN, 1);
32 
33 	/* Issue the abort */
34 	XI2C_IOWRITE_BITS(pdata, IC_ENABLE, ABORT, 1);
35 
36 	while (wait--) {
37 		if (!XI2C_IOREAD_BITS(pdata, IC_ENABLE, ABORT))
38 			return 0;
39 		rte_delay_us(500);
40 	}
41 
42 	return -EBUSY;
43 }
44 
45 static int axgbe_i2c_set_enable(struct axgbe_port *pdata, bool enable)
46 {
47 	unsigned int wait = AXGBE_DISABLE_COUNT;
48 	unsigned int mode = enable ? 1 : 0;
49 
50 	while (wait--) {
51 		XI2C_IOWRITE_BITS(pdata, IC_ENABLE, EN, mode);
52 		if (XI2C_IOREAD_BITS(pdata, IC_ENABLE_STATUS, EN) == mode)
53 			return 0;
54 
55 		rte_delay_us(100);
56 	}
57 
58 	return -EBUSY;
59 }
60 
61 static int axgbe_i2c_disable(struct axgbe_port *pdata)
62 {
63 	unsigned int ret;
64 
65 	ret = axgbe_i2c_set_enable(pdata, false);
66 	if (ret) {
67 		/* Disable failed, try an abort */
68 		ret = axgbe_i2c_abort(pdata);
69 		if (ret)
70 			return ret;
71 
72 		/* Abort succeeded, try to disable again */
73 		ret = axgbe_i2c_set_enable(pdata, false);
74 	}
75 
76 	return ret;
77 }
78 
79 static int axgbe_i2c_enable(struct axgbe_port *pdata)
80 {
81 	return axgbe_i2c_set_enable(pdata, true);
82 }
83 
84 static void axgbe_i2c_clear_all_interrupts(struct axgbe_port *pdata)
85 {
86 	XI2C_IOREAD(pdata, IC_CLR_INTR);
87 }
88 
89 static void axgbe_i2c_disable_interrupts(struct axgbe_port *pdata)
90 {
91 	XI2C_IOWRITE(pdata, IC_INTR_MASK, 0);
92 }
93 
94 static void axgbe_i2c_enable_interrupts(struct axgbe_port *pdata)
95 {
96 	XI2C_IOWRITE(pdata, IC_INTR_MASK, AXGBE_DEFAULT_INT_MASK);
97 }
98 
99 static void axgbe_i2c_write(struct axgbe_port *pdata)
100 {
101 	struct axgbe_i2c_op_state *state = &pdata->i2c.op_state;
102 	unsigned int tx_slots;
103 	unsigned int cmd;
104 
105 	/* Configured to never receive Rx overflows, so fill up Tx fifo */
106 	tx_slots = pdata->i2c.tx_fifo_size - XI2C_IOREAD(pdata, IC_TXFLR);
107 	while (tx_slots && state->tx_len) {
108 		if (state->op->cmd == AXGBE_I2C_CMD_READ)
109 			cmd = AXGBE_I2C_READ;
110 		else
111 			cmd = *state->tx_buf++;
112 
113 		if (state->tx_len == 1)
114 			XI2C_SET_BITS(cmd, IC_DATA_CMD, STOP, 1);
115 
116 		XI2C_IOWRITE(pdata, IC_DATA_CMD, cmd);
117 
118 		tx_slots--;
119 		state->tx_len--;
120 	}
121 
122 	/* No more Tx operations, so ignore TX_EMPTY and return */
123 	if (!state->tx_len)
124 		XI2C_IOWRITE_BITS(pdata, IC_INTR_MASK, TX_EMPTY, 0);
125 }
126 
127 static void axgbe_i2c_read(struct axgbe_port *pdata)
128 {
129 	struct axgbe_i2c_op_state *state = &pdata->i2c.op_state;
130 	unsigned int rx_slots;
131 
132 	/* Anything to be read? */
133 	if (state->op->cmd != AXGBE_I2C_CMD_READ)
134 		return;
135 
136 	rx_slots = XI2C_IOREAD(pdata, IC_RXFLR);
137 	while (rx_slots && state->rx_len) {
138 		*state->rx_buf++ = XI2C_IOREAD(pdata, IC_DATA_CMD);
139 		state->rx_len--;
140 		rx_slots--;
141 	}
142 }
143 
144 static void axgbe_i2c_clear_isr_interrupts(struct axgbe_port *pdata,
145 					  unsigned int isr)
146 {
147 	struct axgbe_i2c_op_state *state = &pdata->i2c.op_state;
148 
149 	if (isr & AXGBE_INTR_TX_ABRT) {
150 		state->tx_abort_source = XI2C_IOREAD(pdata, IC_TX_ABRT_SOURCE);
151 		XI2C_IOREAD(pdata, IC_CLR_TX_ABRT);
152 	}
153 
154 	if (isr & AXGBE_INTR_STOP_DET)
155 		XI2C_IOREAD(pdata, IC_CLR_STOP_DET);
156 }
157 
158 static int axgbe_i2c_isr(struct axgbe_port *pdata)
159 {
160 	struct axgbe_i2c_op_state *state = &pdata->i2c.op_state;
161 	unsigned int isr;
162 
163 	isr = XI2C_IOREAD(pdata, IC_RAW_INTR_STAT);
164 
165 	axgbe_i2c_clear_isr_interrupts(pdata, isr);
166 
167 	if (isr & AXGBE_INTR_TX_ABRT) {
168 		axgbe_i2c_disable_interrupts(pdata);
169 
170 		state->ret = -EIO;
171 		goto out;
172 	}
173 
174 	/* Check for data in the Rx fifo */
175 	axgbe_i2c_read(pdata);
176 
177 	/* Fill up the Tx fifo next */
178 	axgbe_i2c_write(pdata);
179 
180 out:
181 	/* Complete on an error or STOP condition */
182 	if (state->ret || XI2C_GET_BITS(isr, IC_RAW_INTR_STAT, STOP_DET))
183 		return 1;
184 
185 	return 0;
186 }
187 
188 static void axgbe_i2c_set_mode(struct axgbe_port *pdata)
189 {
190 	unsigned int reg;
191 
192 	reg = XI2C_IOREAD(pdata, IC_CON);
193 	XI2C_SET_BITS(reg, IC_CON, MASTER_MODE, 1);
194 	XI2C_SET_BITS(reg, IC_CON, SLAVE_DISABLE, 1);
195 	XI2C_SET_BITS(reg, IC_CON, RESTART_EN, 1);
196 	XI2C_SET_BITS(reg, IC_CON, SPEED, AXGBE_STD_SPEED);
197 	XI2C_SET_BITS(reg, IC_CON, RX_FIFO_FULL_HOLD, 1);
198 	XI2C_IOWRITE(pdata, IC_CON, reg);
199 }
200 
201 static void axgbe_i2c_get_features(struct axgbe_port *pdata)
202 {
203 	struct axgbe_i2c *i2c = &pdata->i2c;
204 	unsigned int reg;
205 
206 	reg = XI2C_IOREAD(pdata, IC_COMP_PARAM_1);
207 	i2c->max_speed_mode = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
208 					    MAX_SPEED_MODE);
209 	i2c->rx_fifo_size = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
210 					  RX_BUFFER_DEPTH);
211 	i2c->tx_fifo_size = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
212 					  TX_BUFFER_DEPTH);
213 }
214 
215 static void axgbe_i2c_set_target(struct axgbe_port *pdata, unsigned int addr)
216 {
217 	XI2C_IOWRITE(pdata, IC_TAR, addr);
218 }
219 
220 static int axgbe_i2c_xfer(struct axgbe_port *pdata, struct axgbe_i2c_op *op)
221 {
222 	struct axgbe_i2c_op_state *state = &pdata->i2c.op_state;
223 	int ret;
224 	uint64_t timeout;
225 
226 	pthread_mutex_lock(&pdata->i2c_mutex);
227 	ret = axgbe_i2c_disable(pdata);
228 	if (ret) {
229 		PMD_DRV_LOG(ERR, "failed to disable i2c master\n");
230 		return ret;
231 	}
232 
233 	axgbe_i2c_set_target(pdata, op->target);
234 
235 	memset(state, 0, sizeof(*state));
236 	state->op = op;
237 	state->tx_len = op->len;
238 	state->tx_buf = (unsigned char *)op->buf;
239 	state->rx_len = op->len;
240 	state->rx_buf = (unsigned char *)op->buf;
241 
242 	axgbe_i2c_clear_all_interrupts(pdata);
243 	ret = axgbe_i2c_enable(pdata);
244 	if (ret) {
245 		PMD_DRV_LOG(ERR, "failed to enable i2c master\n");
246 		return ret;
247 	}
248 
249 	/* Enabling the interrupts will cause the TX FIFO empty interrupt to
250 	 * fire and begin to process the command via the ISR.
251 	 */
252 	axgbe_i2c_enable_interrupts(pdata);
253 	timeout = rte_get_timer_cycles() + rte_get_timer_hz();
254 
255 	while (time_before(rte_get_timer_cycles(), timeout)) {
256 		rte_delay_us(100);
257 		if (XI2C_IOREAD(pdata, IC_RAW_INTR_STAT)) {
258 			if (axgbe_i2c_isr(pdata))
259 				goto success;
260 		}
261 	}
262 
263 	PMD_DRV_LOG(ERR, "i2c operation timed out\n");
264 	axgbe_i2c_disable_interrupts(pdata);
265 	axgbe_i2c_disable(pdata);
266 	ret = -ETIMEDOUT;
267 	goto unlock;
268 
269 success:
270 	ret = state->ret;
271 	if (ret) {
272 		if (state->tx_abort_source & IC_TX_ABRT_7B_ADDR_NOACK)
273 			ret = -ENOTCONN;
274 		else if (state->tx_abort_source & IC_TX_ABRT_ARB_LOST)
275 			ret = -EAGAIN;
276 	}
277 
278 unlock:
279 	pthread_mutex_unlock(&pdata->i2c_mutex);
280 	return ret;
281 }
282 
283 static void axgbe_i2c_stop(struct axgbe_port *pdata)
284 {
285 	if (!pdata->i2c.started)
286 		return;
287 
288 	pdata->i2c.started = 0;
289 	axgbe_i2c_disable_interrupts(pdata);
290 	axgbe_i2c_disable(pdata);
291 	axgbe_i2c_clear_all_interrupts(pdata);
292 }
293 
294 static int axgbe_i2c_start(struct axgbe_port *pdata)
295 {
296 	if (pdata->i2c.started)
297 		return 0;
298 
299 	pdata->i2c.started = 1;
300 
301 	return 0;
302 }
303 
304 static int axgbe_i2c_init(struct axgbe_port *pdata)
305 {
306 	int ret;
307 
308 	axgbe_i2c_disable_interrupts(pdata);
309 
310 	ret = axgbe_i2c_disable(pdata);
311 	if (ret) {
312 		PMD_DRV_LOG(ERR, "failed to disable i2c master\n");
313 		return ret;
314 	}
315 
316 	axgbe_i2c_get_features(pdata);
317 
318 	axgbe_i2c_set_mode(pdata);
319 
320 	axgbe_i2c_clear_all_interrupts(pdata);
321 
322 	return 0;
323 }
324 
325 void axgbe_init_function_ptrs_i2c(struct axgbe_i2c_if *i2c_if)
326 {
327 	i2c_if->i2c_init		= axgbe_i2c_init;
328 	i2c_if->i2c_start		= axgbe_i2c_start;
329 	i2c_if->i2c_stop		= axgbe_i2c_stop;
330 	i2c_if->i2c_xfer		= axgbe_i2c_xfer;
331 }
332