xref: /openbmc/linux/drivers/fpga/dfl-n3000-nios.c (revision 8938c48f)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * DFL device driver for Nios private feature on Intel PAC (Programmable
4  * Acceleration Card) N3000
5  *
6  * Copyright (C) 2019-2020 Intel Corporation, Inc.
7  *
8  * Authors:
9  *   Wu Hao <hao.wu@intel.com>
10  *   Xu Yilun <yilun.xu@intel.com>
11  */
12 #include <linux/bitfield.h>
13 #include <linux/dfl.h>
14 #include <linux/errno.h>
15 #include <linux/io.h>
16 #include <linux/io-64-nonatomic-lo-hi.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/regmap.h>
21 #include <linux/stddef.h>
22 #include <linux/spi/altera.h>
23 #include <linux/spi/spi.h>
24 #include <linux/types.h>
25 
26 /*
27  * N3000 Nios private feature registers, named as NIOS_SPI_XX on spec.
28  * NS is the abbreviation of NIOS_SPI.
29  */
30 #define N3000_NS_PARAM				0x8
31 #define N3000_NS_PARAM_SHIFT_MODE_MSK		BIT_ULL(1)
32 #define N3000_NS_PARAM_SHIFT_MODE_MSB		0
33 #define N3000_NS_PARAM_SHIFT_MODE_LSB		1
34 #define N3000_NS_PARAM_DATA_WIDTH		GENMASK_ULL(7, 2)
35 #define N3000_NS_PARAM_NUM_CS			GENMASK_ULL(13, 8)
36 #define N3000_NS_PARAM_CLK_POL			BIT_ULL(14)
37 #define N3000_NS_PARAM_CLK_PHASE		BIT_ULL(15)
38 #define N3000_NS_PARAM_PERIPHERAL_ID		GENMASK_ULL(47, 32)
39 
40 #define N3000_NS_CTRL				0x10
41 #define N3000_NS_CTRL_WR_DATA			GENMASK_ULL(31, 0)
42 #define N3000_NS_CTRL_ADDR			GENMASK_ULL(44, 32)
43 #define N3000_NS_CTRL_CMD_MSK			GENMASK_ULL(63, 62)
44 #define N3000_NS_CTRL_CMD_NOP			0
45 #define N3000_NS_CTRL_CMD_RD			1
46 #define N3000_NS_CTRL_CMD_WR			2
47 
48 #define N3000_NS_STAT				0x18
49 #define N3000_NS_STAT_RD_DATA			GENMASK_ULL(31, 0)
50 #define N3000_NS_STAT_RW_VAL			BIT_ULL(32)
51 
52 /* Nios handshake registers, indirect access */
53 #define N3000_NIOS_INIT				0x1000
54 #define N3000_NIOS_INIT_DONE			BIT(0)
55 #define N3000_NIOS_INIT_START			BIT(1)
56 /* Mode for retimer A, link 0, the same below */
57 #define N3000_NIOS_INIT_REQ_FEC_MODE_A0_MSK	GENMASK(9, 8)
58 #define N3000_NIOS_INIT_REQ_FEC_MODE_A1_MSK	GENMASK(11, 10)
59 #define N3000_NIOS_INIT_REQ_FEC_MODE_A2_MSK	GENMASK(13, 12)
60 #define N3000_NIOS_INIT_REQ_FEC_MODE_A3_MSK	GENMASK(15, 14)
61 #define N3000_NIOS_INIT_REQ_FEC_MODE_B0_MSK	GENMASK(17, 16)
62 #define N3000_NIOS_INIT_REQ_FEC_MODE_B1_MSK	GENMASK(19, 18)
63 #define N3000_NIOS_INIT_REQ_FEC_MODE_B2_MSK	GENMASK(21, 20)
64 #define N3000_NIOS_INIT_REQ_FEC_MODE_B3_MSK	GENMASK(23, 22)
65 #define N3000_NIOS_INIT_REQ_FEC_MODE_NO		0x0
66 #define N3000_NIOS_INIT_REQ_FEC_MODE_KR		0x1
67 #define N3000_NIOS_INIT_REQ_FEC_MODE_RS		0x2
68 
69 #define N3000_NIOS_FW_VERSION			0x1004
70 #define N3000_NIOS_FW_VERSION_PATCH		GENMASK(23, 20)
71 #define N3000_NIOS_FW_VERSION_MINOR		GENMASK(27, 24)
72 #define N3000_NIOS_FW_VERSION_MAJOR		GENMASK(31, 28)
73 
74 /* The retimers we use on Intel PAC N3000 is Parkvale, abbreviated to PKVL */
75 #define N3000_NIOS_PKVL_A_MODE_STS		0x1020
76 #define N3000_NIOS_PKVL_B_MODE_STS		0x1024
77 #define N3000_NIOS_PKVL_MODE_STS_GROUP_MSK	GENMASK(15, 8)
78 #define N3000_NIOS_PKVL_MODE_STS_GROUP_OK	0x0
79 #define N3000_NIOS_PKVL_MODE_STS_ID_MSK		GENMASK(7, 0)
80 /* When GROUP MASK field == GROUP_OK  */
81 #define N3000_NIOS_PKVL_MODE_ID_RESET		0x0
82 #define N3000_NIOS_PKVL_MODE_ID_4X10G		0x1
83 #define N3000_NIOS_PKVL_MODE_ID_4X25G		0x2
84 #define N3000_NIOS_PKVL_MODE_ID_2X25G		0x3
85 #define N3000_NIOS_PKVL_MODE_ID_2X25G_2X10G	0x4
86 #define N3000_NIOS_PKVL_MODE_ID_1X25G		0x5
87 
88 #define N3000_NIOS_REGBUS_RETRY_COUNT		10000	/* loop count */
89 
90 #define N3000_NIOS_INIT_TIMEOUT			10000000	/* usec */
91 #define N3000_NIOS_INIT_TIME_INTV		100000		/* usec */
92 
93 #define N3000_NIOS_INIT_REQ_FEC_MODE_MSK_ALL	\
94 	(N3000_NIOS_INIT_REQ_FEC_MODE_A0_MSK |	\
95 	 N3000_NIOS_INIT_REQ_FEC_MODE_A1_MSK |	\
96 	 N3000_NIOS_INIT_REQ_FEC_MODE_A2_MSK |	\
97 	 N3000_NIOS_INIT_REQ_FEC_MODE_A3_MSK |	\
98 	 N3000_NIOS_INIT_REQ_FEC_MODE_B0_MSK |	\
99 	 N3000_NIOS_INIT_REQ_FEC_MODE_B1_MSK |	\
100 	 N3000_NIOS_INIT_REQ_FEC_MODE_B2_MSK |	\
101 	 N3000_NIOS_INIT_REQ_FEC_MODE_B3_MSK)
102 
103 #define N3000_NIOS_INIT_REQ_FEC_MODE_NO_ALL			\
104 	(FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A0_MSK,	\
105 		    N3000_NIOS_INIT_REQ_FEC_MODE_NO) |		\
106 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A1_MSK,	\
107 		    N3000_NIOS_INIT_REQ_FEC_MODE_NO) |		\
108 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A2_MSK,	\
109 		    N3000_NIOS_INIT_REQ_FEC_MODE_NO) |		\
110 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A3_MSK,	\
111 		    N3000_NIOS_INIT_REQ_FEC_MODE_NO) |		\
112 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B0_MSK,	\
113 		    N3000_NIOS_INIT_REQ_FEC_MODE_NO) |		\
114 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B1_MSK,	\
115 		    N3000_NIOS_INIT_REQ_FEC_MODE_NO) |		\
116 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B2_MSK,	\
117 		    N3000_NIOS_INIT_REQ_FEC_MODE_NO) |		\
118 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B3_MSK,	\
119 		    N3000_NIOS_INIT_REQ_FEC_MODE_NO))
120 
121 #define N3000_NIOS_INIT_REQ_FEC_MODE_KR_ALL			\
122 	(FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A0_MSK,	\
123 		    N3000_NIOS_INIT_REQ_FEC_MODE_KR) |		\
124 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A1_MSK,	\
125 		    N3000_NIOS_INIT_REQ_FEC_MODE_KR) |		\
126 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A2_MSK,	\
127 		    N3000_NIOS_INIT_REQ_FEC_MODE_KR) |		\
128 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A3_MSK,	\
129 		    N3000_NIOS_INIT_REQ_FEC_MODE_KR) |		\
130 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B0_MSK,	\
131 		    N3000_NIOS_INIT_REQ_FEC_MODE_KR) |		\
132 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B1_MSK,	\
133 		    N3000_NIOS_INIT_REQ_FEC_MODE_KR) |		\
134 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B2_MSK,	\
135 		    N3000_NIOS_INIT_REQ_FEC_MODE_KR) |		\
136 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B3_MSK,	\
137 		    N3000_NIOS_INIT_REQ_FEC_MODE_KR))
138 
139 #define N3000_NIOS_INIT_REQ_FEC_MODE_RS_ALL			\
140 	(FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A0_MSK,	\
141 		    N3000_NIOS_INIT_REQ_FEC_MODE_RS) |		\
142 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A1_MSK,	\
143 		    N3000_NIOS_INIT_REQ_FEC_MODE_RS) |		\
144 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A2_MSK,	\
145 		    N3000_NIOS_INIT_REQ_FEC_MODE_RS) |		\
146 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_A3_MSK,	\
147 		    N3000_NIOS_INIT_REQ_FEC_MODE_RS) |		\
148 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B0_MSK,	\
149 		    N3000_NIOS_INIT_REQ_FEC_MODE_RS) |		\
150 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B1_MSK,	\
151 		    N3000_NIOS_INIT_REQ_FEC_MODE_RS) |		\
152 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B2_MSK,	\
153 		    N3000_NIOS_INIT_REQ_FEC_MODE_RS) |		\
154 	 FIELD_PREP(N3000_NIOS_INIT_REQ_FEC_MODE_B3_MSK,	\
155 		    N3000_NIOS_INIT_REQ_FEC_MODE_RS))
156 
157 struct n3000_nios {
158 	void __iomem *base;
159 	struct regmap *regmap;
160 	struct device *dev;
161 	struct platform_device *altera_spi;
162 };
163 
164 static ssize_t nios_fw_version_show(struct device *dev,
165 				    struct device_attribute *attr, char *buf)
166 {
167 	struct n3000_nios *nn = dev_get_drvdata(dev);
168 	unsigned int val;
169 	int ret;
170 
171 	ret = regmap_read(nn->regmap, N3000_NIOS_FW_VERSION, &val);
172 	if (ret)
173 		return ret;
174 
175 	return sysfs_emit(buf, "%x.%x.%x\n",
176 			  (u8)FIELD_GET(N3000_NIOS_FW_VERSION_MAJOR, val),
177 			  (u8)FIELD_GET(N3000_NIOS_FW_VERSION_MINOR, val),
178 			  (u8)FIELD_GET(N3000_NIOS_FW_VERSION_PATCH, val));
179 }
180 static DEVICE_ATTR_RO(nios_fw_version);
181 
182 #define IS_MODE_STATUS_OK(mode_stat)					\
183 	(FIELD_GET(N3000_NIOS_PKVL_MODE_STS_GROUP_MSK, (mode_stat)) ==	\
184 	 N3000_NIOS_PKVL_MODE_STS_GROUP_OK)
185 
186 #define IS_RETIMER_FEC_SUPPORTED(retimer_mode)			\
187 	((retimer_mode) != N3000_NIOS_PKVL_MODE_ID_RESET &&	\
188 	 (retimer_mode) != N3000_NIOS_PKVL_MODE_ID_4X10G)
189 
190 static int get_retimer_mode(struct n3000_nios *nn, unsigned int mode_stat_reg,
191 			    unsigned int *retimer_mode)
192 {
193 	unsigned int val;
194 	int ret;
195 
196 	ret = regmap_read(nn->regmap, mode_stat_reg, &val);
197 	if (ret)
198 		return ret;
199 
200 	if (!IS_MODE_STATUS_OK(val))
201 		return -EFAULT;
202 
203 	*retimer_mode = FIELD_GET(N3000_NIOS_PKVL_MODE_STS_ID_MSK, val);
204 
205 	return 0;
206 }
207 
208 static ssize_t retimer_A_mode_show(struct device *dev,
209 				   struct device_attribute *attr, char *buf)
210 {
211 	struct n3000_nios *nn = dev_get_drvdata(dev);
212 	unsigned int mode;
213 	int ret;
214 
215 	ret = get_retimer_mode(nn, N3000_NIOS_PKVL_A_MODE_STS, &mode);
216 	if (ret)
217 		return ret;
218 
219 	return sysfs_emit(buf, "0x%x\n", mode);
220 }
221 static DEVICE_ATTR_RO(retimer_A_mode);
222 
223 static ssize_t retimer_B_mode_show(struct device *dev,
224 				   struct device_attribute *attr, char *buf)
225 {
226 	struct n3000_nios *nn = dev_get_drvdata(dev);
227 	unsigned int mode;
228 	int ret;
229 
230 	ret = get_retimer_mode(nn, N3000_NIOS_PKVL_B_MODE_STS, &mode);
231 	if (ret)
232 		return ret;
233 
234 	return sysfs_emit(buf, "0x%x\n", mode);
235 }
236 static DEVICE_ATTR_RO(retimer_B_mode);
237 
238 static ssize_t fec_mode_show(struct device *dev,
239 			     struct device_attribute *attr, char *buf)
240 {
241 	unsigned int val, retimer_a_mode, retimer_b_mode, fec_modes;
242 	struct n3000_nios *nn = dev_get_drvdata(dev);
243 	int ret;
244 
245 	/* FEC mode setting is not supported in early FW versions */
246 	ret = regmap_read(nn->regmap, N3000_NIOS_FW_VERSION, &val);
247 	if (ret)
248 		return ret;
249 
250 	if (FIELD_GET(N3000_NIOS_FW_VERSION_MAJOR, val) < 3)
251 		return sysfs_emit(buf, "not supported\n");
252 
253 	/* If no 25G links, FEC mode setting is not supported either */
254 	ret = get_retimer_mode(nn, N3000_NIOS_PKVL_A_MODE_STS, &retimer_a_mode);
255 	if (ret)
256 		return ret;
257 
258 	ret = get_retimer_mode(nn, N3000_NIOS_PKVL_B_MODE_STS, &retimer_b_mode);
259 	if (ret)
260 		return ret;
261 
262 	if (!IS_RETIMER_FEC_SUPPORTED(retimer_a_mode) &&
263 	    !IS_RETIMER_FEC_SUPPORTED(retimer_b_mode))
264 		return sysfs_emit(buf, "not supported\n");
265 
266 	/* get the valid FEC mode for 25G links */
267 	ret = regmap_read(nn->regmap, N3000_NIOS_INIT, &val);
268 	if (ret)
269 		return ret;
270 
271 	/*
272 	 * FEC mode should always be the same for all links, as we set them
273 	 * in this way.
274 	 */
275 	fec_modes = (val & N3000_NIOS_INIT_REQ_FEC_MODE_MSK_ALL);
276 	if (fec_modes == N3000_NIOS_INIT_REQ_FEC_MODE_NO_ALL)
277 		return sysfs_emit(buf, "no\n");
278 	else if (fec_modes == N3000_NIOS_INIT_REQ_FEC_MODE_KR_ALL)
279 		return sysfs_emit(buf, "kr\n");
280 	else if (fec_modes == N3000_NIOS_INIT_REQ_FEC_MODE_RS_ALL)
281 		return sysfs_emit(buf, "rs\n");
282 
283 	return -EFAULT;
284 }
285 static DEVICE_ATTR_RO(fec_mode);
286 
287 static struct attribute *n3000_nios_attrs[] = {
288 	&dev_attr_nios_fw_version.attr,
289 	&dev_attr_retimer_A_mode.attr,
290 	&dev_attr_retimer_B_mode.attr,
291 	&dev_attr_fec_mode.attr,
292 	NULL,
293 };
294 ATTRIBUTE_GROUPS(n3000_nios);
295 
296 static int n3000_nios_init_done_check(struct n3000_nios *nn)
297 {
298 	unsigned int val, state_a, state_b;
299 	struct device *dev = nn->dev;
300 	int ret, ret2;
301 
302 	/*
303 	 * The SPI is shared by the Nios core inside the FPGA, Nios will use
304 	 * this SPI master to do some one time initialization after power up,
305 	 * and then release the control to OS. The driver needs to poll on
306 	 * INIT_DONE to see when driver could take the control.
307 	 *
308 	 * Please note that after Nios firmware version 3.0.0, INIT_START is
309 	 * introduced, so driver needs to trigger START firstly and then check
310 	 * INIT_DONE.
311 	 */
312 
313 	ret = regmap_read(nn->regmap, N3000_NIOS_FW_VERSION, &val);
314 	if (ret)
315 		return ret;
316 
317 	/*
318 	 * If Nios version register is totally uninitialized(== 0x0), then the
319 	 * Nios firmware is missing. So host could take control of SPI master
320 	 * safely, but initialization work for Nios is not done. To restore the
321 	 * card, we need to reprogram a new Nios firmware via the BMC chip on
322 	 * SPI bus. So the driver doesn't error out, it continues to create the
323 	 * spi controller device and spi_board_info for BMC.
324 	 */
325 	if (val == 0) {
326 		dev_err(dev, "Nios version reg = 0x%x, skip INIT_DONE check, but the retimer may be uninitialized\n",
327 			val);
328 		return 0;
329 	}
330 
331 	if (FIELD_GET(N3000_NIOS_FW_VERSION_MAJOR, val) >= 3) {
332 		/* read NIOS_INIT to check if retimer initialization is done */
333 		ret = regmap_read(nn->regmap, N3000_NIOS_INIT, &val);
334 		if (ret)
335 			return ret;
336 
337 		/* check if retimers are initialized already */
338 		if (val & (N3000_NIOS_INIT_DONE | N3000_NIOS_INIT_START))
339 			goto nios_init_done;
340 
341 		/* configure FEC mode per module param */
342 		val = N3000_NIOS_INIT_START;
343 
344 		/*
345 		 * When the retimer is to be set to 10G mode, there is no FEC
346 		 * mode setting, so the REQ_FEC_MODE field will be ignored by
347 		 * Nios firmware in this case. But we should still fill the FEC
348 		 * mode field cause host could not get the retimer working mode
349 		 * until the Nios init is done.
350 		 *
351 		 * For now the driver doesn't support the retimer FEC mode
352 		 * switching per user's request. It is always set to Reed
353 		 * Solomon FEC.
354 		 *
355 		 * The driver will set the same FEC mode for all links.
356 		 */
357 		val |= N3000_NIOS_INIT_REQ_FEC_MODE_RS_ALL;
358 
359 		ret = regmap_write(nn->regmap, N3000_NIOS_INIT, val);
360 		if (ret)
361 			return ret;
362 	}
363 
364 nios_init_done:
365 	/* polls on NIOS_INIT_DONE */
366 	ret = regmap_read_poll_timeout(nn->regmap, N3000_NIOS_INIT, val,
367 				       val & N3000_NIOS_INIT_DONE,
368 				       N3000_NIOS_INIT_TIME_INTV,
369 				       N3000_NIOS_INIT_TIMEOUT);
370 	if (ret)
371 		dev_err(dev, "NIOS_INIT_DONE %s\n",
372 			(ret == -ETIMEDOUT) ? "timed out" : "check error");
373 
374 	ret2 = regmap_read(nn->regmap, N3000_NIOS_PKVL_A_MODE_STS, &state_a);
375 	if (ret2)
376 		return ret2;
377 
378 	ret2 = regmap_read(nn->regmap, N3000_NIOS_PKVL_B_MODE_STS, &state_b);
379 	if (ret2)
380 		return ret2;
381 
382 	if (!ret) {
383 		/*
384 		 * After INIT_DONE is detected, it still needs to check if the
385 		 * Nios firmware reports any error during the retimer
386 		 * configuration.
387 		 */
388 		if (IS_MODE_STATUS_OK(state_a) && IS_MODE_STATUS_OK(state_b))
389 			return 0;
390 
391 		/*
392 		 * If the retimer configuration is failed, the Nios firmware
393 		 * will still release the spi controller for host to
394 		 * communicate with the BMC. It makes possible for people to
395 		 * reprogram a new Nios firmware and restore the card. So the
396 		 * driver doesn't error out, it continues to create the spi
397 		 * controller device and spi_board_info for BMC.
398 		 */
399 		dev_err(dev, "NIOS_INIT_DONE OK, but err on retimer init\n");
400 	}
401 
402 	dev_err(nn->dev, "PKVL_A_MODE_STS 0x%x\n", state_a);
403 	dev_err(nn->dev, "PKVL_B_MODE_STS 0x%x\n", state_b);
404 
405 	return ret;
406 }
407 
408 static struct spi_board_info m10_n3000_info = {
409 	.modalias = "m10-n3000",
410 	.max_speed_hz = 12500000,
411 	.bus_num = 0,
412 	.chip_select = 0,
413 };
414 
415 static int create_altera_spi_controller(struct n3000_nios *nn)
416 {
417 	struct altera_spi_platform_data pdata = { 0 };
418 	struct platform_device_info pdevinfo = { 0 };
419 	void __iomem *base = nn->base;
420 	u64 v;
421 
422 	v = readq(base + N3000_NS_PARAM);
423 
424 	pdata.mode_bits = SPI_CS_HIGH;
425 	if (FIELD_GET(N3000_NS_PARAM_CLK_POL, v))
426 		pdata.mode_bits |= SPI_CPOL;
427 	if (FIELD_GET(N3000_NS_PARAM_CLK_PHASE, v))
428 		pdata.mode_bits |= SPI_CPHA;
429 
430 	pdata.num_chipselect = FIELD_GET(N3000_NS_PARAM_NUM_CS, v);
431 	pdata.bits_per_word_mask =
432 		SPI_BPW_RANGE_MASK(1, FIELD_GET(N3000_NS_PARAM_DATA_WIDTH, v));
433 
434 	pdata.num_devices = 1;
435 	pdata.devices = &m10_n3000_info;
436 
437 	dev_dbg(nn->dev, "%s cs %u bpm 0x%x mode 0x%x\n", __func__,
438 		pdata.num_chipselect, pdata.bits_per_word_mask,
439 		pdata.mode_bits);
440 
441 	pdevinfo.name = "subdev_spi_altera";
442 	pdevinfo.id = PLATFORM_DEVID_AUTO;
443 	pdevinfo.parent = nn->dev;
444 	pdevinfo.data = &pdata;
445 	pdevinfo.size_data = sizeof(pdata);
446 
447 	nn->altera_spi = platform_device_register_full(&pdevinfo);
448 	return PTR_ERR_OR_ZERO(nn->altera_spi);
449 }
450 
451 static void destroy_altera_spi_controller(struct n3000_nios *nn)
452 {
453 	platform_device_unregister(nn->altera_spi);
454 }
455 
456 static int n3000_nios_poll_stat_timeout(void __iomem *base, u64 *v)
457 {
458 	int loops;
459 
460 	/*
461 	 * We don't use the time based timeout here for performance.
462 	 *
463 	 * The regbus read/write is on the critical path of Intel PAC N3000
464 	 * image programing. The time based timeout checking will add too much
465 	 * overhead on it. Usually the state changes in 1 or 2 loops on the
466 	 * test server, and we set 10000 times loop here for safety.
467 	 */
468 	for (loops = N3000_NIOS_REGBUS_RETRY_COUNT; loops > 0 ; loops--) {
469 		*v = readq(base + N3000_NS_STAT);
470 		if (*v & N3000_NS_STAT_RW_VAL)
471 			break;
472 		cpu_relax();
473 	}
474 
475 	return (loops > 0) ? 0 : -ETIMEDOUT;
476 }
477 
478 static int n3000_nios_reg_write(void *context, unsigned int reg, unsigned int val)
479 {
480 	struct n3000_nios *nn = context;
481 	u64 v;
482 	int ret;
483 
484 	v = FIELD_PREP(N3000_NS_CTRL_CMD_MSK, N3000_NS_CTRL_CMD_WR) |
485 	    FIELD_PREP(N3000_NS_CTRL_ADDR, reg) |
486 	    FIELD_PREP(N3000_NS_CTRL_WR_DATA, val);
487 	writeq(v, nn->base + N3000_NS_CTRL);
488 
489 	ret = n3000_nios_poll_stat_timeout(nn->base, &v);
490 	if (ret)
491 		dev_err(nn->dev, "fail to write reg 0x%x val 0x%x: %d\n",
492 			reg, val, ret);
493 
494 	return ret;
495 }
496 
497 static int n3000_nios_reg_read(void *context, unsigned int reg, unsigned int *val)
498 {
499 	struct n3000_nios *nn = context;
500 	u64 v;
501 	int ret;
502 
503 	v = FIELD_PREP(N3000_NS_CTRL_CMD_MSK, N3000_NS_CTRL_CMD_RD) |
504 	    FIELD_PREP(N3000_NS_CTRL_ADDR, reg);
505 	writeq(v, nn->base + N3000_NS_CTRL);
506 
507 	ret = n3000_nios_poll_stat_timeout(nn->base, &v);
508 	if (ret)
509 		dev_err(nn->dev, "fail to read reg 0x%x: %d\n", reg, ret);
510 	else
511 		*val = FIELD_GET(N3000_NS_STAT_RD_DATA, v);
512 
513 	return ret;
514 }
515 
516 static const struct regmap_config n3000_nios_regbus_cfg = {
517 	.reg_bits = 32,
518 	.reg_stride = 4,
519 	.val_bits = 32,
520 	.fast_io = true,
521 
522 	.reg_write = n3000_nios_reg_write,
523 	.reg_read = n3000_nios_reg_read,
524 };
525 
526 static int n3000_nios_probe(struct dfl_device *ddev)
527 {
528 	struct device *dev = &ddev->dev;
529 	struct n3000_nios *nn;
530 	int ret;
531 
532 	nn = devm_kzalloc(dev, sizeof(*nn), GFP_KERNEL);
533 	if (!nn)
534 		return -ENOMEM;
535 
536 	dev_set_drvdata(&ddev->dev, nn);
537 
538 	nn->dev = dev;
539 
540 	nn->base = devm_ioremap_resource(&ddev->dev, &ddev->mmio_res);
541 	if (IS_ERR(nn->base))
542 		return PTR_ERR(nn->base);
543 
544 	nn->regmap = devm_regmap_init(dev, NULL, nn, &n3000_nios_regbus_cfg);
545 	if (IS_ERR(nn->regmap))
546 		return PTR_ERR(nn->regmap);
547 
548 	ret = n3000_nios_init_done_check(nn);
549 	if (ret)
550 		return ret;
551 
552 	ret = create_altera_spi_controller(nn);
553 	if (ret)
554 		dev_err(dev, "altera spi controller create failed: %d\n", ret);
555 
556 	return ret;
557 }
558 
559 static void n3000_nios_remove(struct dfl_device *ddev)
560 {
561 	struct n3000_nios *nn = dev_get_drvdata(&ddev->dev);
562 
563 	destroy_altera_spi_controller(nn);
564 }
565 
566 #define FME_FEATURE_ID_N3000_NIOS	0xd
567 
568 static const struct dfl_device_id n3000_nios_ids[] = {
569 	{ FME_ID, FME_FEATURE_ID_N3000_NIOS },
570 	{ }
571 };
572 MODULE_DEVICE_TABLE(dfl, n3000_nios_ids);
573 
574 static struct dfl_driver n3000_nios_driver = {
575 	.drv	= {
576 		.name       = "dfl-n3000-nios",
577 		.dev_groups = n3000_nios_groups,
578 	},
579 	.id_table = n3000_nios_ids,
580 	.probe   = n3000_nios_probe,
581 	.remove  = n3000_nios_remove,
582 };
583 
584 module_dfl_driver(n3000_nios_driver);
585 
586 MODULE_DESCRIPTION("Driver for Nios private feature on Intel PAC N3000");
587 MODULE_AUTHOR("Intel Corporation");
588 MODULE_LICENSE("GPL v2");
589