1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * JZ4780 NAND/external memory controller (NEMC)
4 *
5 * Copyright (c) 2015 Imagination Technologies
6 * Author: Alex Smith <alex@alex-smith.me.uk>
7 */
8
9 #include <linux/clk.h>
10 #include <linux/init.h>
11 #include <linux/io.h>
12 #include <linux/math64.h>
13 #include <linux/of.h>
14 #include <linux/of_address.h>
15 #include <linux/of_platform.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
19
20 #include <linux/jz4780-nemc.h>
21
22 #define NEMC_SMCRn(n) (0x14 + (((n) - 1) * 4))
23 #define NEMC_NFCSR 0x50
24
25 #define NEMC_REG_LEN 0x54
26
27 #define NEMC_SMCR_SMT BIT(0)
28 #define NEMC_SMCR_BW_SHIFT 6
29 #define NEMC_SMCR_BW_MASK (0x3 << NEMC_SMCR_BW_SHIFT)
30 #define NEMC_SMCR_BW_8 (0 << 6)
31 #define NEMC_SMCR_TAS_SHIFT 8
32 #define NEMC_SMCR_TAS_MASK (0xf << NEMC_SMCR_TAS_SHIFT)
33 #define NEMC_SMCR_TAH_SHIFT 12
34 #define NEMC_SMCR_TAH_MASK (0xf << NEMC_SMCR_TAH_SHIFT)
35 #define NEMC_SMCR_TBP_SHIFT 16
36 #define NEMC_SMCR_TBP_MASK (0xf << NEMC_SMCR_TBP_SHIFT)
37 #define NEMC_SMCR_TAW_SHIFT 20
38 #define NEMC_SMCR_TAW_MASK (0xf << NEMC_SMCR_TAW_SHIFT)
39 #define NEMC_SMCR_TSTRV_SHIFT 24
40 #define NEMC_SMCR_TSTRV_MASK (0x3f << NEMC_SMCR_TSTRV_SHIFT)
41
42 #define NEMC_NFCSR_NFEn(n) BIT(((n) - 1) << 1)
43 #define NEMC_NFCSR_NFCEn(n) BIT((((n) - 1) << 1) + 1)
44 #define NEMC_NFCSR_TNFEn(n) BIT(16 + (n) - 1)
45
46 struct jz_soc_info {
47 u8 tas_tah_cycles_max;
48 };
49
50 struct jz4780_nemc {
51 spinlock_t lock;
52 struct device *dev;
53 const struct jz_soc_info *soc_info;
54 void __iomem *base;
55 struct clk *clk;
56 uint32_t clk_period;
57 unsigned long banks_present;
58 };
59
60 /**
61 * jz4780_nemc_num_banks() - count the number of banks referenced by a device
62 * @dev: device to count banks for, must be a child of the NEMC.
63 *
64 * Return: The number of unique NEMC banks referred to by the specified NEMC
65 * child device. Unique here means that a device that references the same bank
66 * multiple times in its "reg" property will only count once.
67 */
jz4780_nemc_num_banks(struct device * dev)68 unsigned int jz4780_nemc_num_banks(struct device *dev)
69 {
70 const __be32 *prop;
71 unsigned int bank, count = 0;
72 unsigned long referenced = 0;
73 int i = 0;
74
75 while ((prop = of_get_address(dev->of_node, i++, NULL, NULL))) {
76 bank = of_read_number(prop, 1);
77 if (!(referenced & BIT(bank))) {
78 referenced |= BIT(bank);
79 count++;
80 }
81 }
82
83 return count;
84 }
85 EXPORT_SYMBOL(jz4780_nemc_num_banks);
86
87 /**
88 * jz4780_nemc_set_type() - set the type of device connected to a bank
89 * @dev: child device of the NEMC.
90 * @bank: bank number to configure.
91 * @type: type of device connected to the bank.
92 */
jz4780_nemc_set_type(struct device * dev,unsigned int bank,enum jz4780_nemc_bank_type type)93 void jz4780_nemc_set_type(struct device *dev, unsigned int bank,
94 enum jz4780_nemc_bank_type type)
95 {
96 struct jz4780_nemc *nemc = dev_get_drvdata(dev->parent);
97 uint32_t nfcsr;
98
99 nfcsr = readl(nemc->base + NEMC_NFCSR);
100
101 /* TODO: Support toggle NAND devices. */
102 switch (type) {
103 case JZ4780_NEMC_BANK_SRAM:
104 nfcsr &= ~(NEMC_NFCSR_TNFEn(bank) | NEMC_NFCSR_NFEn(bank));
105 break;
106 case JZ4780_NEMC_BANK_NAND:
107 nfcsr &= ~NEMC_NFCSR_TNFEn(bank);
108 nfcsr |= NEMC_NFCSR_NFEn(bank);
109 break;
110 }
111
112 writel(nfcsr, nemc->base + NEMC_NFCSR);
113 }
114 EXPORT_SYMBOL(jz4780_nemc_set_type);
115
116 /**
117 * jz4780_nemc_assert() - (de-)assert a NAND device's chip enable pin
118 * @dev: child device of the NEMC.
119 * @bank: bank number of device.
120 * @assert: whether the chip enable pin should be asserted.
121 *
122 * (De-)asserts the chip enable pin for the NAND device connected to the
123 * specified bank.
124 */
jz4780_nemc_assert(struct device * dev,unsigned int bank,bool assert)125 void jz4780_nemc_assert(struct device *dev, unsigned int bank, bool assert)
126 {
127 struct jz4780_nemc *nemc = dev_get_drvdata(dev->parent);
128 uint32_t nfcsr;
129
130 nfcsr = readl(nemc->base + NEMC_NFCSR);
131
132 if (assert)
133 nfcsr |= NEMC_NFCSR_NFCEn(bank);
134 else
135 nfcsr &= ~NEMC_NFCSR_NFCEn(bank);
136
137 writel(nfcsr, nemc->base + NEMC_NFCSR);
138 }
139 EXPORT_SYMBOL(jz4780_nemc_assert);
140
jz4780_nemc_clk_period(struct jz4780_nemc * nemc)141 static uint32_t jz4780_nemc_clk_period(struct jz4780_nemc *nemc)
142 {
143 unsigned long rate;
144
145 rate = clk_get_rate(nemc->clk);
146 if (!rate)
147 return 0;
148
149 /* Return in picoseconds. */
150 return div64_ul(1000000000000ull, rate);
151 }
152
jz4780_nemc_ns_to_cycles(struct jz4780_nemc * nemc,uint32_t ns)153 static uint32_t jz4780_nemc_ns_to_cycles(struct jz4780_nemc *nemc, uint32_t ns)
154 {
155 return ((ns * 1000) + nemc->clk_period - 1) / nemc->clk_period;
156 }
157
jz4780_nemc_configure_bank(struct jz4780_nemc * nemc,unsigned int bank,struct device_node * node)158 static bool jz4780_nemc_configure_bank(struct jz4780_nemc *nemc,
159 unsigned int bank,
160 struct device_node *node)
161 {
162 uint32_t smcr, val, cycles;
163
164 /*
165 * Conversion of tBP and tAW cycle counts to values supported by the
166 * hardware (round up to the next supported value).
167 */
168 static const u8 convert_tBP_tAW[] = {
169 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
170
171 /* 11 - 12 -> 12 cycles */
172 11, 11,
173
174 /* 13 - 15 -> 15 cycles */
175 12, 12, 12,
176
177 /* 16 - 20 -> 20 cycles */
178 13, 13, 13, 13, 13,
179
180 /* 21 - 25 -> 25 cycles */
181 14, 14, 14, 14, 14,
182
183 /* 26 - 31 -> 31 cycles */
184 15, 15, 15, 15, 15, 15
185 };
186
187 smcr = readl(nemc->base + NEMC_SMCRn(bank));
188 smcr &= ~NEMC_SMCR_SMT;
189
190 if (!of_property_read_u32(node, "ingenic,nemc-bus-width", &val)) {
191 smcr &= ~NEMC_SMCR_BW_MASK;
192 switch (val) {
193 case 8:
194 smcr |= NEMC_SMCR_BW_8;
195 break;
196 default:
197 /*
198 * Earlier SoCs support a 16 bit bus width (the 4780
199 * does not), until those are properly supported, error.
200 */
201 dev_err(nemc->dev, "unsupported bus width: %u\n", val);
202 return false;
203 }
204 }
205
206 if (of_property_read_u32(node, "ingenic,nemc-tAS", &val) == 0) {
207 smcr &= ~NEMC_SMCR_TAS_MASK;
208 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
209 if (cycles > nemc->soc_info->tas_tah_cycles_max) {
210 dev_err(nemc->dev, "tAS %u is too high (%u cycles)\n",
211 val, cycles);
212 return false;
213 }
214
215 smcr |= cycles << NEMC_SMCR_TAS_SHIFT;
216 }
217
218 if (of_property_read_u32(node, "ingenic,nemc-tAH", &val) == 0) {
219 smcr &= ~NEMC_SMCR_TAH_MASK;
220 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
221 if (cycles > nemc->soc_info->tas_tah_cycles_max) {
222 dev_err(nemc->dev, "tAH %u is too high (%u cycles)\n",
223 val, cycles);
224 return false;
225 }
226
227 smcr |= cycles << NEMC_SMCR_TAH_SHIFT;
228 }
229
230 if (of_property_read_u32(node, "ingenic,nemc-tBP", &val) == 0) {
231 smcr &= ~NEMC_SMCR_TBP_MASK;
232 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
233 if (cycles > 31) {
234 dev_err(nemc->dev, "tBP %u is too high (%u cycles)\n",
235 val, cycles);
236 return false;
237 }
238
239 smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TBP_SHIFT;
240 }
241
242 if (of_property_read_u32(node, "ingenic,nemc-tAW", &val) == 0) {
243 smcr &= ~NEMC_SMCR_TAW_MASK;
244 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
245 if (cycles > 31) {
246 dev_err(nemc->dev, "tAW %u is too high (%u cycles)\n",
247 val, cycles);
248 return false;
249 }
250
251 smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TAW_SHIFT;
252 }
253
254 if (of_property_read_u32(node, "ingenic,nemc-tSTRV", &val) == 0) {
255 smcr &= ~NEMC_SMCR_TSTRV_MASK;
256 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
257 if (cycles > 63) {
258 dev_err(nemc->dev, "tSTRV %u is too high (%u cycles)\n",
259 val, cycles);
260 return false;
261 }
262
263 smcr |= cycles << NEMC_SMCR_TSTRV_SHIFT;
264 }
265
266 writel(smcr, nemc->base + NEMC_SMCRn(bank));
267 return true;
268 }
269
jz4780_nemc_probe(struct platform_device * pdev)270 static int jz4780_nemc_probe(struct platform_device *pdev)
271 {
272 struct device *dev = &pdev->dev;
273 struct jz4780_nemc *nemc;
274 struct resource *res;
275 struct device_node *child;
276 const __be32 *prop;
277 unsigned int bank;
278 unsigned long referenced;
279 int i, ret;
280
281 nemc = devm_kzalloc(dev, sizeof(*nemc), GFP_KERNEL);
282 if (!nemc)
283 return -ENOMEM;
284
285 nemc->soc_info = device_get_match_data(dev);
286 if (!nemc->soc_info)
287 return -EINVAL;
288
289 spin_lock_init(&nemc->lock);
290 nemc->dev = dev;
291
292 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
293 if (!res)
294 return -EINVAL;
295
296 /*
297 * The driver currently only uses the registers up to offset
298 * NEMC_REG_LEN. Since the EFUSE registers are in the middle of the
299 * NEMC registers, we only request the registers we will use for now;
300 * that way the EFUSE driver can probe too.
301 */
302 if (!devm_request_mem_region(dev, res->start, NEMC_REG_LEN, dev_name(dev))) {
303 dev_err(dev, "unable to request I/O memory region\n");
304 return -EBUSY;
305 }
306
307 nemc->base = devm_ioremap(dev, res->start, NEMC_REG_LEN);
308 if (!nemc->base) {
309 dev_err(dev, "failed to get I/O memory\n");
310 return -ENOMEM;
311 }
312
313 writel(0, nemc->base + NEMC_NFCSR);
314
315 nemc->clk = devm_clk_get(dev, NULL);
316 if (IS_ERR(nemc->clk)) {
317 dev_err(dev, "failed to get clock\n");
318 return PTR_ERR(nemc->clk);
319 }
320
321 ret = clk_prepare_enable(nemc->clk);
322 if (ret) {
323 dev_err(dev, "failed to enable clock: %d\n", ret);
324 return ret;
325 }
326
327 nemc->clk_period = jz4780_nemc_clk_period(nemc);
328 if (!nemc->clk_period) {
329 dev_err(dev, "failed to calculate clock period\n");
330 clk_disable_unprepare(nemc->clk);
331 return -EINVAL;
332 }
333
334 /*
335 * Iterate over child devices, check that they do not conflict with
336 * each other, and register child devices for them. If a child device
337 * has invalid properties, it is ignored and no platform device is
338 * registered for it.
339 */
340 for_each_child_of_node(nemc->dev->of_node, child) {
341 referenced = 0;
342 i = 0;
343 while ((prop = of_get_address(child, i++, NULL, NULL))) {
344 bank = of_read_number(prop, 1);
345 if (bank < 1 || bank >= JZ4780_NEMC_NUM_BANKS) {
346 dev_err(nemc->dev,
347 "%pOF requests invalid bank %u\n",
348 child, bank);
349
350 /* Will continue the outer loop below. */
351 referenced = 0;
352 break;
353 }
354
355 referenced |= BIT(bank);
356 }
357
358 if (!referenced) {
359 dev_err(nemc->dev, "%pOF has no addresses\n",
360 child);
361 continue;
362 } else if (nemc->banks_present & referenced) {
363 dev_err(nemc->dev, "%pOF conflicts with another node\n",
364 child);
365 continue;
366 }
367
368 /* Configure bank parameters. */
369 for_each_set_bit(bank, &referenced, JZ4780_NEMC_NUM_BANKS) {
370 if (!jz4780_nemc_configure_bank(nemc, bank, child)) {
371 referenced = 0;
372 break;
373 }
374 }
375
376 if (referenced) {
377 if (of_platform_device_create(child, NULL, nemc->dev))
378 nemc->banks_present |= referenced;
379 }
380 }
381
382 platform_set_drvdata(pdev, nemc);
383 dev_info(dev, "JZ4780 NEMC initialised\n");
384 return 0;
385 }
386
jz4780_nemc_remove(struct platform_device * pdev)387 static int jz4780_nemc_remove(struct platform_device *pdev)
388 {
389 struct jz4780_nemc *nemc = platform_get_drvdata(pdev);
390
391 clk_disable_unprepare(nemc->clk);
392 return 0;
393 }
394
395 static const struct jz_soc_info jz4740_soc_info = {
396 .tas_tah_cycles_max = 7,
397 };
398
399 static const struct jz_soc_info jz4780_soc_info = {
400 .tas_tah_cycles_max = 15,
401 };
402
403 static const struct of_device_id jz4780_nemc_dt_match[] = {
404 { .compatible = "ingenic,jz4740-nemc", .data = &jz4740_soc_info, },
405 { .compatible = "ingenic,jz4780-nemc", .data = &jz4780_soc_info, },
406 {},
407 };
408
409 static struct platform_driver jz4780_nemc_driver = {
410 .probe = jz4780_nemc_probe,
411 .remove = jz4780_nemc_remove,
412 .driver = {
413 .name = "jz4780-nemc",
414 .of_match_table = of_match_ptr(jz4780_nemc_dt_match),
415 },
416 };
417
jz4780_nemc_init(void)418 static int __init jz4780_nemc_init(void)
419 {
420 return platform_driver_register(&jz4780_nemc_driver);
421 }
422 subsys_initcall(jz4780_nemc_init);
423
