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