1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * TI AEMIF driver
4 *
5 * Copyright (C) 2010 - 2013 Texas Instruments Incorporated. http://www.ti.com/
6 *
7 * Authors:
8 * Murali Karicheri <m-karicheri2@ti.com>
9 * Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
10 */
11
12 #include <linux/clk.h>
13 #include <linux/err.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/of_platform.h>
19 #include <linux/platform_device.h>
20 #include <linux/platform_data/ti-aemif.h>
21
22 #define TA_SHIFT 2
23 #define RHOLD_SHIFT 4
24 #define RSTROBE_SHIFT 7
25 #define RSETUP_SHIFT 13
26 #define WHOLD_SHIFT 17
27 #define WSTROBE_SHIFT 20
28 #define WSETUP_SHIFT 26
29 #define EW_SHIFT 30
30 #define SSTROBE_SHIFT 31
31
32 #define TA(x) ((x) << TA_SHIFT)
33 #define RHOLD(x) ((x) << RHOLD_SHIFT)
34 #define RSTROBE(x) ((x) << RSTROBE_SHIFT)
35 #define RSETUP(x) ((x) << RSETUP_SHIFT)
36 #define WHOLD(x) ((x) << WHOLD_SHIFT)
37 #define WSTROBE(x) ((x) << WSTROBE_SHIFT)
38 #define WSETUP(x) ((x) << WSETUP_SHIFT)
39 #define EW(x) ((x) << EW_SHIFT)
40 #define SSTROBE(x) ((x) << SSTROBE_SHIFT)
41
42 #define ASIZE_MAX 0x1
43 #define TA_MAX 0x3
44 #define RHOLD_MAX 0x7
45 #define RSTROBE_MAX 0x3f
46 #define RSETUP_MAX 0xf
47 #define WHOLD_MAX 0x7
48 #define WSTROBE_MAX 0x3f
49 #define WSETUP_MAX 0xf
50 #define EW_MAX 0x1
51 #define SSTROBE_MAX 0x1
52 #define NUM_CS 4
53
54 #define TA_VAL(x) (((x) & TA(TA_MAX)) >> TA_SHIFT)
55 #define RHOLD_VAL(x) (((x) & RHOLD(RHOLD_MAX)) >> RHOLD_SHIFT)
56 #define RSTROBE_VAL(x) (((x) & RSTROBE(RSTROBE_MAX)) >> RSTROBE_SHIFT)
57 #define RSETUP_VAL(x) (((x) & RSETUP(RSETUP_MAX)) >> RSETUP_SHIFT)
58 #define WHOLD_VAL(x) (((x) & WHOLD(WHOLD_MAX)) >> WHOLD_SHIFT)
59 #define WSTROBE_VAL(x) (((x) & WSTROBE(WSTROBE_MAX)) >> WSTROBE_SHIFT)
60 #define WSETUP_VAL(x) (((x) & WSETUP(WSETUP_MAX)) >> WSETUP_SHIFT)
61 #define EW_VAL(x) (((x) & EW(EW_MAX)) >> EW_SHIFT)
62 #define SSTROBE_VAL(x) (((x) & SSTROBE(SSTROBE_MAX)) >> SSTROBE_SHIFT)
63
64 #define NRCSR_OFFSET 0x00
65 #define AWCCR_OFFSET 0x04
66 #define A1CR_OFFSET 0x10
67
68 #define ACR_ASIZE_MASK 0x3
69 #define ACR_EW_MASK BIT(30)
70 #define ACR_SSTROBE_MASK BIT(31)
71 #define ASIZE_16BIT 1
72
73 #define CONFIG_MASK (TA(TA_MAX) | \
74 RHOLD(RHOLD_MAX) | \
75 RSTROBE(RSTROBE_MAX) | \
76 RSETUP(RSETUP_MAX) | \
77 WHOLD(WHOLD_MAX) | \
78 WSTROBE(WSTROBE_MAX) | \
79 WSETUP(WSETUP_MAX) | \
80 EW(EW_MAX) | SSTROBE(SSTROBE_MAX) | \
81 ASIZE_MAX)
82
83 /**
84 * struct aemif_cs_data: structure to hold cs parameters
85 * @cs: chip-select number
86 * @wstrobe: write strobe width, ns
87 * @rstrobe: read strobe width, ns
88 * @wsetup: write setup width, ns
89 * @whold: write hold width, ns
90 * @rsetup: read setup width, ns
91 * @rhold: read hold width, ns
92 * @ta: minimum turn around time, ns
93 * @enable_ss: enable/disable select strobe mode
94 * @enable_ew: enable/disable extended wait mode
95 * @asize: width of the asynchronous device's data bus
96 */
97 struct aemif_cs_data {
98 u8 cs;
99 u16 wstrobe;
100 u16 rstrobe;
101 u8 wsetup;
102 u8 whold;
103 u8 rsetup;
104 u8 rhold;
105 u8 ta;
106 u8 enable_ss;
107 u8 enable_ew;
108 u8 asize;
109 };
110
111 /**
112 * struct aemif_device: structure to hold device data
113 * @base: base address of AEMIF registers
114 * @clk: source clock
115 * @clk_rate: clock's rate in kHz
116 * @num_cs: number of assigned chip-selects
117 * @cs_offset: start number of cs nodes
118 * @cs_data: array of chip-select settings
119 */
120 struct aemif_device {
121 void __iomem *base;
122 struct clk *clk;
123 unsigned long clk_rate;
124 u8 num_cs;
125 int cs_offset;
126 struct aemif_cs_data cs_data[NUM_CS];
127 };
128
129 /**
130 * aemif_calc_rate - calculate timing data.
131 * @pdev: platform device to calculate for
132 * @wanted: The cycle time needed in nanoseconds.
133 * @clk: The input clock rate in kHz.
134 * @max: The maximum divider value that can be programmed.
135 *
136 * On success, returns the calculated timing value minus 1 for easy
137 * programming into AEMIF timing registers, else negative errno.
138 */
aemif_calc_rate(struct platform_device * pdev,int wanted,unsigned long clk,int max)139 static int aemif_calc_rate(struct platform_device *pdev, int wanted,
140 unsigned long clk, int max)
141 {
142 int result;
143
144 result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1;
145
146 dev_dbg(&pdev->dev, "%s: result %d from %ld, %d\n", __func__, result,
147 clk, wanted);
148
149 /* It is generally OK to have a more relaxed timing than requested... */
150 if (result < 0)
151 result = 0;
152
153 /* ... But configuring tighter timings is not an option. */
154 else if (result > max)
155 result = -EINVAL;
156
157 return result;
158 }
159
160 /**
161 * aemif_config_abus - configure async bus parameters
162 * @pdev: platform device to configure for
163 * @csnum: aemif chip select number
164 *
165 * This function programs the given timing values (in real clock) into the
166 * AEMIF registers taking the AEMIF clock into account.
167 *
168 * This function does not use any locking while programming the AEMIF
169 * because it is expected that there is only one user of a given
170 * chip-select.
171 *
172 * Returns 0 on success, else negative errno.
173 */
aemif_config_abus(struct platform_device * pdev,int csnum)174 static int aemif_config_abus(struct platform_device *pdev, int csnum)
175 {
176 struct aemif_device *aemif = platform_get_drvdata(pdev);
177 struct aemif_cs_data *data = &aemif->cs_data[csnum];
178 int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
179 unsigned long clk_rate = aemif->clk_rate;
180 unsigned offset;
181 u32 set, val;
182
183 offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
184
185 ta = aemif_calc_rate(pdev, data->ta, clk_rate, TA_MAX);
186 rhold = aemif_calc_rate(pdev, data->rhold, clk_rate, RHOLD_MAX);
187 rstrobe = aemif_calc_rate(pdev, data->rstrobe, clk_rate, RSTROBE_MAX);
188 rsetup = aemif_calc_rate(pdev, data->rsetup, clk_rate, RSETUP_MAX);
189 whold = aemif_calc_rate(pdev, data->whold, clk_rate, WHOLD_MAX);
190 wstrobe = aemif_calc_rate(pdev, data->wstrobe, clk_rate, WSTROBE_MAX);
191 wsetup = aemif_calc_rate(pdev, data->wsetup, clk_rate, WSETUP_MAX);
192
193 if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 ||
194 whold < 0 || wstrobe < 0 || wsetup < 0) {
195 dev_err(&pdev->dev, "%s: cannot get suitable timings\n",
196 __func__);
197 return -EINVAL;
198 }
199
200 set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) |
201 WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup);
202
203 set |= (data->asize & ACR_ASIZE_MASK);
204 if (data->enable_ew)
205 set |= ACR_EW_MASK;
206 if (data->enable_ss)
207 set |= ACR_SSTROBE_MASK;
208
209 val = readl(aemif->base + offset);
210 val &= ~CONFIG_MASK;
211 val |= set;
212 writel(val, aemif->base + offset);
213
214 return 0;
215 }
216
aemif_cycles_to_nsec(int val,unsigned long clk_rate)217 static inline int aemif_cycles_to_nsec(int val, unsigned long clk_rate)
218 {
219 return ((val + 1) * NSEC_PER_MSEC) / clk_rate;
220 }
221
222 /**
223 * aemif_get_hw_params - function to read hw register values
224 * @pdev: platform device to read for
225 * @csnum: aemif chip select number
226 *
227 * This function reads the defaults from the registers and update
228 * the timing values. Required for get/set commands and also for
229 * the case when driver needs to use defaults in hardware.
230 */
aemif_get_hw_params(struct platform_device * pdev,int csnum)231 static void aemif_get_hw_params(struct platform_device *pdev, int csnum)
232 {
233 struct aemif_device *aemif = platform_get_drvdata(pdev);
234 struct aemif_cs_data *data = &aemif->cs_data[csnum];
235 unsigned long clk_rate = aemif->clk_rate;
236 u32 val, offset;
237
238 offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
239 val = readl(aemif->base + offset);
240
241 data->ta = aemif_cycles_to_nsec(TA_VAL(val), clk_rate);
242 data->rhold = aemif_cycles_to_nsec(RHOLD_VAL(val), clk_rate);
243 data->rstrobe = aemif_cycles_to_nsec(RSTROBE_VAL(val), clk_rate);
244 data->rsetup = aemif_cycles_to_nsec(RSETUP_VAL(val), clk_rate);
245 data->whold = aemif_cycles_to_nsec(WHOLD_VAL(val), clk_rate);
246 data->wstrobe = aemif_cycles_to_nsec(WSTROBE_VAL(val), clk_rate);
247 data->wsetup = aemif_cycles_to_nsec(WSETUP_VAL(val), clk_rate);
248 data->enable_ew = EW_VAL(val);
249 data->enable_ss = SSTROBE_VAL(val);
250 data->asize = val & ASIZE_MAX;
251 }
252
253 /**
254 * of_aemif_parse_abus_config - parse CS configuration from DT
255 * @pdev: platform device to parse for
256 * @np: device node ptr
257 *
258 * This function update the emif async bus configuration based on the values
259 * configured in a cs device binding node.
260 */
of_aemif_parse_abus_config(struct platform_device * pdev,struct device_node * np)261 static int of_aemif_parse_abus_config(struct platform_device *pdev,
262 struct device_node *np)
263 {
264 struct aemif_device *aemif = platform_get_drvdata(pdev);
265 struct aemif_cs_data *data;
266 u32 cs;
267 u32 val;
268
269 if (of_property_read_u32(np, "ti,cs-chipselect", &cs)) {
270 dev_dbg(&pdev->dev, "cs property is required");
271 return -EINVAL;
272 }
273
274 if (cs - aemif->cs_offset >= NUM_CS || cs < aemif->cs_offset) {
275 dev_dbg(&pdev->dev, "cs number is incorrect %d", cs);
276 return -EINVAL;
277 }
278
279 if (aemif->num_cs >= NUM_CS) {
280 dev_dbg(&pdev->dev, "cs count is more than %d", NUM_CS);
281 return -EINVAL;
282 }
283
284 data = &aemif->cs_data[aemif->num_cs];
285 data->cs = cs;
286
287 /* read the current value in the hw register */
288 aemif_get_hw_params(pdev, aemif->num_cs++);
289
290 /* override the values from device node */
291 if (!of_property_read_u32(np, "ti,cs-min-turnaround-ns", &val))
292 data->ta = val;
293
294 if (!of_property_read_u32(np, "ti,cs-read-hold-ns", &val))
295 data->rhold = val;
296
297 if (!of_property_read_u32(np, "ti,cs-read-strobe-ns", &val))
298 data->rstrobe = val;
299
300 if (!of_property_read_u32(np, "ti,cs-read-setup-ns", &val))
301 data->rsetup = val;
302
303 if (!of_property_read_u32(np, "ti,cs-write-hold-ns", &val))
304 data->whold = val;
305
306 if (!of_property_read_u32(np, "ti,cs-write-strobe-ns", &val))
307 data->wstrobe = val;
308
309 if (!of_property_read_u32(np, "ti,cs-write-setup-ns", &val))
310 data->wsetup = val;
311
312 if (!of_property_read_u32(np, "ti,cs-bus-width", &val))
313 if (val == 16)
314 data->asize = 1;
315 data->enable_ew = of_property_read_bool(np, "ti,cs-extended-wait-mode");
316 data->enable_ss = of_property_read_bool(np, "ti,cs-select-strobe-mode");
317 return 0;
318 }
319
320 static const struct of_device_id aemif_of_match[] = {
321 { .compatible = "ti,davinci-aemif", },
322 { .compatible = "ti,da850-aemif", },
323 {},
324 };
325 MODULE_DEVICE_TABLE(of, aemif_of_match);
326
aemif_probe(struct platform_device * pdev)327 static int aemif_probe(struct platform_device *pdev)
328 {
329 int i;
330 int ret = -ENODEV;
331 struct device *dev = &pdev->dev;
332 struct device_node *np = dev->of_node;
333 struct device_node *child_np;
334 struct aemif_device *aemif;
335 struct aemif_platform_data *pdata;
336 struct of_dev_auxdata *dev_lookup;
337
338 aemif = devm_kzalloc(dev, sizeof(*aemif), GFP_KERNEL);
339 if (!aemif)
340 return -ENOMEM;
341
342 pdata = dev_get_platdata(&pdev->dev);
343 dev_lookup = pdata ? pdata->dev_lookup : NULL;
344
345 platform_set_drvdata(pdev, aemif);
346
347 aemif->clk = devm_clk_get(dev, NULL);
348 if (IS_ERR(aemif->clk)) {
349 dev_err(dev, "cannot get clock 'aemif'\n");
350 return PTR_ERR(aemif->clk);
351 }
352
353 ret = clk_prepare_enable(aemif->clk);
354 if (ret)
355 return ret;
356
357 aemif->clk_rate = clk_get_rate(aemif->clk) / MSEC_PER_SEC;
358
359 if (np && of_device_is_compatible(np, "ti,da850-aemif"))
360 aemif->cs_offset = 2;
361 else if (pdata)
362 aemif->cs_offset = pdata->cs_offset;
363
364 aemif->base = devm_platform_ioremap_resource(pdev, 0);
365 if (IS_ERR(aemif->base)) {
366 ret = PTR_ERR(aemif->base);
367 goto error;
368 }
369
370 if (np) {
371 /*
372 * For every controller device node, there is a cs device node
373 * that describe the bus configuration parameters. This
374 * functions iterate over these nodes and update the cs data
375 * array.
376 */
377 for_each_available_child_of_node(np, child_np) {
378 ret = of_aemif_parse_abus_config(pdev, child_np);
379 if (ret < 0) {
380 of_node_put(child_np);
381 goto error;
382 }
383 }
384 } else if (pdata && pdata->num_abus_data > 0) {
385 for (i = 0; i < pdata->num_abus_data; i++, aemif->num_cs++) {
386 aemif->cs_data[i].cs = pdata->abus_data[i].cs;
387 aemif_get_hw_params(pdev, i);
388 }
389 }
390
391 for (i = 0; i < aemif->num_cs; i++) {
392 ret = aemif_config_abus(pdev, i);
393 if (ret < 0) {
394 dev_err(dev, "Error configuring chip select %d\n",
395 aemif->cs_data[i].cs);
396 goto error;
397 }
398 }
399
400 /*
401 * Create a child devices explicitly from here to guarantee that the
402 * child will be probed after the AEMIF timing parameters are set.
403 */
404 if (np) {
405 for_each_available_child_of_node(np, child_np) {
406 ret = of_platform_populate(child_np, NULL,
407 dev_lookup, dev);
408 if (ret < 0) {
409 of_node_put(child_np);
410 goto error;
411 }
412 }
413 } else if (pdata) {
414 for (i = 0; i < pdata->num_sub_devices; i++) {
415 pdata->sub_devices[i].dev.parent = dev;
416 ret = platform_device_register(&pdata->sub_devices[i]);
417 if (ret) {
418 dev_warn(dev, "Error register sub device %s\n",
419 pdata->sub_devices[i].name);
420 }
421 }
422 }
423
424 return 0;
425 error:
426 clk_disable_unprepare(aemif->clk);
427 return ret;
428 }
429
aemif_remove(struct platform_device * pdev)430 static int aemif_remove(struct platform_device *pdev)
431 {
432 struct aemif_device *aemif = platform_get_drvdata(pdev);
433
434 clk_disable_unprepare(aemif->clk);
435 return 0;
436 }
437
438 static struct platform_driver aemif_driver = {
439 .probe = aemif_probe,
440 .remove = aemif_remove,
441 .driver = {
442 .name = "ti-aemif",
443 .of_match_table = of_match_ptr(aemif_of_match),
444 },
445 };
446
447 module_platform_driver(aemif_driver);
448
449 MODULE_AUTHOR("Murali Karicheri <m-karicheri2@ti.com>");
450 MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");
451 MODULE_DESCRIPTION("Texas Instruments AEMIF driver");
452 MODULE_LICENSE("GPL v2");
453 MODULE_ALIAS("platform:" KBUILD_MODNAME);
454