Merge tag 'misc-5.15-2021-09-05' of git://git.kernel.dk/linux-block
[linux-2.6-microblaze.git] / drivers / thermal / sun8i_thermal.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Thermal sensor driver for Allwinner SOC
4  * Copyright (C) 2019 Yangtao Li
5  *
6  * Based on the work of Icenowy Zheng <icenowy@aosc.io>
7  * Based on the work of Ondrej Jirman <megous@megous.com>
8  * Based on the work of Josef Gajdusek <atx@atx.name>
9  */
10
11 #include <linux/bitmap.h>
12 #include <linux/clk.h>
13 #include <linux/device.h>
14 #include <linux/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/nvmem-consumer.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/regmap.h>
20 #include <linux/reset.h>
21 #include <linux/slab.h>
22 #include <linux/thermal.h>
23
24 #include "thermal_hwmon.h"
25
26 #define MAX_SENSOR_NUM  4
27
28 #define FT_TEMP_MASK                            GENMASK(11, 0)
29 #define TEMP_CALIB_MASK                         GENMASK(11, 0)
30 #define CALIBRATE_DEFAULT                       0x800
31
32 #define SUN8I_THS_CTRL0                         0x00
33 #define SUN8I_THS_CTRL2                         0x40
34 #define SUN8I_THS_IC                            0x44
35 #define SUN8I_THS_IS                            0x48
36 #define SUN8I_THS_MFC                           0x70
37 #define SUN8I_THS_TEMP_CALIB                    0x74
38 #define SUN8I_THS_TEMP_DATA                     0x80
39
40 #define SUN50I_THS_CTRL0                        0x00
41 #define SUN50I_H6_THS_ENABLE                    0x04
42 #define SUN50I_H6_THS_PC                        0x08
43 #define SUN50I_H6_THS_DIC                       0x10
44 #define SUN50I_H6_THS_DIS                       0x20
45 #define SUN50I_H6_THS_MFC                       0x30
46 #define SUN50I_H6_THS_TEMP_CALIB                0xa0
47 #define SUN50I_H6_THS_TEMP_DATA                 0xc0
48
49 #define SUN8I_THS_CTRL0_T_ACQ0(x)               (GENMASK(15, 0) & (x))
50 #define SUN8I_THS_CTRL2_T_ACQ1(x)               ((GENMASK(15, 0) & (x)) << 16)
51 #define SUN8I_THS_DATA_IRQ_STS(x)               BIT(x + 8)
52
53 #define SUN50I_THS_CTRL0_T_ACQ(x)               ((GENMASK(15, 0) & (x)) << 16)
54 #define SUN50I_THS_FILTER_EN                    BIT(2)
55 #define SUN50I_THS_FILTER_TYPE(x)               (GENMASK(1, 0) & (x))
56 #define SUN50I_H6_THS_PC_TEMP_PERIOD(x)         ((GENMASK(19, 0) & (x)) << 12)
57 #define SUN50I_H6_THS_DATA_IRQ_STS(x)           BIT(x)
58
59 /* millidegree celsius */
60
61 struct tsensor {
62         struct ths_device               *tmdev;
63         struct thermal_zone_device      *tzd;
64         int                             id;
65 };
66
67 struct ths_thermal_chip {
68         bool            has_mod_clk;
69         bool            has_bus_clk_reset;
70         int             sensor_num;
71         int             offset;
72         int             scale;
73         int             ft_deviation;
74         int             temp_data_base;
75         int             (*calibrate)(struct ths_device *tmdev,
76                                      u16 *caldata, int callen);
77         int             (*init)(struct ths_device *tmdev);
78         unsigned long   (*irq_ack)(struct ths_device *tmdev);
79         int             (*calc_temp)(struct ths_device *tmdev,
80                                      int id, int reg);
81 };
82
83 struct ths_device {
84         const struct ths_thermal_chip           *chip;
85         struct device                           *dev;
86         struct regmap                           *regmap;
87         struct reset_control                    *reset;
88         struct clk                              *bus_clk;
89         struct clk                              *mod_clk;
90         struct tsensor                          sensor[MAX_SENSOR_NUM];
91 };
92
93 /* Temp Unit: millidegree Celsius */
94 static int sun8i_ths_calc_temp(struct ths_device *tmdev,
95                                int id, int reg)
96 {
97         return tmdev->chip->offset - (reg * tmdev->chip->scale / 10);
98 }
99
100 static int sun50i_h5_calc_temp(struct ths_device *tmdev,
101                                int id, int reg)
102 {
103         if (reg >= 0x500)
104                 return -1191 * reg / 10 + 223000;
105         else if (!id)
106                 return -1452 * reg / 10 + 259000;
107         else
108                 return -1590 * reg / 10 + 276000;
109 }
110
111 static int sun8i_ths_get_temp(void *data, int *temp)
112 {
113         struct tsensor *s = data;
114         struct ths_device *tmdev = s->tmdev;
115         int val = 0;
116
117         regmap_read(tmdev->regmap, tmdev->chip->temp_data_base +
118                     0x4 * s->id, &val);
119
120         /* ths have no data yet */
121         if (!val)
122                 return -EAGAIN;
123
124         *temp = tmdev->chip->calc_temp(tmdev, s->id, val);
125         /*
126          * According to the original sdk, there are some platforms(rarely)
127          * that add a fixed offset value after calculating the temperature
128          * value. We can't simply put it on the formula for calculating the
129          * temperature above, because the formula for calculating the
130          * temperature above is also used when the sensor is calibrated. If
131          * do this, the correct calibration formula is hard to know.
132          */
133         *temp += tmdev->chip->ft_deviation;
134
135         return 0;
136 }
137
138 static const struct thermal_zone_of_device_ops ths_ops = {
139         .get_temp = sun8i_ths_get_temp,
140 };
141
142 static const struct regmap_config config = {
143         .reg_bits = 32,
144         .val_bits = 32,
145         .reg_stride = 4,
146         .fast_io = true,
147         .max_register = 0xfc,
148 };
149
150 static unsigned long sun8i_h3_irq_ack(struct ths_device *tmdev)
151 {
152         unsigned long irq_bitmap = 0;
153         int i, state;
154
155         regmap_read(tmdev->regmap, SUN8I_THS_IS, &state);
156
157         for (i = 0; i < tmdev->chip->sensor_num; i++) {
158                 if (state & SUN8I_THS_DATA_IRQ_STS(i)) {
159                         regmap_write(tmdev->regmap, SUN8I_THS_IS,
160                                      SUN8I_THS_DATA_IRQ_STS(i));
161                         bitmap_set(&irq_bitmap, i, 1);
162                 }
163         }
164
165         return irq_bitmap;
166 }
167
168 static unsigned long sun50i_h6_irq_ack(struct ths_device *tmdev)
169 {
170         unsigned long irq_bitmap = 0;
171         int i, state;
172
173         regmap_read(tmdev->regmap, SUN50I_H6_THS_DIS, &state);
174
175         for (i = 0; i < tmdev->chip->sensor_num; i++) {
176                 if (state & SUN50I_H6_THS_DATA_IRQ_STS(i)) {
177                         regmap_write(tmdev->regmap, SUN50I_H6_THS_DIS,
178                                      SUN50I_H6_THS_DATA_IRQ_STS(i));
179                         bitmap_set(&irq_bitmap, i, 1);
180                 }
181         }
182
183         return irq_bitmap;
184 }
185
186 static irqreturn_t sun8i_irq_thread(int irq, void *data)
187 {
188         struct ths_device *tmdev = data;
189         unsigned long irq_bitmap = tmdev->chip->irq_ack(tmdev);
190         int i;
191
192         for_each_set_bit(i, &irq_bitmap, tmdev->chip->sensor_num) {
193                 thermal_zone_device_update(tmdev->sensor[i].tzd,
194                                            THERMAL_EVENT_UNSPECIFIED);
195         }
196
197         return IRQ_HANDLED;
198 }
199
200 static int sun8i_h3_ths_calibrate(struct ths_device *tmdev,
201                                   u16 *caldata, int callen)
202 {
203         int i;
204
205         if (!caldata[0] || callen < 2 * tmdev->chip->sensor_num)
206                 return -EINVAL;
207
208         for (i = 0; i < tmdev->chip->sensor_num; i++) {
209                 int offset = (i % 2) << 4;
210
211                 regmap_update_bits(tmdev->regmap,
212                                    SUN8I_THS_TEMP_CALIB + (4 * (i >> 1)),
213                                    0xfff << offset,
214                                    caldata[i] << offset);
215         }
216
217         return 0;
218 }
219
220 static int sun50i_h6_ths_calibrate(struct ths_device *tmdev,
221                                    u16 *caldata, int callen)
222 {
223         struct device *dev = tmdev->dev;
224         int i, ft_temp;
225
226         if (!caldata[0] || callen < 2 + 2 * tmdev->chip->sensor_num)
227                 return -EINVAL;
228
229         /*
230          * efuse layout:
231          *
232          *      0   11  16       32
233          *      +-------+-------+-------+
234          *      |temp|  |sensor0|sensor1|
235          *      +-------+-------+-------+
236          *
237          * The calibration data on the H6 is the ambient temperature and
238          * sensor values that are filled during the factory test stage.
239          *
240          * The unit of stored FT temperature is 0.1 degreee celusis.
241          *
242          * We need to calculate a delta between measured and caluclated
243          * register values and this will become a calibration offset.
244          */
245         ft_temp = (caldata[0] & FT_TEMP_MASK) * 100;
246
247         for (i = 0; i < tmdev->chip->sensor_num; i++) {
248                 int sensor_reg = caldata[i + 1] & TEMP_CALIB_MASK;
249                 int cdata, offset;
250                 int sensor_temp = tmdev->chip->calc_temp(tmdev, i, sensor_reg);
251
252                 /*
253                  * Calibration data is CALIBRATE_DEFAULT - (calculated
254                  * temperature from sensor reading at factory temperature
255                  * minus actual factory temperature) * 14.88 (scale from
256                  * temperature to register values)
257                  */
258                 cdata = CALIBRATE_DEFAULT -
259                         ((sensor_temp - ft_temp) * 10 / tmdev->chip->scale);
260                 if (cdata & ~TEMP_CALIB_MASK) {
261                         /*
262                          * Calibration value more than 12-bit, but calibration
263                          * register is 12-bit. In this case, ths hardware can
264                          * still work without calibration, although the data
265                          * won't be so accurate.
266                          */
267                         dev_warn(dev, "sensor%d is not calibrated.\n", i);
268                         continue;
269                 }
270
271                 offset = (i % 2) * 16;
272                 regmap_update_bits(tmdev->regmap,
273                                    SUN50I_H6_THS_TEMP_CALIB + (i / 2 * 4),
274                                    0xfff << offset,
275                                    cdata << offset);
276         }
277
278         return 0;
279 }
280
281 static int sun8i_ths_calibrate(struct ths_device *tmdev)
282 {
283         struct nvmem_cell *calcell;
284         struct device *dev = tmdev->dev;
285         u16 *caldata;
286         size_t callen;
287         int ret = 0;
288
289         calcell = devm_nvmem_cell_get(dev, "calibration");
290         if (IS_ERR(calcell)) {
291                 if (PTR_ERR(calcell) == -EPROBE_DEFER)
292                         return -EPROBE_DEFER;
293                 /*
294                  * Even if the external calibration data stored in sid is
295                  * not accessible, the THS hardware can still work, although
296                  * the data won't be so accurate.
297                  *
298                  * The default value of calibration register is 0x800 for
299                  * every sensor, and the calibration value is usually 0x7xx
300                  * or 0x8xx, so they won't be away from the default value
301                  * for a lot.
302                  *
303                  * So here we do not return error if the calibration data is
304                  * not available, except the probe needs deferring.
305                  */
306                 goto out;
307         }
308
309         caldata = nvmem_cell_read(calcell, &callen);
310         if (IS_ERR(caldata)) {
311                 ret = PTR_ERR(caldata);
312                 goto out;
313         }
314
315         tmdev->chip->calibrate(tmdev, caldata, callen);
316
317         kfree(caldata);
318 out:
319         return ret;
320 }
321
322 static int sun8i_ths_resource_init(struct ths_device *tmdev)
323 {
324         struct device *dev = tmdev->dev;
325         struct platform_device *pdev = to_platform_device(dev);
326         void __iomem *base;
327         int ret;
328
329         base = devm_platform_ioremap_resource(pdev, 0);
330         if (IS_ERR(base))
331                 return PTR_ERR(base);
332
333         tmdev->regmap = devm_regmap_init_mmio(dev, base, &config);
334         if (IS_ERR(tmdev->regmap))
335                 return PTR_ERR(tmdev->regmap);
336
337         if (tmdev->chip->has_bus_clk_reset) {
338                 tmdev->reset = devm_reset_control_get(dev, NULL);
339                 if (IS_ERR(tmdev->reset))
340                         return PTR_ERR(tmdev->reset);
341
342                 tmdev->bus_clk = devm_clk_get(&pdev->dev, "bus");
343                 if (IS_ERR(tmdev->bus_clk))
344                         return PTR_ERR(tmdev->bus_clk);
345         }
346
347         if (tmdev->chip->has_mod_clk) {
348                 tmdev->mod_clk = devm_clk_get(&pdev->dev, "mod");
349                 if (IS_ERR(tmdev->mod_clk))
350                         return PTR_ERR(tmdev->mod_clk);
351         }
352
353         ret = reset_control_deassert(tmdev->reset);
354         if (ret)
355                 return ret;
356
357         ret = clk_prepare_enable(tmdev->bus_clk);
358         if (ret)
359                 goto assert_reset;
360
361         ret = clk_set_rate(tmdev->mod_clk, 24000000);
362         if (ret)
363                 goto bus_disable;
364
365         ret = clk_prepare_enable(tmdev->mod_clk);
366         if (ret)
367                 goto bus_disable;
368
369         ret = sun8i_ths_calibrate(tmdev);
370         if (ret)
371                 goto mod_disable;
372
373         return 0;
374
375 mod_disable:
376         clk_disable_unprepare(tmdev->mod_clk);
377 bus_disable:
378         clk_disable_unprepare(tmdev->bus_clk);
379 assert_reset:
380         reset_control_assert(tmdev->reset);
381
382         return ret;
383 }
384
385 static int sun8i_h3_thermal_init(struct ths_device *tmdev)
386 {
387         int val;
388
389         /* average over 4 samples */
390         regmap_write(tmdev->regmap, SUN8I_THS_MFC,
391                      SUN50I_THS_FILTER_EN |
392                      SUN50I_THS_FILTER_TYPE(1));
393         /*
394          * clkin = 24MHz
395          * filter_samples = 4
396          * period = 0.25s
397          *
398          * x = period * clkin / 4096 / filter_samples - 1
399          *   = 365
400          */
401         val = GENMASK(7 + tmdev->chip->sensor_num, 8);
402         regmap_write(tmdev->regmap, SUN8I_THS_IC,
403                      SUN50I_H6_THS_PC_TEMP_PERIOD(365) | val);
404         /*
405          * T_acq = 20us
406          * clkin = 24MHz
407          *
408          * x = T_acq * clkin - 1
409          *   = 479
410          */
411         regmap_write(tmdev->regmap, SUN8I_THS_CTRL0,
412                      SUN8I_THS_CTRL0_T_ACQ0(479));
413         val = GENMASK(tmdev->chip->sensor_num - 1, 0);
414         regmap_write(tmdev->regmap, SUN8I_THS_CTRL2,
415                      SUN8I_THS_CTRL2_T_ACQ1(479) | val);
416
417         return 0;
418 }
419
420 /*
421  * Without this undocumented value, the returned temperatures would
422  * be higher than real ones by about 20C.
423  */
424 #define SUN50I_H6_CTRL0_UNK 0x0000002f
425
426 static int sun50i_h6_thermal_init(struct ths_device *tmdev)
427 {
428         int val;
429
430         /*
431          * T_acq = 20us
432          * clkin = 24MHz
433          *
434          * x = T_acq * clkin - 1
435          *   = 479
436          */
437         regmap_write(tmdev->regmap, SUN50I_THS_CTRL0,
438                      SUN50I_H6_CTRL0_UNK | SUN50I_THS_CTRL0_T_ACQ(479));
439         /* average over 4 samples */
440         regmap_write(tmdev->regmap, SUN50I_H6_THS_MFC,
441                      SUN50I_THS_FILTER_EN |
442                      SUN50I_THS_FILTER_TYPE(1));
443         /*
444          * clkin = 24MHz
445          * filter_samples = 4
446          * period = 0.25s
447          *
448          * x = period * clkin / 4096 / filter_samples - 1
449          *   = 365
450          */
451         regmap_write(tmdev->regmap, SUN50I_H6_THS_PC,
452                      SUN50I_H6_THS_PC_TEMP_PERIOD(365));
453         /* enable sensor */
454         val = GENMASK(tmdev->chip->sensor_num - 1, 0);
455         regmap_write(tmdev->regmap, SUN50I_H6_THS_ENABLE, val);
456         /* thermal data interrupt enable */
457         val = GENMASK(tmdev->chip->sensor_num - 1, 0);
458         regmap_write(tmdev->regmap, SUN50I_H6_THS_DIC, val);
459
460         return 0;
461 }
462
463 static int sun8i_ths_register(struct ths_device *tmdev)
464 {
465         int i;
466
467         for (i = 0; i < tmdev->chip->sensor_num; i++) {
468                 tmdev->sensor[i].tmdev = tmdev;
469                 tmdev->sensor[i].id = i;
470                 tmdev->sensor[i].tzd =
471                         devm_thermal_zone_of_sensor_register(tmdev->dev,
472                                                              i,
473                                                              &tmdev->sensor[i],
474                                                              &ths_ops);
475                 if (IS_ERR(tmdev->sensor[i].tzd))
476                         return PTR_ERR(tmdev->sensor[i].tzd);
477
478                 if (devm_thermal_add_hwmon_sysfs(tmdev->sensor[i].tzd))
479                         dev_warn(tmdev->dev,
480                                  "Failed to add hwmon sysfs attributes\n");
481         }
482
483         return 0;
484 }
485
486 static int sun8i_ths_probe(struct platform_device *pdev)
487 {
488         struct ths_device *tmdev;
489         struct device *dev = &pdev->dev;
490         int ret, irq;
491
492         tmdev = devm_kzalloc(dev, sizeof(*tmdev), GFP_KERNEL);
493         if (!tmdev)
494                 return -ENOMEM;
495
496         tmdev->dev = dev;
497         tmdev->chip = of_device_get_match_data(&pdev->dev);
498         if (!tmdev->chip)
499                 return -EINVAL;
500
501         platform_set_drvdata(pdev, tmdev);
502
503         ret = sun8i_ths_resource_init(tmdev);
504         if (ret)
505                 return ret;
506
507         irq = platform_get_irq(pdev, 0);
508         if (irq < 0)
509                 return irq;
510
511         ret = tmdev->chip->init(tmdev);
512         if (ret)
513                 return ret;
514
515         ret = sun8i_ths_register(tmdev);
516         if (ret)
517                 return ret;
518
519         /*
520          * Avoid entering the interrupt handler, the thermal device is not
521          * registered yet, we deffer the registration of the interrupt to
522          * the end.
523          */
524         ret = devm_request_threaded_irq(dev, irq, NULL,
525                                         sun8i_irq_thread,
526                                         IRQF_ONESHOT, "ths", tmdev);
527         if (ret)
528                 return ret;
529
530         return 0;
531 }
532
533 static int sun8i_ths_remove(struct platform_device *pdev)
534 {
535         struct ths_device *tmdev = platform_get_drvdata(pdev);
536
537         clk_disable_unprepare(tmdev->mod_clk);
538         clk_disable_unprepare(tmdev->bus_clk);
539         reset_control_assert(tmdev->reset);
540
541         return 0;
542 }
543
544 static const struct ths_thermal_chip sun8i_a83t_ths = {
545         .sensor_num = 3,
546         .scale = 705,
547         .offset = 191668,
548         .temp_data_base = SUN8I_THS_TEMP_DATA,
549         .calibrate = sun8i_h3_ths_calibrate,
550         .init = sun8i_h3_thermal_init,
551         .irq_ack = sun8i_h3_irq_ack,
552         .calc_temp = sun8i_ths_calc_temp,
553 };
554
555 static const struct ths_thermal_chip sun8i_h3_ths = {
556         .sensor_num = 1,
557         .scale = 1211,
558         .offset = 217000,
559         .has_mod_clk = true,
560         .has_bus_clk_reset = true,
561         .temp_data_base = SUN8I_THS_TEMP_DATA,
562         .calibrate = sun8i_h3_ths_calibrate,
563         .init = sun8i_h3_thermal_init,
564         .irq_ack = sun8i_h3_irq_ack,
565         .calc_temp = sun8i_ths_calc_temp,
566 };
567
568 static const struct ths_thermal_chip sun8i_r40_ths = {
569         .sensor_num = 2,
570         .offset = 251086,
571         .scale = 1130,
572         .has_mod_clk = true,
573         .has_bus_clk_reset = true,
574         .temp_data_base = SUN8I_THS_TEMP_DATA,
575         .calibrate = sun8i_h3_ths_calibrate,
576         .init = sun8i_h3_thermal_init,
577         .irq_ack = sun8i_h3_irq_ack,
578         .calc_temp = sun8i_ths_calc_temp,
579 };
580
581 static const struct ths_thermal_chip sun50i_a64_ths = {
582         .sensor_num = 3,
583         .offset = 260890,
584         .scale = 1170,
585         .has_mod_clk = true,
586         .has_bus_clk_reset = true,
587         .temp_data_base = SUN8I_THS_TEMP_DATA,
588         .calibrate = sun8i_h3_ths_calibrate,
589         .init = sun8i_h3_thermal_init,
590         .irq_ack = sun8i_h3_irq_ack,
591         .calc_temp = sun8i_ths_calc_temp,
592 };
593
594 static const struct ths_thermal_chip sun50i_a100_ths = {
595         .sensor_num = 3,
596         .has_bus_clk_reset = true,
597         .ft_deviation = 8000,
598         .offset = 187744,
599         .scale = 672,
600         .temp_data_base = SUN50I_H6_THS_TEMP_DATA,
601         .calibrate = sun50i_h6_ths_calibrate,
602         .init = sun50i_h6_thermal_init,
603         .irq_ack = sun50i_h6_irq_ack,
604         .calc_temp = sun8i_ths_calc_temp,
605 };
606
607 static const struct ths_thermal_chip sun50i_h5_ths = {
608         .sensor_num = 2,
609         .has_mod_clk = true,
610         .has_bus_clk_reset = true,
611         .temp_data_base = SUN8I_THS_TEMP_DATA,
612         .calibrate = sun8i_h3_ths_calibrate,
613         .init = sun8i_h3_thermal_init,
614         .irq_ack = sun8i_h3_irq_ack,
615         .calc_temp = sun50i_h5_calc_temp,
616 };
617
618 static const struct ths_thermal_chip sun50i_h6_ths = {
619         .sensor_num = 2,
620         .has_bus_clk_reset = true,
621         .ft_deviation = 7000,
622         .offset = 187744,
623         .scale = 672,
624         .temp_data_base = SUN50I_H6_THS_TEMP_DATA,
625         .calibrate = sun50i_h6_ths_calibrate,
626         .init = sun50i_h6_thermal_init,
627         .irq_ack = sun50i_h6_irq_ack,
628         .calc_temp = sun8i_ths_calc_temp,
629 };
630
631 static const struct of_device_id of_ths_match[] = {
632         { .compatible = "allwinner,sun8i-a83t-ths", .data = &sun8i_a83t_ths },
633         { .compatible = "allwinner,sun8i-h3-ths", .data = &sun8i_h3_ths },
634         { .compatible = "allwinner,sun8i-r40-ths", .data = &sun8i_r40_ths },
635         { .compatible = "allwinner,sun50i-a64-ths", .data = &sun50i_a64_ths },
636         { .compatible = "allwinner,sun50i-a100-ths", .data = &sun50i_a100_ths },
637         { .compatible = "allwinner,sun50i-h5-ths", .data = &sun50i_h5_ths },
638         { .compatible = "allwinner,sun50i-h6-ths", .data = &sun50i_h6_ths },
639         { /* sentinel */ },
640 };
641 MODULE_DEVICE_TABLE(of, of_ths_match);
642
643 static struct platform_driver ths_driver = {
644         .probe = sun8i_ths_probe,
645         .remove = sun8i_ths_remove,
646         .driver = {
647                 .name = "sun8i-thermal",
648                 .of_match_table = of_ths_match,
649         },
650 };
651 module_platform_driver(ths_driver);
652
653 MODULE_DESCRIPTION("Thermal sensor driver for Allwinner SOC");
654 MODULE_LICENSE("GPL v2");