Magnus Damm | b9dbf95 | 2012-05-25 16:03:44 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Emma Mobile Timer Support - STI |
| 3 | * |
| 4 | * Copyright (C) 2012 Magnus Damm |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 18 | */ |
| 19 | |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/platform_device.h> |
| 22 | #include <linux/spinlock.h> |
| 23 | #include <linux/interrupt.h> |
| 24 | #include <linux/ioport.h> |
| 25 | #include <linux/io.h> |
| 26 | #include <linux/clk.h> |
| 27 | #include <linux/irq.h> |
| 28 | #include <linux/err.h> |
| 29 | #include <linux/delay.h> |
| 30 | #include <linux/clocksource.h> |
| 31 | #include <linux/clockchips.h> |
| 32 | #include <linux/slab.h> |
| 33 | #include <linux/module.h> |
| 34 | |
| 35 | enum { USER_CLOCKSOURCE, USER_CLOCKEVENT, USER_NR }; |
| 36 | |
| 37 | struct em_sti_priv { |
| 38 | void __iomem *base; |
| 39 | struct clk *clk; |
| 40 | struct platform_device *pdev; |
| 41 | unsigned int active[USER_NR]; |
| 42 | unsigned long rate; |
| 43 | raw_spinlock_t lock; |
| 44 | struct clock_event_device ced; |
| 45 | struct clocksource cs; |
| 46 | }; |
| 47 | |
| 48 | #define STI_CONTROL 0x00 |
| 49 | #define STI_COMPA_H 0x10 |
| 50 | #define STI_COMPA_L 0x14 |
| 51 | #define STI_COMPB_H 0x18 |
| 52 | #define STI_COMPB_L 0x1c |
| 53 | #define STI_COUNT_H 0x20 |
| 54 | #define STI_COUNT_L 0x24 |
| 55 | #define STI_COUNT_RAW_H 0x28 |
| 56 | #define STI_COUNT_RAW_L 0x2c |
| 57 | #define STI_SET_H 0x30 |
| 58 | #define STI_SET_L 0x34 |
| 59 | #define STI_INTSTATUS 0x40 |
| 60 | #define STI_INTRAWSTATUS 0x44 |
| 61 | #define STI_INTENSET 0x48 |
| 62 | #define STI_INTENCLR 0x4c |
| 63 | #define STI_INTFFCLR 0x50 |
| 64 | |
| 65 | static inline unsigned long em_sti_read(struct em_sti_priv *p, int offs) |
| 66 | { |
| 67 | return ioread32(p->base + offs); |
| 68 | } |
| 69 | |
| 70 | static inline void em_sti_write(struct em_sti_priv *p, int offs, |
| 71 | unsigned long value) |
| 72 | { |
| 73 | iowrite32(value, p->base + offs); |
| 74 | } |
| 75 | |
| 76 | static int em_sti_enable(struct em_sti_priv *p) |
| 77 | { |
| 78 | int ret; |
| 79 | |
| 80 | /* enable clock */ |
| 81 | ret = clk_enable(p->clk); |
| 82 | if (ret) { |
| 83 | dev_err(&p->pdev->dev, "cannot enable clock\n"); |
| 84 | return ret; |
| 85 | } |
| 86 | |
| 87 | /* configure channel, periodic mode and maximum timeout */ |
| 88 | p->rate = clk_get_rate(p->clk); |
| 89 | |
| 90 | /* reset the counter */ |
| 91 | em_sti_write(p, STI_SET_H, 0x40000000); |
| 92 | em_sti_write(p, STI_SET_L, 0x00000000); |
| 93 | |
| 94 | /* mask and clear pending interrupts */ |
| 95 | em_sti_write(p, STI_INTENCLR, 3); |
| 96 | em_sti_write(p, STI_INTFFCLR, 3); |
| 97 | |
| 98 | /* enable updates of counter registers */ |
| 99 | em_sti_write(p, STI_CONTROL, 1); |
| 100 | |
| 101 | return 0; |
| 102 | } |
| 103 | |
| 104 | static void em_sti_disable(struct em_sti_priv *p) |
| 105 | { |
| 106 | /* mask interrupts */ |
| 107 | em_sti_write(p, STI_INTENCLR, 3); |
| 108 | |
| 109 | /* stop clock */ |
| 110 | clk_disable(p->clk); |
| 111 | } |
| 112 | |
| 113 | static cycle_t em_sti_count(struct em_sti_priv *p) |
| 114 | { |
| 115 | cycle_t ticks; |
| 116 | unsigned long flags; |
| 117 | |
| 118 | /* the STI hardware buffers the 48-bit count, but to |
| 119 | * break it out into two 32-bit access the registers |
| 120 | * must be accessed in a certain order. |
| 121 | * Always read STI_COUNT_H before STI_COUNT_L. |
| 122 | */ |
| 123 | raw_spin_lock_irqsave(&p->lock, flags); |
| 124 | ticks = (cycle_t)(em_sti_read(p, STI_COUNT_H) & 0xffff) << 32; |
| 125 | ticks |= em_sti_read(p, STI_COUNT_L); |
| 126 | raw_spin_unlock_irqrestore(&p->lock, flags); |
| 127 | |
| 128 | return ticks; |
| 129 | } |
| 130 | |
| 131 | static cycle_t em_sti_set_next(struct em_sti_priv *p, cycle_t next) |
| 132 | { |
| 133 | unsigned long flags; |
| 134 | |
| 135 | raw_spin_lock_irqsave(&p->lock, flags); |
| 136 | |
| 137 | /* mask compare A interrupt */ |
| 138 | em_sti_write(p, STI_INTENCLR, 1); |
| 139 | |
| 140 | /* update compare A value */ |
| 141 | em_sti_write(p, STI_COMPA_H, next >> 32); |
| 142 | em_sti_write(p, STI_COMPA_L, next & 0xffffffff); |
| 143 | |
| 144 | /* clear compare A interrupt source */ |
| 145 | em_sti_write(p, STI_INTFFCLR, 1); |
| 146 | |
| 147 | /* unmask compare A interrupt */ |
| 148 | em_sti_write(p, STI_INTENSET, 1); |
| 149 | |
| 150 | raw_spin_unlock_irqrestore(&p->lock, flags); |
| 151 | |
| 152 | return next; |
| 153 | } |
| 154 | |
| 155 | static irqreturn_t em_sti_interrupt(int irq, void *dev_id) |
| 156 | { |
| 157 | struct em_sti_priv *p = dev_id; |
| 158 | |
| 159 | p->ced.event_handler(&p->ced); |
| 160 | return IRQ_HANDLED; |
| 161 | } |
| 162 | |
| 163 | static int em_sti_start(struct em_sti_priv *p, unsigned int user) |
| 164 | { |
| 165 | unsigned long flags; |
| 166 | int used_before; |
| 167 | int ret = 0; |
| 168 | |
| 169 | raw_spin_lock_irqsave(&p->lock, flags); |
| 170 | used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; |
| 171 | if (!used_before) |
| 172 | ret = em_sti_enable(p); |
| 173 | |
| 174 | if (!ret) |
| 175 | p->active[user] = 1; |
| 176 | raw_spin_unlock_irqrestore(&p->lock, flags); |
| 177 | |
| 178 | return ret; |
| 179 | } |
| 180 | |
| 181 | static void em_sti_stop(struct em_sti_priv *p, unsigned int user) |
| 182 | { |
| 183 | unsigned long flags; |
| 184 | int used_before, used_after; |
| 185 | |
| 186 | raw_spin_lock_irqsave(&p->lock, flags); |
| 187 | used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; |
| 188 | p->active[user] = 0; |
| 189 | used_after = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; |
| 190 | |
| 191 | if (used_before && !used_after) |
| 192 | em_sti_disable(p); |
| 193 | raw_spin_unlock_irqrestore(&p->lock, flags); |
| 194 | } |
| 195 | |
| 196 | static struct em_sti_priv *cs_to_em_sti(struct clocksource *cs) |
| 197 | { |
| 198 | return container_of(cs, struct em_sti_priv, cs); |
| 199 | } |
| 200 | |
| 201 | static cycle_t em_sti_clocksource_read(struct clocksource *cs) |
| 202 | { |
| 203 | return em_sti_count(cs_to_em_sti(cs)); |
| 204 | } |
| 205 | |
| 206 | static int em_sti_clocksource_enable(struct clocksource *cs) |
| 207 | { |
| 208 | int ret; |
| 209 | struct em_sti_priv *p = cs_to_em_sti(cs); |
| 210 | |
| 211 | ret = em_sti_start(p, USER_CLOCKSOURCE); |
| 212 | if (!ret) |
| 213 | __clocksource_updatefreq_hz(cs, p->rate); |
| 214 | return ret; |
| 215 | } |
| 216 | |
| 217 | static void em_sti_clocksource_disable(struct clocksource *cs) |
| 218 | { |
| 219 | em_sti_stop(cs_to_em_sti(cs), USER_CLOCKSOURCE); |
| 220 | } |
| 221 | |
| 222 | static void em_sti_clocksource_resume(struct clocksource *cs) |
| 223 | { |
| 224 | em_sti_clocksource_enable(cs); |
| 225 | } |
| 226 | |
| 227 | static int em_sti_register_clocksource(struct em_sti_priv *p) |
| 228 | { |
| 229 | struct clocksource *cs = &p->cs; |
| 230 | |
| 231 | memset(cs, 0, sizeof(*cs)); |
| 232 | cs->name = dev_name(&p->pdev->dev); |
| 233 | cs->rating = 200; |
| 234 | cs->read = em_sti_clocksource_read; |
| 235 | cs->enable = em_sti_clocksource_enable; |
| 236 | cs->disable = em_sti_clocksource_disable; |
| 237 | cs->suspend = em_sti_clocksource_disable; |
| 238 | cs->resume = em_sti_clocksource_resume; |
| 239 | cs->mask = CLOCKSOURCE_MASK(48); |
| 240 | cs->flags = CLOCK_SOURCE_IS_CONTINUOUS; |
| 241 | |
| 242 | dev_info(&p->pdev->dev, "used as clock source\n"); |
| 243 | |
| 244 | /* Register with dummy 1 Hz value, gets updated in ->enable() */ |
| 245 | clocksource_register_hz(cs, 1); |
| 246 | return 0; |
| 247 | } |
| 248 | |
| 249 | static struct em_sti_priv *ced_to_em_sti(struct clock_event_device *ced) |
| 250 | { |
| 251 | return container_of(ced, struct em_sti_priv, ced); |
| 252 | } |
| 253 | |
| 254 | static void em_sti_clock_event_mode(enum clock_event_mode mode, |
| 255 | struct clock_event_device *ced) |
| 256 | { |
| 257 | struct em_sti_priv *p = ced_to_em_sti(ced); |
| 258 | |
| 259 | /* deal with old setting first */ |
| 260 | switch (ced->mode) { |
| 261 | case CLOCK_EVT_MODE_ONESHOT: |
| 262 | em_sti_stop(p, USER_CLOCKEVENT); |
| 263 | break; |
| 264 | default: |
| 265 | break; |
| 266 | } |
| 267 | |
| 268 | switch (mode) { |
| 269 | case CLOCK_EVT_MODE_ONESHOT: |
| 270 | dev_info(&p->pdev->dev, "used for oneshot clock events\n"); |
| 271 | em_sti_start(p, USER_CLOCKEVENT); |
| 272 | clockevents_config(&p->ced, p->rate); |
| 273 | break; |
| 274 | case CLOCK_EVT_MODE_SHUTDOWN: |
| 275 | case CLOCK_EVT_MODE_UNUSED: |
| 276 | em_sti_stop(p, USER_CLOCKEVENT); |
| 277 | break; |
| 278 | default: |
| 279 | break; |
| 280 | } |
| 281 | } |
| 282 | |
| 283 | static int em_sti_clock_event_next(unsigned long delta, |
| 284 | struct clock_event_device *ced) |
| 285 | { |
| 286 | struct em_sti_priv *p = ced_to_em_sti(ced); |
| 287 | cycle_t next; |
| 288 | int safe; |
| 289 | |
| 290 | next = em_sti_set_next(p, em_sti_count(p) + delta); |
| 291 | safe = em_sti_count(p) < (next - 1); |
| 292 | |
| 293 | return !safe; |
| 294 | } |
| 295 | |
| 296 | static void em_sti_register_clockevent(struct em_sti_priv *p) |
| 297 | { |
| 298 | struct clock_event_device *ced = &p->ced; |
| 299 | |
| 300 | memset(ced, 0, sizeof(*ced)); |
| 301 | ced->name = dev_name(&p->pdev->dev); |
| 302 | ced->features = CLOCK_EVT_FEAT_ONESHOT; |
| 303 | ced->rating = 200; |
| 304 | ced->cpumask = cpumask_of(0); |
| 305 | ced->set_next_event = em_sti_clock_event_next; |
| 306 | ced->set_mode = em_sti_clock_event_mode; |
| 307 | |
| 308 | dev_info(&p->pdev->dev, "used for clock events\n"); |
| 309 | |
| 310 | /* Register with dummy 1 Hz value, gets updated in ->set_mode() */ |
| 311 | clockevents_config_and_register(ced, 1, 2, 0xffffffff); |
| 312 | } |
| 313 | |
Greg Kroah-Hartman | 1850514 | 2012-12-21 15:11:38 -0800 | [diff] [blame^] | 314 | static int em_sti_probe(struct platform_device *pdev) |
Magnus Damm | b9dbf95 | 2012-05-25 16:03:44 +0900 | [diff] [blame] | 315 | { |
| 316 | struct em_sti_priv *p; |
| 317 | struct resource *res; |
| 318 | int irq, ret; |
| 319 | |
| 320 | p = kzalloc(sizeof(*p), GFP_KERNEL); |
| 321 | if (p == NULL) { |
| 322 | dev_err(&pdev->dev, "failed to allocate driver data\n"); |
| 323 | ret = -ENOMEM; |
| 324 | goto err0; |
| 325 | } |
| 326 | |
| 327 | p->pdev = pdev; |
| 328 | platform_set_drvdata(pdev, p); |
| 329 | |
| 330 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 331 | if (!res) { |
| 332 | dev_err(&pdev->dev, "failed to get I/O memory\n"); |
| 333 | ret = -EINVAL; |
| 334 | goto err0; |
| 335 | } |
| 336 | |
| 337 | irq = platform_get_irq(pdev, 0); |
| 338 | if (irq < 0) { |
| 339 | dev_err(&pdev->dev, "failed to get irq\n"); |
| 340 | ret = -EINVAL; |
| 341 | goto err0; |
| 342 | } |
| 343 | |
| 344 | /* map memory, let base point to the STI instance */ |
| 345 | p->base = ioremap_nocache(res->start, resource_size(res)); |
| 346 | if (p->base == NULL) { |
| 347 | dev_err(&pdev->dev, "failed to remap I/O memory\n"); |
| 348 | ret = -ENXIO; |
| 349 | goto err0; |
| 350 | } |
| 351 | |
| 352 | /* get hold of clock */ |
| 353 | p->clk = clk_get(&pdev->dev, "sclk"); |
| 354 | if (IS_ERR(p->clk)) { |
| 355 | dev_err(&pdev->dev, "cannot get clock\n"); |
| 356 | ret = PTR_ERR(p->clk); |
| 357 | goto err1; |
| 358 | } |
| 359 | |
| 360 | if (request_irq(irq, em_sti_interrupt, |
| 361 | IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, |
| 362 | dev_name(&pdev->dev), p)) { |
| 363 | dev_err(&pdev->dev, "failed to request low IRQ\n"); |
| 364 | ret = -ENOENT; |
| 365 | goto err2; |
| 366 | } |
| 367 | |
| 368 | raw_spin_lock_init(&p->lock); |
| 369 | em_sti_register_clockevent(p); |
| 370 | em_sti_register_clocksource(p); |
| 371 | return 0; |
| 372 | |
| 373 | err2: |
| 374 | clk_put(p->clk); |
| 375 | err1: |
| 376 | iounmap(p->base); |
| 377 | err0: |
| 378 | kfree(p); |
| 379 | return ret; |
| 380 | } |
| 381 | |
Greg Kroah-Hartman | 1850514 | 2012-12-21 15:11:38 -0800 | [diff] [blame^] | 382 | static int em_sti_remove(struct platform_device *pdev) |
Magnus Damm | b9dbf95 | 2012-05-25 16:03:44 +0900 | [diff] [blame] | 383 | { |
| 384 | return -EBUSY; /* cannot unregister clockevent and clocksource */ |
| 385 | } |
| 386 | |
Greg Kroah-Hartman | 1850514 | 2012-12-21 15:11:38 -0800 | [diff] [blame^] | 387 | static const struct of_device_id em_sti_dt_ids[] = { |
Magnus Damm | fc0830f | 2012-05-09 23:39:50 +0900 | [diff] [blame] | 388 | { .compatible = "renesas,em-sti", }, |
| 389 | {}, |
| 390 | }; |
| 391 | MODULE_DEVICE_TABLE(of, em_sti_dt_ids); |
| 392 | |
Magnus Damm | b9dbf95 | 2012-05-25 16:03:44 +0900 | [diff] [blame] | 393 | static struct platform_driver em_sti_device_driver = { |
| 394 | .probe = em_sti_probe, |
Greg Kroah-Hartman | 1850514 | 2012-12-21 15:11:38 -0800 | [diff] [blame^] | 395 | .remove = em_sti_remove, |
Magnus Damm | b9dbf95 | 2012-05-25 16:03:44 +0900 | [diff] [blame] | 396 | .driver = { |
| 397 | .name = "em_sti", |
Magnus Damm | fc0830f | 2012-05-09 23:39:50 +0900 | [diff] [blame] | 398 | .of_match_table = em_sti_dt_ids, |
Magnus Damm | b9dbf95 | 2012-05-25 16:03:44 +0900 | [diff] [blame] | 399 | } |
| 400 | }; |
| 401 | |
| 402 | module_platform_driver(em_sti_device_driver); |
| 403 | |
| 404 | MODULE_AUTHOR("Magnus Damm"); |
| 405 | MODULE_DESCRIPTION("Renesas Emma Mobile STI Timer Driver"); |
| 406 | MODULE_LICENSE("GPL v2"); |