2 * Copyright (c) 2015, 2017-2018, The Linux Foundation. All rights reserved.
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 and
6 * only version 2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
14 #include <linux/bitops.h>
15 #include <linux/delay.h>
16 #include <linux/err.h>
17 #include <linux/jiffies.h>
18 #include <linux/kernel.h>
19 #include <linux/ktime.h>
20 #include <linux/pm_domain.h>
21 #include <linux/regmap.h>
22 #include <linux/reset-controller.h>
23 #include <linux/slab.h>
26 #define PWR_ON_MASK BIT(31)
27 #define EN_REST_WAIT_MASK GENMASK_ULL(23, 20)
28 #define EN_FEW_WAIT_MASK GENMASK_ULL(19, 16)
29 #define CLK_DIS_WAIT_MASK GENMASK_ULL(15, 12)
30 #define SW_OVERRIDE_MASK BIT(2)
31 #define HW_CONTROL_MASK BIT(1)
32 #define SW_COLLAPSE_MASK BIT(0)
33 #define GMEM_CLAMP_IO_MASK BIT(0)
34 #define GMEM_RESET_MASK BIT(4)
37 #define GDSC_POWER_UP_COMPLETE BIT(16)
38 #define GDSC_POWER_DOWN_COMPLETE BIT(15)
39 #define CFG_GDSCR_OFFSET 0x4
41 /* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
42 #define EN_REST_WAIT_VAL (0x2 << 20)
43 #define EN_FEW_WAIT_VAL (0x8 << 16)
44 #define CLK_DIS_WAIT_VAL (0x2 << 12)
46 #define RETAIN_MEM BIT(14)
47 #define RETAIN_PERIPH BIT(13)
49 #define TIMEOUT_US 500
51 #define domain_to_gdsc(domain) container_of(domain, struct gdsc, pd)
53 static int gdsc_is_enabled(struct gdsc *sc, bool en)
59 if (sc->flags & POLL_CFG_GDSCR)
60 reg = sc->gdscr + CFG_GDSCR_OFFSET;
62 reg = sc->gds_hw_ctrl ? sc->gds_hw_ctrl : sc->gdscr;
64 ret = regmap_read(sc->regmap, reg, &val);
68 if (sc->flags & POLL_CFG_GDSCR) {
70 return !!(val & GDSC_POWER_UP_COMPLETE);
72 return !(val & GDSC_POWER_DOWN_COMPLETE);
75 return !!(val & PWR_ON_MASK);
78 static int gdsc_hwctrl(struct gdsc *sc, bool en)
80 u32 val = en ? HW_CONTROL_MASK : 0;
82 return regmap_update_bits(sc->regmap, sc->gdscr, HW_CONTROL_MASK, val);
85 static int gdsc_poll_status(struct gdsc *sc, bool en)
91 if (gdsc_is_enabled(sc, en) == en)
93 } while (ktime_us_delta(ktime_get(), start) < TIMEOUT_US);
95 if (gdsc_is_enabled(sc, en) == en)
101 static int gdsc_toggle_logic(struct gdsc *sc, bool en)
104 u32 val = en ? 0 : SW_COLLAPSE_MASK;
106 ret = regmap_update_bits(sc->regmap, sc->gdscr, SW_COLLAPSE_MASK, val);
110 /* If disabling votable gdscs, don't poll on status */
111 if ((sc->flags & VOTABLE) && !en) {
113 * Add a short delay here to ensure that an enable
114 * right after it was disabled does not put it in an
123 * The gds hw controller asserts/de-asserts the status bit soon
124 * after it receives a power on/off request from a master.
125 * The controller then takes around 8 xo cycles to start its
126 * internal state machine and update the status bit. During
127 * this time, the status bit does not reflect the true status
129 * Add a delay of 1 us between writing to the SW_COLLAPSE bit
130 * and polling the status bit.
134 return gdsc_poll_status(sc, en);
137 static inline int gdsc_deassert_reset(struct gdsc *sc)
141 for (i = 0; i < sc->reset_count; i++)
142 sc->rcdev->ops->deassert(sc->rcdev, sc->resets[i]);
146 static inline int gdsc_assert_reset(struct gdsc *sc)
150 for (i = 0; i < sc->reset_count; i++)
151 sc->rcdev->ops->assert(sc->rcdev, sc->resets[i]);
155 static inline void gdsc_force_mem_on(struct gdsc *sc)
158 u32 mask = RETAIN_MEM | RETAIN_PERIPH;
160 for (i = 0; i < sc->cxc_count; i++)
161 regmap_update_bits(sc->regmap, sc->cxcs[i], mask, mask);
164 static inline void gdsc_clear_mem_on(struct gdsc *sc)
167 u32 mask = RETAIN_MEM | RETAIN_PERIPH;
169 for (i = 0; i < sc->cxc_count; i++)
170 regmap_update_bits(sc->regmap, sc->cxcs[i], mask, 0);
173 static inline void gdsc_deassert_clamp_io(struct gdsc *sc)
175 regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
176 GMEM_CLAMP_IO_MASK, 0);
179 static inline void gdsc_assert_clamp_io(struct gdsc *sc)
181 regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
182 GMEM_CLAMP_IO_MASK, 1);
185 static inline void gdsc_assert_reset_aon(struct gdsc *sc)
187 regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
190 regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
193 static int gdsc_enable(struct generic_pm_domain *domain)
195 struct gdsc *sc = domain_to_gdsc(domain);
198 if (sc->pwrsts == PWRSTS_ON)
199 return gdsc_deassert_reset(sc);
201 if (sc->flags & SW_RESET) {
202 gdsc_assert_reset(sc);
204 gdsc_deassert_reset(sc);
207 if (sc->flags & CLAMP_IO) {
208 if (sc->flags & AON_RESET)
209 gdsc_assert_reset_aon(sc);
210 gdsc_deassert_clamp_io(sc);
213 ret = gdsc_toggle_logic(sc, true);
217 if (sc->pwrsts & PWRSTS_OFF)
218 gdsc_force_mem_on(sc);
221 * If clocks to this power domain were already on, they will take an
222 * additional 4 clock cycles to re-enable after the power domain is
223 * enabled. Delay to account for this. A delay is also needed to ensure
224 * clocks are not enabled within 400ns of enabling power to the
229 /* Turn on HW trigger mode if supported */
230 if (sc->flags & HW_CTRL) {
231 ret = gdsc_hwctrl(sc, true);
235 * Wait for the GDSC to go through a power down and
236 * up cycle. In case a firmware ends up polling status
237 * bits for the gdsc, it might read an 'on' status before
238 * the GDSC can finish the power cycle.
239 * We wait 1us before returning to ensure the firmware
240 * can't immediately poll the status bits.
248 static int gdsc_disable(struct generic_pm_domain *domain)
250 struct gdsc *sc = domain_to_gdsc(domain);
253 if (sc->pwrsts == PWRSTS_ON)
254 return gdsc_assert_reset(sc);
256 /* Turn off HW trigger mode if supported */
257 if (sc->flags & HW_CTRL) {
258 ret = gdsc_hwctrl(sc, false);
262 * Wait for the GDSC to go through a power down and
263 * up cycle. In case we end up polling status
264 * bits for the gdsc before the power cycle is completed
265 * it might read an 'on' status wrongly.
269 ret = gdsc_poll_status(sc, true);
274 if (sc->pwrsts & PWRSTS_OFF)
275 gdsc_clear_mem_on(sc);
277 ret = gdsc_toggle_logic(sc, false);
281 if (sc->flags & CLAMP_IO)
282 gdsc_assert_clamp_io(sc);
287 static int gdsc_init(struct gdsc *sc)
293 * Disable HW trigger: collapse/restore occur based on registers writes.
294 * Disable SW override: Use hardware state-machine for sequencing.
295 * Configure wait time between states.
297 mask = HW_CONTROL_MASK | SW_OVERRIDE_MASK |
298 EN_REST_WAIT_MASK | EN_FEW_WAIT_MASK | CLK_DIS_WAIT_MASK;
299 val = EN_REST_WAIT_VAL | EN_FEW_WAIT_VAL | CLK_DIS_WAIT_VAL;
300 ret = regmap_update_bits(sc->regmap, sc->gdscr, mask, val);
304 /* Force gdsc ON if only ON state is supported */
305 if (sc->pwrsts == PWRSTS_ON) {
306 ret = gdsc_toggle_logic(sc, true);
311 on = gdsc_is_enabled(sc, true);
316 * Votable GDSCs can be ON due to Vote from other masters.
317 * If a Votable GDSC is ON, make sure we have a Vote.
319 if ((sc->flags & VOTABLE) && on)
320 gdsc_enable(&sc->pd);
322 if (on || (sc->pwrsts & PWRSTS_RET))
323 gdsc_force_mem_on(sc);
325 gdsc_clear_mem_on(sc);
327 sc->pd.power_off = gdsc_disable;
328 sc->pd.power_on = gdsc_enable;
329 pm_genpd_init(&sc->pd, NULL, !on);
334 int gdsc_register(struct gdsc_desc *desc,
335 struct reset_controller_dev *rcdev, struct regmap *regmap)
338 struct genpd_onecell_data *data;
339 struct device *dev = desc->dev;
340 struct gdsc **scs = desc->scs;
341 size_t num = desc->num;
343 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
347 data->domains = devm_kcalloc(dev, num, sizeof(*data->domains),
352 data->num_domains = num;
353 for (i = 0; i < num; i++) {
356 scs[i]->regmap = regmap;
357 scs[i]->rcdev = rcdev;
358 ret = gdsc_init(scs[i]);
361 data->domains[i] = &scs[i]->pd;
365 for (i = 0; i < num; i++) {
369 pm_genpd_add_subdomain(scs[i]->parent, &scs[i]->pd);
372 return of_genpd_add_provider_onecell(dev->of_node, data);
375 void gdsc_unregister(struct gdsc_desc *desc)
378 struct device *dev = desc->dev;
379 struct gdsc **scs = desc->scs;
380 size_t num = desc->num;
382 /* Remove subdomains */
383 for (i = 0; i < num; i++) {
387 pm_genpd_remove_subdomain(scs[i]->parent, &scs[i]->pd);
389 of_genpd_del_provider(dev->of_node);