--- /dev/null
+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include "gdsc.h"
+
+#define PWR_ON_MASK BIT(31)
+#define EN_REST_WAIT_MASK GENMASK_ULL(23, 20)
+#define EN_FEW_WAIT_MASK GENMASK_ULL(19, 16)
+#define CLK_DIS_WAIT_MASK GENMASK_ULL(15, 12)
+#define SW_OVERRIDE_MASK BIT(2)
+#define HW_CONTROL_MASK BIT(1)
+#define SW_COLLAPSE_MASK BIT(0)
+
+/* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
+#define EN_REST_WAIT_VAL (0x2 << 20)
+#define EN_FEW_WAIT_VAL (0x8 << 16)
+#define CLK_DIS_WAIT_VAL (0x2 << 12)
+
+#define RETAIN_MEM BIT(14)
+#define RETAIN_PERIPH BIT(13)
+
+#define TIMEOUT_US 100
+
+#define domain_to_gdsc(domain) container_of(domain, struct gdsc, pd)
+
+static int gdsc_is_enabled(struct gdsc *sc)
+{
+ u32 val;
+ int ret;
+
+ ret = regmap_read(sc->regmap, sc->gdscr, &val);
+ if (ret)
+ return ret;
+
+ return !!(val & PWR_ON_MASK);
+}
+
+static int gdsc_toggle_logic(struct gdsc *sc, bool en)
+{
+ int ret;
+ u32 val = en ? 0 : SW_COLLAPSE_MASK;
+ u32 check = en ? PWR_ON_MASK : 0;
+ unsigned long timeout;
+
+ ret = regmap_update_bits(sc->regmap, sc->gdscr, SW_COLLAPSE_MASK, val);
+ if (ret)
+ return ret;
+
+ timeout = jiffies + usecs_to_jiffies(TIMEOUT_US);
+ do {
+ ret = regmap_read(sc->regmap, sc->gdscr, &val);
+ if (ret)
+ return ret;
+
+ if ((val & PWR_ON_MASK) == check)
+ return 0;
+ } while (time_before(jiffies, timeout));
+
+ ret = regmap_read(sc->regmap, sc->gdscr, &val);
+ if (ret)
+ return ret;
+
+ if ((val & PWR_ON_MASK) == check)
+ return 0;
+
+ return -ETIMEDOUT;
+}
+
+static inline int gdsc_deassert_reset(struct gdsc *sc)
+{
+ int i;
+
+ for (i = 0; i < sc->reset_count; i++)
+ sc->rcdev->ops->deassert(sc->rcdev, sc->resets[i]);
+ return 0;
+}
+
+static inline int gdsc_assert_reset(struct gdsc *sc)
+{
+ int i;
+
+ for (i = 0; i < sc->reset_count; i++)
+ sc->rcdev->ops->assert(sc->rcdev, sc->resets[i]);
+ return 0;
+}
+
+static inline void gdsc_force_mem_on(struct gdsc *sc)
+{
+ int i;
+ u32 mask = RETAIN_MEM | RETAIN_PERIPH;
+
+ for (i = 0; i < sc->cxc_count; i++)
+ regmap_update_bits(sc->regmap, sc->cxcs[i], mask, mask);
+}
+
+static inline void gdsc_clear_mem_on(struct gdsc *sc)
+{
+ int i;
+ u32 mask = RETAIN_MEM | RETAIN_PERIPH;
+
+ for (i = 0; i < sc->cxc_count; i++)
+ regmap_update_bits(sc->regmap, sc->cxcs[i], mask, 0);
+}
+
+static int gdsc_enable(struct generic_pm_domain *domain)
+{
+ struct gdsc *sc = domain_to_gdsc(domain);
+ int ret;
+
+ if (sc->pwrsts == PWRSTS_ON)
+ return gdsc_deassert_reset(sc);
+
+ ret = gdsc_toggle_logic(sc, true);
+ if (ret)
+ return ret;
+
+ if (sc->pwrsts & PWRSTS_OFF)
+ gdsc_force_mem_on(sc);
+
+ /*
+ * If clocks to this power domain were already on, they will take an
+ * additional 4 clock cycles to re-enable after the power domain is
+ * enabled. Delay to account for this. A delay is also needed to ensure
+ * clocks are not enabled within 400ns of enabling power to the
+ * memories.
+ */
+ udelay(1);
+
+ return 0;
+}
+
+static int gdsc_disable(struct generic_pm_domain *domain)
+{
+ struct gdsc *sc = domain_to_gdsc(domain);
+
+ if (sc->pwrsts == PWRSTS_ON)
+ return gdsc_assert_reset(sc);
+
+ if (sc->pwrsts & PWRSTS_OFF)
+ gdsc_clear_mem_on(sc);
+
+ return gdsc_toggle_logic(sc, false);
+}
+
+static int gdsc_init(struct gdsc *sc)
+{
+ u32 mask, val;
+ int on, ret;
+
+ /*
+ * Disable HW trigger: collapse/restore occur based on registers writes.
+ * Disable SW override: Use hardware state-machine for sequencing.
+ * Configure wait time between states.
+ */
+ mask = HW_CONTROL_MASK | SW_OVERRIDE_MASK |
+ EN_REST_WAIT_MASK | EN_FEW_WAIT_MASK | CLK_DIS_WAIT_MASK;
+ val = EN_REST_WAIT_VAL | EN_FEW_WAIT_VAL | CLK_DIS_WAIT_VAL;
+ ret = regmap_update_bits(sc->regmap, sc->gdscr, mask, val);
+ if (ret)
+ return ret;
+
+ /* Force gdsc ON if only ON state is supported */
+ if (sc->pwrsts == PWRSTS_ON) {
+ ret = gdsc_toggle_logic(sc, true);
+ if (ret)
+ return ret;
+ }
+
+ on = gdsc_is_enabled(sc);
+ if (on < 0)
+ return on;
+
+ if (on || (sc->pwrsts & PWRSTS_RET))
+ gdsc_force_mem_on(sc);
+ else
+ gdsc_clear_mem_on(sc);
+
+ sc->pd.power_off = gdsc_disable;
+ sc->pd.power_on = gdsc_enable;
+ pm_genpd_init(&sc->pd, NULL, !on);
+
+ return 0;
+}
+
+int gdsc_register(struct device *dev, struct gdsc **scs, size_t num,
+ struct reset_controller_dev *rcdev, struct regmap *regmap)
+{
+ int i, ret;
+ struct genpd_onecell_data *data;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->domains = devm_kcalloc(dev, num, sizeof(*data->domains),
+ GFP_KERNEL);
+ if (!data->domains)
+ return -ENOMEM;
+
+ data->num_domains = num;
+ for (i = 0; i < num; i++) {
+ if (!scs[i])
+ continue;
+ scs[i]->regmap = regmap;
+ scs[i]->rcdev = rcdev;
+ ret = gdsc_init(scs[i]);
+ if (ret)
+ return ret;
+ data->domains[i] = &scs[i]->pd;
+ }
+
+ return of_genpd_add_provider_onecell(dev->of_node, data);
+}
+
+void gdsc_unregister(struct device *dev)
+{
+ of_genpd_del_provider(dev->of_node);
+}
Code Review / kvmfornfv.git / blobdiff