1 files changed, 416 insertions, 0 deletions
diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
new file mode 100644
index 000000000..a077133c7
--- /dev/null
+++ b/drivers/clk/qcom/gdsc.c
@@ -0,0 +1,416 @@
+/*
+ * Copyright (c) 2015, 2017-2018, 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/ktime.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)
+#define GMEM_CLAMP_IO_MASK	BIT(0)
+#define GMEM_RESET_MASK		BIT(4)
+
+/* CFG_GDSCR */
+#define GDSC_POWER_UP_COMPLETE		BIT(16)
+#define GDSC_POWER_DOWN_COMPLETE	BIT(15)
+#define CFG_GDSCR_OFFSET		0x4
+
+/* 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		500
+
+#define domain_to_gdsc(domain) container_of(domain, struct gdsc, pd)
+
+enum gdsc_status {
+	GDSC_OFF,
+	GDSC_ON
+};
+
+/* Returns 1 if GDSC status is status, 0 if not, and < 0 on error */
+static int gdsc_check_status(struct gdsc *sc, enum gdsc_status status)
+{
+	unsigned int reg;
+	u32 val;
+	int ret;
+
+	if (sc->flags & POLL_CFG_GDSCR)
+		reg = sc->gdscr + CFG_GDSCR_OFFSET;
+	else if (sc->gds_hw_ctrl)
+		reg = sc->gds_hw_ctrl;
+	else
+		reg = sc->gdscr;
+
+	ret = regmap_read(sc->regmap, reg, &val);
+	if (ret)
+		return ret;
+
+	if (sc->flags & POLL_CFG_GDSCR) {
+		switch (status) {
+		case GDSC_ON:
+			return !!(val & GDSC_POWER_UP_COMPLETE);
+		case GDSC_OFF:
+			return !!(val & GDSC_POWER_DOWN_COMPLETE);
+		}
+	}
+
+	switch (status) {
+	case GDSC_ON:
+		return !!(val & PWR_ON_MASK);
+	case GDSC_OFF:
+		return !(val & PWR_ON_MASK);
+	}
+
+	return -EINVAL;
+}
+
+static int gdsc_hwctrl(struct gdsc *sc, bool en)
+{
+	u32 val = en ? HW_CONTROL_MASK : 0;
+
+	return regmap_update_bits(sc->regmap, sc->gdscr, HW_CONTROL_MASK, val);
+}
+
+static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status)
+{
+	ktime_t start;
+
+	start = ktime_get();
+	do {
+		if (gdsc_check_status(sc, status))
+			return 0;
+	} while (ktime_us_delta(ktime_get(), start) < TIMEOUT_US);
+
+	if (gdsc_check_status(sc, status))
+		return 0;
+
+	return -ETIMEDOUT;
+}
+
+static int gdsc_toggle_logic(struct gdsc *sc, enum gdsc_status status)
+{
+	int ret;
+	u32 val = (status == GDSC_ON) ? 0 : SW_COLLAPSE_MASK;
+
+	ret = regmap_update_bits(sc->regmap, sc->gdscr, SW_COLLAPSE_MASK, val);
+	if (ret)
+		return ret;
+
+	/* If disabling votable gdscs, don't poll on status */
+	if ((sc->flags & VOTABLE) && status == GDSC_OFF) {
+		/*
+		 * Add a short delay here to ensure that an enable
+		 * right after it was disabled does not put it in an
+		 * unknown state
+		 */
+		udelay(TIMEOUT_US);
+		return 0;
+	}
+
+	if (sc->gds_hw_ctrl) {
+		/*
+		 * The gds hw controller asserts/de-asserts the status bit soon
+		 * after it receives a power on/off request from a master.
+		 * The controller then takes around 8 xo cycles to start its
+		 * internal state machine and update the status bit. During
+		 * this time, the status bit does not reflect the true status
+		 * of the core.
+		 * Add a delay of 1 us between writing to the SW_COLLAPSE bit
+		 * and polling the status bit.
+		 */
+		udelay(1);
+	}
+
+	return gdsc_poll_status(sc, status);
+}
+
+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 inline void gdsc_deassert_clamp_io(struct gdsc *sc)
+{
+	regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
+			   GMEM_CLAMP_IO_MASK, 0);
+}
+
+static inline void gdsc_assert_clamp_io(struct gdsc *sc)
+{
+	regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
+			   GMEM_CLAMP_IO_MASK, 1);
+}
+
+static inline void gdsc_assert_reset_aon(struct gdsc *sc)
+{
+	regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
+			   GMEM_RESET_MASK, 1);
+	udelay(1);
+	regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
+			   GMEM_RESET_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);
+
+	if (sc->flags & SW_RESET) {
+		gdsc_assert_reset(sc);
+		udelay(1);
+		gdsc_deassert_reset(sc);
+	}
+
+	if (sc->flags & CLAMP_IO) {
+		if (sc->flags & AON_RESET)
+			gdsc_assert_reset_aon(sc);
+		gdsc_deassert_clamp_io(sc);
+	}
+
+	ret = gdsc_toggle_logic(sc, GDSC_ON);
+	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);
+
+	/* Turn on HW trigger mode if supported */
+	if (sc->flags & HW_CTRL) {
+		ret = gdsc_hwctrl(sc, true);
+		if (ret)
+			return ret;
+		/*
+		 * Wait for the GDSC to go through a power down and
+		 * up cycle.  In case a firmware ends up polling status
+		 * bits for the gdsc, it might read an 'on' status before
+		 * the GDSC can finish the power cycle.
+		 * We wait 1us before returning to ensure the firmware
+		 * can't immediately poll the status bits.
+		 */
+		udelay(1);
+	}
+
+	return 0;
+}
+
+static int gdsc_disable(struct generic_pm_domain *domain)
+{
+	struct gdsc *sc = domain_to_gdsc(domain);
+	int ret;
+
+	if (sc->pwrsts == PWRSTS_ON)
+		return gdsc_assert_reset(sc);
+
+	/* Turn off HW trigger mode if supported */
+	if (sc->flags & HW_CTRL) {
+		ret = gdsc_hwctrl(sc, false);
+		if (ret < 0)
+			return ret;
+		/*
+		 * Wait for the GDSC to go through a power down and
+		 * up cycle.  In case we end up polling status
+		 * bits for the gdsc before the power cycle is completed
+		 * it might read an 'on' status wrongly.
+		 */
+		udelay(1);
+
+		ret = gdsc_poll_status(sc, GDSC_ON);
+		if (ret)
+			return ret;
+	}
+
+	if (sc->pwrsts & PWRSTS_OFF)
+		gdsc_clear_mem_on(sc);
+
+	ret = gdsc_toggle_logic(sc, GDSC_OFF);
+	if (ret)
+		return ret;
+
+	if (sc->flags & CLAMP_IO)
+		gdsc_assert_clamp_io(sc);
+
+	return 0;
+}
+
+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, GDSC_ON);
+		if (ret)
+			return ret;
+	}
+
+	on = gdsc_check_status(sc, GDSC_ON);
+	if (on < 0)
+		return on;
+
+	/*
+	 * Votable GDSCs can be ON due to Vote from other masters.
+	 * If a Votable GDSC is ON, make sure we have a Vote.
+	 */
+	if ((sc->flags & VOTABLE) && on)
+		gdsc_enable(&sc->pd);
+
+	/* If ALWAYS_ON GDSCs are not ON, turn them ON */
+	if (sc->flags & ALWAYS_ON) {
+		if (!on)
+			gdsc_enable(&sc->pd);
+		on = true;
+		sc->pd.flags |= GENPD_FLAG_ALWAYS_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 gdsc_desc *desc,
+		  struct reset_controller_dev *rcdev, struct regmap *regmap)
+{
+	int i, ret;
+	struct genpd_onecell_data *data;
+	struct device *dev = desc->dev;
+	struct gdsc **scs = desc->scs;
+	size_t num = desc->num;
+
+	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;
+	}
+
+	/* Add subdomains */
+	for (i = 0; i < num; i++) {
+		if (!scs[i])
+			continue;
+		if (scs[i]->parent)
+			pm_genpd_add_subdomain(scs[i]->parent, &scs[i]->pd);
+	}
+
+	return of_genpd_add_provider_onecell(dev->of_node, data);
+}
+
+void gdsc_unregister(struct gdsc_desc *desc)
+{
+	int i;
+	struct device *dev = desc->dev;
+	struct gdsc **scs = desc->scs;
+	size_t num = desc->num;
+
+	/* Remove subdomains */
+	for (i = 0; i < num; i++) {
+		if (!scs[i])
+			continue;
+		if (scs[i]->parent)
+			pm_genpd_remove_subdomain(scs[i]->parent, &scs[i]->pd);
+	}
+	of_genpd_del_provider(dev->of_node);
+}