Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 749 insertions, 0 deletions

diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
new file mode 100644
index 000000000..b99d70149
--- /dev/null
+++ b/drivers/clk/qcom/gdsc.c
@@ -0,0 +1,749 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2015, 2017-2018, 2022, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/interconnect.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.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 GDSC_RETAIN_FF_ENABLE		BIT(11)
+#define CFG_GDSCR_OFFSET		0x4
+
+/* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
+#define EN_REST_WAIT_VAL	0x2
+#define EN_FEW_WAIT_VAL		0x8
+#define CLK_DIS_WAIT_VAL	0x2
+
+/* Transition delay shifts */
+#define EN_REST_WAIT_SHIFT	20
+#define EN_FEW_WAIT_SHIFT	16
+#define CLK_DIS_WAIT_SHIFT	12
+
+#define RETAIN_MEM		BIT(14)
+#define RETAIN_PERIPH		BIT(13)
+
+#define STATUS_POLL_TIMEOUT_US	2000
+#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;
+	int ret;
+
+	start = ktime_get();
+	do {
+		ret = gdsc_check_status(sc, status);
+		if (ret < 0)
+			return ret;
+		if (ret)
+			return 0;
+	} while (ktime_us_delta(ktime_get(), start) < STATUS_POLL_TIMEOUT_US);
+
+	ret = gdsc_check_status(sc, status);
+	if (ret < 0)
+		return ret;
+	if (ret)
+		return 0;
+
+	return -ETIMEDOUT;
+}
+
+static int gdsc_update_collapse_bit(struct gdsc *sc, bool val)
+{
+	u32 reg, mask;
+	int ret;
+
+	if (sc->collapse_mask) {
+		reg = sc->collapse_ctrl;
+		mask = sc->collapse_mask;
+	} else {
+		reg = sc->gdscr;
+		mask = SW_COLLAPSE_MASK;
+	}
+
+	ret = regmap_update_bits(sc->regmap, reg, mask, val ? mask : 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int gdsc_toggle_logic(struct gdsc *sc, enum gdsc_status status,
+		bool wait)
+{
+	int ret;
+
+	if (status == GDSC_ON && sc->rsupply) {
+		ret = regulator_enable(sc->rsupply);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (status == GDSC_ON) {
+		ret = icc_set_bw(sc->icc_path, 1, 1);
+		if (ret)
+			goto err_disable_supply;
+	}
+
+	ret = gdsc_update_collapse_bit(sc, status == GDSC_OFF);
+
+	/* If disabling votable gdscs, don't poll on status */
+	if ((sc->flags & VOTABLE) && status == GDSC_OFF && !wait) {
+		/*
+		 * 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);
+	}
+
+	ret = gdsc_poll_status(sc, status);
+	WARN(ret, "%s status stuck at 'o%s'", sc->pd.name, status ? "ff" : "n");
+
+	if (!ret && status == GDSC_OFF) {
+		ret = icc_set_bw(sc->icc_path, 0, 0);
+		if (ret)
+			return ret;
+	}
+
+	if (!ret && status == GDSC_OFF && sc->rsupply) {
+		ret = regulator_disable(sc->rsupply);
+		if (ret < 0)
+			return ret;
+	}
+
+	return ret;
+
+err_disable_supply:
+	if (status == GDSC_ON && sc->rsupply)
+		regulator_disable(sc->rsupply);
+
+	return ret;
+}
+
+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;
+
+	if (!(sc->flags & NO_RET_PERIPH))
+		mask |= 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;
+
+	if (!(sc->flags & NO_RET_PERIPH))
+		mask |= 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 void gdsc_retain_ff_on(struct gdsc *sc)
+{
+	u32 mask = GDSC_RETAIN_FF_ENABLE;
+
+	regmap_update_bits(sc->regmap, sc->gdscr, mask, mask);
+}
+
+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, false);
+	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);
+
+	if (sc->flags & RETAIN_FF_ENABLE)
+		gdsc_retain_ff_on(sc);
+
+	/* 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);
+
+	/*
+	 * If the GDSC supports only a Retention state, apart from ON,
+	 * leave it in ON state.
+	 * There is no SW control to transition the GDSC into
+	 * Retention state. This happens in HW when the parent
+	 * domain goes down to a Low power state
+	 */
+	if (sc->pwrsts == PWRSTS_RET_ON)
+		return 0;
+
+	ret = gdsc_toggle_logic(sc, GDSC_OFF, domain->synced_poweroff);
+	if (ret)
+		return ret;
+
+	if (sc->flags & CLAMP_IO)
+		gdsc_assert_clamp_io(sc);
+
+	return 0;
+}
+
+static int gdsc_set_hwmode(struct generic_pm_domain *domain, struct device *dev, bool mode)
+{
+	struct gdsc *sc = domain_to_gdsc(domain);
+	int ret;
+
+	ret = gdsc_hwctrl(sc, mode);
+	if (ret)
+		return ret;
+
+	/*
+	 * Wait for the GDSC to go through a power down and
+	 * up cycle. If we poll the status register before the
+	 * power cycle is finished we might read incorrect values.
+	 */
+	udelay(1);
+
+	/*
+	 * When the GDSC is switched to HW mode, HW can disable the GDSC.
+	 * When the GDSC is switched back to SW mode, the GDSC will be enabled
+	 * again, hence we need to poll for GDSC to complete the power up.
+	 */
+	if (!mode)
+		return gdsc_poll_status(sc, GDSC_ON);
+
+	return 0;
+}
+
+static bool gdsc_get_hwmode(struct generic_pm_domain *domain, struct device *dev)
+{
+	struct gdsc *sc = domain_to_gdsc(domain);
+	u32 val;
+
+	regmap_read(sc->regmap, sc->gdscr, &val);
+
+	return !!(val & HW_CONTROL_MASK);
+}
+
+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;
+
+	if (!sc->en_rest_wait_val)
+		sc->en_rest_wait_val = EN_REST_WAIT_VAL;
+	if (!sc->en_few_wait_val)
+		sc->en_few_wait_val = EN_FEW_WAIT_VAL;
+	if (!sc->clk_dis_wait_val)
+		sc->clk_dis_wait_val = CLK_DIS_WAIT_VAL;
+
+	val = sc->en_rest_wait_val << EN_REST_WAIT_SHIFT |
+		sc->en_few_wait_val << EN_FEW_WAIT_SHIFT |
+		sc->clk_dis_wait_val << CLK_DIS_WAIT_SHIFT;
+
+	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, false);
+		if (ret)
+			return ret;
+	}
+
+	on = gdsc_check_status(sc, GDSC_ON);
+	if (on < 0)
+		return on;
+
+	if (on) {
+		/* The regulator must be on, sync the kernel state */
+		if (sc->rsupply) {
+			ret = regulator_enable(sc->rsupply);
+			if (ret < 0)
+				return ret;
+		}
+
+		/*
+		 * 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) {
+			ret = gdsc_update_collapse_bit(sc, false);
+			if (ret)
+				goto err_disable_supply;
+		}
+
+		/*
+		 * Make sure the retain bit is set if the GDSC is already on,
+		 * otherwise we end up turning off the GDSC and destroying all
+		 * the register contents that we thought we were saving.
+		 */
+		if (sc->flags & RETAIN_FF_ENABLE)
+			gdsc_retain_ff_on(sc);
+
+		/* Turn on HW trigger mode if supported */
+		if (sc->flags & HW_CTRL) {
+			ret = gdsc_hwctrl(sc, true);
+			if (ret < 0)
+				goto err_disable_supply;
+		}
+
+	} else if (sc->flags & ALWAYS_ON) {
+		/* If ALWAYS_ON GDSCs are not ON, turn them ON */
+		ret = gdsc_enable(&sc->pd);
+		if (ret)
+			return ret;
+		on = true;
+	}
+
+	if (on || (sc->pwrsts & PWRSTS_RET))
+		gdsc_force_mem_on(sc);
+	else
+		gdsc_clear_mem_on(sc);
+
+	if (sc->flags & ALWAYS_ON)
+		sc->pd.flags |= GENPD_FLAG_ALWAYS_ON;
+	if (!sc->pd.power_off)
+		sc->pd.power_off = gdsc_disable;
+	if (!sc->pd.power_on)
+		sc->pd.power_on = gdsc_enable;
+	if (sc->flags & HW_CTRL_TRIGGER) {
+		sc->pd.set_hwmode_dev = gdsc_set_hwmode;
+		sc->pd.get_hwmode_dev = gdsc_get_hwmode;
+	}
+
+	ret = pm_genpd_init(&sc->pd, NULL, !on);
+	if (ret)
+		goto err_disable_supply;
+
+	return 0;
+
+err_disable_supply:
+	if (on && sc->rsupply)
+		regulator_disable(sc->rsupply);
+
+	return ret;
+}
+
+static int gdsc_add_subdomain_list(struct dev_pm_domain_list *pd_list,
+				   struct generic_pm_domain *subdomain)
+{
+	int i, ret;
+
+	for (i = 0; i < pd_list->num_pds; i++) {
+		struct device *dev = pd_list->pd_devs[i];
+		struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
+
+		ret = pm_genpd_add_subdomain(genpd, subdomain);
+		if (ret)
+			goto remove_added_subdomains;
+	}
+
+	return 0;
+
+remove_added_subdomains:
+	for (i--; i >= 0; i--) {
+		struct device *dev = pd_list->pd_devs[i];
+		struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
+
+		pm_genpd_remove_subdomain(genpd, subdomain);
+	}
+
+	return ret;
+}
+
+static void gdsc_remove_subdomain_list(struct dev_pm_domain_list *pd_list,
+				       struct generic_pm_domain *subdomain)
+{
+	int i;
+
+	for (i = 0; i < pd_list->num_pds; i++) {
+		struct device *dev = pd_list->pd_devs[i];
+		struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
+
+		pm_genpd_remove_subdomain(genpd, subdomain);
+	}
+}
+
+static void gdsc_pm_subdomain_remove(struct gdsc_desc *desc, size_t num)
+{
+	struct device *dev = desc->dev;
+	struct gdsc **scs = desc->scs;
+	int i;
+
+	/* Remove subdomains */
+	for (i = num - 1; i >= 0; i--) {
+		if (!scs[i])
+			continue;
+		if (scs[i]->parent)
+			pm_genpd_remove_subdomain(scs[i]->parent, &scs[i]->pd);
+		else if (!IS_ERR_OR_NULL(dev->pm_domain))
+			pm_genpd_remove_subdomain(pd_to_genpd(dev->pm_domain), &scs[i]->pd);
+		else if (desc->pd_list)
+			gdsc_remove_subdomain_list(desc->pd_list, &scs[i]->pd);
+	}
+}
+
+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;
+
+	for (i = 0; i < num; i++) {
+		if (!scs[i] || !scs[i]->needs_icc)
+			continue;
+
+		scs[i]->icc_path = devm_of_icc_get_by_index(dev, scs[i]->icc_path_index);
+		if (IS_ERR(scs[i]->icc_path)) {
+			ret = PTR_ERR(scs[i]->icc_path);
+			if (ret != -ENODEV)
+				return ret;
+
+			scs[i]->icc_path = NULL;
+		}
+	}
+
+	for (i = 0; i < num; i++) {
+		if (!scs[i] || !scs[i]->supply)
+			continue;
+
+		scs[i]->rsupply = devm_regulator_get_optional(dev, scs[i]->supply);
+		if (IS_ERR(scs[i]->rsupply)) {
+			ret = PTR_ERR(scs[i]->rsupply);
+			if (ret != -ENODEV)
+				return ret;
+
+			scs[i]->rsupply = NULL;
+		}
+	}
+
+	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)
+			ret = pm_genpd_add_subdomain(scs[i]->parent, &scs[i]->pd);
+		else if (!IS_ERR_OR_NULL(dev->pm_domain))
+			ret = pm_genpd_add_subdomain(pd_to_genpd(dev->pm_domain), &scs[i]->pd);
+		else if (desc->pd_list)
+			ret = gdsc_add_subdomain_list(desc->pd_list, &scs[i]->pd);
+
+		if (ret)
+			goto err_pm_subdomain_remove;
+	}
+
+	return of_genpd_add_provider_onecell(dev->of_node, data);
+
+err_pm_subdomain_remove:
+	gdsc_pm_subdomain_remove(desc, i);
+
+	return ret;
+}
+
+void gdsc_unregister(struct gdsc_desc *desc)
+{
+	struct device *dev = desc->dev;
+	struct gdsc **scs = desc->scs;
+	size_t num = desc->num;
+	int i;
+
+	of_genpd_del_provider(dev->of_node);
+	gdsc_pm_subdomain_remove(desc, num);
+
+	for (i = 0; i < num; i++) {
+		if (!scs[i])
+			continue;
+		pm_genpd_remove(&scs[i]->pd);
+	}
+}
+
+/*
+ * On SDM845+ the GPU GX domain is *almost* entirely controlled by the GMU
+ * running in the CX domain so the CPU doesn't need to know anything about the
+ * GX domain EXCEPT....
+ *
+ * Hardware constraints dictate that the GX be powered down before the CX. If
+ * the GMU crashes it could leave the GX on. In order to successfully bring back
+ * the device the CPU needs to disable the GX headswitch. There being no sane
+ * way to reach in and touch that register from deep inside the GPU driver we
+ * need to set up the infrastructure to be able to ensure that the GPU can
+ * ensure that the GX is off during this super special case. We do this by
+ * defining a GX gdsc with a dummy enable function and a "default" disable
+ * function.
+ *
+ * This allows us to attach with genpd_dev_pm_attach_by_name() in the GPU
+ * driver. During power up, nothing will happen from the CPU (and the GMU will
+ * power up normally but during power down this will ensure that the GX domain
+ * is *really* off - this gives us a semi standard way of doing what we need.
+ */
+int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain)
+{
+	struct gdsc *sc = domain_to_gdsc(domain);
+	int ret = 0;
+
+	/* Enable the parent supply, when controlled through the regulator framework. */
+	if (sc->rsupply)
+		ret = regulator_enable(sc->rsupply);
+
+	/* Do nothing with the GDSC itself */
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gdsc_gx_do_nothing_enable);
+
+/*
+ * GX GDSC is a special power domain. Normally, its disable sequence
+ * is managed by the GMU firmware, and high level OS must not attempt
+ * to disable it. The only exception is during GMU recovery, where the
+ * GMU driver can set GenPD’s synced_poweroff flag to allow explicitly
+ * disable GX GDSC in hardware.
+ */
+int gdsc_gx_disable(struct generic_pm_domain *domain)
+{
+	struct gdsc *sc = domain_to_gdsc(domain);
+
+	if (domain->synced_poweroff)
+		return gdsc_disable(domain);
+
+	/* Remove parent-supply placed in enable */
+	if (sc->rsupply)
+		return regulator_disable(sc->rsupply);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gdsc_gx_disable);