power: Add power domain driver for i.MX8

Add the power domain DM driver for i.MX8, that it depends on the DTB
power domain trees to generate the power domain provider devices. Users
need to add power domain trees with property "compatible = "nxp,imx8-pd";"

When power on a PD device, the driver will power on its ancestor PD
devices in power domain tree.

When power off a PD device, the driver will check its child PD devices
first. Only if all child PD devices are off, then power off the current PD
device. Then the driver checks sibling PD devices. If sibling PD devices
are off, then it will power off parent PD device.

There is no counter maintained in this driver, but a state to hold current
on/off state. So the request and free functions are empty.

The power domain implementation in i.MX8 DTB set the "#power-domain-cells"
to 0, so there is no ID binding with each PD device. We don't use "id"
variable in struct power_domain. At the same time, we have to set of_xlate
to empty to bypass standard of_xlate in uclass driver.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Cc: Stefano Babic <sbabic@denx.de>

arch/arm/include/asm/arch-imx8/power-domain.h

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2017 NXP
+ */
+
+#ifndef _ASM_ARCH_IMX8_POWER_DOMAIN_H
+#define _ASM_ARCH_IMX8_POWER_DOMAIN_H
+
+#include <asm/arch/sci/types.h>
+
+struct imx8_power_domain_platdata {
+	sc_rsrc_t resource_id;
+};
+
+#endif

drivers/power/domain/Kconfig

@@ -16,6 +16,13 @@ config BCM6328_POWER_DOMAIN
 	  Enable support for manipulating BCM6345 power domains via MMIO
 	  mapped registers.
 
+config IMX8_POWER_DOMAIN
+	bool "Enable i.MX8 power domain driver"
+        depends on ARCH_IMX8
+        help
+          Enable support for manipulating NXP i.MX8 on-SoC power domains via IPC
+          requests to the SCU.
+
 config MESON_GX_VPU_POWER_DOMAIN
 	bool "Enable Amlogic Meson GX VPU power domain driver"
 	depends on ARCH_MESON
@@ -44,5 +51,4 @@ config TI_SCI_POWER_DOMAIN
 	help
 	  Generic power domain implementation for TI devices implementing the
 	  TI SCI protocol.
-
 endmenu

drivers/power/domain/Makefile

@@ -4,6 +4,7 @@
 
 obj-$(CONFIG_$(SPL_)POWER_DOMAIN) += power-domain-uclass.o
 obj-$(CONFIG_BCM6328_POWER_DOMAIN) += bcm6328-power-domain.o
+obj-$(CONFIG_IMX8_POWER_DOMAIN) += imx8-power-domain.o
 obj-$(CONFIG_MESON_GX_VPU_POWER_DOMAIN) += meson-gx-pwrc-vpu.o
 obj-$(CONFIG_SANDBOX_POWER_DOMAIN) += sandbox-power-domain.o
 obj-$(CONFIG_SANDBOX_POWER_DOMAIN) += sandbox-power-domain-test.o

drivers/power/domain/imx8-power-domain.c

@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2017 NXP
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <power-domain-uclass.h>
+#include <asm/io.h>
+#include <asm/arch/power-domain.h>
+#include <dm/device-internal.h>
+#include <dm/device.h>
+#include <asm/arch/sci/sci.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct imx8_power_domain_priv {
+	bool state_on;
+};
+
+static int imx8_power_domain_request(struct power_domain *power_domain)
+{
+	debug("%s(power_domain=%p)\n", __func__, power_domain);
+
+	return 0;
+}
+
+static int imx8_power_domain_free(struct power_domain *power_domain)
+{
+	debug("%s(power_domain=%p)\n", __func__, power_domain);
+
+	return 0;
+}
+
+static int imx8_power_domain_on(struct power_domain *power_domain)
+{
+	struct udevice *dev = power_domain->dev;
+	struct imx8_power_domain_platdata *pdata;
+	struct imx8_power_domain_priv *ppriv;
+	sc_err_t ret;
+	int err;
+
+	struct power_domain parent_domain;
+	struct udevice *parent = dev_get_parent(dev);
+
+	/* Need to power on parent node first */
+	if (device_get_uclass_id(parent) == UCLASS_POWER_DOMAIN) {
+		parent_domain.dev = parent;
+		err = imx8_power_domain_on(&parent_domain);
+		if (err)
+			return err;
+	}
+
+	pdata = (struct imx8_power_domain_platdata *)dev_get_platdata(dev);
+	ppriv = (struct imx8_power_domain_priv *)dev_get_priv(dev);
+
+	debug("%s(power_domain=%s) resource_id %d\n", __func__, dev->name,
+	      pdata->resource_id);
+
+	/* Already powered on */
+	if (ppriv->state_on)
+		return 0;
+
+	if (pdata->resource_id != SC_R_LAST) {
+		ret = sc_pm_set_resource_power_mode(-1, pdata->resource_id,
+						    SC_PM_PW_MODE_ON);
+		if (ret) {
+			printf("Error: %s Power up failed! (error = %d)\n",
+			       dev->name, ret);
+			return -EIO;
+		}
+	}
+
+	ppriv->state_on = true;
+	debug("%s is powered on\n", dev->name);
+
+	return 0;
+}
+
+static int imx8_power_domain_off_node(struct power_domain *power_domain)
+{
+	struct udevice *dev = power_domain->dev;
+	struct udevice *child;
+	struct imx8_power_domain_priv *ppriv;
+	struct imx8_power_domain_priv *child_ppriv;
+	struct imx8_power_domain_platdata *pdata;
+	sc_err_t ret;
+
+	ppriv = dev_get_priv(dev);
+	pdata = dev_get_platdata(dev);
+
+	debug("%s, %s, state_on %d\n", __func__, dev->name, ppriv->state_on);
+
+	/* Already powered off */
+	if (!ppriv->state_on)
+		return 0;
+
+	/* Check if all subnodes are off */
+	for (device_find_first_child(dev, &child);
+		child;
+		device_find_next_child(&child)) {
+		if (device_active(child)) {
+			child_ppriv =
+			(struct imx8_power_domain_priv *)dev_get_priv(child);
+			if (child_ppriv->state_on)
+				return -EPERM;
+		}
+	}
+
+	if (pdata->resource_id != SC_R_LAST) {
+		if (!sc_rm_is_resource_owned(-1, pdata->resource_id)) {
+			printf("%s not owned by curr partition\n", dev->name);
+			return 0;
+		}
+		ret = sc_pm_set_resource_power_mode(-1, pdata->resource_id,
+						    SC_PM_PW_MODE_OFF);
+		if (ret) {
+			printf("Error: %s Power off failed! (error = %d)\n",
+			       dev->name, ret);
+			return -EIO;
+		}
+	}
+
+	ppriv->state_on = false;
+	debug("%s is powered off\n", dev->name);
+
+	return 0;
+}
+
+static int imx8_power_domain_off_parentnodes(struct power_domain *power_domain)
+{
+	struct udevice *dev = power_domain->dev;
+	struct udevice *parent = dev_get_parent(dev);
+	struct udevice *child;
+	struct imx8_power_domain_priv *ppriv;
+	struct imx8_power_domain_priv *child_ppriv;
+	struct imx8_power_domain_platdata *pdata;
+	sc_err_t ret;
+	struct power_domain parent_pd;
+
+	if (device_get_uclass_id(parent) == UCLASS_POWER_DOMAIN) {
+		pdata =
+		(struct imx8_power_domain_platdata *)dev_get_platdata(parent);
+		ppriv = (struct imx8_power_domain_priv *)dev_get_priv(parent);
+
+		debug("%s, %s, state_on %d\n", __func__, parent->name,
+		      ppriv->state_on);
+
+		/* Already powered off */
+		if (!ppriv->state_on)
+			return 0;
+
+		/*
+		 * Check if all sibling nodes are off. If yes,
+		 * power off parent
+		 */
+		for (device_find_first_child(parent, &child); child;
+		     device_find_next_child(&child)) {
+			if (device_active(child)) {
+				child_ppriv = (struct imx8_power_domain_priv *)
+						dev_get_priv(child);
+				/* Find a power on sibling */
+				if (child_ppriv->state_on) {
+					debug("sibling %s, state_on %d\n",
+					      child->name,
+					      child_ppriv->state_on);
+					return 0;
+				}
+			}
+		}
+
+		/* power off parent */
+		if (pdata->resource_id != SC_R_LAST) {
+			ret = sc_pm_set_resource_power_mode(-1,
+							    pdata->resource_id,
+							    SC_PM_PW_MODE_OFF);
+			if (ret) {
+				printf("%s Power off failed! (error = %d)\n",
+				       parent->name, ret);
+				return -EIO;
+			}
+		}
+
+		ppriv->state_on = false;
+		debug("%s is powered off\n", parent->name);
+
+		parent_pd.dev = parent;
+		imx8_power_domain_off_parentnodes(&parent_pd);
+	}
+
+	return 0;
+}
+
+static int imx8_power_domain_off(struct power_domain *power_domain)
+{
+	int ret;
+
+	debug("%s(power_domain=%p)\n", __func__, power_domain);
+
+	/* Turn off the node */
+	ret = imx8_power_domain_off_node(power_domain);
+	if (ret) {
+		debug("Can't power off the node of dev %s, ret = %d\n",
+		      power_domain->dev->name, ret);
+		return ret;
+	}
+
+	/* Turn off parent nodes, if sibling nodes are all off */
+	ret = imx8_power_domain_off_parentnodes(power_domain);
+	if (ret) {
+		printf("Failed to power off parent nodes of dev %s, ret = %d\n",
+		       power_domain->dev->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int imx8_power_domain_of_xlate(struct power_domain *power_domain,
+				      struct ofnode_phandle_args *args)
+{
+	debug("%s(power_domain=%p)\n", __func__, power_domain);
+
+	/* Do nothing to the xlate, since we don't have args used */
+
+	return 0;
+}
+
+static int imx8_power_domain_bind(struct udevice *dev)
+{
+	int offset;
+	const char *name;
+	int ret = 0;
+
+	debug("%s(dev=%p)\n", __func__, dev);
+
+	offset = dev_of_offset(dev);
+	for (offset = fdt_first_subnode(gd->fdt_blob, offset); offset > 0;
+	     offset = fdt_next_subnode(gd->fdt_blob, offset)) {
+		/* Bind the subnode to this driver */
+		name = fdt_get_name(gd->fdt_blob, offset, NULL);
+
+		ret = device_bind_with_driver_data(dev, dev->driver, name,
+						   dev->driver_data,
+						   offset_to_ofnode(offset),
+						   NULL);
+
+		if (ret == -ENODEV)
+			printf("Driver '%s' refuses to bind\n",
+			       dev->driver->name);
+
+		if (ret)
+			printf("Error binding driver '%s': %d\n",
+			       dev->driver->name, ret);
+	}
+
+	return 0;
+}
+
+static int imx8_power_domain_probe(struct udevice *dev)
+{
+	struct imx8_power_domain_priv *ppriv;
+
+	debug("%s(dev=%s)\n", __func__, dev->name);
+
+	ppriv = (struct imx8_power_domain_priv *)dev_get_priv(dev);
+
+	/* Set default to power off */
+	if (ppriv)
+		ppriv->state_on = false;
+
+	return 0;
+}
+
+static int imx8_power_domain_ofdata_to_platdata(struct udevice *dev)
+{
+	int reg;
+	struct imx8_power_domain_platdata *pdata = dev_get_platdata(dev);
+
+	reg = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev), "reg", -1);
+	if (reg == -1) {
+		debug("%s: Invalid resource id %d\n", __func__, reg);
+		return -EINVAL;
+	}
+	pdata->resource_id = (sc_rsrc_t)reg;
+
+	debug("%s resource_id %d\n", __func__, pdata->resource_id);
+
+	return 0;
+}
+
+static const struct udevice_id imx8_power_domain_ids[] = {
+	{ .compatible = "nxp,imx8-pd" },
+	{ }
+};
+
+struct power_domain_ops imx8_power_domain_ops = {
+	.request = imx8_power_domain_request,
+	.free = imx8_power_domain_free,
+	.on = imx8_power_domain_on,
+	.off = imx8_power_domain_off,
+	.of_xlate = imx8_power_domain_of_xlate,
+};
+
+U_BOOT_DRIVER(imx8_power_domain) = {
+	.name = "imx8_power_domain",
+	.id = UCLASS_POWER_DOMAIN,
+	.of_match = imx8_power_domain_ids,
+	.bind = imx8_power_domain_bind,
+	.probe = imx8_power_domain_probe,
+	.ofdata_to_platdata = imx8_power_domain_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct imx8_power_domain_platdata),
+	.priv_auto_alloc_size = sizeof(struct imx8_power_domain_priv),
+	.ops = &imx8_power_domain_ops,
+};