[PATCH v3 3/8] rsb: Linux driver framework for Reduced Serial Bus (RSB)
Chen-Yu Tsai
wens at csie.org
Tue Aug 18 21:20:04 PDT 2015
Reduced Serial Bus (RSB) is an Allwinner proprietery interface
used to communicate with PMICs and other peripheral ICs.
RSB is a two-wire push-pull serial bus that supports 1 master
device and up to 15 active slave devices.
Signed-off-by: Chen-Yu Tsai <wens at csie.org>
---
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/rsb/Kconfig | 11 ++
drivers/rsb/Makefile | 4 +
drivers/rsb/rsb-core.c | 511 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/rsb.h | 144 ++++++++++++++
6 files changed, 673 insertions(+)
create mode 100644 drivers/rsb/Kconfig
create mode 100644 drivers/rsb/Makefile
create mode 100644 drivers/rsb/rsb-core.c
create mode 100644 include/linux/rsb.h
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 6e973b8e3a3b..4ada2d3eb832 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -54,6 +54,8 @@ source "drivers/spi/Kconfig"
source "drivers/spmi/Kconfig"
+source "drivers/rsb/Kconfig"
+
source "drivers/hsi/Kconfig"
source "drivers/pps/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index e4b260ecec15..75e0fc8fe28c 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_TARGET_CORE) += target/
obj-$(CONFIG_MTD) += mtd/
obj-$(CONFIG_SPI) += spi/
obj-$(CONFIG_SPMI) += spmi/
+obj-$(CONFIG_RSB) += rsb/
obj-y += hsi/
obj-y += net/
obj-$(CONFIG_ATM) += atm/
diff --git a/drivers/rsb/Kconfig b/drivers/rsb/Kconfig
new file mode 100644
index 000000000000..6642e1db6d98
--- /dev/null
+++ b/drivers/rsb/Kconfig
@@ -0,0 +1,11 @@
+#
+# RSB driver configuration
+#
+menuconfig RSB
+ tristate "RSB support"
+ help
+ RSB (Reduced Serial Bus) is a two-wire serial interface between
+ baseband and application processors and Power Management
+ Integrated Circuits (PMIC) or other peripherals.
+
+ These are commonly seen on newer Allwinner SoCs and X-Powers ICs.
diff --git a/drivers/rsb/Makefile b/drivers/rsb/Makefile
new file mode 100644
index 000000000000..6fe56526fbf3
--- /dev/null
+++ b/drivers/rsb/Makefile
@@ -0,0 +1,4 @@
+#
+# Makefile for kernel RSB framework.
+#
+obj-$(CONFIG_RSB) += rsb-core.o
diff --git a/drivers/rsb/rsb-core.c b/drivers/rsb/rsb-core.c
new file mode 100644
index 000000000000..6682d827aebb
--- /dev/null
+++ b/drivers/rsb/rsb-core.c
@@ -0,0 +1,511 @@
+/*
+ * Copyright (c) 2015, Chen-Yu Tsai
+ *
+ * Chen-Yu Tsai <wens at csie.org>
+ *
+ * Allwinner Reduced Serial Bus (RSB) driver
+ *
+ * based on spmi/spmi.c
+ *
+ * Copyright (c) 2012-2015, 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/clk/clk-conf.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/idr.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/rsb.h>
+#include <linux/slab.h>
+
+static DEFINE_IDA(ctrl_ida);
+
+static void rsb_dev_release(struct device *dev)
+{
+ struct rsb_device *rdev = to_rsb_device(dev);
+
+ kfree(rdev);
+}
+
+static const struct device_type rsb_dev_type = {
+ .release = rsb_dev_release,
+};
+
+static void rsb_ctrl_release(struct device *dev)
+{
+ struct rsb_controller *ctrl = to_rsb_controller(dev);
+
+ ida_simple_remove(&ctrl_ida, ctrl->nr);
+ kfree(ctrl);
+}
+
+static const struct device_type rsb_ctrl_type = {
+ .release = rsb_ctrl_release,
+};
+
+static int rsb_device_match(struct device *dev, struct device_driver *drv)
+{
+ if (of_driver_match_device(dev, drv))
+ return 1;
+
+ return strcmp(dev_name(dev), drv->name) == 0;
+}
+
+static inline int rsb_init_cmd(struct rsb_controller *ctrl)
+{
+ int ret;
+
+ if (!ctrl || !ctrl->init_cmd || ctrl->dev.type != &rsb_ctrl_type)
+ return -EINVAL;
+
+ mutex_lock(&ctrl->lock);
+ ret = ctrl->init_cmd(ctrl);
+ mutex_unlock(&ctrl->lock);
+
+ return ret;
+}
+
+static inline int rsb_rtsaddr_cmd(struct rsb_controller *ctrl, u16 hwaddr,
+ u8 rtaddr)
+{
+ int ret;
+
+ if (!ctrl || !ctrl->rtsaddr_cmd || ctrl->dev.type != &rsb_ctrl_type)
+ return -EINVAL;
+
+ mutex_lock(&ctrl->lock);
+ ret = ctrl->rtsaddr_cmd(ctrl, hwaddr, rtaddr);
+ mutex_unlock(&ctrl->lock);
+
+ return ret;
+}
+
+static inline int rsb_read_cmd(struct rsb_controller *ctrl, u8 rtaddr,
+ u8 addr, u32 *buf, size_t len)
+{
+ int ret;
+
+ if (!ctrl || !ctrl->read_cmd || ctrl->dev.type != &rsb_ctrl_type)
+ return -EINVAL;
+
+ mutex_lock(&ctrl->lock);
+ ret = ctrl->read_cmd(ctrl, rtaddr, addr, buf, len);
+ mutex_unlock(&ctrl->lock);
+
+ return ret;
+}
+
+static inline int rsb_write_cmd(struct rsb_controller *ctrl, u8 rtaddr,
+ u8 addr, const u32 *buf, size_t len)
+{
+ int ret;
+
+ if (!ctrl || !ctrl->write_cmd || ctrl->dev.type != &rsb_ctrl_type)
+ return -EINVAL;
+
+ mutex_lock(&ctrl->lock);
+ ret = ctrl->write_cmd(ctrl, rtaddr, addr, buf, len);
+ mutex_unlock(&ctrl->lock);
+
+ return ret;
+}
+
+/**
+ * rsb_register_read() - register read
+ * @rdev: RSB device.
+ * @addr: slave register address.
+ * @buf: buffer to be populated with data from the Slave.
+ * @size: width of the slave register in bytes
+ *
+ * Reads data from a Slave device register.
+ */
+int rsb_register_read(struct rsb_device *rdev, u8 addr, u32 *buf, int size)
+{
+ switch (size) {
+ case 1:
+ case 2:
+ case 4:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return rsb_read_cmd(rdev->ctrl, rdev->rtaddr, addr, buf, size);
+}
+EXPORT_SYMBOL_GPL(rsb_register_read);
+
+/**
+ * rsb_register_write() - register write
+ * @rdev: RSB device
+ * @addr: slave register address.
+ * @data: buffer containing the data to be transferred to the Slave.
+ * @size: width of the slave register in bytes
+ *
+ * Writes data to a Slave device register.
+ */
+int rsb_register_write(struct rsb_device *rdev, u8 addr, u32 data, int size)
+{
+ switch (size) {
+ case 1:
+ case 2:
+ case 4:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return rsb_write_cmd(rdev->ctrl, rdev->rtaddr, addr, &data, size);
+}
+EXPORT_SYMBOL_GPL(rsb_register_write);
+
+static struct bus_type rsb_bus_type;
+
+static int rsb_device_probe(struct device *dev)
+{
+ const struct rsb_driver *drv = to_rsb_driver(dev->driver);
+ struct rsb_device *rsb = to_rsb_device(dev);
+ int ret;
+
+ if (dev->type != &rsb_dev_type)
+ return 0;
+
+ if (!drv->probe)
+ return -ENODEV;
+
+ if (!rsb->irq) {
+ int irq = -ENOENT;
+
+ if (dev->of_node)
+ irq = of_irq_get(dev->of_node, 0);
+
+ if (irq == -EPROBE_DEFER)
+ return irq;
+ if (irq < 0)
+ irq = 0;
+
+ rsb->irq = irq;
+ }
+
+ ret = of_clk_set_defaults(dev->of_node, false);
+ if (ret < 0)
+ return ret;
+
+ return drv->probe(rsb);
+}
+
+static int rsb_device_remove(struct device *dev)
+{
+ const struct rsb_driver *drv = to_rsb_driver(dev->driver);
+
+ if (dev->type != &rsb_dev_type)
+ return 0;
+
+ return drv->remove(to_rsb_device(dev));
+}
+
+static struct bus_type rsb_bus_type = {
+ .name = "rsb",
+ .match = rsb_device_match,
+ .probe = rsb_device_probe,
+ .remove = rsb_device_remove,
+};
+
+/**
+ * rsb_device_alloc() - Allocate a new RSB device
+ * @ctrl: associated controller
+ *
+ * Caller is responsible for either calling rsb_device_add() to add the
+ * newly allocated controller, or calling rsb_device_put() to discard it.
+ */
+static struct rsb_device *rsb_device_alloc(struct rsb_controller *ctrl)
+{
+ struct rsb_device *rdev;
+
+ rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
+ if (!rdev)
+ return NULL;
+
+ rdev->ctrl = ctrl;
+ device_initialize(&rdev->dev);
+ rdev->dev.parent = &ctrl->dev;
+ rdev->dev.bus = &rsb_bus_type;
+ rdev->dev.type = &rsb_dev_type;
+ return rdev;
+}
+
+static inline void rsb_device_put(struct rsb_device *rdev)
+{
+ if (rdev)
+ put_device(&rdev->dev);
+}
+
+/* 15 valid runtime addresses for RSB slaves */
+static const u8 rsb_valid_rtaddr[] = {
+ 0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
+ 0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff,
+};
+
+static inline int rsb_check_rt_addr(u8 addr)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(rsb_valid_rtaddr); i++)
+ if (addr == rsb_valid_rtaddr[i])
+ return 0;
+
+ return -EINVAL;
+}
+
+/**
+ * rsb_device_add() - add a device previously constructed via rsb_device_alloc()
+ * @rdev: rsb_device to be added
+ */
+static int rsb_device_add(struct rsb_device *rdev)
+{
+ struct rsb_controller *ctrl = rdev->ctrl;
+ int err;
+
+ dev_set_name(&rdev->dev, "%d-%02x", ctrl->nr, rdev->rtaddr);
+
+ err = device_add(&rdev->dev);
+ if (err < 0) {
+ dev_err(&rdev->dev, "Can't add %s, status %d\n",
+ dev_name(&rdev->dev), err);
+ goto err_device_add;
+ }
+
+ dev_dbg(&rdev->dev, "device %s registered\n", dev_name(&rdev->dev));
+
+err_device_add:
+ return err;
+}
+
+/**
+ * rsb_device_unregister(): unregister an RSB device
+ * @rdev: rsb_device to be removed
+ */
+static void rsb_device_unregister(struct rsb_device *rdev)
+{
+ device_unregister(&rdev->dev);
+}
+
+/**
+ * rsb_controller_alloc() - Allocate a new RSB controller
+ * @parent: parent device
+ * @size: size of private data
+ *
+ * Caller is responsible for either calling rsb_controller_add() to add the
+ * newly allocated controller, or calling rsb_controller_put() to discard it.
+ * The allocated private data region may be accessed via
+ * rsb_controller_get_drvdata()
+ */
+struct rsb_controller *rsb_controller_alloc(struct device *parent, size_t size)
+{
+ struct rsb_controller *ctrl;
+ int id;
+
+ if (WARN_ON(!parent))
+ return NULL;
+
+ ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
+ if (!ctrl)
+ return NULL;
+
+ device_initialize(&ctrl->dev);
+ mutex_init(&ctrl->lock);
+ ctrl->dev.type = &rsb_ctrl_type;
+ ctrl->dev.bus = &rsb_bus_type;
+ ctrl->dev.parent = parent;
+ ctrl->dev.of_node = parent->of_node;
+ rsb_controller_set_drvdata(ctrl, &ctrl[1]);
+
+ id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
+ if (id < 0) {
+ dev_err(parent,
+ "unable to allocate RSB controller identifier.\n");
+ rsb_controller_put(ctrl);
+ return NULL;
+ }
+
+ ctrl->nr = id;
+ dev_set_name(&ctrl->dev, "rsb-%d", id);
+ dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
+
+ return ctrl;
+}
+EXPORT_SYMBOL_GPL(rsb_controller_alloc);
+
+static void of_rsb_register_devices(struct rsb_controller *ctrl)
+{
+ struct device_node *node;
+ int err;
+ u32 reg[2];
+
+ if (!ctrl->dev.of_node)
+ return;
+
+ /* Runtime addresses for all slaves should be set first */
+ for_each_available_child_of_node(ctrl->dev.of_node, node) {
+ dev_dbg(&ctrl->dev, "setting child %s runtime address\n",
+ node->full_name);
+
+ err = of_property_read_u32_array(node, "reg", reg, 2);
+ if (err) {
+ dev_err(&ctrl->dev,
+ "node %s err (%d) does not have 'reg' property\n",
+ node->full_name, err);
+ continue;
+ }
+
+ if (reg[0] > 0xff || rsb_check_rt_addr(reg[0]) < 0) {
+ dev_err(&ctrl->dev,
+ "invalid runtime address on node %s\n",
+ node->full_name);
+ continue;
+ }
+
+ /* This fails if the slave device was already initialized */
+ err = rsb_rtsaddr_cmd(ctrl, (u16)reg[1], (u8)reg[0]);
+ if (err)
+ dev_info(&ctrl->dev,
+ "failed to set runtime address: %d\n", err);
+ }
+
+ for_each_available_child_of_node(ctrl->dev.of_node, node) {
+ struct rsb_device *rdev;
+
+ dev_dbg(&ctrl->dev, "adding child %s\n", node->full_name);
+
+ err = of_property_read_u32_array(node, "reg", reg, 2);
+ if (err)
+ continue;
+
+ if (reg[0] > 0xff || rsb_check_rt_addr(reg[0]) < 0)
+ continue;
+
+ rdev = rsb_device_alloc(ctrl);
+ if (!rdev)
+ continue;
+
+ rdev->dev.of_node = node;
+ rdev->rtaddr = (u8)reg[0];
+ rdev->hwaddr = (u16)reg[1];
+
+ err = rsb_device_add(rdev);
+ if (err) {
+ dev_err(&rdev->dev, "failed to add device: %d\n", err);
+ rsb_device_put(rdev);
+ }
+ }
+}
+
+/**
+ * rsb_controller_add() - Add an RSB controller
+ * @ctrl: controller to be registered.
+ *
+ * Register a controller previously allocated via rsb_controller_alloc() with
+ * the RSB core.
+ */
+int rsb_controller_add(struct rsb_controller *ctrl)
+{
+ int ret;
+
+ /* Can't register until after driver model init */
+ if (WARN_ON(!rsb_bus_type.p))
+ return -EAGAIN;
+
+ ret = device_add(&ctrl->dev);
+ if (ret)
+ return ret;
+
+ /*
+ * Send RSB init sequence on the bus. This fails if the bus was
+ * already initialized.
+ */
+ ret = rsb_init_cmd(ctrl);
+ if (ret)
+ dev_info(&ctrl->dev, "RSB init sequence failed: %d\n", ret);
+
+ if (IS_ENABLED(CONFIG_OF))
+ of_rsb_register_devices(ctrl);
+
+ dev_dbg(&ctrl->dev, "rsb-%d registered: dev:%p\n",
+ ctrl->nr, &ctrl->dev);
+
+ return 0;
+};
+EXPORT_SYMBOL_GPL(rsb_controller_add);
+
+/* Remove a device associated with a controller */
+static int rsb_ctrl_remove_device(struct device *dev, void *data)
+{
+ struct rsb_device *rsb = to_rsb_device(dev);
+
+ if (dev->type == &rsb_dev_type)
+ rsb_device_unregister(rsb);
+ return 0;
+}
+
+/**
+ * rsb_controller_remove(): remove an RSB controller
+ * @ctrl: controller to remove
+ *
+ * Remove a RSB controller. Caller is responsible for calling
+ * rsb_controller_put() to discard the allocated controller.
+ */
+void rsb_controller_remove(struct rsb_controller *ctrl)
+{
+ int dummy;
+
+ if (!ctrl)
+ return;
+
+ dummy = device_for_each_child(&ctrl->dev, NULL,
+ rsb_ctrl_remove_device);
+ mutex_destroy(&ctrl->lock);
+ device_del(&ctrl->dev);
+}
+EXPORT_SYMBOL_GPL(rsb_controller_remove);
+
+/**
+ * rsb_driver_register() - Register device driver with RSB core
+ * @rdrv: device driver to be associated with slave-device.
+ *
+ * This API will register the client driver with the RSB framework.
+ * It is typically called from the driver's module-init function.
+ */
+int rsb_driver_register(struct rsb_driver *rdrv)
+{
+ rdrv->driver.bus = &rsb_bus_type;
+ return driver_register(&rdrv->driver);
+}
+EXPORT_SYMBOL_GPL(rsb_driver_register);
+
+static void __exit rsb_exit(void)
+{
+ bus_unregister(&rsb_bus_type);
+}
+module_exit(rsb_exit);
+
+static int __init rsb_init(void)
+{
+ return bus_register(&rsb_bus_type);
+}
+postcore_initcall(rsb_init);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Reduce Serial Bus (RSB) core module");
+MODULE_ALIAS("platform:rsb");
diff --git a/include/linux/rsb.h b/include/linux/rsb.h
new file mode 100644
index 000000000000..51a53468f547
--- /dev/null
+++ b/include/linux/rsb.h
@@ -0,0 +1,144 @@
+/* Copyright (c) 2012-2013, 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.
+ */
+#ifndef _LINUX_RSB_H
+#define _LINUX_RSB_H
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+/**
+ * struct rsb_device - Basic representation of an RSB device
+ * @dev: Driver model representation of the device.
+ * @ctrl: RSB controller managing the bus hosting this device.
+ * @rtaddr: This device's runtime address
+ * @hwaddr: This device's hardware address
+ */
+struct rsb_device {
+ struct device dev;
+ struct rsb_controller *ctrl;
+ int irq;
+ u8 rtaddr;
+ u16 hwaddr;
+};
+
+static inline struct rsb_device *to_rsb_device(struct device *d)
+{
+ return container_of(d, struct rsb_device, dev);
+}
+
+static inline void *rsb_device_get_drvdata(const struct rsb_device *rdev)
+{
+ return dev_get_drvdata(&rdev->dev);
+}
+
+static inline void rsb_device_set_drvdata(struct rsb_device *rdev, void *data)
+{
+ dev_set_drvdata(&rdev->dev, data);
+}
+
+/**
+ * struct rsb_controller - interface to the RSB master controller
+ * @dev: Driver model representation of the device.
+ * @nr: board-specific number identifier for this controller/bus
+ * @init_cmd: sends a device initialization command sequence on the bus.
+ * @rtsaddr_cmd: sends a "set runtime address" command sequence on the bus.
+ * @read_cmd: sends a register read command sequence on the RSB bus.
+ * @write_cmd: sends a register write command sequence on the RSB bus.
+ */
+struct rsb_controller {
+ struct device dev;
+ unsigned int nr;
+ struct mutex lock; /* serialize access to the bus */
+ int (*init_cmd)(struct rsb_controller *ctrl);
+ int (*rtsaddr_cmd)(struct rsb_controller *ctrl,
+ u16 hwaddr, u8 rtaddr);
+ int (*read_cmd)(struct rsb_controller *ctrl, u8 rtaddr,
+ u8 addr, u32 *buf, size_t len);
+ int (*write_cmd)(struct rsb_controller *ctrl, u8 rtaddr,
+ u8 addr, const u32 *buf, size_t len);
+};
+
+static inline struct rsb_controller *to_rsb_controller(struct device *d)
+{
+ return container_of(d, struct rsb_controller, dev);
+}
+
+static inline
+void *rsb_controller_get_drvdata(const struct rsb_controller *ctrl)
+{
+ return dev_get_drvdata(&ctrl->dev);
+}
+
+static inline void rsb_controller_set_drvdata(struct rsb_controller *ctrl,
+ void *data)
+{
+ dev_set_drvdata(&ctrl->dev, data);
+}
+
+struct rsb_controller *rsb_controller_alloc(struct device *parent,
+ size_t size);
+
+/**
+ * rsb_controller_put() - decrement controller refcount
+ * @ctrl RSB controller.
+ */
+static inline void rsb_controller_put(struct rsb_controller *ctrl)
+{
+ if (ctrl) {
+ mutex_destroy(&ctrl->lock);
+ put_device(&ctrl->dev);
+ }
+}
+
+int rsb_controller_add(struct rsb_controller *ctrl);
+void rsb_controller_remove(struct rsb_controller *ctrl);
+
+/**
+ * struct rsb_driver - RSB slave device driver
+ * @driver: RSB device drivers should initialize name and owner field of
+ * this structure.
+ * @probe: binds this driver to a RSB device.
+ * @remove: unbinds this driver from the RSB device.
+ */
+struct rsb_driver {
+ struct device_driver driver;
+ int (*probe)(struct rsb_device *rdev);
+ int (*remove)(struct rsb_device *rdev);
+};
+
+static inline struct rsb_driver *to_rsb_driver(struct device_driver *d)
+{
+ return container_of(d, struct rsb_driver, driver);
+}
+
+int rsb_driver_register(struct rsb_driver *rdrv);
+
+/**
+ * rsb_driver_unregister() - unregister an RSB client driver
+ * @rdrv: the driver to unregister
+ */
+static inline void rsb_driver_unregister(struct rsb_driver *rdrv)
+{
+ if (rdrv)
+ driver_unregister(&rdrv->driver);
+}
+
+#define module_rsb_driver(__rsb_driver) \
+ module_driver(__rsb_driver, rsb_driver_register, \
+ rsb_driver_unregister)
+
+int rsb_register_read(struct rsb_device *rdev, u8 addr, u32 *buf, int size);
+int rsb_register_write(struct rsb_device *rdev, u8 addr, u32 data, int size);
+
+#endif
--
2.5.0
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