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![Sagar Dharia](/assets/img/avatar_default.png)
Per SLIMbus specification, a reconfiguration sequence known as 'clock pause' needs to be broadcast over the bus while entering low- power mode. Clock-pause is initiated by the controller driver. To exit clock-pause, controller typically wakes up the framer device. Since wakeup precedure is controller-specific, framework calls it via controller's function pointer to invoke it. Signed-off-by: Sagar Dharia <sdharia@codeaurora.org> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Reviwed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
480 lines
11 KiB
C
480 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2011-2017, The Linux Foundation
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/idr.h>
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#include <linux/of.h>
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#include <linux/pm_runtime.h>
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#include <linux/slimbus.h>
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#include "slimbus.h"
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static DEFINE_IDA(ctrl_ida);
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static const struct slim_device_id *slim_match(const struct slim_device_id *id,
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const struct slim_device *sbdev)
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{
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while (id->manf_id != 0 || id->prod_code != 0) {
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if (id->manf_id == sbdev->e_addr.manf_id &&
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id->prod_code == sbdev->e_addr.prod_code)
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return id;
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id++;
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}
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return NULL;
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}
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static int slim_device_match(struct device *dev, struct device_driver *drv)
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{
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struct slim_device *sbdev = to_slim_device(dev);
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struct slim_driver *sbdrv = to_slim_driver(drv);
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return !!slim_match(sbdrv->id_table, sbdev);
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}
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static int slim_device_probe(struct device *dev)
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{
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struct slim_device *sbdev = to_slim_device(dev);
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struct slim_driver *sbdrv = to_slim_driver(dev->driver);
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return sbdrv->probe(sbdev);
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}
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static int slim_device_remove(struct device *dev)
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{
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struct slim_device *sbdev = to_slim_device(dev);
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struct slim_driver *sbdrv;
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if (dev->driver) {
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sbdrv = to_slim_driver(dev->driver);
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if (sbdrv->remove)
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sbdrv->remove(sbdev);
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}
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return 0;
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}
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struct bus_type slimbus_bus = {
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.name = "slimbus",
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.match = slim_device_match,
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.probe = slim_device_probe,
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.remove = slim_device_remove,
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};
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EXPORT_SYMBOL_GPL(slimbus_bus);
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/*
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* __slim_driver_register() - Client driver registration with SLIMbus
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*
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* @drv:Client driver to be associated with client-device.
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* @owner: owning module/driver
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*
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* This API will register the client driver with the SLIMbus
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* It is called from the driver's module-init function.
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*/
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int __slim_driver_register(struct slim_driver *drv, struct module *owner)
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{
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/* ID table and probe are mandatory */
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if (!drv->id_table || !drv->probe)
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return -EINVAL;
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drv->driver.bus = &slimbus_bus;
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drv->driver.owner = owner;
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return driver_register(&drv->driver);
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}
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EXPORT_SYMBOL_GPL(__slim_driver_register);
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/*
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* slim_driver_unregister() - Undo effect of slim_driver_register
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*
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* @drv: Client driver to be unregistered
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*/
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void slim_driver_unregister(struct slim_driver *drv)
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{
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driver_unregister(&drv->driver);
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}
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EXPORT_SYMBOL_GPL(slim_driver_unregister);
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static void slim_dev_release(struct device *dev)
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{
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struct slim_device *sbdev = to_slim_device(dev);
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kfree(sbdev);
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}
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static int slim_add_device(struct slim_controller *ctrl,
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struct slim_device *sbdev,
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struct device_node *node)
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{
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sbdev->dev.bus = &slimbus_bus;
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sbdev->dev.parent = ctrl->dev;
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sbdev->dev.release = slim_dev_release;
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sbdev->dev.driver = NULL;
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sbdev->ctrl = ctrl;
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if (node)
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sbdev->dev.of_node = of_node_get(node);
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dev_set_name(&sbdev->dev, "%x:%x:%x:%x",
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sbdev->e_addr.manf_id,
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sbdev->e_addr.prod_code,
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sbdev->e_addr.dev_index,
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sbdev->e_addr.instance);
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return device_register(&sbdev->dev);
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}
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static struct slim_device *slim_alloc_device(struct slim_controller *ctrl,
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struct slim_eaddr *eaddr,
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struct device_node *node)
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{
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struct slim_device *sbdev;
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int ret;
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sbdev = kzalloc(sizeof(*sbdev), GFP_KERNEL);
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if (!sbdev)
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return NULL;
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sbdev->e_addr = *eaddr;
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ret = slim_add_device(ctrl, sbdev, node);
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if (ret) {
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kfree(sbdev);
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return NULL;
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}
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return sbdev;
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}
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static void of_register_slim_devices(struct slim_controller *ctrl)
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{
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struct device *dev = ctrl->dev;
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struct device_node *node;
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if (!ctrl->dev->of_node)
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return;
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for_each_child_of_node(ctrl->dev->of_node, node) {
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struct slim_device *sbdev;
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struct slim_eaddr e_addr;
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const char *compat = NULL;
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int reg[2], ret;
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int manf_id, prod_code;
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compat = of_get_property(node, "compatible", NULL);
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if (!compat)
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continue;
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ret = sscanf(compat, "slim%x,%x", &manf_id, &prod_code);
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if (ret != 2) {
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dev_err(dev, "Manf ID & Product code not found %s\n",
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compat);
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continue;
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}
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ret = of_property_read_u32_array(node, "reg", reg, 2);
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if (ret) {
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dev_err(dev, "Device and Instance id not found:%d\n",
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ret);
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continue;
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}
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e_addr.dev_index = reg[0];
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e_addr.instance = reg[1];
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e_addr.manf_id = manf_id;
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e_addr.prod_code = prod_code;
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sbdev = slim_alloc_device(ctrl, &e_addr, node);
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if (!sbdev)
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continue;
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}
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}
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/*
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* slim_register_controller() - Controller bring-up and registration.
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*
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* @ctrl: Controller to be registered.
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*
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* A controller is registered with the framework using this API.
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* If devices on a controller were registered before controller,
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* this will make sure that they get probed when controller is up
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*/
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int slim_register_controller(struct slim_controller *ctrl)
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{
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int id;
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id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
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if (id < 0)
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return id;
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ctrl->id = id;
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if (!ctrl->min_cg)
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ctrl->min_cg = SLIM_MIN_CLK_GEAR;
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if (!ctrl->max_cg)
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ctrl->max_cg = SLIM_MAX_CLK_GEAR;
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ida_init(&ctrl->laddr_ida);
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idr_init(&ctrl->tid_idr);
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mutex_init(&ctrl->lock);
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mutex_init(&ctrl->sched.m_reconf);
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init_completion(&ctrl->sched.pause_comp);
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dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
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ctrl->name, ctrl->dev);
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of_register_slim_devices(ctrl);
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return 0;
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}
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EXPORT_SYMBOL_GPL(slim_register_controller);
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/* slim_remove_device: Remove the effect of slim_add_device() */
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static void slim_remove_device(struct slim_device *sbdev)
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{
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device_unregister(&sbdev->dev);
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}
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static int slim_ctrl_remove_device(struct device *dev, void *null)
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{
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slim_remove_device(to_slim_device(dev));
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return 0;
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}
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/**
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* slim_unregister_controller() - Controller tear-down.
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*
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* @ctrl: Controller to tear-down.
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*/
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int slim_unregister_controller(struct slim_controller *ctrl)
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{
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/* Remove all clients */
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device_for_each_child(ctrl->dev, NULL, slim_ctrl_remove_device);
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/* Enter Clock Pause */
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slim_ctrl_clk_pause(ctrl, false, 0);
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ida_simple_remove(&ctrl_ida, ctrl->id);
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return 0;
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}
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EXPORT_SYMBOL_GPL(slim_unregister_controller);
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static void slim_device_update_status(struct slim_device *sbdev,
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enum slim_device_status status)
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{
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struct slim_driver *sbdrv;
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if (sbdev->status == status)
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return;
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sbdev->status = status;
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if (!sbdev->dev.driver)
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return;
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sbdrv = to_slim_driver(sbdev->dev.driver);
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if (sbdrv->device_status)
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sbdrv->device_status(sbdev, sbdev->status);
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}
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/**
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* slim_report_absent() - Controller calls this function when a device
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* reports absent, OR when the device cannot be communicated with
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*
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* @sbdev: Device that cannot be reached, or sent report absent
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*/
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void slim_report_absent(struct slim_device *sbdev)
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{
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struct slim_controller *ctrl = sbdev->ctrl;
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if (!ctrl)
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return;
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/* invalidate logical addresses */
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mutex_lock(&ctrl->lock);
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sbdev->is_laddr_valid = false;
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mutex_unlock(&ctrl->lock);
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ida_simple_remove(&ctrl->laddr_ida, sbdev->laddr);
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slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_DOWN);
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}
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EXPORT_SYMBOL_GPL(slim_report_absent);
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static bool slim_eaddr_equal(struct slim_eaddr *a, struct slim_eaddr *b)
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{
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return (a->manf_id == b->manf_id &&
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a->prod_code == b->prod_code &&
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a->dev_index == b->dev_index &&
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a->instance == b->instance);
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}
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static int slim_match_dev(struct device *dev, void *data)
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{
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struct slim_eaddr *e_addr = data;
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struct slim_device *sbdev = to_slim_device(dev);
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return slim_eaddr_equal(&sbdev->e_addr, e_addr);
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}
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static struct slim_device *find_slim_device(struct slim_controller *ctrl,
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struct slim_eaddr *eaddr)
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{
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struct slim_device *sbdev;
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struct device *dev;
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dev = device_find_child(ctrl->dev, eaddr, slim_match_dev);
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if (dev) {
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sbdev = to_slim_device(dev);
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return sbdev;
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}
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return NULL;
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}
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/**
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* slim_get_device() - get handle to a device.
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*
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* @ctrl: Controller on which this device will be added/queried
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* @e_addr: Enumeration address of the device to be queried
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*
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* Return: pointer to a device if it has already reported. Creates a new
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* device and returns pointer to it if the device has not yet enumerated.
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*/
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struct slim_device *slim_get_device(struct slim_controller *ctrl,
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struct slim_eaddr *e_addr)
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{
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struct slim_device *sbdev;
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sbdev = find_slim_device(ctrl, e_addr);
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if (!sbdev) {
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sbdev = slim_alloc_device(ctrl, e_addr, NULL);
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if (!sbdev)
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return ERR_PTR(-ENOMEM);
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}
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return sbdev;
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}
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EXPORT_SYMBOL_GPL(slim_get_device);
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static int slim_device_alloc_laddr(struct slim_device *sbdev,
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bool report_present)
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{
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struct slim_controller *ctrl = sbdev->ctrl;
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u8 laddr;
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int ret;
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mutex_lock(&ctrl->lock);
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if (ctrl->get_laddr) {
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ret = ctrl->get_laddr(ctrl, &sbdev->e_addr, &laddr);
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if (ret < 0)
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goto err;
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} else if (report_present) {
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ret = ida_simple_get(&ctrl->laddr_ida,
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0, SLIM_LA_MANAGER - 1, GFP_KERNEL);
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if (ret < 0)
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goto err;
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laddr = ret;
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} else {
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ret = -EINVAL;
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goto err;
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}
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if (ctrl->set_laddr) {
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ret = ctrl->set_laddr(ctrl, &sbdev->e_addr, laddr);
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if (ret) {
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ret = -EINVAL;
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goto err;
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}
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}
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sbdev->laddr = laddr;
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sbdev->is_laddr_valid = true;
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slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_UP);
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dev_dbg(ctrl->dev, "setting slimbus l-addr:%x, ea:%x,%x,%x,%x\n",
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laddr, sbdev->e_addr.manf_id, sbdev->e_addr.prod_code,
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sbdev->e_addr.dev_index, sbdev->e_addr.instance);
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err:
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mutex_unlock(&ctrl->lock);
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return ret;
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}
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/**
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* slim_device_report_present() - Report enumerated device.
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*
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* @ctrl: Controller with which device is enumerated.
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* @e_addr: Enumeration address of the device.
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* @laddr: Return logical address (if valid flag is false)
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*
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* Called by controller in response to REPORT_PRESENT. Framework will assign
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* a logical address to this enumeration address.
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* Function returns -EXFULL to indicate that all logical addresses are already
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* taken.
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*/
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int slim_device_report_present(struct slim_controller *ctrl,
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struct slim_eaddr *e_addr, u8 *laddr)
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{
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struct slim_device *sbdev;
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int ret;
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ret = pm_runtime_get_sync(ctrl->dev);
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if (ctrl->sched.clk_state != SLIM_CLK_ACTIVE) {
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dev_err(ctrl->dev, "slim ctrl not active,state:%d, ret:%d\n",
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ctrl->sched.clk_state, ret);
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goto slimbus_not_active;
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}
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sbdev = slim_get_device(ctrl, e_addr);
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if (IS_ERR(sbdev))
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return -ENODEV;
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if (sbdev->is_laddr_valid) {
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*laddr = sbdev->laddr;
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return 0;
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}
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ret = slim_device_alloc_laddr(sbdev, true);
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slimbus_not_active:
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pm_runtime_mark_last_busy(ctrl->dev);
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pm_runtime_put_autosuspend(ctrl->dev);
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return ret;
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}
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EXPORT_SYMBOL_GPL(slim_device_report_present);
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/**
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* slim_get_logical_addr() - get/allocate logical address of a SLIMbus device.
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*
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* @sbdev: client handle requesting the address.
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*
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* Return: zero if a logical address is valid or a new logical address
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* has been assigned. error code in case of error.
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*/
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int slim_get_logical_addr(struct slim_device *sbdev)
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{
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if (!sbdev->is_laddr_valid)
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return slim_device_alloc_laddr(sbdev, false);
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return 0;
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}
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EXPORT_SYMBOL_GPL(slim_get_logical_addr);
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static void __exit slimbus_exit(void)
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{
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bus_unregister(&slimbus_bus);
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}
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module_exit(slimbus_exit);
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static int __init slimbus_init(void)
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{
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return bus_register(&slimbus_bus);
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}
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postcore_initcall(slimbus_init);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("SLIMbus core");
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