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slimbus: core: Add slim controllers support
This patch adds support to slim controllers in the slim core, including some utility functions invoked by the controller and slim device drivers. 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>
This commit is contained in:
Sagar Dharia
Greg Kroah-Hartman
parent
3648e78ec7
commit
46a2bb5a7f
@ -7,7 +7,11 @@
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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/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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@ -92,6 +96,308 @@ void slim_driver_unregister(struct slim_driver *drv)
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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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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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/*
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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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dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
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ctrl->name, ctrl->dev);
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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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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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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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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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108
drivers/slimbus/slimbus.h
Normal file
108
drivers/slimbus/slimbus.h
Normal file
@ -0,0 +1,108 @@
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// 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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#ifndef _DRIVERS_SLIMBUS_H
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#define _DRIVERS_SLIMBUS_H
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/mutex.h>
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#include <linux/slimbus.h>
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/* Standard values per SLIMbus spec needed by controllers and devices */
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#define SLIM_MAX_CLK_GEAR 10
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#define SLIM_MIN_CLK_GEAR 1
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/* Manager's logical address is set to 0xFF per spec */
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#define SLIM_LA_MANAGER 0xFF
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/**
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* struct slim_framer - Represents SLIMbus framer.
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* Every controller may have multiple framers. There is 1 active framer device
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* responsible for clocking the bus.
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* Manager is responsible for framer hand-over.
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* @dev: Driver model representation of the device.
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* @e_addr: Enumeration address of the framer.
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* @rootfreq: Root Frequency at which the framer can run. This is maximum
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* frequency ('clock gear 10') at which the bus can operate.
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* @superfreq: Superframes per root frequency. Every frame is 6144 bits.
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*/
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struct slim_framer {
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struct device dev;
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struct slim_eaddr e_addr;
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int rootfreq;
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int superfreq;
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};
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#define to_slim_framer(d) container_of(d, struct slim_framer, dev)
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/**
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* struct slim_controller - Controls every instance of SLIMbus
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* (similar to 'master' on SPI)
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* @dev: Device interface to this driver
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* @id: Board-specific number identifier for this controller/bus
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* @name: Name for this controller
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* @min_cg: Minimum clock gear supported by this controller (default value: 1)
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* @max_cg: Maximum clock gear supported by this controller (default value: 10)
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* @clkgear: Current clock gear in which this bus is running
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* @laddr_ida: logical address id allocator
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* @a_framer: Active framer which is clocking the bus managed by this controller
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* @lock: Mutex protecting controller data structures
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* @devices: Slim device list
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* @tid_idr: tid id allocator
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* @txn_lock: Lock to protect table of transactions
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* @set_laddr: Setup logical address at laddr for the slave with elemental
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* address e_addr. Drivers implementing controller will be expected to
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* send unicast message to this device with its logical address.
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* @get_laddr: It is possible that controller needs to set fixed logical
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* address table and get_laddr can be used in that case so that controller
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* can do this assignment. Use case is when the master is on the remote
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* processor side, who is resposible for allocating laddr.
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*
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* 'Manager device' is responsible for device management, bandwidth
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* allocation, channel setup, and port associations per channel.
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* Device management means Logical address assignment/removal based on
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* enumeration (report-present, report-absent) of a device.
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* Bandwidth allocation is done dynamically by the manager based on active
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* channels on the bus, message-bandwidth requests made by SLIMbus devices.
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* Based on current bandwidth usage, manager chooses a frequency to run
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* the bus at (in steps of 'clock-gear', 1 through 10, each clock gear
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* representing twice the frequency than the previous gear).
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* Manager is also responsible for entering (and exiting) low-power-mode
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* (known as 'clock pause').
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* Manager can do handover of framer if there are multiple framers on the
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* bus and a certain usecase warrants using certain framer to avoid keeping
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* previous framer being powered-on.
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*
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* Controller here performs duties of the manager device, and 'interface
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* device'. Interface device is responsible for monitoring the bus and
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* reporting information such as loss-of-synchronization, data
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* slot-collision.
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*/
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struct slim_controller {
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struct device *dev;
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unsigned int id;
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char name[SLIMBUS_NAME_SIZE];
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int min_cg;
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int max_cg;
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int clkgear;
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struct ida laddr_ida;
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struct slim_framer *a_framer;
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struct mutex lock;
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struct list_head devices;
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struct idr tid_idr;
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spinlock_t txn_lock;
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int (*set_laddr)(struct slim_controller *ctrl,
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struct slim_eaddr *ea, u8 laddr);
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int (*get_laddr)(struct slim_controller *ctrl,
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struct slim_eaddr *ea, u8 *laddr);
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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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void slim_report_absent(struct slim_device *sbdev);
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int slim_register_controller(struct slim_controller *ctrl);
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int slim_unregister_controller(struct slim_controller *ctrl);
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#endif /* _LINUX_SLIMBUS_H */
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@ -37,11 +37,14 @@ enum slim_device_status {
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SLIM_DEVICE_STATUS_RESERVED,
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};
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struct slim_controller;
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/**
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* struct slim_device - Slim device handle.
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* @dev: Driver model representation of the device.
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* @e_addr: Enumeration address of this device.
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* @status: slim device status
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* @ctrl: slim controller instance.
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* @laddr: 1-byte Logical address of this device.
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* @is_laddr_valid: indicates if the laddr is valid or not
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*
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@ -52,6 +55,7 @@ enum slim_device_status {
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struct slim_device {
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struct device dev;
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struct slim_eaddr e_addr;
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struct slim_controller *ctrl;
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enum slim_device_status status;
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u8 laddr;
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bool is_laddr_valid;
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@ -113,4 +117,8 @@ static inline void slim_set_devicedata(struct slim_device *dev, void *data)
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{
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dev_set_drvdata(&dev->dev, data);
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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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int slim_get_logical_addr(struct slim_device *sbdev);
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#endif /* _LINUX_SLIMBUS_H */
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