From: Sagar Dharia sdharia@codeaurora.org
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 --- drivers/slimbus/core.c | 306 ++++++++++++++++++++++++++++++++++++++++++++++ drivers/slimbus/slimbus.h | 106 ++++++++++++++++ include/linux/slimbus.h | 8 ++ 3 files changed, 420 insertions(+) create mode 100644 drivers/slimbus/slimbus.h
diff --git a/drivers/slimbus/core.c b/drivers/slimbus/core.c index f4e6bfdeef92..a59a88a7a52d 100644 --- a/drivers/slimbus/core.c +++ b/drivers/slimbus/core.c @@ -5,7 +5,11 @@ #include <linux/errno.h> #include <linux/slab.h> #include <linux/init.h> +#include <linux/idr.h> #include <linux/slimbus.h> +#include "slimbus.h" + +static DEFINE_IDA(ctrl_ida);
static const struct slim_device_id *slim_match(const struct slim_device_id *id, const struct slim_device *sbdev) @@ -90,6 +94,308 @@ void slim_driver_unregister(struct slim_driver *drv) } EXPORT_SYMBOL_GPL(slim_driver_unregister);
+static void slim_dev_release(struct device *dev) +{ + struct slim_device *sbdev = to_slim_device(dev); + + kfree(sbdev); +} + +static int slim_add_device(struct slim_controller *ctrl, + struct slim_device *sbdev, + struct device_node *node) +{ + sbdev->dev.bus = &slimbus_bus; + sbdev->dev.parent = ctrl->dev; + sbdev->dev.release = slim_dev_release; + sbdev->dev.driver = NULL; + sbdev->ctrl = ctrl; + + dev_set_name(&sbdev->dev, "%x:%x:%x:%x", + sbdev->e_addr.manf_id, + sbdev->e_addr.prod_code, + sbdev->e_addr.dev_index, + sbdev->e_addr.instance); + + return device_register(&sbdev->dev); +} + +static struct slim_device *slim_alloc_device(struct slim_controller *ctrl, + struct slim_eaddr *eaddr, + struct device_node *node) +{ + struct slim_device *sbdev; + int ret; + + sbdev = kzalloc(sizeof(*sbdev), GFP_KERNEL); + if (!sbdev) + return NULL; + + sbdev->e_addr = *eaddr; + ret = slim_add_device(ctrl, sbdev, node); + if (ret) { + kfree(sbdev); + return NULL; + } + + return sbdev; +} + +/* + * slim_register_controller() - Controller bring-up and registration. + * + * @ctrl: Controller to be registered. + * + * A controller is registered with the framework using this API. + * If devices on a controller were registered before controller, + * this will make sure that they get probed when controller is up + */ +int slim_register_controller(struct slim_controller *ctrl) +{ + int id; + + id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL); + if (id < 0) + return id; + + ctrl->id = id; + + if (!ctrl->min_cg) + ctrl->min_cg = SLIM_MIN_CLK_GEAR; + if (!ctrl->max_cg) + ctrl->max_cg = SLIM_MAX_CLK_GEAR; + + ida_init(&ctrl->laddr_ida); + idr_init(&ctrl->tid_idr); + mutex_init(&ctrl->lock); + + dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n", + ctrl->name, ctrl->dev); + + return 0; +} +EXPORT_SYMBOL_GPL(slim_register_controller); + +/* slim_remove_device: Remove the effect of slim_add_device() */ +static void slim_remove_device(struct slim_device *sbdev) +{ + device_unregister(&sbdev->dev); +} + +static int slim_ctrl_remove_device(struct device *dev, void *null) +{ + slim_remove_device(to_slim_device(dev)); + return 0; +} + +/** + * slim_unregister_controller() - Controller tear-down. + * + * @ctrl: Controller to tear-down. + */ +int slim_unregister_controller(struct slim_controller *ctrl) +{ + /* Remove all clients */ + device_for_each_child(ctrl->dev, NULL, slim_ctrl_remove_device); + ida_simple_remove(&ctrl_ida, ctrl->id); + + return 0; +} +EXPORT_SYMBOL_GPL(slim_unregister_controller); + +static void slim_device_update_status(struct slim_device *sbdev, + enum slim_device_status status) +{ + struct slim_driver *sbdrv; + + if (sbdev->status == status) + return; + + sbdev->status = status; + if (!sbdev->dev.driver) + return; + + sbdrv = to_slim_driver(sbdev->dev.driver); + if (sbdrv->device_status) + sbdrv->device_status(sbdev, sbdev->status); +} + +/** + * slim_report_absent() - Controller calls this function when a device + * reports absent, OR when the device cannot be communicated with + * + * @sbdev: Device that cannot be reached, or sent report absent + */ +void slim_report_absent(struct slim_device *sbdev) +{ + struct slim_controller *ctrl = sbdev->ctrl; + + if (!ctrl) + return; + + /* invalidate logical addresses */ + mutex_lock(&ctrl->lock); + sbdev->is_laddr_valid = false; + mutex_unlock(&ctrl->lock); + + ida_simple_remove(&ctrl->laddr_ida, sbdev->laddr); + slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_DOWN); +} +EXPORT_SYMBOL_GPL(slim_report_absent); + +static bool slim_eaddr_equal(struct slim_eaddr *a, struct slim_eaddr *b) +{ + return (a->manf_id == b->manf_id && + a->prod_code == b->prod_code && + a->dev_index == b->dev_index && + a->instance == b->instance); +} + +static int slim_match_dev(struct device *dev, void *data) +{ + struct slim_eaddr *e_addr = data; + struct slim_device *sbdev = to_slim_device(dev); + + return slim_eaddr_equal(&sbdev->e_addr, e_addr); +} + +static struct slim_device *find_slim_device(struct slim_controller *ctrl, + struct slim_eaddr *eaddr) +{ + struct slim_device *sbdev; + struct device *dev; + + dev = device_find_child(ctrl->dev, eaddr, slim_match_dev); + if (dev) { + sbdev = to_slim_device(dev); + return sbdev; + } + + return NULL; +} + +/** + * slim_get_device() - get handle to a device. + * + * @ctrl: Controller on which this device will be added/queried + * @e_addr: Enumeration address of the device to be queried + * + * Return: pointer to a device if it has already reported. Creates a new + * device and returns pointer to it if the device has not yet enumerated. + */ +struct slim_device *slim_get_device(struct slim_controller *ctrl, + struct slim_eaddr *e_addr) +{ + struct slim_device *sbdev; + + sbdev = find_slim_device(ctrl, e_addr); + if (!sbdev) { + sbdev = slim_alloc_device(ctrl, e_addr, NULL); + if (!sbdev) + return ERR_PTR(-ENOMEM); + } + + return sbdev; +} +EXPORT_SYMBOL_GPL(slim_get_device); + +static int slim_device_alloc_laddr(struct slim_device *sbdev, + bool report_present) +{ + struct slim_controller *ctrl = sbdev->ctrl; + u8 laddr; + int ret; + + mutex_lock(&ctrl->lock); + if (ctrl->get_laddr) { + ret = ctrl->get_laddr(ctrl, &sbdev->e_addr, &laddr); + if (ret < 0) + goto err; + } else if (report_present) { + ret = ida_simple_get(&ctrl->laddr_ida, + 0, SLIM_LA_MANAGER - 1, GFP_KERNEL); + if (ret < 0) + goto err; + + laddr = ret; + } else { + ret = -EINVAL; + goto err; + } + + if (ctrl->set_laddr) { + ret = ctrl->set_laddr(ctrl, &sbdev->e_addr, laddr); + if (ret) { + ret = -EINVAL; + goto err; + } + } + + sbdev->laddr = laddr; + sbdev->is_laddr_valid = true; + + slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_UP); + + dev_dbg(ctrl->dev, "setting slimbus l-addr:%x, ea:%x,%x,%x,%x\n", + laddr, sbdev->e_addr.manf_id, sbdev->e_addr.prod_code, + sbdev->e_addr.dev_index, sbdev->e_addr.instance); + +err: + mutex_unlock(&ctrl->lock); + return ret; + +} + +/** + * slim_device_report_present() - Report enumerated device. + * + * @ctrl: Controller with which device is enumerated. + * @e_addr: Enumeration address of the device. + * @laddr: Return logical address (if valid flag is false) + * + * Called by controller in response to REPORT_PRESENT. Framework will assign + * a logical address to this enumeration address. + * Function returns -EXFULL to indicate that all logical addresses are already + * taken. + */ +int slim_device_report_present(struct slim_controller *ctrl, + struct slim_eaddr *e_addr, u8 *laddr) +{ + struct slim_device *sbdev; + int ret; + + sbdev = slim_get_device(ctrl, e_addr); + if (IS_ERR(sbdev)) + return -ENODEV; + + if (sbdev->is_laddr_valid) { + *laddr = sbdev->laddr; + return 0; + } + + ret = slim_device_alloc_laddr(sbdev, true); + + return ret; +} +EXPORT_SYMBOL_GPL(slim_device_report_present); + +/** + * slim_get_logical_addr() - get/allocate logical address of a SLIMbus device. + * + * @sbdev: client handle requesting the address. + * + * Return: zero if a logical address is valid or a new logical address + * has been assigned. error code in case of error. + */ +int slim_get_logical_addr(struct slim_device *sbdev) +{ + if (!sbdev->is_laddr_valid) + return slim_device_alloc_laddr(sbdev, false); + + return 0; +} +EXPORT_SYMBOL_GPL(slim_get_logical_addr); + static void __exit slimbus_exit(void) { bus_unregister(&slimbus_bus); diff --git a/drivers/slimbus/slimbus.h b/drivers/slimbus/slimbus.h new file mode 100644 index 000000000000..155d7231627d --- /dev/null +++ b/drivers/slimbus/slimbus.h @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2011-2017, The Linux Foundation + +#ifndef _DRIVERS_SLIMBUS_H +#define _DRIVERS_SLIMBUS_H +#include <linux/module.h> +#include <linux/device.h> +#include <linux/mutex.h> +#include <linux/slimbus.h> + +/* Standard values per SLIMbus spec needed by controllers and devices */ +#define SLIM_MAX_CLK_GEAR 10 +#define SLIM_MIN_CLK_GEAR 1 + +/* Manager's logical address is set to 0xFF per spec */ +#define SLIM_LA_MANAGER 0xFF + +/** + * struct slim_framer - Represents SLIMbus framer. + * Every controller may have multiple framers. There is 1 active framer device + * responsible for clocking the bus. + * Manager is responsible for framer hand-over. + * @dev: Driver model representation of the device. + * @e_addr: Enumeration address of the framer. + * @rootfreq: Root Frequency at which the framer can run. This is maximum + * frequency ('clock gear 10') at which the bus can operate. + * @superfreq: Superframes per root frequency. Every frame is 6144 bits. + */ +struct slim_framer { + struct device dev; + struct slim_eaddr e_addr; + int rootfreq; + int superfreq; +}; + +#define to_slim_framer(d) container_of(d, struct slim_framer, dev) + +/** + * struct slim_controller - Controls every instance of SLIMbus + * (similar to 'master' on SPI) + * @dev: Device interface to this driver + * @id: Board-specific number identifier for this controller/bus + * @name: Name for this controller + * @min_cg: Minimum clock gear supported by this controller (default value: 1) + * @max_cg: Maximum clock gear supported by this controller (default value: 10) + * @clkgear: Current clock gear in which this bus is running + * @laddr_ida: logical address id allocator + * @a_framer: Active framer which is clocking the bus managed by this controller + * @lock: Mutex protecting controller data structures + * @devices: Slim device list + * @tid_idr: tid id allocator + * @txn_lock: Lock to protect table of transactions + * @set_laddr: Setup logical address at laddr for the slave with elemental + * address e_addr. Drivers implementing controller will be expected to + * send unicast message to this device with its logical address. + * @get_laddr: It is possible that controller needs to set fixed logical + * address table and get_laddr can be used in that case so that controller + * can do this assignment. Use case is when the master is on the remote + * processor side, who is resposible for allocating laddr. + * + * 'Manager device' is responsible for device management, bandwidth + * allocation, channel setup, and port associations per channel. + * Device management means Logical address assignment/removal based on + * enumeration (report-present, report-absent) of a device. + * Bandwidth allocation is done dynamically by the manager based on active + * channels on the bus, message-bandwidth requests made by SLIMbus devices. + * Based on current bandwidth usage, manager chooses a frequency to run + * the bus at (in steps of 'clock-gear', 1 through 10, each clock gear + * representing twice the frequency than the previous gear). + * Manager is also responsible for entering (and exiting) low-power-mode + * (known as 'clock pause'). + * Manager can do handover of framer if there are multiple framers on the + * bus and a certain usecase warrants using certain framer to avoid keeping + * previous framer being powered-on. + * + * Controller here performs duties of the manager device, and 'interface + * device'. Interface device is responsible for monitoring the bus and + * reporting information such as loss-of-synchronization, data + * slot-collision. + */ +struct slim_controller { + struct device *dev; + unsigned int id; + char name[SLIMBUS_NAME_SIZE]; + int min_cg; + int max_cg; + int clkgear; + struct ida laddr_ida; + struct slim_framer *a_framer; + struct mutex lock; + struct list_head devices; + struct idr tid_idr; + spinlock_t txn_lock; + int (*set_laddr)(struct slim_controller *ctrl, + struct slim_eaddr *ea, u8 laddr); + int (*get_laddr)(struct slim_controller *ctrl, + struct slim_eaddr *ea, u8 *laddr); +}; + +int slim_device_report_present(struct slim_controller *ctrl, + struct slim_eaddr *e_addr, u8 *laddr); +void slim_report_absent(struct slim_device *sbdev); +int slim_register_controller(struct slim_controller *ctrl); +int slim_unregister_controller(struct slim_controller *ctrl); + +#endif /* _LINUX_SLIMBUS_H */ diff --git a/include/linux/slimbus.h b/include/linux/slimbus.h index a52f8e530f27..b59b272666b6 100644 --- a/include/linux/slimbus.h +++ b/include/linux/slimbus.h @@ -35,11 +35,14 @@ enum slim_device_status { SLIM_DEVICE_STATUS_RESERVED, };
+struct slim_controller; + /** * struct slim_device - Slim device handle. * @dev: Driver model representation of the device. * @e_addr: Enumeration address of this device. * @status: slim device status + * @ctrl: slim controller instance. * @laddr: 1-byte Logical address of this device. * @is_laddr_valid: indicates if the laddr is valid or not * @@ -50,6 +53,7 @@ enum slim_device_status { struct slim_device { struct device dev; struct slim_eaddr e_addr; + struct slim_controller *ctrl; enum slim_device_status status; u8 laddr; bool is_laddr_valid; @@ -111,4 +115,8 @@ static inline void slim_set_devicedata(struct slim_device *dev, void *data) { dev_set_drvdata(&dev->dev, data); } + +struct slim_device *slim_get_device(struct slim_controller *ctrl, + struct slim_eaddr *e_addr); +int slim_get_logical_addr(struct slim_device *sbdev); #endif /* _LINUX_SLIMBUS_H */