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 2017-12-11 23:42:58 +00:00 committed by Greg Kroah-Hartman
parent 3648e78ec7
commit 46a2bb5a7f
3 changed files with 422 additions and 0 deletions

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@ -7,7 +7,11 @@
#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)
@ -92,6 +96,308 @@ 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);

108
drivers/slimbus/slimbus.h Normal file
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@ -0,0 +1,108 @@
// 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 */

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@ -37,11 +37,14 @@ 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
*
@ -52,6 +55,7 @@ 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;
@ -113,4 +117,8 @@ 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 */