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firmware: arm_scmi: Refactor device create/destroy helpers

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Refactor SCMI device create/destroy helpers: it is now possible to ask
for the creation of all the currently requested devices for a whole
protocol, not only for the creation of a single well-defined device.

While at that, re-instate uniqueness checks on the creation of SCMI
SystemPower devices.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222185049.737625-8-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Cristian Marussi 2022-12-22 18:50:47 +00:00 committed by Sudeep Holla
parent 971fc0665f
commit 2c3e674465
4 changed files with 141 additions and 22 deletions
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141
drivers/firmware/arm_scmi/bus.c
View File

@ -7,6 +7,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/atomic.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/of.h>
@ -30,6 +31,9 @@ struct scmi_requested_dev {
struct list_head node;
};
/* Track globally the creation of SCMI SystemPower related devices */
static atomic_t scmi_syspower_registered = ATOMIC_INIT(0);
/**
* scmi_protocol_device_request - Helper to request a device
*
@ -213,11 +217,11 @@ static int scmi_match_by_id_table(struct device *dev, void *data)
struct scmi_device_id *id_table = data;
return sdev->protocol_id == id_table->protocol_id &&
!strcmp(sdev->name, id_table->name);
(id_table->name && !strcmp(sdev->name, id_table->name));
}
struct scmi_device *scmi_child_dev_find(struct device *parent,
int prot_id, const char *name)
static struct scmi_device *scmi_child_dev_find(struct device *parent,
int prot_id, const char *name)
{
struct scmi_device_id id_table;
struct device *dev;
@ -297,13 +301,53 @@ static void scmi_device_release(struct device *dev)
kfree(to_scmi_dev(dev));
}
struct scmi_device *
scmi_device_create(struct device_node *np, struct device *parent, int protocol,
const char *name)
static void __scmi_device_destroy(struct scmi_device *scmi_dev)
{
pr_debug("(%s) Destroying SCMI device '%s' for protocol 0x%x (%s)\n",
of_node_full_name(scmi_dev->dev.parent->of_node),
dev_name(&scmi_dev->dev), scmi_dev->protocol_id,
scmi_dev->name);
if (scmi_dev->protocol_id == SCMI_PROTOCOL_SYSTEM)
atomic_set(&scmi_syspower_registered, 0);
kfree_const(scmi_dev->name);
ida_free(&scmi_bus_id, scmi_dev->id);
device_unregister(&scmi_dev->dev);
}
static struct scmi_device *
__scmi_device_create(struct device_node *np, struct device *parent,
int protocol, const char *name)
{
int id, retval;
struct scmi_device *scmi_dev;
/*
* If the same protocol/name device already exist under the same parent
* (i.e. SCMI instance) just return the existent device.
* This avoids any race between the SCMI driver, creating devices for
* each DT defined protocol at probe time, and the concurrent
* registration of SCMI drivers.
*/
scmi_dev = scmi_child_dev_find(parent, protocol, name);
if (scmi_dev)
return scmi_dev;
/*
* Ignore any possible subsequent failures while creating the device
* since we are doomed anyway at that point; not using a mutex which
* spans across this whole function to keep things simple and to avoid
* to serialize all the __scmi_device_create calls across possibly
* different SCMI server instances (parent)
*/
if (protocol == SCMI_PROTOCOL_SYSTEM &&
atomic_cmpxchg(&scmi_syspower_registered, 0, 1)) {
dev_warn(parent,
"SCMI SystemPower protocol device must be unique !\n");
return NULL;
}
scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
if (!scmi_dev)
return NULL;
@ -333,6 +377,10 @@ scmi_device_create(struct device_node *np, struct device *parent, int protocol,
if (retval)
goto put_dev;
pr_debug("(%s) Created SCMI device '%s' for protocol 0x%x (%s)\n",
of_node_full_name(parent->of_node),
dev_name(&scmi_dev->dev), protocol, name);
return scmi_dev;
put_dev:
kfree_const(scmi_dev->name);
@ -341,18 +389,85 @@ scmi_device_create(struct device_node *np, struct device *parent, int protocol,
return NULL;
}
void scmi_device_destroy(struct scmi_device *scmi_dev)
/**
* scmi_device_create - A method to create one or more SCMI devices
*
* @np: A reference to the device node to use for the new device(s)
* @parent: The parent device to use identifying a specific SCMI instance
* @protocol: The SCMI protocol to be associated with this device
* @name: The requested-name of the device to be created; this is optional
* and if no @name is provided, all the devices currently known to
* be requested on the SCMI bus for @protocol will be created.
*
* This method can be invoked to create a single well-defined device (like
* a transport device or a device requested by an SCMI driver loaded after
* the core SCMI stack has been probed), or to create all the devices currently
* known to have been requested by the loaded SCMI drivers for a specific
* protocol (typically during SCMI core protocol enumeration at probe time).
*
* Return: The created device (or one of them if @name was NOT provided and
* multiple devices were created) or NULL if no device was created;
* note that NULL indicates an error ONLY in case a specific @name
* was provided: when @name param was not provided, a number of devices
* could have been potentially created for a whole protocol, unless no
* device was found to have been requested for that specific protocol.
*/
struct scmi_device *scmi_device_create(struct device_node *np,
struct device *parent, int protocol,
const char *name)
{
kfree_const(scmi_dev->name);
ida_free(&scmi_bus_id, scmi_dev->id);
device_unregister(&scmi_dev->dev);
struct list_head *phead;
struct scmi_requested_dev *rdev;
struct scmi_device *scmi_dev = NULL;
if (name)
return __scmi_device_create(np, parent, protocol, name);
mutex_lock(&scmi_requested_devices_mtx);
phead = idr_find(&scmi_requested_devices, protocol);
/* Nothing to do. */
if (!phead) {
mutex_unlock(&scmi_requested_devices_mtx);
return scmi_dev;
}
/* Walk the list of requested devices for protocol and create them */
list_for_each_entry(rdev, phead, node) {
struct scmi_device *sdev;
sdev = __scmi_device_create(np, parent,
rdev->id_table->protocol_id,
rdev->id_table->name);
/* Report errors and carry on... */
if (sdev)
scmi_dev = sdev;
else
pr_err("(%s) Failed to create device for protocol 0x%x (%s)\n",
of_node_full_name(parent->of_node),
rdev->id_table->protocol_id,
rdev->id_table->name);
}
mutex_unlock(&scmi_requested_devices_mtx);
return scmi_dev;
}
EXPORT_SYMBOL_GPL(scmi_device_create);
void scmi_device_destroy(struct device *parent, int protocol, const char *name)
{
struct scmi_device *scmi_dev;
scmi_dev = scmi_child_dev_find(parent, protocol, name);
if (scmi_dev)
__scmi_device_destroy(scmi_dev);
}
EXPORT_SYMBOL_GPL(scmi_device_destroy);
static int __scmi_devices_unregister(struct device *dev, void *data)
{
struct scmi_device *scmi_dev = to_scmi_dev(dev);
scmi_device_destroy(scmi_dev);
__scmi_device_destroy(scmi_dev);
return 0;
}
@ -374,6 +489,10 @@ int __init scmi_bus_init(void)
void __exit scmi_bus_exit(void)
{
/*
* Destroy all remaining devices: just in case the drivers were
* manually unbound and at first and then the modules unloaded.
*/
scmi_devices_unregister();
bus_unregister(&scmi_bus_type);
ida_destroy(&scmi_bus_id);

8
drivers/firmware/arm_scmi/common.h
View File

@ -107,6 +107,11 @@ extern struct bus_type scmi_bus_type;
#define SCMI_BUS_NOTIFY_DEVICE_UNREQUEST 1
extern struct blocking_notifier_head scmi_requested_devices_nh;
struct scmi_device *scmi_device_create(struct device_node *np,
struct device *parent, int protocol,
const char *name);
void scmi_device_destroy(struct device *parent, int protocol, const char *name);
int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id);
void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);
@ -168,9 +173,6 @@ struct scmi_transport_ops {
bool (*poll_done)(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer);
};
struct scmi_device *scmi_child_dev_find(struct device *parent,
int prot_id, const char *name);
/**
* struct scmi_desc - Description of SoC integration
*

9
drivers/firmware/arm_scmi/driver.c
View File

@ -2091,6 +2091,8 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
/* Create a uniquely named, dedicated transport device for this chan */
tdev = scmi_device_create(of_node, info->dev, prot_id, name);
if (!tdev) {
dev_err(info->dev,
"failed to create transport device (%s)\n", name);
devm_kfree(info->dev, cinfo);
return -EINVAL;
}
@ -2100,7 +2102,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
ret = info->desc->ops->chan_setup(cinfo, info->dev, tx);
if (ret) {
of_node_put(of_node);
scmi_device_destroy(tdev);
scmi_device_destroy(info->dev, prot_id, name);
devm_kfree(info->dev, cinfo);
return ret;
}
@ -2123,7 +2125,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
/* Destroy channel and device only if created by this call. */
if (tdev) {
of_node_put(of_node);
scmi_device_destroy(tdev);
scmi_device_destroy(info->dev, prot_id, name);
devm_kfree(info->dev, cinfo);
}
return ret;
@ -2202,10 +2204,11 @@ static int scmi_chan_destroy(int id, void *p, void *idr)
struct scmi_chan_info *cinfo = p;
if (cinfo->dev) {
struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
struct scmi_device *sdev = to_scmi_dev(cinfo->dev);
of_node_put(cinfo->dev->of_node);
scmi_device_destroy(sdev);
scmi_device_destroy(info->dev, id, sdev->name);
cinfo->dev = NULL;
}

5
include/linux/scmi_protocol.h
View File

@ -804,11 +804,6 @@ struct scmi_device {
#define to_scmi_dev(d) container_of(d, struct scmi_device, dev)
struct scmi_device *
scmi_device_create(struct device_node *np, struct device *parent, int protocol,
const char *name);
void scmi_device_destroy(struct scmi_device *scmi_dev);
struct scmi_device_id {
u8 protocol_id;
const char *name;