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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
#include <linux/memregion.h>
#include <linux/genalloc.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <cxl.h>
#include "core.h"
/**
* DOC: cxl core region
*
* CXL Regions represent mapped memory capacity in system physical address
* space. Whereas the CXL Root Decoders identify the bounds of potential CXL
* Memory ranges, Regions represent the active mapped capacity by the HDM
* Decoder Capability structures throughout the Host Bridges, Switches, and
* Endpoints in the topology.
*/
static struct cxl_region *to_cxl_region(struct device *dev);
static void cxl_region_release(struct device *dev)
{
struct cxl_region *cxlr = to_cxl_region(dev);
memregion_free(cxlr->id);
kfree(cxlr);
}
static const struct device_type cxl_region_type = {
.name = "cxl_region",
.release = cxl_region_release,
};
bool is_cxl_region(struct device *dev)
{
return dev->type == &cxl_region_type;
}
EXPORT_SYMBOL_NS_GPL(is_cxl_region, CXL);
static struct cxl_region *to_cxl_region(struct device *dev)
{
if (dev_WARN_ONCE(dev, dev->type != &cxl_region_type,
"not a cxl_region device\n"))
return NULL;
return container_of(dev, struct cxl_region, dev);
}
static void unregister_region(void *dev)
{
device_unregister(dev);
}
static struct lock_class_key cxl_region_key;
static struct cxl_region *cxl_region_alloc(struct cxl_root_decoder *cxlrd, int id)
{
struct cxl_region *cxlr;
struct device *dev;
cxlr = kzalloc(sizeof(*cxlr), GFP_KERNEL);
if (!cxlr) {
memregion_free(id);
return ERR_PTR(-ENOMEM);
}
dev = &cxlr->dev;
device_initialize(dev);
lockdep_set_class(&dev->mutex, &cxl_region_key);
dev->parent = &cxlrd->cxlsd.cxld.dev;
device_set_pm_not_required(dev);
dev->bus = &cxl_bus_type;
dev->type = &cxl_region_type;
cxlr->id = id;
return cxlr;
}
/**
* devm_cxl_add_region - Adds a region to a decoder
* @cxlrd: root decoder
* @id: memregion id to create, or memregion_free() on failure
* @mode: mode for the endpoint decoders of this region
* @type: select whether this is an expander or accelerator (type-2 or type-3)
*
* This is the second step of region initialization. Regions exist within an
* address space which is mapped by a @cxlrd.
*
* Return: 0 if the region was added to the @cxlrd, else returns negative error
* code. The region will be named "regionZ" where Z is the unique region number.
*/
static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
int id,
enum cxl_decoder_mode mode,
enum cxl_decoder_type type)
{
struct cxl_port *port = to_cxl_port(cxlrd->cxlsd.cxld.dev.parent);
struct cxl_region *cxlr;
struct device *dev;
int rc;
cxlr = cxl_region_alloc(cxlrd, id);
if (IS_ERR(cxlr))
return cxlr;
cxlr->mode = mode;
cxlr->type = type;
dev = &cxlr->dev;
rc = dev_set_name(dev, "region%d", id);
if (rc)
goto err;
rc = device_add(dev);
if (rc)
goto err;
rc = devm_add_action_or_reset(port->uport, unregister_region, cxlr);
if (rc)
return ERR_PTR(rc);
dev_dbg(port->uport, "%s: created %s\n",
dev_name(&cxlrd->cxlsd.cxld.dev), dev_name(dev));
return cxlr;
err:
put_device(dev);
return ERR_PTR(rc);
}
static ssize_t create_pmem_region_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
return sysfs_emit(buf, "region%u\n", atomic_read(&cxlrd->region_id));
}
static ssize_t create_pmem_region_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
struct cxl_region *cxlr;
int id, rc;
rc = sscanf(buf, "region%d\n", &id);
if (rc != 1)
return -EINVAL;
rc = memregion_alloc(GFP_KERNEL);
if (rc < 0)
return rc;
if (atomic_cmpxchg(&cxlrd->region_id, id, rc) != id) {
memregion_free(rc);
return -EBUSY;
}
cxlr = devm_cxl_add_region(cxlrd, id, CXL_DECODER_PMEM,
CXL_DECODER_EXPANDER);
if (IS_ERR(cxlr))
return PTR_ERR(cxlr);
return len;
}
DEVICE_ATTR_RW(create_pmem_region);
static struct cxl_region *
cxl_find_region_by_name(struct cxl_root_decoder *cxlrd, const char *name)
{
struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
struct device *region_dev;
region_dev = device_find_child_by_name(&cxld->dev, name);
if (!region_dev)
return ERR_PTR(-ENODEV);
return to_cxl_region(region_dev);
}
static ssize_t delete_region_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
struct cxl_port *port = to_cxl_port(dev->parent);
struct cxl_region *cxlr;
cxlr = cxl_find_region_by_name(cxlrd, buf);
if (IS_ERR(cxlr))
return PTR_ERR(cxlr);
devm_release_action(port->uport, unregister_region, cxlr);
put_device(&cxlr->dev);
return len;
}
DEVICE_ATTR_WO(delete_region);
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