drivers/cxl/cxl.h

/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright(c) 2020 Intel Corporation. */

#ifndef __CXL_H__
#define __CXL_H__

#include <linux/libnvdimm.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/io.h>

/**
 * DOC: cxl objects
 *
 * The CXL core objects like ports, decoders, and regions are shared
 * between the subsystem drivers cxl_acpi, cxl_pci, and core drivers
 * (port-driver, region-driver, nvdimm object-drivers... etc).
 */

/* CXL 2.0 8.2.4 CXL Component Register Layout and Definition */
#define CXL_COMPONENT_REG_BLOCK_SIZE SZ_64K

/* CXL 2.0 8.2.5 CXL.cache and CXL.mem Registers*/
#define CXL_CM_OFFSET 0x1000
#define CXL_CM_CAP_HDR_OFFSET 0x0
#define   CXL_CM_CAP_HDR_ID_MASK GENMASK(15, 0)
#define     CM_CAP_HDR_CAP_ID 1
#define   CXL_CM_CAP_HDR_VERSION_MASK GENMASK(19, 16)
#define     CM_CAP_HDR_CAP_VERSION 1
#define   CXL_CM_CAP_HDR_CACHE_MEM_VERSION_MASK GENMASK(23, 20)
#define     CM_CAP_HDR_CACHE_MEM_VERSION 1
#define   CXL_CM_CAP_HDR_ARRAY_SIZE_MASK GENMASK(31, 24)
#define CXL_CM_CAP_PTR_MASK GENMASK(31, 20)

#define   CXL_CM_CAP_CAP_ID_HDM 0x5
#define   CXL_CM_CAP_CAP_HDM_VERSION 1

/* HDM decoders CXL 2.0 8.2.5.12 CXL HDM Decoder Capability Structure */
#define CXL_HDM_DECODER_CAP_OFFSET 0x0
#define   CXL_HDM_DECODER_COUNT_MASK GENMASK(3, 0)
#define   CXL_HDM_DECODER_TARGET_COUNT_MASK GENMASK(7, 4)
#define   CXL_HDM_DECODER_INTERLEAVE_11_8 BIT(8)
#define   CXL_HDM_DECODER_INTERLEAVE_14_12 BIT(9)
#define CXL_HDM_DECODER_CTRL_OFFSET 0x4
#define   CXL_HDM_DECODER_ENABLE BIT(1)
#define CXL_HDM_DECODER0_BASE_LOW_OFFSET(i) (0x20 * (i) + 0x10)
#define CXL_HDM_DECODER0_BASE_HIGH_OFFSET(i) (0x20 * (i) + 0x14)
#define CXL_HDM_DECODER0_SIZE_LOW_OFFSET(i) (0x20 * (i) + 0x18)
#define CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(i) (0x20 * (i) + 0x1c)
#define CXL_HDM_DECODER0_CTRL_OFFSET(i) (0x20 * (i) + 0x20)
#define   CXL_HDM_DECODER0_CTRL_IG_MASK GENMASK(3, 0)
#define   CXL_HDM_DECODER0_CTRL_IW_MASK GENMASK(7, 4)
#define   CXL_HDM_DECODER0_CTRL_LOCK BIT(8)
#define   CXL_HDM_DECODER0_CTRL_COMMIT BIT(9)
#define   CXL_HDM_DECODER0_CTRL_COMMITTED BIT(10)
#define   CXL_HDM_DECODER0_CTRL_TYPE BIT(12)
#define CXL_HDM_DECODER0_TL_LOW(i) (0x20 * (i) + 0x24)
#define CXL_HDM_DECODER0_TL_HIGH(i) (0x20 * (i) + 0x28)

static inline int cxl_hdm_decoder_count(u32 cap_hdr)
{
	int val = FIELD_GET(CXL_HDM_DECODER_COUNT_MASK, cap_hdr);

	return val ? val * 2 : 1;
}

/* CXL 2.0 8.2.8.1 Device Capabilities Array Register */
#define CXLDEV_CAP_ARRAY_OFFSET 0x0
#define   CXLDEV_CAP_ARRAY_CAP_ID 0
#define   CXLDEV_CAP_ARRAY_ID_MASK GENMASK_ULL(15, 0)
#define   CXLDEV_CAP_ARRAY_COUNT_MASK GENMASK_ULL(47, 32)
/* CXL 2.0 8.2.8.2 CXL Device Capability Header Register */
#define CXLDEV_CAP_HDR_CAP_ID_MASK GENMASK(15, 0)
/* CXL 2.0 8.2.8.2.1 CXL Device Capabilities */
#define CXLDEV_CAP_CAP_ID_DEVICE_STATUS 0x1
#define CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX 0x2
#define CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX 0x3
#define CXLDEV_CAP_CAP_ID_MEMDEV 0x4000

/* CXL 2.0 8.2.8.4 Mailbox Registers */
#define CXLDEV_MBOX_CAPS_OFFSET 0x00
#define   CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK GENMASK(4, 0)
#define CXLDEV_MBOX_CTRL_OFFSET 0x04
#define   CXLDEV_MBOX_CTRL_DOORBELL BIT(0)
#define CXLDEV_MBOX_CMD_OFFSET 0x08
#define   CXLDEV_MBOX_CMD_COMMAND_OPCODE_MASK GENMASK_ULL(15, 0)
#define   CXLDEV_MBOX_CMD_PAYLOAD_LENGTH_MASK GENMASK_ULL(36, 16)
#define CXLDEV_MBOX_STATUS_OFFSET 0x10
#define   CXLDEV_MBOX_STATUS_RET_CODE_MASK GENMASK_ULL(47, 32)
#define CXLDEV_MBOX_BG_CMD_STATUS_OFFSET 0x18
#define CXLDEV_MBOX_PAYLOAD_OFFSET 0x20

/*
 * Using struct_group() allows for per register-block-type helper routines,
 * without requiring block-type agnostic code to include the prefix.
 */
struct cxl_regs {
	/*
	 * Common set of CXL Component register block base pointers
	 * @hdm_decoder: CXL 2.0 8.2.5.12 CXL HDM Decoder Capability Structure
	 */
	struct_group_tagged(cxl_component_regs, component,
		void __iomem *hdm_decoder;
	);
	/*
	 * Common set of CXL Device register block base pointers
	 * @status: CXL 2.0 8.2.8.3 Device Status Registers
	 * @mbox: CXL 2.0 8.2.8.4 Mailbox Registers
	 * @memdev: CXL 2.0 8.2.8.5 Memory Device Registers
	 */
	struct_group_tagged(cxl_device_regs, device_regs,
		void __iomem *status, *mbox, *memdev;
	);
};

struct cxl_reg_map {
	bool valid;
	unsigned long offset;
	unsigned long size;
};

struct cxl_component_reg_map {
	struct cxl_reg_map hdm_decoder;
};

struct cxl_device_reg_map {
	struct cxl_reg_map status;
	struct cxl_reg_map mbox;
	struct cxl_reg_map memdev;
};

/**
 * struct cxl_register_map - DVSEC harvested register block mapping parameters
 * @base: virtual base of the register-block-BAR + @block_offset
 * @block_offset: offset to start of register block in @barno
 * @reg_type: see enum cxl_regloc_type
 * @barno: PCI BAR number containing the register block
 * @component_map: cxl_reg_map for component registers
 * @device_map: cxl_reg_maps for device registers
 */
struct cxl_register_map {
	void __iomem *base;
	u64 block_offset;
	u8 reg_type;
	u8 barno;
	union {
		struct cxl_component_reg_map component_map;
		struct cxl_device_reg_map device_map;
	};
};

void cxl_probe_component_regs(struct device *dev, void __iomem *base,
			      struct cxl_component_reg_map *map);
void cxl_probe_device_regs(struct device *dev, void __iomem *base,
			   struct cxl_device_reg_map *map);
int cxl_map_component_regs(struct pci_dev *pdev,
			   struct cxl_component_regs *regs,
			   struct cxl_register_map *map);
int cxl_map_device_regs(struct pci_dev *pdev,
			struct cxl_device_regs *regs,
			struct cxl_register_map *map);

enum cxl_regloc_type;
int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
		      struct cxl_register_map *map);
void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
				   resource_size_t length);

#define CXL_RESOURCE_NONE ((resource_size_t) -1)
#define CXL_TARGET_STRLEN 20

/*
 * cxl_decoder flags that define the type of memory / devices this
 * decoder supports as well as configuration lock status See "CXL 2.0
 * 8.2.5.12.7 CXL HDM Decoder 0 Control Register" for details.
 */
#define CXL_DECODER_F_RAM   BIT(0)
#define CXL_DECODER_F_PMEM  BIT(1)
#define CXL_DECODER_F_TYPE2 BIT(2)
#define CXL_DECODER_F_TYPE3 BIT(3)
#define CXL_DECODER_F_LOCK  BIT(4)
#define CXL_DECODER_F_ENABLE    BIT(5)
#define CXL_DECODER_F_MASK  GENMASK(5, 0)

enum cxl_decoder_type {
       CXL_DECODER_ACCELERATOR = 2,
       CXL_DECODER_EXPANDER = 3,
};

/*
 * Current specification goes up to 8, double that seems a reasonable
 * software max for the foreseeable future
 */
#define CXL_DECODER_MAX_INTERLEAVE 16

/**
 * struct cxl_decoder - CXL address range decode configuration
 * @dev: this decoder's device
 * @id: kernel device name id
 * @platform_res: address space resources considered by root decoder
 * @decoder_range: address space resources considered by midlevel decoder
 * @interleave_ways: number of cxl_dports in this decode
 * @interleave_granularity: data stride per dport
 * @target_type: accelerator vs expander (type2 vs type3) selector
 * @flags: memory type capabilities and locking
 * @target_lock: coordinate coherent reads of the target list
 * @nr_targets: number of elements in @target
 * @target: active ordered target list in current decoder configuration
 */
struct cxl_decoder {
	struct device dev;
	int id;
	union {
		struct resource platform_res;
		struct range decoder_range;
	};
	int interleave_ways;
	int interleave_granularity;
	enum cxl_decoder_type target_type;
	unsigned long flags;
	seqlock_t target_lock;
	int nr_targets;
	struct cxl_dport *target[];
};


/**
 * enum cxl_nvdimm_brige_state - state machine for managing bus rescans
 * @CXL_NVB_NEW: Set at bridge create and after cxl_pmem_wq is destroyed
 * @CXL_NVB_DEAD: Set at brige unregistration to preclude async probing
 * @CXL_NVB_ONLINE: Target state after successful ->probe()
 * @CXL_NVB_OFFLINE: Target state after ->remove() or failed ->probe()
 */
enum cxl_nvdimm_brige_state {
	CXL_NVB_NEW,
	CXL_NVB_DEAD,
	CXL_NVB_ONLINE,
	CXL_NVB_OFFLINE,
};

struct cxl_nvdimm_bridge {
	int id;
	struct device dev;
	struct cxl_port *port;
	struct nvdimm_bus *nvdimm_bus;
	struct nvdimm_bus_descriptor nd_desc;
	struct work_struct state_work;
	enum cxl_nvdimm_brige_state state;
};

struct cxl_nvdimm {
	struct device dev;
	struct cxl_memdev *cxlmd;
	struct nvdimm *nvdimm;
};

/**
 * struct cxl_port - logical collection of upstream port devices and
 *		     downstream port devices to construct a CXL memory
 *		     decode hierarchy.
 * @dev: this port's device
 * @uport: PCI or platform device implementing the upstream port capability
 * @id: id for port device-name
 * @dports: cxl_dport instances referenced by decoders
 * @endpoints: cxl_ep instances, endpoints that are a descendant of this port
 * @decoder_ida: allocator for decoder ids
 * @component_reg_phys: component register capability base address (optional)
 * @dead: last ep has been removed, force port re-creation
 * @depth: How deep this port is relative to the root. depth 0 is the root.
 */
struct cxl_port {
	struct device dev;
	struct device *uport;
	int id;
	struct list_head dports;
	struct list_head endpoints;
	struct ida decoder_ida;
	resource_size_t component_reg_phys;
	bool dead;
	unsigned int depth;
};

/**
 * struct cxl_dport - CXL downstream port
 * @dport: PCI bridge or firmware device representing the downstream link
 * @port_id: unique hardware identifier for dport in decoder target list
 * @component_reg_phys: downstream port component registers
 * @port: reference to cxl_port that contains this downstream port
 * @list: node for a cxl_port's list of cxl_dport instances
 */
struct cxl_dport {
	struct device *dport;
	int port_id;
	resource_size_t component_reg_phys;
	struct cxl_port *port;
	struct list_head list;
};

/**
 * struct cxl_ep - track an endpoint's interest in a port
 * @ep: device that hosts a generic CXL endpoint (expander or accelerator)
 * @list: node on port->endpoints list
 */
struct cxl_ep {
	struct device *ep;
	struct list_head list;
};

/*
 * The platform firmware device hosting the root is also the top of the
 * CXL port topology. All other CXL ports have another CXL port as their
 * parent and their ->uport / host device is out-of-line of the port
 * ancestry.
 */
static inline bool is_cxl_root(struct cxl_port *port)
{
	return port->uport == port->dev.parent;
}

bool is_cxl_port(struct device *dev);
struct cxl_port *to_cxl_port(struct device *dev);
struct pci_bus;
int devm_cxl_register_pci_bus(struct device *host, struct device *uport,
			      struct pci_bus *bus);
struct pci_bus *cxl_port_to_pci_bus(struct cxl_port *port);
struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
				   resource_size_t component_reg_phys,
				   struct cxl_port *parent_port);
struct cxl_port *find_cxl_root(struct device *dev);
int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd);
int cxl_bus_rescan(void);
struct cxl_port *cxl_mem_find_port(struct cxl_memdev *cxlmd);
bool schedule_cxl_memdev_detach(struct cxl_memdev *cxlmd);

struct cxl_dport *devm_cxl_add_dport(struct cxl_port *port,
				     struct device *dport, int port_id,
				     resource_size_t component_reg_phys);
struct cxl_dport *cxl_find_dport_by_dev(struct cxl_port *port,
					const struct device *dev);

struct cxl_decoder *to_cxl_decoder(struct device *dev);
bool is_root_decoder(struct device *dev);
bool is_cxl_decoder(struct device *dev);
struct cxl_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
					   unsigned int nr_targets);
struct cxl_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
					     unsigned int nr_targets);
int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map);
struct cxl_decoder *cxl_endpoint_decoder_alloc(struct cxl_port *port);
int cxl_decoder_add_locked(struct cxl_decoder *cxld, int *target_map);
int cxl_decoder_autoremove(struct device *host, struct cxl_decoder *cxld);
int cxl_endpoint_autoremove(struct cxl_memdev *cxlmd, struct cxl_port *endpoint);

struct cxl_hdm;
struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port);
int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm);
int devm_cxl_add_passthrough_decoder(struct cxl_port *port);

extern struct bus_type cxl_bus_type;

struct cxl_driver {
	const char *name;
	int (*probe)(struct device *dev);
	void (*remove)(struct device *dev);
	struct device_driver drv;
	int id;
};

static inline struct cxl_driver *to_cxl_drv(struct device_driver *drv)
{
	return container_of(drv, struct cxl_driver, drv);
}

int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner,
			  const char *modname);
#define cxl_driver_register(x) __cxl_driver_register(x, THIS_MODULE, KBUILD_MODNAME)
void cxl_driver_unregister(struct cxl_driver *cxl_drv);

#define module_cxl_driver(__cxl_driver) \
	module_driver(__cxl_driver, cxl_driver_register, cxl_driver_unregister)

#define CXL_DEVICE_NVDIMM_BRIDGE	1
#define CXL_DEVICE_NVDIMM		2
#define CXL_DEVICE_PORT			3
#define CXL_DEVICE_ROOT			4
#define CXL_DEVICE_MEMORY_EXPANDER	5

#define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
#define CXL_MODALIAS_FMT "cxl:t%d"

struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev);
struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
						     struct cxl_port *port);
struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev);
bool is_cxl_nvdimm(struct device *dev);
bool is_cxl_nvdimm_bridge(struct device *dev);
int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd);
struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_nvdimm *cxl_nvd);

/*
 * Unit test builds overrides this to __weak, find the 'strong' version
 * of these symbols in tools/testing/cxl/.
 */
#ifndef __mock
#define __mock static
#endif

#ifdef CONFIG_PROVE_CXL_LOCKING
enum cxl_lock_class {
	CXL_ANON_LOCK,
	CXL_NVDIMM_LOCK,
	CXL_NVDIMM_BRIDGE_LOCK,
	CXL_PORT_LOCK,
	/*
	 * Be careful to add new lock classes here, CXL_PORT_LOCK is
	 * extended by the port depth, so a maximum CXL port topology
	 * depth would need to be defined first.
	 */
};

static inline void cxl_nested_lock(struct device *dev)
{
	if (is_cxl_port(dev)) {
		struct cxl_port *port = to_cxl_port(dev);

		mutex_lock_nested(&dev->lockdep_mutex,
				  CXL_PORT_LOCK + port->depth);
	} else if (is_cxl_decoder(dev)) {
		struct cxl_port *port = to_cxl_port(dev->parent);

		/*
		 * A decoder is the immediate child of a port, so set
		 * its lock class equal to other child device siblings.
		 */
		mutex_lock_nested(&dev->lockdep_mutex,
				  CXL_PORT_LOCK + port->depth + 1);
	} else if (is_cxl_nvdimm_bridge(dev))
		mutex_lock_nested(&dev->lockdep_mutex, CXL_NVDIMM_BRIDGE_LOCK);
	else if (is_cxl_nvdimm(dev))
		mutex_lock_nested(&dev->lockdep_mutex, CXL_NVDIMM_LOCK);
	else
		mutex_lock_nested(&dev->lockdep_mutex, CXL_ANON_LOCK);
}

static inline void cxl_nested_unlock(struct device *dev)
{
	mutex_unlock(&dev->lockdep_mutex);
}

static inline void cxl_device_lock(struct device *dev)
{
	/*
	 * For double lock errors the lockup will happen before lockdep
	 * warns at cxl_nested_lock(), so assert explicitly.
	 */
	lockdep_assert_not_held(&dev->lockdep_mutex);

	device_lock(dev);
	cxl_nested_lock(dev);
}

static inline void cxl_device_unlock(struct device *dev)
{
	cxl_nested_unlock(dev);
	device_unlock(dev);
}
#else
static inline void cxl_nested_lock(struct device *dev)
{
}

static inline void cxl_nested_unlock(struct device *dev)
{
}

static inline void cxl_device_lock(struct device *dev)
{
	device_lock(dev);
}

static inline void cxl_device_unlock(struct device *dev)
{
	device_unlock(dev);
}
#endif
#endif /* __CXL_H__ */