blob: 7239858790353a8cd03cac2a4e397166e88b2b31 [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
#ifndef _MHI_H_
#define _MHI_H_
#include <linux/device.h>
#include <linux/dma-direction.h>
#include <linux/mutex.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
struct mhi_chan;
struct mhi_event;
struct mhi_ctxt;
struct mhi_cmd;
struct mhi_buf_info;
* enum mhi_callback - MHI callback
* @MHI_CB_IDLE: MHI entered idle state
* @MHI_CB_PENDING_DATA: New data available for client to process
* @MHI_CB_LPM_ENTER: MHI host entered low power mode
* @MHI_CB_LPM_EXIT: MHI host about to exit low power mode
* @MHI_CB_EE_RDDM: MHI device entered RDDM exec env
* @MHI_CB_EE_MISSION_MODE: MHI device entered Mission Mode exec env
* @MHI_CB_SYS_ERROR: MHI device entered error state (may recover)
* @MHI_CB_FATAL_ERROR: MHI device entered fatal error state
* @MHI_CB_BW_REQ: Received a bandwidth switch request from device
enum mhi_callback {
* enum mhi_flags - Transfer flags
* @MHI_EOB: End of buffer for bulk transfer
* @MHI_EOT: End of transfer
* @MHI_CHAIN: Linked transfer
enum mhi_flags {
* enum mhi_device_type - Device types
* @MHI_DEVICE_XFER: Handles data transfer
* @MHI_DEVICE_CONTROLLER: Control device
enum mhi_device_type {
* enum mhi_ch_type - Channel types
* @MHI_CH_TYPE_INVALID: Invalid channel type
* @MHI_CH_TYPE_OUTBOUND: Outbound channel to the device
* @MHI_CH_TYPE_INBOUND: Inbound channel from the device
* @MHI_CH_TYPE_INBOUND_COALESCED: Coalesced channel for the device to combine
* multiple packets and send them as a single
* large packet to reduce CPU consumption
enum mhi_ch_type {
* struct image_info - Firmware and RDDM table
* @mhi_buf: Buffer for firmware and RDDM table
* @entries: # of entries in table
struct image_info {
struct mhi_buf *mhi_buf;
/* private: from internal.h */
struct bhi_vec_entry *bhi_vec;
/* public: */
u32 entries;
* struct mhi_link_info - BW requirement
* target_link_speed - Link speed as defined by TLS bits in LinkControl reg
* target_link_width - Link width as defined by NLW bits in LinkStatus reg
struct mhi_link_info {
unsigned int target_link_speed;
unsigned int target_link_width;
* enum mhi_ee_type - Execution environment types
* @MHI_EE_PBL: Primary Bootloader
* @MHI_EE_SBL: Secondary Bootloader
* @MHI_EE_AMSS: Modem, aka the primary runtime EE
* @MHI_EE_RDDM: Ram dump download mode
* @MHI_EE_WFW: WLAN firmware mode
* @MHI_EE_PTHRU: Passthrough
* @MHI_EE_EDL: Embedded downloader
* @MHI_EE_FP: Flash Programmer Environment
enum mhi_ee_type {
MHI_EE_DISABLE_TRANSITION, /* local EE, not related to mhi spec */
* enum mhi_state - MHI states
* @MHI_STATE_RESET: Reset state
* @MHI_STATE_READY: Ready state
* @MHI_STATE_M0: M0 state
* @MHI_STATE_M1: M1 state
* @MHI_STATE_M2: M2 state
* @MHI_STATE_M3: M3 state
* @MHI_STATE_M3_FAST: M3 Fast state
* @MHI_STATE_SYS_ERR: System Error state
enum mhi_state {
MHI_STATE_M0 = 0x2,
MHI_STATE_M1 = 0x3,
MHI_STATE_M2 = 0x4,
MHI_STATE_M3 = 0x5,
* enum mhi_ch_ee_mask - Execution environment mask for channel
* @MHI_CH_EE_PBL: Allow channel to be used in PBL EE
* @MHI_CH_EE_SBL: Allow channel to be used in SBL EE
* @MHI_CH_EE_AMSS: Allow channel to be used in AMSS EE
* @MHI_CH_EE_RDDM: Allow channel to be used in RDDM EE
* @MHI_CH_EE_PTHRU: Allow channel to be used in PTHRU EE
* @MHI_CH_EE_WFW: Allow channel to be used in WFW EE
* @MHI_CH_EE_EDL: Allow channel to be used in EDL EE
enum mhi_ch_ee_mask {
* enum mhi_er_data_type - Event ring data types
* @MHI_ER_DATA: Only client data over this ring
* @MHI_ER_CTRL: MHI control data and client data
enum mhi_er_data_type {
* enum mhi_db_brst_mode - Doorbell mode
* @MHI_DB_BRST_DISABLE: Burst mode disable
* @MHI_DB_BRST_ENABLE: Burst mode enable
enum mhi_db_brst_mode {
* struct mhi_channel_config - Channel configuration structure for controller
* @name: The name of this channel
* @num: The number assigned to this channel
* @num_elements: The number of elements that can be queued to this channel
* @local_elements: The local ring length of the channel
* @event_ring: The event ring index that services this channel
* @dir: Direction that data may flow on this channel
* @type: Channel type
* @ee_mask: Execution Environment mask for this channel
* @pollcfg: Polling configuration for burst mode. 0 is default. milliseconds
for UL channels, multiple of 8 ring elements for DL channels
* @doorbell: Doorbell mode
* @lpm_notify: The channel master requires low power mode notifications
* @offload_channel: The client manages the channel completely
* @doorbell_mode_switch: Channel switches to doorbell mode on M0 transition
* @auto_queue: Framework will automatically queue buffers for DL traffic
* @wake-capable: Channel capable of waking up the system
struct mhi_channel_config {
char *name;
u32 num;
u32 num_elements;
u32 local_elements;
u32 event_ring;
enum dma_data_direction dir;
enum mhi_ch_type type;
u32 ee_mask;
u32 pollcfg;
enum mhi_db_brst_mode doorbell;
bool lpm_notify;
bool offload_channel;
bool doorbell_mode_switch;
bool auto_queue;
bool wake_capable;
* struct mhi_event_config - Event ring configuration structure for controller
* @num_elements: The number of elements that can be queued to this ring
* @irq_moderation_ms: Delay irq for additional events to be aggregated
* @irq: IRQ associated with this ring
* @channel: Dedicated channel number. U32_MAX indicates a non-dedicated ring
* @priority: Priority of this ring. Use 1 for now
* @mode: Doorbell mode
* @data_type: Type of data this ring will process
* @hardware_event: This ring is associated with hardware channels
* @client_managed: This ring is client managed
* @offload_channel: This ring is associated with an offloaded channel
struct mhi_event_config {
u32 num_elements;
u32 irq_moderation_ms;
u32 irq;
u32 channel;
u32 priority;
enum mhi_db_brst_mode mode;
enum mhi_er_data_type data_type;
bool hardware_event;
bool client_managed;
bool offload_channel;
* struct mhi_controller_config - Root MHI controller configuration
* @max_channels: Maximum number of channels supported
* @timeout_ms: Timeout value for operations. 0 means use default
* @buf_len: Size of automatically allocated buffers. 0 means use default
* @num_channels: Number of channels defined in @ch_cfg
* @ch_cfg: Array of defined channels
* @num_events: Number of event rings defined in @event_cfg
* @event_cfg: Array of defined event rings
* @use_bounce_buf: Use a bounce buffer pool due to limited DDR access
* @m2_no_db: Host is not allowed to ring DB in M2 state
struct mhi_controller_config {
u32 max_channels;
u32 timeout_ms;
u32 buf_len;
u32 num_channels;
const struct mhi_channel_config *ch_cfg;
u32 num_events;
struct mhi_event_config *event_cfg;
bool use_bounce_buf;
bool m2_no_db;
* struct mhi_controller - Master MHI controller structure
* @cntrl_dev: Pointer to the struct device of physical bus acting as the MHI
* controller (required)
* @mhi_dev: MHI device instance for the controller
* @debugfs_dentry: MHI controller debugfs directory
* @regs: Base address of MHI MMIO register space (required)
* @bhi: Points to base of MHI BHI register space
* @bhie: Points to base of MHI BHIe register space
* @wake_db: MHI WAKE doorbell register address
* @iova_start: IOMMU starting address for data (required)
* @iova_stop: IOMMU stop address for data (required)
* @fw_image: Firmware image name for normal booting (optional)
* @edl_image: Firmware image name for emergency download mode (optional)
* @rddm_size: RAM dump size that host should allocate for debugging purpose
* @sbl_size: SBL image size downloaded through BHIe (optional)
* @seg_len: BHIe vector size (optional)
* @reg_len: Length of the MHI MMIO region (required)
* @fbc_image: Points to firmware image buffer
* @rddm_image: Points to RAM dump buffer
* @mhi_chan: Points to the channel configuration table
* @lpm_chans: List of channels that require LPM notifications
* @irq: base irq # to request (required)
* @max_chan: Maximum number of channels the controller supports
* @total_ev_rings: Total # of event rings allocated
* @hw_ev_rings: Number of hardware event rings
* @sw_ev_rings: Number of software event rings
* @nr_irqs: Number of IRQ allocated by bus master (required)
* @family_number: MHI controller family number
* @device_number: MHI controller device number
* @major_version: MHI controller major revision number
* @minor_version: MHI controller minor revision number
* @serial_number: MHI controller serial number obtained from BHI
* @oem_pk_hash: MHI controller OEM PK Hash obtained from BHI
* @mhi_event: MHI event ring configurations table
* @mhi_cmd: MHI command ring configurations table
* @mhi_ctxt: MHI device context, shared memory between host and device
* @pm_mutex: Mutex for suspend/resume operation
* @pm_lock: Lock for protecting MHI power management state
* @timeout_ms: Timeout in ms for state transitions
* @pm_state: MHI power management state
* @db_access: DB access states
* @ee: MHI device execution environment
* @dev_state: MHI device state
* @dev_wake: Device wakeup count
* @pending_pkts: Pending packets for the controller
* @M0, M2, M3: Counters to track number of device MHI state changes
* @transition_list: List of MHI state transitions
* @transition_lock: Lock for protecting MHI state transition list
* @wlock: Lock for protecting device wakeup
* @mhi_link_info: Device bandwidth info
* @st_worker: State transition worker
* @hiprio_wq: High priority workqueue for MHI work such as state transitions
* @state_event: State change event
* @status_cb: CB function to notify power states of the device (required)
* @wake_get: CB function to assert device wake (optional)
* @wake_put: CB function to de-assert device wake (optional)
* @wake_toggle: CB function to assert and de-assert device wake (optional)
* @runtime_get: CB function to controller runtime resume (required)
* @runtime_put: CB function to decrement pm usage (required)
* @map_single: CB function to create TRE buffer
* @unmap_single: CB function to destroy TRE buffer
* @read_reg: Read a MHI register via the physical link (required)
* @write_reg: Write a MHI register via the physical link (required)
* @reset: Controller specific reset function (optional)
* @buffer_len: Bounce buffer length
* @index: Index of the MHI controller instance
* @bounce_buf: Use of bounce buffer
* @fbc_download: MHI host needs to do complete image transfer (optional)
* @wake_set: Device wakeup set flag
* @irq_flags: irq flags passed to request_irq (optional)
* @mru: the default MRU for the MHI device
* Fields marked as (required) need to be populated by the controller driver
* before calling mhi_register_controller(). For the fields marked as (optional)
* they can be populated depending on the usecase.
* The following fields are present for the purpose of implementing any device
* specific quirks or customizations for specific MHI revisions used in device
* by the controller drivers. The MHI stack will just populate these fields
* during mhi_register_controller():
* family_number
* device_number
* major_version
* minor_version
struct mhi_controller {
struct device *cntrl_dev;
struct mhi_device *mhi_dev;
struct dentry *debugfs_dentry;
void __iomem *regs;
void __iomem *bhi;
void __iomem *bhie;
void __iomem *wake_db;
dma_addr_t iova_start;
dma_addr_t iova_stop;
const char *fw_image;
const char *edl_image;
size_t rddm_size;
size_t sbl_size;
size_t seg_len;
size_t reg_len;
struct image_info *fbc_image;
struct image_info *rddm_image;
struct mhi_chan *mhi_chan;
struct list_head lpm_chans;
int *irq;
u32 max_chan;
u32 total_ev_rings;
u32 hw_ev_rings;
u32 sw_ev_rings;
u32 nr_irqs;
u32 family_number;
u32 device_number;
u32 major_version;
u32 minor_version;
u32 serial_number;
u32 oem_pk_hash[MHI_MAX_OEM_PK_HASH_SEGMENTS];
struct mhi_event *mhi_event;
struct mhi_cmd *mhi_cmd;
struct mhi_ctxt *mhi_ctxt;
struct mutex pm_mutex;
rwlock_t pm_lock;
u32 timeout_ms;
u32 pm_state;
u32 db_access;
enum mhi_ee_type ee;
enum mhi_state dev_state;
atomic_t dev_wake;
atomic_t pending_pkts;
u32 M0, M2, M3;
struct list_head transition_list;
spinlock_t transition_lock;
spinlock_t wlock;
struct mhi_link_info mhi_link_info;
struct work_struct st_worker;
struct workqueue_struct *hiprio_wq;
wait_queue_head_t state_event;
void (*status_cb)(struct mhi_controller *mhi_cntrl,
enum mhi_callback cb);
void (*wake_get)(struct mhi_controller *mhi_cntrl, bool override);
void (*wake_put)(struct mhi_controller *mhi_cntrl, bool override);
void (*wake_toggle)(struct mhi_controller *mhi_cntrl);
int (*runtime_get)(struct mhi_controller *mhi_cntrl);
void (*runtime_put)(struct mhi_controller *mhi_cntrl);
int (*map_single)(struct mhi_controller *mhi_cntrl,
struct mhi_buf_info *buf);
void (*unmap_single)(struct mhi_controller *mhi_cntrl,
struct mhi_buf_info *buf);
int (*read_reg)(struct mhi_controller *mhi_cntrl, void __iomem *addr,
u32 *out);
void (*write_reg)(struct mhi_controller *mhi_cntrl, void __iomem *addr,
u32 val);
void (*reset)(struct mhi_controller *mhi_cntrl);
size_t buffer_len;
int index;
bool bounce_buf;
bool fbc_download;
bool wake_set;
unsigned long irq_flags;
u32 mru;
* struct mhi_device - Structure representing an MHI device which binds
* to channels or is associated with controllers
* @id: Pointer to MHI device ID struct
* @name: Name of the associated MHI device
* @mhi_cntrl: Controller the device belongs to
* @ul_chan: UL channel for the device
* @dl_chan: DL channel for the device
* @dev: Driver model device node for the MHI device
* @dev_type: MHI device type
* @ul_chan_id: MHI channel id for UL transfer
* @dl_chan_id: MHI channel id for DL transfer
* @dev_wake: Device wakeup counter
struct mhi_device {
const struct mhi_device_id *id;
const char *name;
struct mhi_controller *mhi_cntrl;
struct mhi_chan *ul_chan;
struct mhi_chan *dl_chan;
struct device dev;
enum mhi_device_type dev_type;
int ul_chan_id;
int dl_chan_id;
u32 dev_wake;
* struct mhi_result - Completed buffer information
* @buf_addr: Address of data buffer
* @bytes_xferd: # of bytes transferred
* @dir: Channel direction
* @transaction_status: Status of last transaction
struct mhi_result {
void *buf_addr;
size_t bytes_xferd;
enum dma_data_direction dir;
int transaction_status;
* struct mhi_buf - MHI Buffer description
* @buf: Virtual address of the buffer
* @name: Buffer label. For offload channel, configurations name must be:
* ECA - Event context array data
* CCA - Channel context array data
* @dma_addr: IOMMU address of the buffer
* @len: # of bytes
struct mhi_buf {
void *buf;
const char *name;
dma_addr_t dma_addr;
size_t len;
* struct mhi_driver - Structure representing a MHI client driver
* @probe: CB function for client driver probe function
* @remove: CB function for client driver remove function
* @ul_xfer_cb: CB function for UL data transfer
* @dl_xfer_cb: CB function for DL data transfer
* @status_cb: CB functions for asynchronous status
* @driver: Device driver model driver
struct mhi_driver {
const struct mhi_device_id *id_table;
int (*probe)(struct mhi_device *mhi_dev,
const struct mhi_device_id *id);
void (*remove)(struct mhi_device *mhi_dev);
void (*ul_xfer_cb)(struct mhi_device *mhi_dev,
struct mhi_result *result);
void (*dl_xfer_cb)(struct mhi_device *mhi_dev,
struct mhi_result *result);
void (*status_cb)(struct mhi_device *mhi_dev, enum mhi_callback mhi_cb);
struct device_driver driver;
#define to_mhi_driver(drv) container_of(drv, struct mhi_driver, driver)
#define to_mhi_device(dev) container_of(dev, struct mhi_device, dev)
* mhi_alloc_controller - Allocate the MHI Controller structure
* Allocate the mhi_controller structure using zero initialized memory
struct mhi_controller *mhi_alloc_controller(void);
* mhi_free_controller - Free the MHI Controller structure
* Free the mhi_controller structure which was previously allocated
void mhi_free_controller(struct mhi_controller *mhi_cntrl);
* mhi_register_controller - Register MHI controller
* @mhi_cntrl: MHI controller to register
* @config: Configuration to use for the controller
int mhi_register_controller(struct mhi_controller *mhi_cntrl,
const struct mhi_controller_config *config);
* mhi_unregister_controller - Unregister MHI controller
* @mhi_cntrl: MHI controller to unregister
void mhi_unregister_controller(struct mhi_controller *mhi_cntrl);
* module_mhi_driver() - Helper macro for drivers that don't do
* anything special other than using default mhi_driver_register() and
* mhi_driver_unregister(). This eliminates a lot of boilerplate.
* Each module may only use this macro once.
#define module_mhi_driver(mhi_drv) \
module_driver(mhi_drv, mhi_driver_register, \
* Macro to avoid include chaining to get THIS_MODULE
#define mhi_driver_register(mhi_drv) \
__mhi_driver_register(mhi_drv, THIS_MODULE)
* __mhi_driver_register - Register driver with MHI framework
* @mhi_drv: Driver associated with the device
* @owner: The module owner
int __mhi_driver_register(struct mhi_driver *mhi_drv, struct module *owner);
* mhi_driver_unregister - Unregister a driver for mhi_devices
* @mhi_drv: Driver associated with the device
void mhi_driver_unregister(struct mhi_driver *mhi_drv);
* mhi_set_mhi_state - Set MHI device state
* @mhi_cntrl: MHI controller
* @state: State to set
void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
enum mhi_state state);
* mhi_notify - Notify the MHI client driver about client device status
* @mhi_dev: MHI device instance
* @cb_reason: MHI callback reason
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
* mhi_get_free_desc_count - Get transfer ring length
* Get # of TD available to queue buffers
* @mhi_dev: Device associated with the channels
* @dir: Direction of the channel
int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
enum dma_data_direction dir);
* mhi_prepare_for_power_up - Do pre-initialization before power up.
* This is optional, call this before power up if
* the controller does not want bus framework to
* automatically free any allocated memory during
* shutdown process.
* @mhi_cntrl: MHI controller
int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl);
* mhi_async_power_up - Start MHI power up sequence
* @mhi_cntrl: MHI controller
int mhi_async_power_up(struct mhi_controller *mhi_cntrl);
* mhi_sync_power_up - Start MHI power up sequence and wait till the device
* enters valid EE state
* @mhi_cntrl: MHI controller
int mhi_sync_power_up(struct mhi_controller *mhi_cntrl);
* mhi_power_down - Start MHI power down sequence
* @mhi_cntrl: MHI controller
* @graceful: Link is still accessible, so do a graceful shutdown process
void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful);
* mhi_unprepare_after_power_down - Free any allocated memory after power down
* @mhi_cntrl: MHI controller
void mhi_unprepare_after_power_down(struct mhi_controller *mhi_cntrl);
* mhi_pm_suspend - Move MHI into a suspended state
* @mhi_cntrl: MHI controller
int mhi_pm_suspend(struct mhi_controller *mhi_cntrl);
* mhi_pm_resume - Resume MHI from suspended state
* @mhi_cntrl: MHI controller
int mhi_pm_resume(struct mhi_controller *mhi_cntrl);
* mhi_download_rddm_image - Download ramdump image from device for
* debugging purpose.
* @mhi_cntrl: MHI controller
* @in_panic: Download rddm image during kernel panic
int mhi_download_rddm_image(struct mhi_controller *mhi_cntrl, bool in_panic);
* mhi_force_rddm_mode - Force device into rddm mode
* @mhi_cntrl: MHI controller
int mhi_force_rddm_mode(struct mhi_controller *mhi_cntrl);
* mhi_get_exec_env - Get BHI execution environment of the device
* @mhi_cntrl: MHI controller
enum mhi_ee_type mhi_get_exec_env(struct mhi_controller *mhi_cntrl);
* mhi_get_mhi_state - Get MHI state of the device
* @mhi_cntrl: MHI controller
enum mhi_state mhi_get_mhi_state(struct mhi_controller *mhi_cntrl);
* mhi_soc_reset - Trigger a device reset. This can be used as a last resort
* to reset and recover a device.
* @mhi_cntrl: MHI controller
void mhi_soc_reset(struct mhi_controller *mhi_cntrl);
* mhi_device_get - Disable device low power mode
* @mhi_dev: Device associated with the channel
void mhi_device_get(struct mhi_device *mhi_dev);
* mhi_device_get_sync - Disable device low power mode. Synchronously
* take the controller out of suspended state
* @mhi_dev: Device associated with the channel
int mhi_device_get_sync(struct mhi_device *mhi_dev);
* mhi_device_put - Re-enable device low power mode
* @mhi_dev: Device associated with the channel
void mhi_device_put(struct mhi_device *mhi_dev);
* mhi_prepare_for_transfer - Setup UL and DL channels for data transfer.
* Allocate and initialize the channel context and
* also issue the START channel command to both
* channels. Channels can be started only if both
* host and device execution environments match and
* channels are in a DISABLED state.
* @mhi_dev: Device associated with the channels
int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
* mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer.
* Issue the RESET channel command and let the
* device clean-up the context so no incoming
* transfers are seen on the host. Free memory
* associated with the context on host. If device
* is unresponsive, only perform a host side
* clean-up. Channels can be reset only if both
* host and device execution environments match
* and channels are in an ENABLED, STOPPED or
* SUSPENDED state.
* @mhi_dev: Device associated with the channels
void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev);
* mhi_poll - Poll for any available data in DL direction
* @mhi_dev: Device associated with the channels
* @budget: # of events to process
int mhi_poll(struct mhi_device *mhi_dev, u32 budget);
* mhi_queue_dma - Send or receive DMA mapped buffers from client device
* over MHI channel
* @mhi_dev: Device associated with the channels
* @dir: DMA direction for the channel
* @mhi_buf: Buffer for holding the DMA mapped data
* @len: Buffer length
* @mflags: MHI transfer flags used for the transfer
int mhi_queue_dma(struct mhi_device *mhi_dev, enum dma_data_direction dir,
struct mhi_buf *mhi_buf, size_t len, enum mhi_flags mflags);
* mhi_queue_buf - Send or receive raw buffers from client device over MHI
* channel
* @mhi_dev: Device associated with the channels
* @dir: DMA direction for the channel
* @buf: Buffer for holding the data
* @len: Buffer length
* @mflags: MHI transfer flags used for the transfer
int mhi_queue_buf(struct mhi_device *mhi_dev, enum dma_data_direction dir,
void *buf, size_t len, enum mhi_flags mflags);
* mhi_queue_skb - Send or receive SKBs from client device over MHI channel
* @mhi_dev: Device associated with the channels
* @dir: DMA direction for the channel
* @skb: Buffer for holding SKBs
* @len: Buffer length
* @mflags: MHI transfer flags used for the transfer
int mhi_queue_skb(struct mhi_device *mhi_dev, enum dma_data_direction dir,
struct sk_buff *skb, size_t len, enum mhi_flags mflags);
* mhi_queue_is_full - Determine whether queueing new elements is possible
* @mhi_dev: Device associated with the channels
* @dir: DMA direction for the channel
bool mhi_queue_is_full(struct mhi_device *mhi_dev, enum dma_data_direction dir);
#endif /* _MHI_H_ */