Commit 60396183 authored by Emmanuel Grumbach's avatar Emmanuel Grumbach Committed by Wey-Yi Guy
Browse files

iwlwifi: document the transport layer

Fix a few typos in the existing comments too.
Enforce the comments with might_sleep.
Signed-off-by: default avatarEmmanuel Grumbach <>
Signed-off-by: default avatarWey-Yi Guy <>
parent edabfa91
......@@ -70,17 +70,72 @@
#include "iwl-commands.h"
#include "iwl-ucode.h"
/*This file includes the declaration that are exported from the transport
* layer */
* DOC: Transport layer - what is it ?
* The tranport layer is the layer that deals with the HW directly. It provides
* an abstraction of the underlying HW to the upper layer. The transport layer
* doesn't provide any policy, algorithm or anything of this kind, but only
* mechanisms to make the HW do something.It is not completely stateless but
* close to it.
* We will have an implementation for each different supported bus.
* DOC: Life cycle of the transport layer
* The transport layer has a very precise life cycle.
* 1) A helper function is called during the module initialization and
* registers the bus driver's ops with the transport's alloc function.
* 2) Bus's probe calls to the transport layer's allocation functions.
* Of course this function is bus specific.
* 3) This allocation functions will spawn the upper layer which will
* register mac80211.
* 4) At some point (i.e. mac80211's start call), the op_mode will call
* the following sequence:
* start_hw
* start_fw
* 5) Then when finished (or reset):
* stop_fw (a.k.a. stop device for the moment)
* stop_hw
* 6) Eventually, the free function will be called.
* DOC: API needed by the transport layer from the op_mode
struct iwl_priv;
struct iwl_shared;
* DOC: Host command section
* A host command is a commaned issued by the upper layer to the fw. There are
* several versions of fw that have several APIs. The transport layer is
* completely agnostic to these differences.
* The transport does provide helper functionnality (i.e. SYNC / ASYNC mode),
#define SEQ_TO_SN(seq) (((seq) & IEEE80211_SCTL_SEQ) >> 4)
#define SN_TO_SEQ(ssn) (((ssn) << 4) & IEEE80211_SCTL_SEQ)
#define MAX_SN ((IEEE80211_SCTL_SEQ) >> 4)
enum {
* enum CMD_MODE - how to send the host commands ?
* @CMD_SYNC: The caller will be stalled until the fw responds to the command
* @CMD_ASYNC: Return right away and don't want for the response
* @CMD_WANT_SKB: valid only with CMD_SYNC. The caller needs the buffer of the
* response.
* @CMD_ON_DEMAND: This command is sent by the test mode pipe.
enum CMD_MODE {
......@@ -105,20 +160,29 @@ struct iwl_device_cmd {
#define IWL_MAX_CMD_TFDS 2
* struct iwl_hcmd_dataflag - flag for each one of the chunks of the command
* IWL_HCMD_DFL_NOCOPY: By default, the command is copied to the host command's
* ring. The transport layer doesn't map the command's buffer to DMA, but
* rather copies it to an previously allocated DMA buffer. This flag tells
* the transport layer not to copy the command, but to map the existing
* buffer. This can save memcpy and is worth with very big comamnds.
enum iwl_hcmd_dataflag {
* struct iwl_host_cmd - Host command to the uCode
* @data: array of chunks that composes the data of the host command
* @reply_page: pointer to the page that holds the response to the host command
* @handler_status: return value of the handler of the command
* (put in setup_rx_handlers) - valid for SYNC mode only
* @callback:
* @flags: can be CMD_* note CMD_WANT_SKB is incompatible withe CMD_ASYNC
* @flags: can be CMD_*
* @len: array of the lenths of the chunks in data
* @dataflags:
* @dataflags: IWL_HCMD_DFL_*
* @id: id of the host command
struct iwl_host_cmd {
......@@ -134,26 +198,43 @@ struct iwl_host_cmd {
* struct iwl_trans_ops - transport specific operations
* All the handlers MUST be implemented
* @start_hw: starts the HW- from that point on, the HW can send interrupts
* May sleep
* @stop_hw: stops the HW- from that point on, the HW will be in low power but
* will still issue interrupt if the HW RF kill is triggered.
* May sleep
* @start_fw: allocates and inits all the resources for the transport
* layer. Also kick a fw image. This handler may sleep.
* layer. Also kick a fw image.
* May sleep
* @fw_alive: called when the fw sends alive notification
* May sleep
* @wake_any_queue: wake all the queues of a specfic context IWL_RXON_CTX_*
* @stop_device:stops the whole device (embedded CPU put to reset)
* May sleep
* @send_cmd:send a host command
* May sleep only if CMD_SYNC is set
* @tx: send an skb
* Must be atomic
* @reclaim: free packet until ssn. Returns a list of freed packets.
* Must be atomic
* @tx_agg_alloc: allocate resources for a TX BA session
* May sleep
* @tx_agg_setup: setup a tx queue for AMPDU - will be called once the HW is
* ready and a successful ADDBA response has been received.
* ready and a successful ADDBA response has been received.
* May sleep
* @tx_agg_disable: de-configure a Tx queue to send AMPDUs
* May sleep
* @free: release all the ressource for the transport layer itself such as
* irq, tasklet etc...
* irq, tasklet etc... From this point on, the device may not issue
* any interrupt (incl. RFKILL).
* May sleep
* @stop_queue: stop a specific queue
* @check_stuck_queue: check if a specific queue is stuck
* @wait_tx_queue_empty: wait until all tx queues are empty
* May sleep
* @dbgfs_register: add the dbgfs files under this directory. Files will be
* automatically deleted.
* @suspend: stop the device unless WoWLAN is configured
......@@ -217,6 +298,7 @@ struct iwl_calib_result {
* struct iwl_trans - transport common data
* @ops - pointer to iwl_trans_ops
* @shrd - pointer to iwl_shared which holds shared data from the upper layer
* @hcmd_lock: protects HCMD
......@@ -224,7 +306,7 @@ struct iwl_calib_result {
* @dev - pointer to struct device * that represents the device
* @irq - the irq number for the device
* @hw_id: a u32 with the ID of the device / subdevice.
* Set during transport alloaction.
* Set during transport allocation.
* @hw_id_str: a string with info about HW ID. Set during transport allocation.
* @ucode_write_complete: indicates that the ucode has been copied.
* @ucode_rt: run time ucode image
......@@ -246,13 +328,11 @@ struct iwl_trans {
u32 hw_id;
char hw_id_str[52];
u8 ucode_write_complete; /* the image write is complete */
u8 ucode_write_complete;
/* eeprom related variables */
int nvm_device_type;
bool pm_support;
/* init calibration results */
struct list_head calib_results;
/* pointer to trans specific struct */
......@@ -262,16 +342,22 @@ struct iwl_trans {
static inline int iwl_trans_start_hw(struct iwl_trans *trans)
return trans->ops->start_hw(trans);
static inline void iwl_trans_stop_hw(struct iwl_trans *trans)
static inline void iwl_trans_fw_alive(struct iwl_trans *trans)
......@@ -284,6 +370,8 @@ static inline int iwl_trans_start_fw(struct iwl_trans *trans, struct fw_img *fw)
static inline void iwl_trans_stop_device(struct iwl_trans *trans)
......@@ -322,12 +410,16 @@ static inline int iwl_trans_reclaim(struct iwl_trans *trans, int sta_id,
static inline int iwl_trans_tx_agg_disable(struct iwl_trans *trans,
int sta_id, int tid)
return trans->ops->tx_agg_disable(trans, sta_id, tid);
static inline int iwl_trans_tx_agg_alloc(struct iwl_trans *trans,
int sta_id, int tid)
return trans->ops->tx_agg_alloc(trans, sta_id, tid);
......@@ -337,6 +429,8 @@ static inline void iwl_trans_tx_agg_setup(struct iwl_trans *trans,
int sta_id, int tid,
int frame_limit, u16 ssn)
trans->ops->tx_agg_setup(trans, ctx, sta_id, tid, frame_limit, ssn);
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