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 <emmanuel.grumbach@intel.com>
Signed-off-by: default avatarWey-Yi Guy <wey-yi.w.guy@intel.com>
parent edabfa91

drivers/net/wireless/iwlwifi/iwl-trans.h

+107 −13
Original line number Diff line number Diff line
@@ -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

 *

 * TODO

 */



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 {

	CMD_SYNC = 0,

	CMD_ASYNC = BIT(0),

	CMD_WANT_SKB = BIT(1),
@@ -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 {

	IWL_HCMD_DFL_NOCOPY	= BIT(0),

};



/**

 * 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.

 *	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)

{

	might_sleep();



	return trans->ops->start_hw(trans);

}



static inline void iwl_trans_stop_hw(struct iwl_trans *trans)

{

	might_sleep();



	trans->ops->stop_hw(trans);

}



static inline void iwl_trans_fw_alive(struct iwl_trans *trans)

{

	might_sleep();



	trans->ops->fw_alive(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)

{

	might_sleep();



	trans->ops->stop_device(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)

{

	might_sleep();



	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)

{

	might_sleep();



	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)

{

	might_sleep();



	trans->ops->tx_agg_setup(trans, ctx, sta_id, tid, frame_limit, ssn);

}