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Commit f164c421 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 

* master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (94 commits)
  [SCSI] SPI transport class: misc DV fixes
  [SCSI] Switch some more scsi drivers to pci_get_device and refcounted pci structures
  [SCSI] eata_pio cleanup and PCI fix
  [SCSI] aacraid: README update
  [SCSI] aacraid: remove scsi_remove_device
  [SCSI] aacraid: merge rx and rkt code
  [SCSI] aacraid: expose physical devices
  [SCSI] aacraid: misc cleanup
  [SCSI] zfcp: update maintainers file
  [SCSI] zfcp: update maintainers file
  [SCSI] zfcp: fix: avoid removal of fsf reqs before qdio queues are down
  [SCSI] zfcp: introduce struct timer_list in struct zfcp_fsf_req
  [SCSI] zfcp: fix: use correct req_id in eh_abort_handler
  [SCSI] zfcp: create private slab caches to guarantee proper data alignment
  [SCSI] zfcp: remove zfcp_ccw_unregister function
  [SCSI] aic7xxx: pause sequencer before touching SBLKCTL
  [SCSI] aic7xxx: avoid checking SBLKCTL register for certain cards
  [SCSI] scsi_debug version 1.80
  [SCSI] megaraid: Make megaraid_ioctl() check copy_to_user() return value
  [SCSI] aha152x: remove static host array
  ...
parents 6973ddde 1aedf2cc

Documentation/scsi/ChangeLog.arcmsr

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**************************************************************************

** History

**

**   REV#         DATE             NAME         DESCRIPTION

** 1.00.00.00    3/31/2004       Erich Chen     First release

** 1.10.00.04    7/28/2004       Erich Chen     modify for ioctl

** 1.10.00.06    8/28/2004       Erich Chen     modify for 2.6.x

** 1.10.00.08    9/28/2004       Erich Chen     modify for x86_64

** 1.10.00.10   10/10/2004       Erich Chen     bug fix for SMP & ioctl

** 1.20.00.00   11/29/2004       Erich Chen     bug fix with arcmsr_bus_reset when PHY error

** 1.20.00.02   12/09/2004       Erich Chen     bug fix with over 2T bytes RAID Volume

** 1.20.00.04    1/09/2005       Erich Chen     fits for Debian linux kernel version 2.2.xx

** 1.20.00.05    2/20/2005       Erich Chen     cleanly as look like a Linux driver at 2.6.x

**                                              thanks for peoples kindness comment

**						Kornel Wieliczek

**						Christoph Hellwig

**						Adrian Bunk

**						Andrew Morton

**						Christoph Hellwig

**						James Bottomley

**						Arjan van de Ven

** 1.20.00.06    3/12/2005       Erich Chen     fix with arcmsr_pci_unmap_dma "unsigned long" cast,

**						modify PCCB POOL allocated by "dma_alloc_coherent"

**						(Kornel Wieliczek's comment)

** 1.20.00.07    3/23/2005       Erich Chen     bug fix with arcmsr_scsi_host_template_init

**						occur segmentation fault,

**						if RAID adapter does not on PCI slot

**						and modprobe/rmmod this driver twice.

**						bug fix enormous stack usage (Adrian Bunk's comment)

** 1.20.00.08    6/23/2005       Erich Chen     bug fix with abort command,

**						in case of heavy loading when sata cable

**						working on low quality connection

** 1.20.00.09    9/12/2005       Erich Chen     bug fix with abort command handling, firmware version check

**						and firmware update notify for hardware bug fix

** 1.20.00.10    9/23/2005       Erich Chen     enhance sysfs function for change driver's max tag Q number.

**						add DMA_64BIT_MASK for backward compatible with all 2.6.x

**						add some useful message for abort command

**						add ioctl code 'ARCMSR_IOCTL_FLUSH_ADAPTER_CACHE'

**						customer can send this command for sync raid volume data

** 1.20.00.11    9/29/2005       Erich Chen     by comment of Arjan van de Ven fix incorrect msleep redefine

**						cast off sizeof(dma_addr_t) condition for 64bit pci_set_dma_mask

** 1.20.00.12    9/30/2005       Erich Chen     bug fix with 64bit platform's ccbs using if over 4G system memory

**						change 64bit pci_set_consistent_dma_mask into 32bit

**						increcct adapter count if adapter initialize fail.

**						miss edit at arcmsr_build_ccb....

**						psge += sizeof(struct _SG64ENTRY *) =>

**						psge += sizeof(struct _SG64ENTRY)

**						64 bits sg entry would be incorrectly calculated

**						thanks Kornel Wieliczek give me kindly notify

**						and detail description

** 1.20.00.13   11/15/2005       Erich Chen     scheduling pending ccb with FIFO

**						change the architecture of arcmsr command queue list

**						for linux standard list

**						enable usage of pci message signal interrupt

**						follow Randy.Danlup kindness suggestion cleanup this code

**************************************************************************
 
 No newline at end of file

Documentation/scsi/aacraid.txt

+30 −23
Original line number Diff line number Diff line
@@ -11,38 +11,43 @@ the original). 
Supported Cards/Chipsets

-------------------------

	PCI ID (pci.ids)	OEM	Product

	9005:0285:9005:028a	Adaptec	2020ZCR (Skyhawk)

	9005:0285:9005:028e	Adaptec	2020SA (Skyhawk)

	9005:0285:9005:028b	Adaptec 2025ZCR (Terminator)

	9005:0285:9005:028f	Adaptec 2025SA (Terminator)

	9005:0285:9005:0286	Adaptec	2120S (Crusader)

	9005:0286:9005:028d	Adaptec	2130S (Lancer)

	9005:0283:9005:0283	Adaptec	Catapult (3210S with arc firmware)

	9005:0284:9005:0284	Adaptec	Tomcat (3410S with arc firmware)

	9005:0285:9005:0285	Adaptec	2200S (Vulcan)

	9005:0285:9005:0286	Adaptec	2120S (Crusader)

	9005:0285:9005:0287	Adaptec	2200S (Vulcan-2m)

	9005:0285:9005:0288	Adaptec	3230S (Harrier)

	9005:0285:9005:0289	Adaptec	3240S (Tornado)

	9005:0285:9005:028a	Adaptec	2020ZCR (Skyhawk)

	9005:0285:9005:028b	Adaptec 2025ZCR (Terminator)

	9005:0286:9005:028c	Adaptec	2230S (Lancer)

	9005:0286:9005:028c	Adaptec	2230SLP (Lancer)

	9005:0285:9005:0296	Adaptec	2240S (SabreExpress)

	9005:0286:9005:028d	Adaptec	2130S (Lancer)

	9005:0285:9005:028e	Adaptec	2020SA (Skyhawk)

	9005:0285:9005:028f	Adaptec 2025SA (Terminator)

	9005:0285:9005:0290	Adaptec	2410SA (Jaguar)

	9005:0285:9005:0293	Adaptec 21610SA (Corsair-16)

	9005:0285:103c:3227	Adaptec 2610SA (Bearcat HP release)

	9005:0285:9005:0293	Adaptec 21610SA (Corsair-16)

	9005:0285:9005:0296	Adaptec	2240S (SabreExpress)

	9005:0285:9005:0292	Adaptec	2810SA (Corsair-8)

	9005:0285:9005:0294	Adaptec	Prowler

	9005:0286:9005:029d	Adaptec	2420SA (Intruder HP release)

	9005:0286:9005:029c	Adaptec	2620SA (Intruder)

	9005:0286:9005:029b	Adaptec	2820SA (Intruder)

	9005:0286:9005:02a7	Adaptec	2830SA (Skyray)

	9005:0286:9005:02a8	Adaptec	2430SA (Skyray)

	9005:0285:9005:0288	Adaptec	3230S (Harrier)

	9005:0285:9005:0289	Adaptec	3240S (Tornado)

	9005:0285:9005:0298	Adaptec	4000SAS (BlackBird)

	9005:0285:9005:0297	Adaptec	4005SAS (AvonPark)

	9005:0285:9005:0298	Adaptec	4000SAS (BlackBird)

	9005:0285:9005:0299	Adaptec	4800SAS (Marauder-X)

	9005:0285:9005:029a	Adaptec	4805SAS (Marauder-E)

	9005:0286:9005:029b	Adaptec	2820SA (Intruder)

	9005:0286:9005:029c	Adaptec	2620SA (Intruder)

	9005:0286:9005:029d	Adaptec	2420SA (Intruder HP release)

	9005:0286:9005:02a2	Adaptec	3800SAS (Hurricane44)

	9005:0286:9005:02a7	Adaptec	3805SAS (Hurricane80)

	9005:0286:9005:02a8	Adaptec	3400SAS (Hurricane40)

	9005:0286:9005:02ac	Adaptec	1800SAS (Typhoon44)

	9005:0286:9005:02b3	Adaptec	2400SAS (Hurricane40lm)

	9005:0285:9005:02b5	Adaptec ASR5800 (Voodoo44)

	9005:0285:9005:02b6	Adaptec ASR5805 (Voodoo80)

	9005:0285:9005:02b7	Adaptec ASR5808 (Voodoo08)

	1011:0046:9005:0364	Adaptec	5400S (Mustang)

	1011:0046:9005:0365	Adaptec	5400S (Mustang)

	9005:0283:9005:0283	Adaptec	Catapult (3210S with arc firmware)

	9005:0284:9005:0284	Adaptec	Tomcat (3410S with arc firmware)

	9005:0287:9005:0800	Adaptec	Themisto (Jupiter)

	9005:0200:9005:0200	Adaptec	Themisto (Jupiter)

	9005:0286:9005:0800	Adaptec	Callisto (Jupiter)
@@ -64,18 +69,20 @@ Supported Cards/Chipsets 
	9005:0285:9005:0290	IBM	ServeRAID 7t (Jaguar)

	9005:0285:1014:02F2	IBM	ServeRAID 8i (AvonPark)

	9005:0285:1014:0312	IBM	ServeRAID 8i (AvonParkLite)

	9005:0286:1014:9580	IBM	ServeRAID 8k/8k-l8 (Aurora)

	9005:0286:1014:9540	IBM	ServeRAID 8k/8k-l4 (AuroraLite)

	9005:0286:9005:029f	ICP	ICP9014R0 (Lancer)

	9005:0286:1014:9580	IBM	ServeRAID 8k/8k-l8 (Aurora)

	9005:0286:1014:034d	IBM	ServeRAID 8s (Hurricane)

	9005:0286:9005:029e	ICP	ICP9024R0 (Lancer)

	9005:0286:9005:029f	ICP	ICP9014R0 (Lancer)

	9005:0286:9005:02a0	ICP	ICP9047MA (Lancer)

	9005:0286:9005:02a1	ICP	ICP9087MA (Lancer)

	9005:0286:9005:02a3	ICP	ICP5445AU (Hurricane44)

	9005:0286:9005:02a4	ICP	ICP9085LI (Marauder-X)

	9005:0286:9005:02a5	ICP	ICP5085BR (Marauder-E)

	9005:0286:9005:02a3	ICP	ICP5445AU (Hurricane44)

	9005:0286:9005:02a6	ICP	ICP9067MA (Intruder-6)

	9005:0286:9005:02a9	ICP	ICP5087AU (Skyray)

	9005:0286:9005:02aa	ICP	ICP5047AU (Skyray)

	9005:0286:9005:02a9	ICP	ICP5085AU (Hurricane80)

	9005:0286:9005:02aa	ICP	ICP5045AU (Hurricane40)

	9005:0286:9005:02b4	ICP	ICP5045AL (Hurricane40lm)



People

-------------------------

Documentation/scsi/arcmsr_spec.txt

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Documentation/scsi/libsas.txt

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SAS Layer

---------



The SAS Layer is a management infrastructure which manages

SAS LLDDs.  It sits between SCSI Core and SAS LLDDs.  The

layout is as follows: while SCSI Core is concerned with

SAM/SPC issues, and a SAS LLDD+sequencer is concerned with

phy/OOB/link management, the SAS layer is concerned with:



      * SAS Phy/Port/HA event management (LLDD generates,

        SAS Layer processes),

      * SAS Port management (creation/destruction),

      * SAS Domain discovery and revalidation,

      * SAS Domain device management,

      * SCSI Host registration/unregistration,

      * Device registration with SCSI Core (SAS) or libata

        (SATA), and

      * Expander management and exporting expander control

        to user space.



A SAS LLDD is a PCI device driver.  It is concerned with

phy/OOB management, and vendor specific tasks and generates

events to the SAS layer.



The SAS Layer does most SAS tasks as outlined in the SAS 1.1

spec.



The sas_ha_struct describes the SAS LLDD to the SAS layer.

Most of it is used by the SAS Layer but a few fields need to

be initialized by the LLDDs.



After initializing your hardware, from the probe() function

you call sas_register_ha(). It will register your LLDD with

the SCSI subsystem, creating a SCSI host and it will

register your SAS driver with the sysfs SAS tree it creates.

It will then return.  Then you enable your phys to actually

start OOB (at which point your driver will start calling the

notify_* event callbacks).



Structure descriptions:



struct sas_phy --------------------

Normally this is statically embedded to your driver's

phy structure:

	struct my_phy {

	       blah;

	       struct sas_phy sas_phy;

	       bleh;

	};

And then all the phys are an array of my_phy in your HA

struct (shown below).



Then as you go along and initialize your phys you also

initialize the sas_phy struct, along with your own

phy structure.



In general, the phys are managed by the LLDD and the ports

are managed by the SAS layer.  So the phys are initialized

and updated by the LLDD and the ports are initialized and

updated by the SAS layer.



There is a scheme where the LLDD can RW certain fields,

and the SAS layer can only read such ones, and vice versa.

The idea is to avoid unnecessary locking.



enabled -- must be set (0/1)

id -- must be set [0,MAX_PHYS)

class, proto, type, role, oob_mode, linkrate -- must be set

oob_mode --  you set this when OOB has finished and then notify

the SAS Layer.



sas_addr -- this normally points to an array holding the sas

address of the phy, possibly somewhere in your my_phy

struct.



attached_sas_addr -- set this when you (LLDD) receive an

IDENTIFY frame or a FIS frame, _before_ notifying the SAS

layer.  The idea is that sometimes the LLDD may want to fake

or provide a different SAS address on that phy/port and this

allows it to do this.  At best you should copy the sas

address from the IDENTIFY frame or maybe generate a SAS

address for SATA directly attached devices.  The Discover

process may later change this.



frame_rcvd -- this is where you copy the IDENTIFY/FIS frame

when you get it; you lock, copy, set frame_rcvd_size and

unlock the lock, and then call the event.  It is a pointer

since there's no way to know your hw frame size _exactly_,

so you define the actual array in your phy struct and let

this pointer point to it.  You copy the frame from your

DMAable memory to that area holding the lock.



sas_prim -- this is where primitives go when they're

received.  See sas.h. Grab the lock, set the primitive,

release the lock, notify.



port -- this points to the sas_port if the phy belongs

to a port -- the LLDD only reads this. It points to the

sas_port this phy is part of.  Set by the SAS Layer.



ha -- may be set; the SAS layer sets it anyway.



lldd_phy -- you should set this to point to your phy so you

can find your way around faster when the SAS layer calls one

of your callbacks and passes you a phy.  If the sas_phy is

embedded you can also use container_of -- whatever you

prefer.





struct sas_port --------------------

The LLDD doesn't set any fields of this struct -- it only

reads them.  They should be self explanatory.



phy_mask is 32 bit, this should be enough for now, as I

haven't heard of a HA having more than 8 phys.



lldd_port -- I haven't found use for that -- maybe other

LLDD who wish to have internal port representation can make

use of this.





struct sas_ha_struct --------------------

It normally is statically declared in your own LLDD

structure describing your adapter:

struct my_sas_ha {

       blah;

       struct sas_ha_struct sas_ha;

       struct my_phy phys[MAX_PHYS];

       struct sas_port sas_ports[MAX_PHYS]; /* (1) */

       bleh;

};



(1) If your LLDD doesn't have its own port representation.



What needs to be initialized (sample function given below).



pcidev

sas_addr -- since the SAS layer doesn't want to mess with

	 memory allocation, etc, this points to statically

	 allocated array somewhere (say in your host adapter

	 structure) and holds the SAS address of the host

	 adapter as given by you or the manufacturer, etc.

sas_port

sas_phy -- an array of pointers to structures. (see

	note above on sas_addr).

	These must be set.  See more notes below.

num_phys -- the number of phys present in the sas_phy array,

	 and the number of ports present in the sas_port

	 array.  There can be a maximum num_phys ports (one per

	 port) so we drop the num_ports, and only use

	 num_phys.



The event interface:



	/* LLDD calls these to notify the class of an event. */

	void (*notify_ha_event)(struct sas_ha_struct *, enum ha_event);

	void (*notify_port_event)(struct sas_phy *, enum port_event);

	void (*notify_phy_event)(struct sas_phy *, enum phy_event);



When sas_register_ha() returns, those are set and can be

called by the LLDD to notify the SAS layer of such events

the SAS layer.



The port notification:



	/* The class calls these to notify the LLDD of an event. */

	void (*lldd_port_formed)(struct sas_phy *);

	void (*lldd_port_deformed)(struct sas_phy *);



If the LLDD wants notification when a port has been formed

or deformed it sets those to a function satisfying the type.



A SAS LLDD should also implement at least one of the Task

Management Functions (TMFs) described in SAM:



	/* Task Management Functions. Must be called from process context. */

	int (*lldd_abort_task)(struct sas_task *);

	int (*lldd_abort_task_set)(struct domain_device *, u8 *lun);

	int (*lldd_clear_aca)(struct domain_device *, u8 *lun);

	int (*lldd_clear_task_set)(struct domain_device *, u8 *lun);

	int (*lldd_I_T_nexus_reset)(struct domain_device *);

	int (*lldd_lu_reset)(struct domain_device *, u8 *lun);

	int (*lldd_query_task)(struct sas_task *);



For more information please read SAM from T10.org.



Port and Adapter management:



	/* Port and Adapter management */

	int (*lldd_clear_nexus_port)(struct sas_port *);

	int (*lldd_clear_nexus_ha)(struct sas_ha_struct *);



A SAS LLDD should implement at least one of those.



Phy management:



	/* Phy management */

	int (*lldd_control_phy)(struct sas_phy *, enum phy_func);



lldd_ha -- set this to point to your HA struct. You can also

use container_of if you embedded it as shown above.



A sample initialization and registration function

can look like this (called last thing from probe())

*but* before you enable the phys to do OOB:



static int register_sas_ha(struct my_sas_ha *my_ha)

{

	int i;

	static struct sas_phy   *sas_phys[MAX_PHYS];

	static struct sas_port  *sas_ports[MAX_PHYS];



	my_ha->sas_ha.sas_addr = &my_ha->sas_addr[0];



	for (i = 0; i < MAX_PHYS; i++) {

		sas_phys[i] = &my_ha->phys[i].sas_phy;

		sas_ports[i] = &my_ha->sas_ports[i];

	}



	my_ha->sas_ha.sas_phy  = sas_phys;

	my_ha->sas_ha.sas_port = sas_ports;

	my_ha->sas_ha.num_phys = MAX_PHYS;



	my_ha->sas_ha.lldd_port_formed = my_port_formed;



	my_ha->sas_ha.lldd_dev_found = my_dev_found;

	my_ha->sas_ha.lldd_dev_gone = my_dev_gone;



	my_ha->sas_ha.lldd_max_execute_num = lldd_max_execute_num; (1)



	my_ha->sas_ha.lldd_queue_size = ha_can_queue;

	my_ha->sas_ha.lldd_execute_task = my_execute_task;



	my_ha->sas_ha.lldd_abort_task     = my_abort_task;

	my_ha->sas_ha.lldd_abort_task_set = my_abort_task_set;

	my_ha->sas_ha.lldd_clear_aca      = my_clear_aca;

	my_ha->sas_ha.lldd_clear_task_set = my_clear_task_set;

	my_ha->sas_ha.lldd_I_T_nexus_reset= NULL; (2)

	my_ha->sas_ha.lldd_lu_reset       = my_lu_reset;

	my_ha->sas_ha.lldd_query_task     = my_query_task;



	my_ha->sas_ha.lldd_clear_nexus_port = my_clear_nexus_port;

	my_ha->sas_ha.lldd_clear_nexus_ha = my_clear_nexus_ha;



	my_ha->sas_ha.lldd_control_phy = my_control_phy;



	return sas_register_ha(&my_ha->sas_ha);

}



(1) This is normally a LLDD parameter, something of the

lines of a task collector.  What it tells the SAS Layer is

whether the SAS layer should run in Direct Mode (default:

value 0 or 1) or Task Collector Mode (value greater than 1).



In Direct Mode, the SAS Layer calls Execute Task as soon as

it has a command to send to the SDS, _and_ this is a single

command, i.e. not linked.



Some hardware (e.g. aic94xx) has the capability to DMA more

than one task at a time (interrupt) from host memory.  Task

Collector Mode is an optional feature for HAs which support

this in their hardware.  (Again, it is completely optional

even if your hardware supports it.)



In Task Collector Mode, the SAS Layer would do _natural_

coalescing of tasks and at the appropriate moment it would

call your driver to DMA more than one task in a single HA

interrupt. DMBS may want to use this by insmod/modprobe

setting the lldd_max_execute_num to something greater than

1.



(2) SAS 1.1 does not define I_T Nexus Reset TMF.



Events

------



Events are _the only way_ a SAS LLDD notifies the SAS layer

of anything.  There is no other method or way a LLDD to tell

the SAS layer of anything happening internally or in the SAS

domain.



Phy events:

	PHYE_LOSS_OF_SIGNAL, (C)

	PHYE_OOB_DONE,

	PHYE_OOB_ERROR,      (C)

	PHYE_SPINUP_HOLD.



Port events, passed on a _phy_:

	PORTE_BYTES_DMAED,      (M)

	PORTE_BROADCAST_RCVD,   (E)

	PORTE_LINK_RESET_ERR,   (C)

	PORTE_TIMER_EVENT,      (C)

	PORTE_HARD_RESET.



Host Adapter event:

	HAE_RESET



A SAS LLDD should be able to generate

	- at least one event from group C (choice),

	- events marked M (mandatory) are mandatory (only one),

	- events marked E (expander) if it wants the SAS layer

	  to handle domain revalidation (only one such).

	- Unmarked events are optional.



Meaning:



HAE_RESET -- when your HA got internal error and was reset.



PORTE_BYTES_DMAED -- on receiving an IDENTIFY/FIS frame

PORTE_BROADCAST_RCVD -- on receiving a primitive

PORTE_LINK_RESET_ERR -- timer expired, loss of signal, loss

of DWS, etc. (*)

PORTE_TIMER_EVENT -- DWS reset timeout timer expired (*)

PORTE_HARD_RESET -- Hard Reset primitive received.



PHYE_LOSS_OF_SIGNAL -- the device is gone (*)

PHYE_OOB_DONE -- OOB went fine and oob_mode is valid

PHYE_OOB_ERROR -- Error while doing OOB, the device probably

got disconnected. (*)

PHYE_SPINUP_HOLD -- SATA is present, COMWAKE not sent.



(*) should set/clear the appropriate fields in the phy,

    or alternatively call the inlined sas_phy_disconnected()

    which is just a helper, from their tasklet.



The Execute Command SCSI RPC:



	int (*lldd_execute_task)(struct sas_task *, int num,

				 unsigned long gfp_flags);



Used to queue a task to the SAS LLDD.  @task is the tasks to

be executed.  @num should be the number of tasks being

queued at this function call (they are linked listed via

task::list), @gfp_mask should be the gfp_mask defining the

context of the caller.



This function should implement the Execute Command SCSI RPC,

or if you're sending a SCSI Task as linked commands, you

should also use this function.



That is, when lldd_execute_task() is called, the command(s)

go out on the transport *immediately*.  There is *no*

queuing of any sort and at any level in a SAS LLDD.



The use of task::list is two-fold, one for linked commands,

the other discussed below.



It is possible to queue up more than one task at a time, by

initializing the list element of struct sas_task, and

passing the number of tasks enlisted in this manner in num.



Returns: -SAS_QUEUE_FULL, -ENOMEM, nothing was queued;

	 0, the task(s) were queued.



If you want to pass num > 1, then either

A) you're the only caller of this function and keep track

   of what you've queued to the LLDD, or

B) you know what you're doing and have a strategy of

   retrying.



As opposed to queuing one task at a time (function call),

batch queuing of tasks, by having num > 1, greatly

simplifies LLDD code, sequencer code, and _hardware design_,

and has some performance advantages in certain situations

(DBMS).



The LLDD advertises if it can take more than one command at

a time at lldd_execute_task(), by setting the

lldd_max_execute_num parameter (controlled by "collector"

module parameter in aic94xx SAS LLDD).



You should leave this to the default 1, unless you know what

you're doing.



This is a function of the LLDD, to which the SAS layer can

cater to.



int lldd_queue_size

	The host adapter's queue size.  This is the maximum

number of commands the lldd can have pending to domain

devices on behalf of all upper layers submitting through

lldd_execute_task().



You really want to set this to something (much) larger than

1.



This _really_ has absolutely nothing to do with queuing.

There is no queuing in SAS LLDDs.



struct sas_task {

	dev -- the device this task is destined to

	list -- must be initialized (INIT_LIST_HEAD)

	task_proto -- _one_ of enum sas_proto

	scatter -- pointer to scatter gather list array

	num_scatter -- number of elements in scatter

	total_xfer_len -- total number of bytes expected to be transfered

	data_dir -- PCI_DMA_...

	task_done -- callback when the task has finished execution

};



When an external entity, entity other than the LLDD or the

SAS Layer, wants to work with a struct domain_device, it

_must_ call kobject_get() when getting a handle on the

device and kobject_put() when it is done with the device.



This does two things:

     A) implements proper kfree() for the device;

     B) increments/decrements the kref for all players:

     domain_device

	all domain_device's ... (if past an expander)

	    port

		host adapter

		     pci device

			 and up the ladder, etc.



DISCOVERY

---------



The sysfs tree has the following purposes:

    a) It shows you the physical layout of the SAS domain at

       the current time, i.e. how the domain looks in the

       physical world right now.

    b) Shows some device parameters _at_discovery_time_.



This is a link to the tree(1) program, very useful in

viewing the SAS domain:

ftp://mama.indstate.edu/linux/tree/

I expect user space applications to actually create a

graphical interface of this.



That is, the sysfs domain tree doesn't show or keep state if

you e.g., change the meaning of the READY LED MEANING

setting, but it does show you the current connection status

of the domain device.



Keeping internal device state changes is responsibility of

upper layers (Command set drivers) and user space.



When a device or devices are unplugged from the domain, this

is reflected in the sysfs tree immediately, and the device(s)

removed from the system.



The structure domain_device describes any device in the SAS

domain.  It is completely managed by the SAS layer.  A task

points to a domain device, this is how the SAS LLDD knows

where to send the task(s) to.  A SAS LLDD only reads the

contents of the domain_device structure, but it never creates

or destroys one.



Expander management from User Space

-----------------------------------



In each expander directory in sysfs, there is a file called

"smp_portal".  It is a binary sysfs attribute file, which

implements an SMP portal (Note: this is *NOT* an SMP port),

to which user space applications can send SMP requests and

receive SMP responses.



Functionality is deceptively simple:



1. Build the SMP frame you want to send. The format and layout

   is described in the SAS spec.  Leave the CRC field equal 0.

open(2)

2. Open the expander's SMP portal sysfs file in RW mode.

write(2)

3. Write the frame you built in 1.

read(2)

4. Read the amount of data you expect to receive for the frame you built.

   If you receive different amount of data you expected to receive,

   then there was some kind of error.

close(2)

All this process is shown in detail in the function do_smp_func()

and its callers, in the file "expander_conf.c".



The kernel functionality is implemented in the file

"sas_expander.c".



The program "expander_conf.c" implements this. It takes one

argument, the sysfs file name of the SMP portal to the

expander, and gives expander information, including routing

tables.



The SMP portal gives you complete control of the expander,

so please be careful.

MAINTAINERS

+2 −2
Original line number Diff line number Diff line
@@ -2484,8 +2484,8 @@ W: http://www.ibm.com/developerworks/linux/linux390/ 
S:	Supported



S390 ZFCP DRIVER

P:	Andreas Herrmann

M:	aherrman@de.ibm.com

P:	Swen Schillig

M:	swen@vnet.ibm.com

M:	linux390@de.ibm.com

L:	linux-390@vm.marist.edu

W:	http://www.ibm.com/developerworks/linux/linux390/