When expander connected in x2 or x4 mode and with IO runnning, if
a cable from wideport is plugged out from the phy, IO's start failing
on all the targets.

Observed that when cable is pulled with IO running, cominit is
happening on all the links and IO's start dropping to 0 and eventually
the whole IO fails. Second observation, target is trying to open and
SCU is responding with "Open reject no destination".

A cause of the problem is when the port went from the "ready
configuring substate" back to "ready configuring substate" as a result
of phy being pulled off, scic suspended the port task scheduler
register. As a result no IO was allowed and in the "substate
configuring enter" routine the IO never goes back to 0. As a result
the port never comes out of "ready substate configuring".

The patch adds a mechanism of activate and deactivate phy when a port
link up, which fixes the problem.
Signed-off-by: NBartek Nowakowski <bartek.nowakowski@intel.com>
Signed-off-by: NMaciej Trela <maciej.trela@intel.com>
Signed-off-by: NMarcin Tomczak <marcin.tomczak@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Split scu_link_layer_start_oob function to reset and enable and
add flush after all steps.
Signed-off-by: NMarcin Tomczak <marcin.tomczak@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

When the first phy of a wide port comes up, don't report the port ready
yet, always wait for 250 miliseconds then config the port with all phys
added to the port. So that we can avoid reporting wide port device too
early to kernel, which caused the first IOs (report luns, inquirys)
failed due to not all the phys are configured into its port. Changes
also made that the phys in a wide port don't need to go through half
second wait time for consuming power.
Signed-off-by: NMarcin Tomczak <marcin.tomczak@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

When hot insert the wide port device through the mini-sas port,
the first IOs (Report Luns or Inquiry) may fail due to the device
trying to open to a SCU phy that is still in suspended state. This
IO failure causes the wide port device stuck in UPDATING_PORT_WIDTH
state.
Signed-off-by: NMarcin Tomczak <marcin.tomczak@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Arrange for task_contexts prepared for the wide targets to account for
all the attached phys in the port.
Signed-off-by: NBartek Nowakowski <bartek.nowakowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Failure seen pulling a cable from a x4 port configured in manual port
configuration (MPC) mode (MPC mode is set by the the OEM paramaters
provided by the platform or isci_firmware.bin).  While IO running to
devices behind and expander, plugging out the cable from phy is causing
IO failures and IO drops on disks and never recover.

It happens because during link up/down the phy were being taken out of
the port.

Fix: during link down the phy is kept in the same logical port.
Signed-off-by: NMarcin Tomczak <marcin.tomczak@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Bump the version now that the driver has atapi support and the initial
round of hotplug fixes.  The EXPERIMENTAL tag should have been removed a
while back.  While we're here also kill the "select SCSI_SAS_HOST_SMP"
as the build error was separately fixed by commit d962480e "[SCSI]
libsas: fix try_test_sas_gpio_gp_bit() build error".
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

As the field was never set, isci_print_tmf() using 'isci_tmf->device'
sometimes causes a kernel crash if the dev_dbg() statement is enabled.
Remove the unused field both from isci_tmf struct definition and from
isci_print_tmf()
Signed-off-by: NMaciej Trela <maciej.trela@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Gen-3 operation is marginal, default to gen-2 for now.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

"No task timeout timer reduced from 20 to 2 This timer controls how
long the SCU hardware will hold open the TX side of the connection
before sending a DONE.  The timer allows the hardware to attempt to
optimize the DONE/CLOSE behavior to allow for new COMMAND IU to be
posted.  In practice closing the connection quicker is better."
Signed-off-by: NMarcin Tomczak <marcin.tomczak@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

v1.3 allows the attenuation of the attached cables to be specified to
the driver in terms of 'short', 'medium', and 'long' (see probe_roms.h).
These settings (per phy) are retrieved from the platform oem-parameters
(BIOS rom) or via a module parameter override.
Reviewed-by: NJiangbi Liu <jiangbi.liu@intel.com>
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

v1.1 allows finer grained tuning of the SSC (spread-spectrum-clocking)
settings for SAS and SATA.  See notes in probe_roms.h
Signed-off-by: NDave Jiang <dave.jiang@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

C1 silicon requires updates to the phy tuning recipe and also support
for user provided cable selects (per-phy) for short, medium, and long
cables.  Default to 'short' awaiting support for selecting the cable via
oem parameters.
Reviewed-by: NJiangbi Liu <jiangbi.liu@intel.com>
Signed-off-by: NMarcin Tomczak <marcin.tomczak@intel.com>
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Before updating the code to support the latest platform updates and
silicon revision cleanup some of the long deref chains.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This parameter blob and generator program have been moved to the
linux-firmware.git repository.
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Fixes bug where max_concurr_spinup oem parameter should be
overriden by max_concurr_spinup user parameter. Override should
happen only when max_concurr_spinup user parameter is specified
in command line (greater than 0). Also this fix shortens variables
representing max_conxurr_spinup for oem and user parameters.
Signed-off-by: NAndrzej Jakowski <andrzej.jakowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

The initial bcn filtering implementation was validated on a kernel
baseline that predated the switch to new libata error handling.  Also,
prior to that conversion we borrowed the mvsas MVS_DEV_EH approach to
prevent the unwanted extra ap->ops->phy_reset(ap) that occurred in the
ata_bus_probe() path.

After the conversion to new libata eh resets at discovery are more
frequent and get filtered prematurely by IDEV_EH.  The result is that
our bcn filtering has been blocked from running and at discovery and it
appears to stall discovery completion to the point of triggering hung
task timeouts.  So, revert the implementation for now.  When it returns
it will go into libsas proper.

The domain rediscovery that takes place due to ->lldd_I_T_nexus_reset()
events should now be properly waited for by the ata_port_wait_eh() call
in ata_port_probe().  So the hard coded delay in the isci
->lldd_I_T_nexus_reset() and other libsas drivers should help debounce
the libsas thread from seeing temporary device removals.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

A hard reset can timeout before or after the last phy in the
port goes away.  If after, then notify the OS that the last
phy has failed.

The recovery for the failed hard reset has been removed.
This recovery code was unecessary in that the link would
recover from the failure normally by a new link reset sequence
or hotplug of the remote device.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

The lldd does not need to look at or manage the pending device
reset bit in pending sas_tasks.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Use the existing IREQ_TMF flag as a request type indicator.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

libsas uses the LLDD abort task interface to handle I/O timeouts
in the SATA/STP and SMP discovery paths, so this change will terminate
STP/SMP requests. Also, if the device is gone, the lldd will prevent
libsas from further escalations in the error handler.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

libsas will cleanup pending sas_tasks after error handler
path functions are called; do not call task_done callbacks.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

In the case where "task" requests timeout (note that this class of
requests can also include SATA/STP soft reset FIS transmissions),
handle the case where the task was being managed by some call to
terminate the task request by completing both the tmf and the aborting
process.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Make sure terminated requests and completed task tags are freed.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

In the case where an I/O fails to start in isci_request_execute,
only allow retries if the device is not already gone.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

The LLDD needs to obtain a reference to the device through the request
itself and not through the domain_device, because the
domain_device.lldd_dev is set to NULL early in the lldd_dev_gone call.
This relies on the fact that the isci_remote_device object is keeping a
seperate reference count of outstanding requests.  TODO: unify the
request count tracking with the isci_remote_device kref.

The failure signature of this condition looks like the following
log, where the important bits are the call to lldd_dev_gone followed
by a crash in isci_terminate_request_core:

[  229.151541] isci 0000:0b:00.0: isci_remote_device_gone: domain_device = ffff8801492d4800, isci_device = ffff880143c657d0, isci_port = ffff880143c63658
[  229.166007] isci 0000:0b:00.0: isci_remote_device_stop: isci_device = ffff880143c657d0
[  229.175317] isci 0000:0b:00.0: isci_terminate_pending_requests: idev=ffff880143c657d0 request=ffff88014741f000; task=ffff8801470f46c0 old_state=2
[  229.189702] isci 0000:0b:00.0: isci_terminate_request_core: device = ffff880143c657d0; request = ffff88014741f000
[  229.201339] isci 0000:0b:00.0: isci_terminate_request_core: before completion wait (ffff88014741f000/ffff880149715ad0)
[  229.213414] isci 0000:0b:00.0: sci_controller_process_completions: completion queue entry:0x8000a0e9
[  229.214401] BUG: unable to handle kernel NULL pointer dereference at 0000000000000228
[  229.214401] IP:jdskirvi-testlbo [<ffffffffa00a58be>] sci_request_completed_state_enter+0x50/0xafb [isci]
[  229.214401] PGD 13d19e067 PUD 13d104067 PMD 0
[  229.214401] Oops: 0000 [#1] SMP
[  229.214401] CPU 0 x kernel: [  226
[  229.214401] Modules linked in: ipv6 dm_multipath uinput nouveau snd_hda_codec_realtek snd_hda_intel ttm drm_kms_helper drm snd_hda_codec snd_hwdep snd_pcm snd_timer i2c_algo_bit isci snd libsas ioatdma mxm_wmi iTCO_wdt soundcore snd_page_alloc scsi_transport_sas iTCO_vendor_support wmi dca video i2c_i801 i2c_core [last unloaded: speedstep_lib]
[  229.214401]
[  229.214401] Pid: 5, comm: kworker/u:0 Not tainted 3.0.0-isci-11.7.29+ #30.353196] Buffer  Intel Corporation Stoakley/Pearlcity Workstation
[  229.214401] RIP: 0010:[<ffffffffa00a58be>] I/O error on dev [<ffffffffa00a58be>] sci_request_completed_state_enter+0x50/0xafb [isci]
[  229.214401] RSP: 0018:ffff88014fc03d20  EFLAGS: 00010046
[  229.214401] RAX: 0000000000000000 RBX: ffff88014741f000 RCX: 0000000000000000
[  229.214401] RDX: ffffffffa00b2c90 RSI: 0000000000000017 RDI: ffff88014741f0a0
[  229.214401] RBP: ffff88014fc03d90 R08: 0000000000000018 R09: 0000000000000000
[  229.214401] R10: 0000000000000000 R11: ffffffff81a17d98 R12: 000000000000001d
[  229.214401] R13: ffff8801470f46c0 R14: 0000000000000000 R15: 0000000000008000
[  229.214401] FS:  0000000000000000(0000) GS:ffff88014fc00000(0000) knlGS:0000000000000000
[  229.214401] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  229.214401] CR2: 0000000000000228 CR3: 000000013ceaa000 CR4: 00000000000406f0
[  229.214401] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  229.214401] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  229.214401] Process kworker/u:0 (pid: 5, threadinfo ffff880149714000, task ffff880149718000)
[  229.214401] Call Trace:
[  229.214401]  <IRQ>
[  229.214401]  [<ffffffffa00aa6ce>] sci_change_state+0x4a/0x4f [isci]
[  229.214401]  [<ffffffffa00a4ca6>] sci_io_request_tc_completion+0x79c/0x7a0 [isci]
[  229.214401]  [<ffffffffa00acf35>] sci_controller_process_completions+0x14f/0x396 [isci]
[  229.214401]  [<ffffffffa00abbda>] ? spin_lock_irq+0xe/0x10 [isci]
[  229.214401]  [<ffffffffa00ad2cf>] isci_host_completion_routine+0x71/0x2be [isci]
[  229.214401]  [<ffffffff8107c6b3>] ? mark_held_locks+0x52/0x70
[  229.214401]  [<ffffffff810538e8>] tasklet_action+0x90/0xf1
[  229.214401]  [<ffffffff81054050>] __do_softirq+0xe5/0x1bf
[  229.214401]  [<ffffffff8106d9d1>] ? hrtimer_interrupt+0x129/0x1bb
[  229.214401]  [<ffffffff814ff69c>] call_softirq+0x1c/0x30
[  229.214401]  [<ffffffff8100bb67>] do_softirq+0x4b/0xa3
[  229.214401]  [<ffffffff81053d84>] irq_exit+0x53/0xb4
[  229.214401]  [<ffffffff814fffe7>] smp_apic_timer_interrupt+0x83/0x91
[  229.214401]  [<ffffffff814fee53>] apic_timer_interrupt+0x13/0x20
[  229.214401]  <EOI>
[  229.214401]  [<ffffffff814f7ad4>] ? retint_restore_args+0x13/0x13
[  229.214401]  [<ffffffff8107af29>] ? trace_hardirqs_off+0xd/0xf
[  229.214401]  [<ffffffff8104ea71>] ? vprintk+0x40b/0x452
[  229.214401]  [<ffffffff814f4b5a>] printk+0x41/0x47
[  229.214401]  [<ffffffff81314484>] __dev_printk+0x78/0x7a
[  229.214401]  [<ffffffff8131471e>] dev_printk+0x45/0x47
[  229.214401]  [<ffffffffa00ae2a3>] isci_terminate_request_core+0x15d/0x317 [isci]
[  229.214401]  [<ffffffffa00af1ad>] isci_terminate_pending_requests+0x1a4/0x204 [isci]
[  229.214401]  [<ffffffffa00229f6>] ? sas_phye_oob_error+0xc3/0xc3 [libsas]
[  229.214401]  [<ffffffffa00a7d9e>] isci_remote_device_nuke_requests+0xa6/0xff [isci]
[  229.214401]  [<ffffffffa00a811a>] isci_remote_device_stop+0x7c/0x166 [isci]
[  229.214401]  [<ffffffffa00229f6>] ? sas_phye_oob_error+0xc3/0xc3 [libsas]
[  229.214401]  [<ffffffffa00a827a>] isci_remote_device_gone+0x76/0x7e [isci]
[  229.214401]  [<ffffffffa002363e>] sas_notify_lldd_dev_gone+0x34/0x36 [libsas]
[  229.214401]  [<ffffffffa0023945>] sas_unregister_dev+0x57/0x9c [libsas]
[  229.214401]  [<ffffffffa00239c0>] sas_unregister_domain_devices+0x36/0x65 [libsas]
[  229.214401]  [<ffffffffa0022cb8>] sas_deform_port+0x72/0x1ac [libsas]
[  229.214401]  [<ffffffffa00229f6>] ? sas_phye_oob_error+0xc3/0xc3 [libsas]
[  229.214401]  [<ffffffffa0022a34>] sas_phye_loss_of_signal+0x3e/0x42 [libsas]
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Allow the sas-transport-class to update events for local phys via a new
PHY_FUNC_GET_EVENTS command to ->lldd_control_phy().  Fixup drivers that
are not prepared for new enum phy_func values, and unify
->lldd_control_phy() error codes.

These are the SAS defined phy events that are reported in a
smp-report-phy-error-log command:
 * /sys/class/sas_phy/<phyX>/invalid_dword_count
 * /sys/class/sas_phy/<phyX>/running_disparity_error_count
 * /sys/class/sas_phy/<phyX>/loss_of_dword_sync_count
 * /sys/class/sas_phy/<phyX>/phy_reset_problem_count
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Fixes a bug where any phy removed from the port set the port
state to "stopping" - do this only when the last phy removed
from the port.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

DONE_CRC_ERR is not a RNC suspension condition, so do not change the
state to expect the incoming suspension notification.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
[djbw: dropped DONE_CMD_LL_R_ERR change]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Since libsas has it's own means to escalate SATA/STP device error
handling depending on task status codes, return all SATA/STP I/O
on the normal path.

i.e. skip sas_task_abort() and let sas_ata_task_done() disposition the
qc.  Longer term we want to audit non-essential calls to
sas_task_abort().
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Based on original implementation from Jiangbi Liu and Maciej Trela.

ATAPI transfers happen in two-to-three stages.  The two stage atapi
commands are those that include a dma data transfer.  The data transfer
portion of these operations is handled by the hardware packet-dma
acceleration.  The three-stage commands do not have a data transfer and
are handled without hardware assistance in raw frame mode.

stage1: transmit host-to-device fis to notify the device of an incoming
atapi cdb.  Upon reception of the pio-setup-fis repost the task_context
to perform the dma transfer of the cdb+data (go to stage3), or repost
the task_context to transmit the cdb as a raw frame (go to stage 2).

stage2: wait for hardware notification of the cdb transmission and then
go to stage 3.

stage3: wait for the arrival of the terminating device-to-host fis and
terminate the command.

To keep the implementation simple we only support ATAPI packet-dma
protocol (for commands with data) to avoid needing to handle the data
transfer manually (like we do for SATA-PIO).  This may affect
compatibility for a small number of devices (see
ATA_HORKAGE_ATAPI_MOD16_DMA).

If the data-transfer underruns, or encounters an error the
device-to-host fis is expected to arrive in the unsolicited frame queue
to pass to libata for disposition.  However, in the DONE_UNEXP_FIS (data
underrun) case it appears we need to craft a response.  In the
DONE_REG_ERR case we do receive the UF and propagate it to libsas.
Signed-off-by: NMaciej Trela <maciej.trela@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Needed to jump to scic_lock unlock.

Also spotted by coccicheck.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Kill the local smp response buffer.

Besides being unnecessary, it is too small (currently truncates
responses to 60 bytes).  The mid-layer will have already allocated a
sufficiently sized buffer, just kmap and copy into it directly.

Cc: <stable@kernel.org>
Reported-by: NDerick Marks <derick.w.marks@intel.com>
Tested-by: NDerick Marks <derick.w.marks@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Basic support to initialize the gpio unit, accept an incomming
SAS_GPIO_REG_TX_GP bitstream, and translate it to the ODx.n fields in
the hardware registers.  If register indexes outside the supported range
are specified in the SMP frame we simply accept the write and return how
many registers (SFF-8485) were written (libsas reports this as residue
in the request).
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

output_data_select registers are off by one u32

delete the macros we will never use.
Reported-by: NArtur Wojcik <artur.wojcik@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This is a resend from the original, changing the title from PATCH to
RFC(since this is a review for commit, and I should have put that the first go around).
and also removing some of the commit's with ia64 and bash since it is significant.
let me know if I might have missed anything etc..
Signed-off-by: NJustin P. Mattock <justinmattock@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Now that isci has added a 3rd open coded user of this functionality just
share the libsas version.
Acked-by: NJack Wang <jack_wang@usish.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Hardware only increments the put pointer on event types >= 4.  Do not
increment the get pointer for event type 3.
Reported-by: NKapil Karkra <kapil.karkra@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Hardware allows both an outstanding number commands and a timeout value
(whichever occurs first) as a gate to the next interrupt generation.  This
scheme at completion time looks at the remaining number of outstanding tasks
and sets the timeout to maximize small transaction operation.  If transactions
are large (take more than a few 10s of microseconds to complete) then
performance is not interrupt processing bound, so the small timeouts this
scheme generates are overridden by the time it takes for a completion to
arrive.
Tested-by: NDave Jiang <dave.jiang@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>