Device dependent flags are needed to support functions that are specific
to a particular device.

One such case is - some CXL Flash cards need to be notified of device
shutdown. For other CXL devices, this feature does not prove to be
useful yet. Such distinct features need to be identified in the driver
to bypass or invoke specific functionality.

In this patch, a member 'flags' has been added to device dependent
values. These flags will be used and expanded in the future to support
various device specific functions.
Signed-off-by: NUma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: NManoj N. Kumar <manoj@linux.vnet.ibm.com>
Acked-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

While running 'sg_reset -H' back to back the following exception was seen:

[  735.115695] Faulting instruction address: 0xd0000000098c0864
cpu 0x0: Vector: 300 (Data Access) at [c000000ffffafa80]
    pc: d0000000098c0864: cxlflash_async_err_irq+0x84/0x5c0 [cxlflash]
    lr: c00000000013aed0: handle_irq_event_percpu+0xa0/0x310
    sp: c000000ffffafd00
   msr: 9000000000009033
   dar: 2010000
 dsisr: 40000000
  current = 0xc000000001510880
  paca    = 0xc00000000fb80000   softe: 0        irq_happened: 0x01
    pid   = 0, comm = swapper/0

Linux version 4.5.0-491-26f710d+

enter ? for help
[c000000ffffafe10] c00000000013aed0 handle_irq_event_percpu+0xa0/0x310
[c000000ffffafed0] c00000000013b1a8 handle_irq_event+0x68/0xc0
[c000000ffffaff00] c0000000001404ec handle_fasteoi_irq+0xec/0x2a0
[c000000ffffaff30] c00000000013a084 generic_handle_irq+0x54/0x80
[c000000ffffaff60] c000000000011130 __do_irq+0x80/0x1d0
[c000000ffffaff90] c000000000024d40 call_do_irq+0x14/0x24
[c000000001573a20] c000000000011318 do_IRQ+0x98/0x140
[c000000001573a70] c000000000002594 hardware_interrupt_common+0x114/0x180

This exception is being hit because the async_err interrupt path performs
an MMIO to read the interrupt status register. The MMIO region in this
case is not available.

Commit 6ded8b3c ("cxlflash: Unmap problem state area before detaching
master context") re-ordered the sequence in which term_mc() and stop_afu()
are called. This introduces a window for interrupts to come in with the
problem space area unmapped, that did not exist previously.

The fix is to separate the disabling of all AFU interrupts to a distinct
function, term_intr() so that it is the first thing that is done in the
tear down process.

To keep the initialization process symmetric, separate the AFU interrupt
setup also to a distinct function: init_intr().

Fixes: 6ded8b3c ("cxlflash: Unmap problem state area before detaching master context")
Signed-off-by: NManoj N. Kumar <manoj@linux.vnet.ibm.com>
Acked-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NUma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This drop enables a future card with a device id of 0x0600 to be
recognized by the cxlflash driver.

As per the design, the Accelerator Function Unit (AFU) for this new IBM
CXL Flash Adapter retains the same host interface as the previous
generation. For the early prototypes of the new card, the driver with
this change behaves exactly as the driver prior to this behaved with the
earlier generation card. Therefore, no card specific programming has
been added. These card specific changes can be staged in later if
needed.
Signed-off-by: NManoj N. Kumar <manoj@linux.vnet.ibm.com>
Acked-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Reviewed-by: NAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Having a date for the driver requires it to be updated quite
often. Removing the date which is not necessary. Also made
use of the existing symbol to print the driver name.
Signed-off-by: NUma Krishnan <ukrishn@linux.vnet.ibm.com>
Reviewed-by: NAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Following a link up event, the LUNs available to the host may
have changed. Without rescanning the host, the LUN topology is
unknown to the user. In such a state, the user would be unable
to locate provisioned resources.

To remedy, the host should be rescanned after a link up event.
Signed-off-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NManoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: NBrian King <brking@linux.vnet.ibm.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Introduce support for enhanced I/O error handling.

A device state is added to track 3 possible states of the device:

Normal - the device is operating normally and is fully operational

Limbo - the device is in a reset/recovery scenario and its operational
        status is paused

Failed/terminating - the device has either failed to be reset/recovered
                     or is being terminated (removed); it is no longer
                     operational

All operations are allowed when the device is operating normally. When the
device transitions to limbo state, I/O must be paused. To help accomplish
this, a wait queue is introduced where existing and new threads can wait
until the device is no longer in limbo. When coming out of limbo, threads
need to check the state and error out gracefully when encountering the
failed state. When the device transitions to the failed/terminating state,
normal operations are no longer allowed. Only specially designated
operations related to graceful cleanup are permitted.
Signed-off-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NManoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: NDaniel Axtens <dja@axtens.net>
Reviewed-by: NMichael Neuling <mikey@neuling.org>
Reviewed-by: NWen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: NBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

SCSI device driver to support filesystem access on the IBM CXL Flash adapter.
Supported-by: NStephen Bates <stephen.bates@pmcs.com>
Reviewed-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NManoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: NBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>