powerpc/vas: Fix IRQ name allocation

The VAS device allocates a generic interrupt to handle page faults but
the IRQ name doesn't show under /proc. This is because it's on
stack. Allocate the name.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201212142707.2102141-1-clg@kaod.org

powerpc/vas: Setup thread IRQ handler per VAS instance

When NX encounters translation error on CRB and any request buffer,
raises an interrupt on the CPU to handle the fault. It can raise one
interrupt for multiple faults. Expects OS to handle these faults and
return credits for fault window after processing faults.

Setup thread IRQ handler and IRQ thread function per each VAS instance.
IRQ handler checks if the thread is already woken up and can handle new
faults. If so returns with IRQ_HANDLED, otherwise wake up thread to
process new faults.

The thread functions reads each CRB entry from fault FIFO until sees
invalid entry. After reading each CRB, determine the corresponding
send window using pswid (from CRB) and process fault CRB. Then
invalidate the entry and return credit. Processing fault CRB and
return credit is described in subsequent patches.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016982.2275.1060.camel@hbabu-laptop

powerpc/vas: Setup fault window per VAS instance

Setup fault window for each VAS instance. When NX gets a fault on
request buffer, pastes fault CRB in the corresponding fault FIFO and
then raises an interrupt to the OS. The kernel handles this fault
and process faults CRB from this FIFO.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016846.2275.1053.camel@hbabu-laptop

powerpc/vas: Alloc and setup IRQ and trigger port address

Allocate a xive irq on each chip with a vas instance. The NX coprocessor
raises a host CPU interrupt via vas if it encounters page fault on user
space request buffer. Subsequent patches register the trigger port with
the NX coprocessor, and create a vas fault handler for this interrupt
mapping.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016806.2275.1050.camel@hbabu-laptop

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

powerpc/vas: Fix cleanup when VAS is not configured

When VAS is not configured, unregister the platform driver. Also simplify
cleanup by delaying vas debugfs init until we know VAS is configured.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/vas: Export chip_to_vas_id()

Export the symbol chip_to_vas_id() to fix a build failure when
CONFIG_CRYPTO_DEV_NX_COMPRESS_POWERNV=m.

Fixes: d4ef61b5e895 ("powerpc/vas, nx-842: Define and use chip_to_vas_id()")
Reported-by: Haren Myneni <hbabu@us.ibm.com>
Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/vas: Export HVWC to debugfs

Export the VAS Window context information to debugfs.

We need to hold a mutex when closing the window to prevent a race
with the debugfs read(). Rather than introduce a per-instance mutex,
we use the global vas_mutex for now, since it is not heavily contended.

The window->cop field is only relevant to a receive window so we were
not setting it for a send window (which is is paired to a receive window
anyway). But to simplify reporting in debugfs, set the 'cop' field for the
send window also.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/vas, nx-842: Define and use chip_to_vas_id()

Define a helper, chip_to_vas_id() to map a given chip id to corresponding
vas id.

Normally, callers of vas_rx_win_open() and vas_tx_win_open() want the VAS
window to be on the same chip where the calling thread is executing. These
callers can pass in -1 for the VAS id.

This interface will be useful if a thread running on one chip wants to open
a window on another chip (like the NX-842 driver does during start up).

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/vas: Create cpu to vas id mapping

Create a cpu to vasid mapping so callers can specify -1 instead of
trying to find a VAS id.

Changelog[v2]
[Michael Ellerman] Use per-cpu variables to simplify code.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/powernv/vas: Define vas_init() and vas_exit()

Implement vas_init() and vas_exit() functions for a new VAS module.
This VAS module is essentially a library for other device drivers
and kernel users of the NX coprocessors like NX-842 and NX-GZIP.
In the future this will be extended to add support for user space
to access the NX coprocessors.

VAS is currently only supported with 64K page size.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>