Commit Graph

206 Commits

Author SHA1 Message Date
Ian Munsie b03a7f578a cxl: Refactor cxl_load_segment() and find_free_sste()
This moves the segment table hash calculation from cxl_load_segment()
into find_free_sste() since that is the only place it is actually used.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-28 19:52:24 +11:00
Ian Munsie 5100a9d644 cxl: Disable secondary hash in segment table
This patch simplifies the process of finding a free segment table entry
by disabling the secondary hash. This reduces the number of possible
entries in the segment table for a given address from 16 to 8.

Due to the large segment sizes we use it is extremely unlikely that the
secondary hash would ever have been used in practice, so this should not
have any negative impacts and may even improve performance due to the
reduced number of comparisons that software & hardware need to perform.

This patch clears the SC bit in the hardware's state register
(CXL_PSL_SR_An) to disable the secondary hash in the hardware since we
can no longer fill out entries using it.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-28 19:52:07 +11:00
Ian Munsie d53ba6b3bb cxl: Fix afu_read() not doing finish_wait() on signal or non-blocking
If afu_read() returned due to a signal or the AFU file descriptor being
opened non-blocking it would not call finish_wait() before returning,
which could lead to a crash later when something else wakes up the wait
queue.

This patch restructures the wait logic to ensure that the cleanup is
done correctly.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-09 11:29:57 +11:00
Ian Munsie 881632c905 cxl: Add driver to Kbuild and Makefiles
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-08 20:15:58 +11:00
Ian Munsie f204e0b8ce cxl: Driver code for powernv PCIe based cards for userspace access
This is the core of the cxl driver.

It adds support for using cxl cards in the powernv environment only (ie POWER8
bare metal). It allows access to cxl accelerators by userspace using the
/dev/cxl/afuM.N char devices.

The kernel driver has no knowledge of the function implemented by the
accelerator. It provides services to userspace via the /dev/cxl/afuM.N
devices. When a program opens this device and runs the start work IOCTL, the
accelerator will have coherent access to that processes memory using the same
virtual addresses. That process may mmap the device to access any MMIO space
the accelerator provides.  Also, reads on the device will allow interrupts to
be received. These services are further documented in a later patch in
Documentation/powerpc/cxl.txt.

Documentation of the cxl hardware architecture and userspace API is provided in
subsequent patches.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-08 20:15:57 +11:00
Ian Munsie 10542ca015 cxl: Add base builtin support
This adds the base cxl support that cannot be built as a module. Specifically
it adds the cxl callbacks that are called from the core powerpc mm code which
must always exist irrespective of if the cxl module is loaded or not. This is
similar to how cell works with CONFIG_SPU_BASE.

This adds a cxl_slbia() call (similar to spu_flush_all_slbs()) which checks if
the cxl module is loaded and in use, returning immediately if it is not. If it
is in use it calls into the cxl SLB invalidation code.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-08 20:15:56 +11:00