[PATCH 10/15] cxl: Add preliminary workaround for CX4 interrupt limitation

Andrew Donnellan andrew.donnellan at au1.ibm.com
Wed Jul 13 14:40:07 AEST 2016

On 11/07/16 21:50, Ian Munsie wrote:
> From: Ian Munsie <imunsie at au1.ibm.com>
> The Mellanox CX4 has a hardware limitation where only 4 bits of the
> AFU interrupt number can be passed to the XSL when sending an interrupt,
> limiting it to only 15 interrupts per context (AFU interrupt number 0 is
> invalid).
> In order to overcome this, we will allocate additional contexts linked
> to the default context as extra address space for the extra interrupts -
> this will be implemented in the next patch.
> This patch adds the preliminary support to allow this, by way of adding
> a linked list in the context structure that we use to keep track of the
> contexts dedicated to interrupts, and an API to simultaneously iterate
> over the related context structures, AFU interrupt numbers and hardware
> interrupt numbers. The point of using a single API to iterate these is
> to hide some of the details of the iteration from external code, and to
> reduce the number of APIs that need to be exported via base.c to allow
> built in code to call.
> Signed-off-by: Ian Munsie <imunsie at au1.ibm.com>
> Reviewed-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited

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