cxl/pci: Implement Interface Ready Timeout

Browse source

The original driver implementation used the doorbell timeout for the
Mailbox Interface Ready bit to piggy back off of, since the latter does
not have a defined timeout. This functionality, introduced in commit
8adaf747c9 ("cxl/mem: Find device capabilities"), needs improvement as
the recent "Add Mailbox Ready Time" ECN timeout indicates that the
mailbox ready time can be significantly longer that 2 seconds.

While the specification limits the maximum timeout to 256s, the cxl_pci
driver gives up on the mailbox after 60s. This value corresponds with
important timeout values already present in the kernel. A module
parameter is provided as an emergency override and represents the
default Linux policy for all devices.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[djbw: add modparam, drop check_device_status()]
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/164367306565.208548.1932299464604450843.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

...

This commit is contained in:

Ben Widawsky 2022-01-31 15:51:45 -08:00 • committed by Dan Williams

parent 68cdd3d2af

commit 229e8828c2

1 changed files with 35 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

35

drivers/cxl/pci.c

View file