diff options
| author |   Logan Gunthorpe <logang@deltatee.com> | 2017-11-29 10:55:29 -0700 |
|---|---|---|
| committer |   Jon Mason <jdmason@kudzu.us> | 2018-01-28 22:17:23 -0500 |
| commit | 01752501820277d217a7b52548d9c948f98d2c56 (patch) | |
| tree | 41b9a2ccd2cd66122e97bde970454ace30302c7a /include/linux/ntb.h | |
| parent | ntb_hw_switchtec: Expand PFF CSR registers (diff) | |
| download | linux-dev-01752501820277d217a7b52548d9c948f98d2c56.tar.xz linux-dev-01752501820277d217a7b52548d9c948f98d2c56.zip | |
ntb_hw_switchtec: Add initialization code for crosslink
Crosslink is a feature of the Switchtec switches that is similar to
the B2B mode of other NTB devices. It allows a system to be designed
that is perfectly symmetric with two identical switches that link
two hosts together.
In order for the system to be symmetric, there is an empty host-less
partition between the two switches which the host must enumerate and
assign BAR addresses to. The firmware in the switch manages this
specially so that the BAR addresses on both sides of the empty
partition will be identical despite being in the same partition with
the same address space.
The driver determines whether crosslink is enabled by a flag set in
the NTB partition info registers which are set by the switch's
configuration file.
When crosslink is enabled, a reserved LUT window is setup to point to
the peer's switch's NTB registers and the local MWs are set to forward
to the host-less partition's BARs. (Yes, this hurts my brain too.)
Once this is setup, largely the same NTB infrastructure is used to
communicate between the two hosts.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Diffstat (limited to 'include/linux/ntb.h')
| -rw-r--r-- | include/linux/ntb.h | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/include/linux/ntb.h b/include/linux/ntb.h index c308964777eb..ea3be7275a5e 100644 --- a/include/linux/ntb.h +++ b/include/linux/ntb.h @@ -71,6 +71,7 @@ struct pci_dev; * @NTB_TOPO_B2B_USD: On primary side of local ntb upstream of remote ntb. * @NTB_TOPO_B2B_DSD: On primary side of local ntb downstream of remote ntb. * @NTB_TOPO_SWITCH: Connected via a switch which supports ntb. + * @NTB_TOPO_CROSSLINK: Connected via two symmetric switchecs */ enum ntb_topo { NTB_TOPO_NONE = -1, @@ -79,6 +80,7 @@ enum ntb_topo { NTB_TOPO_B2B_USD, NTB_TOPO_B2B_DSD, NTB_TOPO_SWITCH, + NTB_TOPO_CROSSLINK, }; static inline int ntb_topo_is_b2b(enum ntb_topo topo) @@ -94,12 +96,13 @@ static inline int ntb_topo_is_b2b(enum ntb_topo topo) static inline char *ntb_topo_string(enum ntb_topo topo) { switch (topo) { - case NTB_TOPO_NONE: return "NTB_TOPO_NONE"; - case NTB_TOPO_PRI: return "NTB_TOPO_PRI"; - case NTB_TOPO_SEC: return "NTB_TOPO_SEC"; - case NTB_TOPO_B2B_USD: return "NTB_TOPO_B2B_USD"; - case NTB_TOPO_B2B_DSD: return "NTB_TOPO_B2B_DSD"; - case NTB_TOPO_SWITCH: return "NTB_TOPO_SWITCH"; + case NTB_TOPO_NONE: return "NTB_TOPO_NONE"; + case NTB_TOPO_PRI: return "NTB_TOPO_PRI"; + case NTB_TOPO_SEC: return "NTB_TOPO_SEC"; + case NTB_TOPO_B2B_USD: return "NTB_TOPO_B2B_USD"; + case NTB_TOPO_B2B_DSD: return "NTB_TOPO_B2B_DSD"; + case NTB_TOPO_SWITCH: return "NTB_TOPO_SWITCH"; + case NTB_TOPO_CROSSLINK: return "NTB_TOPO_CROSSLINK"; } return "NTB_TOPO_INVALID"; } |