From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, linux-ntb@googlegroups.com,
linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kselftest@vger.kernel.org, Jon Mason <jdmason@kudzu.us>,
Bjorn Helgaas <bhelgaas@google.com>,
Joerg Roedel <joro@8bytes.org>
Cc: Allen Hubbe <allenbh@gmail.com>,
Dave Jiang <dave.jiang@intel.com>,
Serge Semin <fancer.lancer@gmail.com>,
Eric Pilmore <epilmore@gigaio.com>,
Logan Gunthorpe <logang@deltatee.com>
Subject: [PATCH v2 07/12] NTB: Introduce functions to calculate multi-port resource index
Date: Wed, 13 Feb 2019 10:54:49 -0700 [thread overview]
Message-ID: <20190213175454.7506-8-logang@deltatee.com> (raw)
In-Reply-To: <20190213175454.7506-1-logang@deltatee.com>
When using multi-ports each port uses resources (dbs, msgs, mws, etc)
on every other port. Creating a mapping for these resources such that
each port has a corresponding resource on every other port is a bit
tricky.
Introduce the ntb_peer_resource_idx() function for this purpose.
It returns the peer resource number that will correspond with the
local peer index on the remote peer.
Also, introduce ntb_peer_highest_mw_idx() which will use
ntb_peer_resource_idx() but return the MW index starting with the
highest index and working down.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
---
include/linux/ntb.h | 70 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 70 insertions(+)
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index 181d16601dd9..f5c69d853489 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -1502,4 +1502,74 @@ static inline int ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx,
return ntb->ops->peer_msg_write(ntb, pidx, midx, msg);
}
+/**
+ * ntb_peer_resource_idx() - get a resource index for a given peer idx
+ * @ntb: NTB device context.
+ * @pidx: Peer port index.
+ *
+ * When constructing a graph of peers, each remote peer must use a different
+ * resource index (mw, doorbell, etc) to communicate with each other
+ * peer.
+ *
+ * In a two peer system, this function should always return 0 such that
+ * resource 0 points to the remote peer on both ports.
+ *
+ * In a 5 peer system, this function will return the following matrix
+ *
+ * pidx \ port 0 1 2 3 4
+ * 0 0 0 1 2 3
+ * 1 0 1 2 3 4
+ * 2 0 1 2 3 4
+ * 3 0 1 2 3 4
+ *
+ * For example, if this function is used to program peer's memory
+ * windows, port 0 will program MW 0 on all it's peers to point to itself.
+ * port 1 will program MW 0 in port 0 to point to itself and MW 1 on all
+ * other ports. etc.
+ *
+ * For the legacy two host case, ntb_port_number() and ntb_peer_port_number()
+ * both return zero and therefore this function will always return zero.
+ * So MW 0 on each host would be programmed to point to the other host.
+ *
+ * Return: the resource index to use for that peer.
+ */
+static inline int ntb_peer_resource_idx(struct ntb_dev *ntb, int pidx)
+{
+ int local_port, peer_port;
+
+ if (pidx >= ntb_peer_port_count(ntb))
+ return -EINVAL;
+
+ local_port = ntb_port_number(ntb);
+ peer_port = ntb_peer_port_number(ntb, pidx);
+
+ if (peer_port < local_port)
+ return local_port - 1;
+ else
+ return local_port;
+}
+
+/**
+ * ntb_peer_highest_mw_idx() - get a memory window index for a given peer idx
+ * using the highest index memory windows first
+ *
+ * @ntb: NTB device context.
+ * @pidx: Peer port index.
+ *
+ * Like ntb_peer_resource_idx(), except it returns indexes starting with
+ * last memory window index.
+ *
+ * Return: the resource index to use for that peer.
+ */
+static inline int ntb_peer_highest_mw_idx(struct ntb_dev *ntb, int pidx)
+{
+ int ret;
+
+ ret = ntb_peer_resource_idx(ntb, pidx);
+ if (ret < 0)
+ return ret;
+
+ return ntb_mw_count(ntb, pidx) - ret - 1;
+}
+
#endif
--
2.19.0
next prev parent reply other threads:[~2019-02-13 17:55 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-13 17:54 [PATCH v2 00/12] Support using MSI interrupts in ntb_transport Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 01/12] iommu/vt-d: Implement dma_[un]map_resource() Logan Gunthorpe
2019-02-13 17:57 ` Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 02/12] NTB: ntb_transport: Ensure the destination buffer is mapped for TX DMA Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 03/12] iommu/vt-d: Add helper to set an IRTE to verify only the bus number Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 04/12] iommu/vt-d: Allow interrupts from the entire bus for aliased devices Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 05/12] PCI/MSI: Support allocating virtual MSI interrupts Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 06/12] PCI/switchtec: Add module parameter to request more interrupts Logan Gunthorpe
2019-02-13 17:54 ` Logan Gunthorpe [this message]
2019-03-06 1:24 ` [PATCH v2 07/12] NTB: Introduce functions to calculate multi-port resource index Serge Semin
2019-03-06 19:11 ` Logan Gunthorpe
2019-03-06 22:45 ` Serge Semin
2019-03-06 23:22 ` Logan Gunthorpe
2019-03-12 20:42 ` Serge Semin
2019-03-12 21:30 ` Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 08/12] NTB: Rename ntb.c to support multiple source files in the module Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 09/12] NTB: Introduce MSI library Logan Gunthorpe
2019-03-06 20:26 ` Serge Semin
2019-03-06 21:35 ` Logan Gunthorpe
2019-03-06 23:13 ` Serge Semin
2019-02-13 17:54 ` [PATCH v2 10/12] NTB: Introduce NTB MSI Test Client Logan Gunthorpe
2019-03-06 20:44 ` Serge Semin
2019-03-06 21:39 ` Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 11/12] NTB: Add ntb_msi_test support to ntb_test Logan Gunthorpe
2019-02-13 17:54 ` [PATCH v2 12/12] NTB: Add MSI interrupt support to ntb_transport Logan Gunthorpe
2019-02-26 9:34 ` [PATCH v2 00/12] Support using MSI interrupts in ntb_transport Joerg Roedel
2019-02-26 16:18 ` Logan Gunthorpe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190213175454.7506-8-logang@deltatee.com \
--to=logang@deltatee.com \
--cc=allenbh@gmail.com \
--cc=bhelgaas@google.com \
--cc=dave.jiang@intel.com \
--cc=epilmore@gigaio.com \
--cc=fancer.lancer@gmail.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jdmason@kudzu.us \
--cc=joro@8bytes.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-ntb@googlegroups.com \
--cc=linux-pci@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).