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From: <atull@opensource.altera.com>
To: gregkh@linuxfoundation.org
Cc: Moritz Fischer <moritz.fischer@ettus.com>,
	Josh Cartwright <joshc@ni.com>,
	monstr@monstr.eu, michal.simek@xilinx.com,
	Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	Jonathan Corbet <corbet@lwn.net>,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	linux-doc@vger.kernel.org, pantelis.antoniou@konsulko.com,
	delicious.quinoa@gmail.com, dinguyen@opensource.altera.com,
	Alan Tull <atull@opensource.altera.com>
Subject: [PATCH v12 1/6] fpga: add usage documentation for simple fpga bus
Date: Tue, 27 Oct 2015 17:09:10 -0500	[thread overview]
Message-ID: <1445983755-24007-2-git-send-email-atull@opensource.altera.com> (raw)
In-Reply-To: <1445983755-24007-1-git-send-email-atull@opensource.altera.com>

From: Alan Tull <atull@opensource.altera.com>

Add a document spelling out usage of the simple fpga bus.

Signed-off-by: Alan Tull <atull@opensource.altera.com>
---
v9:  Initial version of this patch in patchset
v10: s/fpga/FPGA/g
     improve formatting
     some rewriting
     move to staging/simple-fpga-bus
v11: No change in this patch for v11 of the patch set
v12: Moved out of staging
     Small changes due to using FPGA bridge framework and not
     representing the bridges as resets.
---
 Documentation/fpga/simple-fpga-bus.txt |   58 ++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 Documentation/fpga/simple-fpga-bus.txt

diff --git a/Documentation/fpga/simple-fpga-bus.txt b/Documentation/fpga/simple-fpga-bus.txt
new file mode 100644
index 0000000..bd43478
--- /dev/null
+++ b/Documentation/fpga/simple-fpga-bus.txt
@@ -0,0 +1,58 @@
+Simple FPGA Bus
+
+Alan Tull 2015
+
+Overview
+========
+
+The simple FPGA bus adds device tree overlay support for FPGA's.  Loading a
+DT overlay will result in the FPGA getting an image loaded, its bridges will
+be released, and the DT populated for nodes below the simple-fpga-bus.  This
+results in drivers getting probed for the hardware that just got added.  This
+is intended to support the FPGA usage where the FPGA has hardware that
+requires drivers.  Removing the overlay will result in the drivers getting
+removed and the bridges being disabled.
+
+The simple FPGA bus will need to disable and enable bridges that will only
+affect the child devices that are below the bus.  If partial reconfiguration
+is to be done, then bridges will need to be added within the FPGA design to
+protect the rest of the bus when one part of the FPGA design is being
+reconfigured.
+
+
+Sequence
+========
+
+Load the DT overlay.  One way to do that from user space is to use Pantelis'
+DT-Overlay configfs interface.
+
+This causes the simple FPGA bus go be probed and will do the following:
+ 1. Disable the FPGA bridges.
+ 2. Call the FPGA manager core to program the FPGA.
+ 3. Release the FPGA bridges.
+ 4. Call of_platform_populate resulting in device drivers getting probed.
+
+
+Requirements
+============
+
+ 1. An FPGA image that has a hardware block or blocks that use drivers that are
+    supported in the kernel.
+ 2. A device tree overlay (example is in the simple-fpga-bus bindings document).
+ 3. A FPGA manager driver supporting writing the FPGA.
+ 4. FPGA bridge drivers.
+
+The DT overlay includes bindings (documented in bindings/simple-fpga-bus.txt)
+that specify:
+ * Which FPGA manager to use.
+ * Which image file to load.
+ * Flags indicating whether this this image is for full reconfiguration or
+   partial.
+ * A list of FPGA bridges.
+ * Child nodes specifying the devices that will be added with appropriate
+   compatible strings, etc.
+
+Since this code uses the firmware interface to get the image and DT overlay,
+they currently have to be files on the file system.  It doesn't have to be that
+way forever as DT bindings could be added to point to other sources for the
+image.
-- 
1.7.9.5

  reply	other threads:[~2015-10-27 22:09 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-27 22:09 [PATCH v12 0/6] simple fpga bus and fpga bridge framework atull
2015-10-27 22:09 ` atull [this message]
     [not found]   ` <1445983755-24007-2-git-send-email-atull-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org>
2015-10-28  0:23     ` [PATCH v12 1/6] fpga: add usage documentation for simple fpga bus Moritz Fischer
2015-10-28 14:59       ` atull
2015-10-27 22:09 ` [PATCH v12 2/6] fpga: add bindings document " atull
2015-10-28  9:00   ` Steffen Trumtrar
2015-10-28 14:53     ` atull
2015-10-28 15:18       ` Moritz Fischer
2015-10-28 15:34         ` atull
2015-10-28  9:40   ` Steffen Trumtrar
2015-10-28 19:45     ` atull
2015-10-28 23:40   ` Rob Herring
2015-10-29 16:02     ` atull
2015-10-30 17:58       ` Rob Herring
2015-11-03 16:28         ` atull
2015-11-03 19:56           ` Rob Herring
2015-10-27 22:09 ` [PATCH v12 3/6] fpga: add simple-fpga-bus atull
2015-10-28  9:43   ` Steffen Trumtrar
2015-10-28 15:39     ` atull
2015-10-28 10:07   ` Josh Cartwright
2015-10-28 12:41     ` atull
2015-10-28 15:37     ` Moritz Fischer
2015-10-28 16:18       ` Josh Cartwright
     [not found]         ` <20151028161859.GJ8245-ew3lsbMjNqt5wtABiV/Xjqyly8cj88Ttqxv4g6HH51o@public.gmane.org>
2015-10-28 16:28           ` Moritz Fischer
2015-10-28 17:03             ` atull
2015-10-28 17:41               ` atull
2015-10-28 17:59               ` Josh Cartwright
2015-10-28 18:02                 ` Josh Cartwright
2015-10-28 18:22                 ` atull
2015-10-28 20:33                 ` Moritz Fischer
2015-10-29  4:04         ` Rob Herring
2015-10-27 22:09 ` [PATCH v12 4/6] fpga: add fpga bridge framework atull
     [not found]   ` <1445983755-24007-5-git-send-email-atull-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org>
2015-10-28  9:50     ` Steffen Trumtrar
2015-10-28 15:31       ` atull
2015-10-27 22:09 ` [PATCH v12 5/6] ARM: socfpga: add bindings document for fpga bridge drivers atull
2015-10-28  9:29   ` Steffen Trumtrar
2015-10-28 15:53     ` atull
2015-10-28 23:44   ` Rob Herring
2015-10-29 15:04     ` atull
2015-10-27 22:09 ` [PATCH v12 6/6] ARM: socfpga: fpga bridge driver support atull
2015-10-28 10:13   ` Steffen Trumtrar
2015-10-28 12:51     ` atull

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