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authorAlan Tull <atull@kernel.org>2018-05-16 18:50:03 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-25 18:23:56 +0200
commit547b822c22b18e346ee1d562d1787486e5c88c3c (patch)
tree6a553b88c0078b567447102a0970b551121b7e69 /Documentation/fpga
parent66c472cdb62d7b00de55722a772f7dfecf88abd1 (diff)
downloadlinux-547b822c22b18e346ee1d562d1787486e5c88c3c.tar.bz2
documentation: fpga: move fpga-mgr.txt to driver-api
Move Documentation/fpga/fpga-mgr.txt to driver-api/fpga/fpga-mgr.rst and: - Add to driver-api/fpga/index.rst - Format changes so documentation builds cleanly. - Minor rewrites that make the doc flow better as ReST documentation. - Such as moving API reference to end of doc - Change API reference section to refer to kernel-doc documentation in fpga-mgr.c driver code rather than statically defining each function. Signed-off-by: Alan Tull <atull@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/fpga')
-rw-r--r--Documentation/fpga/fpga-mgr.txt218
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diff --git a/Documentation/fpga/fpga-mgr.txt b/Documentation/fpga/fpga-mgr.txt
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--- a/Documentation/fpga/fpga-mgr.txt
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@@ -1,218 +0,0 @@
-FPGA Manager Core
-
-Alan Tull 2015
-
-Overview
-========
-
-The FPGA manager core exports a set of functions for programming an FPGA with
-an image. The API is manufacturer agnostic. All manufacturer specifics are
-hidden away in a low level driver which registers a set of ops with the core.
-The FPGA image data itself is very manufacturer specific, but for our purposes
-it's just binary data. The FPGA manager core won't parse it.
-
-The FPGA image to be programmed can be in a scatter gather list, a single
-contiguous buffer, or a firmware file. Because allocating contiguous kernel
-memory for the buffer should be avoided, users are encouraged to use a scatter
-gather list instead if possible.
-
-The particulars for programming the image are presented in a structure (struct
-fpga_image_info). This struct contains parameters such as pointers to the
-FPGA image as well as image-specific particulars such as whether the image was
-built for full or partial reconfiguration.
-
-API Functions:
-==============
-
-To program the FPGA:
---------------------
-
- int fpga_mgr_load(struct fpga_manager *mgr,
- struct fpga_image_info *info);
-
-Load the FPGA from an image which is indicated in the info. If successful,
-the FPGA ends up in operating mode. Return 0 on success or a negative error
-code.
-
-To allocate or free a struct fpga_image_info:
----------------------------------------------
-
- struct fpga_image_info *fpga_image_info_alloc(struct device *dev);
-
- void fpga_image_info_free(struct fpga_image_info *info);
-
-To get/put a reference to a FPGA manager:
------------------------------------------
-
- struct fpga_manager *of_fpga_mgr_get(struct device_node *node);
- struct fpga_manager *fpga_mgr_get(struct device *dev);
- void fpga_mgr_put(struct fpga_manager *mgr);
-
-Given a DT node or device, get a reference to a FPGA manager. This pointer
-can be saved until you are ready to program the FPGA. fpga_mgr_put releases
-the reference.
-
-
-To get exclusive control of a FPGA manager:
--------------------------------------------
-
- int fpga_mgr_lock(struct fpga_manager *mgr);
- void fpga_mgr_unlock(struct fpga_manager *mgr);
-
-The user should call fpga_mgr_lock and verify that it returns 0 before
-attempting to program the FPGA. Likewise, the user should call
-fpga_mgr_unlock when done programming the FPGA.
-
-To alloc/free a FPGA manager struct:
-------------------------------------
-
- struct fpga_manager *fpga_mgr_create(struct device *dev,
- const char *name,
- const struct fpga_manager_ops *mops,
- void *priv);
- void fpga_mgr_free(struct fpga_manager *mgr);
-
-To register or unregister the low level FPGA-specific driver:
--------------------------------------------------------------
-
- int fpga_mgr_register(struct fpga_manager *mgr);
-
- void fpga_mgr_unregister(struct fpga_manager *mgr);
-
-Use of these functions is described below in "How To Support a new FPGA
-device."
-
-
-How to write an image buffer to a supported FPGA
-================================================
-#include <linux/fpga/fpga-mgr.h>
-
-struct fpga_manager *mgr;
-struct fpga_image_info *info;
-int ret;
-
-/*
- * Get a reference to FPGA manager. The manager is not locked, so you can
- * hold onto this reference without it preventing programming.
- *
- * This example uses the device node of the manager. Alternatively, use
- * fpga_mgr_get(dev) instead if you have the device.
- */
-mgr = of_fpga_mgr_get(mgr_node);
-
-/* struct with information about the FPGA image to program. */
-info = fpga_image_info_alloc(dev);
-
-/* flags indicates whether to do full or partial reconfiguration */
-info->flags = FPGA_MGR_PARTIAL_RECONFIG;
-
-/*
- * At this point, indicate where the image is. This is pseudo-code; you're
- * going to use one of these three.
- */
-if (image is in a scatter gather table) {
-
- info->sgt = [your scatter gather table]
-
-} else if (image is in a buffer) {
-
- info->buf = [your image buffer]
- info->count = [image buffer size]
-
-} else if (image is in a firmware file) {
-
- info->firmware_name = devm_kstrdup(dev, firmware_name, GFP_KERNEL);
-
-}
-
-/* Get exclusive control of FPGA manager */
-ret = fpga_mgr_lock(mgr);
-
-/* Load the buffer to the FPGA */
-ret = fpga_mgr_buf_load(mgr, &info, buf, count);
-
-/* Release the FPGA manager */
-fpga_mgr_unlock(mgr);
-fpga_mgr_put(mgr);
-
-/* Deallocate the image info if you're done with it */
-fpga_image_info_free(info);
-
-How to support a new FPGA device
-================================
-To add another FPGA manager, write a driver that implements a set of ops. The
-probe function calls fpga_mgr_register(), such as:
-
-static const struct fpga_manager_ops socfpga_fpga_ops = {
- .write_init = socfpga_fpga_ops_configure_init,
- .write = socfpga_fpga_ops_configure_write,
- .write_complete = socfpga_fpga_ops_configure_complete,
- .state = socfpga_fpga_ops_state,
-};
-
-static int socfpga_fpga_probe(struct platform_device *pdev)
-{
- struct device *dev = &pdev->dev;
- struct socfpga_fpga_priv *priv;
- struct fpga_manager *mgr;
- int ret;
-
- priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
-
- /* ... do ioremaps, get interrupts, etc. and save
- them in priv... */
-
- mgr = fpga_mgr_create(dev, "Altera SOCFPGA FPGA Manager",
- &socfpga_fpga_ops, priv);
- if (!mgr)
- return -ENOMEM;
-
- platform_set_drvdata(pdev, mgr);
-
- ret = fpga_mgr_register(mgr);
- if (ret)
- fpga_mgr_free(mgr);
-
- return ret;
-}
-
-static int socfpga_fpga_remove(struct platform_device *pdev)
-{
- struct fpga_manager *mgr = platform_get_drvdata(pdev);
-
- fpga_mgr_unregister(mgr);
-
- return 0;
-}
-
-
-The ops will implement whatever device specific register writes are needed to
-do the programming sequence for this particular FPGA. These ops return 0 for
-success or negative error codes otherwise.
-
-The programming sequence is:
- 1. .write_init
- 2. .write or .write_sg (may be called once or multiple times)
- 3. .write_complete
-
-The .write_init function will prepare the FPGA to receive the image data. The
-buffer passed into .write_init will be atmost .initial_header_size bytes long,
-if the whole bitstream is not immediately available then the core code will
-buffer up at least this much before starting.
-
-The .write function writes a buffer to the FPGA. The buffer may be contain the
-whole FPGA image or may be a smaller chunk of an FPGA image. In the latter
-case, this function is called multiple times for successive chunks. This interface
-is suitable for drivers which use PIO.
-
-The .write_sg version behaves the same as .write except the input is a sg_table
-scatter list. This interface is suitable for drivers which use DMA.
-
-The .write_complete function is called after all the image has been written
-to put the FPGA into operating mode.
-
-The ops include a .state function which will read the hardware FPGA manager and
-return a code of type enum fpga_mgr_states. It doesn't result in a change in
-hardware state.