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Subject[PATCH v4 02/18] fpga: mgr: API change to replace fpga load functions with single function
Date
fpga-mgr has three methods for programming FPGAs, depending on
whether the image is in a scatter gather list, a contiguous
buffer, or a firmware file. This makes it difficult to write
upper layers as the caller has to assume whether the FPGA image
is in a sg table, as a single buffer, or a firmware file.
This commit moves these parameters to struct fpga_image_info
and adds a single function for programming fpgas.

New functions:
* fpga_mgr_load - given fpga manager and struct fpga_image_info,
program the fpga.

* fpga_image_info_alloc - alloc a struct fpga_image_info.

* fpga_image_info_free - free a struct fpga_image_info.

These three functions are unexported:
* fpga_mgr_buf_load_sg
* fpga_mgr_buf_load
* fpga_mgr_firmware_load

Also use devm_kstrdup to copy firmware_name so we aren't making
assumptions about where it comes from when allocing/freeing the
struct fpga_image_info.

API documentation has been updated and a new document for
FPGA region has been added.

Signed-off-by: Alan Tull <atull@kernel.org>
---
v2: add fpga_image_info_alloc/free
update copyright and author email
v3: fix bisectibility
v4: fix return value of fpga_image_info_alloc()
save device in struct fpga_image_info
remove device param from fpga_image_info_free()
squash in the documentation patch minus stuff about locking
which is included in the next patch
---
Documentation/fpga/fpga-mgr.txt | 119 ++++++++++++++++---------------------
Documentation/fpga/fpga-region.txt | 95 +++++++++++++++++++++++++++++
Documentation/fpga/overview.txt | 23 +++++++
drivers/fpga/fpga-mgr.c | 68 +++++++++++++++++----
drivers/fpga/fpga-region.c | 43 +++++++++-----
include/linux/fpga/fpga-mgr.h | 24 +++++---
6 files changed, 270 insertions(+), 102 deletions(-)
create mode 100644 Documentation/fpga/fpga-region.txt
create mode 100644 Documentation/fpga/overview.txt

diff --git a/Documentation/fpga/fpga-mgr.txt b/Documentation/fpga/fpga-mgr.txt
index 78f197f..6ebc714 100644
--- a/Documentation/fpga/fpga-mgr.txt
+++ b/Documentation/fpga/fpga-mgr.txt
@@ -11,61 +11,53 @@ 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 from a file or from a buffer:
--------------------------------------------------
-
- int fpga_mgr_buf_load(struct fpga_manager *mgr,
- struct fpga_image_info *info,
- const char *buf, size_t count);
-
-Load the FPGA from an image which exists as a contiguous buffer in
-memory. Allocating contiguous kernel memory for the buffer should be avoided,
-users are encouraged to use the _sg interface instead of this.
-
- int fpga_mgr_buf_load_sg(struct fpga_manager *mgr,
- struct fpga_image_info *info,
- struct sg_table *sgt);
+To program the FPGA:
+--------------------

-Load the FPGA from an image from non-contiguous in memory. Callers can
-construct a sg_table using alloc_page backed memory.
+ int fpga_mgr_load(struct fpga_manager *mgr,
+ struct fpga_image_info *info);

- int fpga_mgr_firmware_load(struct fpga_manager *mgr,
- struct fpga_image_info *info,
- const char *image_name);
-
-Load the FPGA from an image which exists as a file. The image file must be on
-the firmware search path (see the firmware class documentation). If successful,
+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.

-A FPGA design contained in a FPGA image file will likely have particulars that
-affect how the image is programmed to the FPGA. These are contained in struct
-fpga_image_info. Currently the only such particular is a single flag bit
-indicating whether the image is for full or partial reconfiguration.
+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);
-
-Given a DT node or device, get an exclusive reference to a FPGA manager.
-
void fpga_mgr_put(struct fpga_manager *mgr);

-Release the reference.
+Given a DT node or device, get an exclusive reference to a FPGA manager.
+fpga_mgr_put releases the reference.


To register or unregister the low level FPGA-specific driver:
-------------------------------------------------------------

int fpga_mgr_register(struct device *dev, const char *name,
- const struct fpga_manager_ops *mops,
- void *priv);
+ const struct fpga_manager_ops *mops,
+ void *priv);

void fpga_mgr_unregister(struct device *dev);

@@ -78,59 +70,50 @@ How to write an image buffer to a supported FPGA
/* Include to get the API */
#include <linux/fpga/fpga-mgr.h>

-/* device node that specifies the FPGA manager to use */
-struct device_node *mgr_node = ...
-
-/* FPGA image is in this buffer. count is size of the buffer. */
-char *buf = ...
-int count = ...
+struct fpga_manager *mgr;
+struct fpga_image_info *info;
+int ret;

/* struct with information about the FPGA image to program. */
-struct fpga_image_info info;
+info = fpga_image_info_alloc(dev);

/* flags indicates whether to do full or partial reconfiguration */
-info.flags = 0;
-
-int ret;
+info->flags = FPGA_MGR_PARTIAL_RECONFIG;

-/* Get exclusive control of FPGA manager */
-struct fpga_manager *mgr = of_fpga_mgr_get(mgr_node);
+/*
+ * 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) {

-/* Load the buffer to the FPGA */
-ret = fpga_mgr_buf_load(mgr, &info, buf, count);
-
-/* Release the FPGA manager */
-fpga_mgr_put(mgr);
+ info->sgt = [your scatter gather table]

+} else if (image is in a buffer) {

-How to write an image file to a supported FPGA
-==============================================
-/* Include to get the API */
-#include <linux/fpga/fpga-mgr.h>
+ info->buf = [your image buffer]
+ info->count = [image buffer size]

-/* device node that specifies the FPGA manager to use */
-struct device_node *mgr_node = ...
+} else if (image is in a firmware file) {

-/* FPGA image is in this file which is in the firmware search path */
-const char *path = "fpga-image-9.rbf"
+ info->firmware_name = devm_kstrdup(dev, firmware_name, GFP_KERNEL);

-/* struct with information about the FPGA image to program. */
-struct fpga_image_info info;
-
-/* flags indicates whether to do full or partial reconfiguration */
-info.flags = 0;
-
-int ret;
+}

-/* Get exclusive control of FPGA manager */
-struct fpga_manager *mgr = of_fpga_mgr_get(mgr_node);
+/*
+ * Get a reference to FPGA manager. This example uses the device node of the
+ * manager. You could use fpga_mgr_get() instead if you have the device instead
+ * of the device node.
+ */
+mgr = of_fpga_mgr_get(mgr_node);

-/* Get the firmware image (path) and load it to the FPGA */
-ret = fpga_mgr_firmware_load(mgr, &info, path);
+/* Load the buffer to the FPGA */
+ret = fpga_mgr_buf_load(mgr, &info, buf, count);

/* Release the FPGA manager */
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
================================
diff --git a/Documentation/fpga/fpga-region.txt b/Documentation/fpga/fpga-region.txt
new file mode 100644
index 0000000..139a02b
--- /dev/null
+++ b/Documentation/fpga/fpga-region.txt
@@ -0,0 +1,95 @@
+FPGA Regions
+
+Alan Tull 2017
+
+CONTENTS
+ - Introduction
+ - The FPGA region API
+ - Usage example
+
+Introduction
+============
+
+This document is meant to be an brief overview of the FPGA region API usage. A
+more conceptual look at regions can be found in [1].
+
+For the purposes of this API document, let's just say that a region associates
+an FPGA Manager and a bridge (or bridges) with a reprogrammable region of an
+FPGA or the whole FPGA. The API provides a way to register a region and to
+program a region.
+
+Currently the only layer above fpga-region.c in the kernel is the Device Tree
+support (of-fpga-region.c) described in [1]. The DT support layer uses regions
+to program the FPGA and then DT to handle enumeration. The common region code
+is intended to be used by other schemes that have other ways of accomplishing
+enumeration after programming.
+
+An fpga-region can be set up to know the following things:
+* which FPGA manager to use to do the programming
+* which bridges to disable before programming and enable afterwards.
+
+Additional info needed to program the FPGA image is passed in the struct
+fpga_image_info [2] including:
+* pointers to the image as either a scatter-gather buffer, a contiguous
+ buffer, or the name of firmware file
+* flags indicating specifics such as whether the image if for partial
+ reconfiguration.
+
+===================
+The FPGA region API
+===================
+
+To register or unregister a region:
+-----------------------------------
+
+ int fpga_region_register(struct device *dev,
+ struct fpga_region *region);
+ int fpga_region_unregister(struct fpga_region *region);
+
+An example of usage can be seen in the probe function of [3]
+
+To program an FPGA:
+-------------------
+ int fpga_region_program_fpga(struct fpga_region *region);
+
+This function operates on info passed in the fpga_image_info
+(region->info).
+
+This function will attempt to:
+ * lock the region's mutex
+ * lock the region's FPGA manager
+ * build a list of FPGA bridges if a method has been specified to do so
+ * disable the bridges
+ * program the FPGA
+ * re-enable the bridges
+ * release the locks
+
+=============
+Usage example
+=============
+
+First, allocate the info struct:
+
+ info = fpga_image_info_alloc(dev);
+ if (!info)
+ return -ENOMEM;
+
+Set flags as needed, i.e.
+
+ info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
+
+Point to your FPGA image, such as:
+
+ info->sgt = &sgt;
+
+Add info to region and do the programming:
+
+ region->info = info;
+ ret = fpga_region_program_fpga(region);
+
+Then enumerate whatever hardware has appeared in the FPGA.
+
+--
+[1] ../devicetree/bindings/fpga/fpga-region.txt
+[2] ./fpga-mgr.txt
+[3] ../../drivers/fpga/of-fpga-region.c
diff --git a/Documentation/fpga/overview.txt b/Documentation/fpga/overview.txt
new file mode 100644
index 0000000..0f1236e
--- /dev/null
+++ b/Documentation/fpga/overview.txt
@@ -0,0 +1,23 @@
+Linux kernel FPGA support
+
+Alan Tull 2017
+
+The main point of this project has been to separate the out the upper layers
+that know when to reprogram a FPGA from the lower layers that know how to
+reprogram a specific FPGA device. The intention is to make this manufacturer
+agnostic, understanding that of course the FPGA images are very device specific
+themselves.
+
+The framework in the kernel includes:
+* low level FPGA manager drivers that know how to program a specific device
+* the fpga-mgr framework they are registered with
+* low level FPGA bridge drivers for hard/soft bridges which are intended to
+ be disable during FPGA programming
+* the fpga-bridge framework they are registered with
+* the fpga-region framework which associates and controls managers and bridges
+ as reconfigurable regions
+* the of-fpga-region support for reprogramming FPGAs when device tree overlays
+ are applied.
+
+I would encourage you the user to add code that creates FPGA regions rather
+that trying to control managers and bridges separately.
diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
index 188ffef..a8dd549 100644
--- a/drivers/fpga/fpga-mgr.c
+++ b/drivers/fpga/fpga-mgr.c
@@ -2,6 +2,7 @@
* FPGA Manager Core
*
* Copyright (C) 2013-2015 Altera Corporation
+ * Copyright (C) 2017 Intel Corporation
*
* With code from the mailing list:
* Copyright (C) 2013 Xilinx, Inc.
@@ -31,6 +32,40 @@
static DEFINE_IDA(fpga_mgr_ida);
static struct class *fpga_mgr_class;

+struct fpga_image_info *fpga_image_info_alloc(struct device *dev)
+{
+ struct fpga_image_info *info;
+
+ get_device(dev);
+
+ info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+ if (!info) {
+ put_device(dev);
+ return NULL;
+ }
+
+ info->dev = dev;
+
+ return info;
+}
+EXPORT_SYMBOL_GPL(fpga_image_info_alloc);
+
+void fpga_image_info_free(struct fpga_image_info *info)
+{
+ struct device *dev;
+
+ if (!info)
+ return;
+
+ dev = info->dev;
+ if (info->firmware_name)
+ devm_kfree(dev, info->firmware_name);
+
+ devm_kfree(dev, info);
+ put_device(dev);
+}
+EXPORT_SYMBOL_GPL(fpga_image_info_free);
+
/*
* Call the low level driver's write_init function. This will do the
* device-specific things to get the FPGA into the state where it is ready to
@@ -137,8 +172,9 @@ static int fpga_mgr_write_complete(struct fpga_manager *mgr,
*
* Return: 0 on success, negative error code otherwise.
*/
-int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info,
- struct sg_table *sgt)
+static int fpga_mgr_buf_load_sg(struct fpga_manager *mgr,
+ struct fpga_image_info *info,
+ struct sg_table *sgt)
{
int ret;

@@ -170,7 +206,6 @@ int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info,

return fpga_mgr_write_complete(mgr, info);
}
-EXPORT_SYMBOL_GPL(fpga_mgr_buf_load_sg);

static int fpga_mgr_buf_load_mapped(struct fpga_manager *mgr,
struct fpga_image_info *info,
@@ -210,8 +245,9 @@ static int fpga_mgr_buf_load_mapped(struct fpga_manager *mgr,
*
* Return: 0 on success, negative error code otherwise.
*/
-int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info,
- const char *buf, size_t count)
+static int fpga_mgr_buf_load(struct fpga_manager *mgr,
+ struct fpga_image_info *info,
+ const char *buf, size_t count)
{
struct page **pages;
struct sg_table sgt;
@@ -266,7 +302,6 @@ int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info,

return rc;
}
-EXPORT_SYMBOL_GPL(fpga_mgr_buf_load);

/**
* fpga_mgr_firmware_load - request firmware and load to fpga
@@ -282,9 +317,9 @@ EXPORT_SYMBOL_GPL(fpga_mgr_buf_load);
*
* Return: 0 on success, negative error code otherwise.
*/
-int fpga_mgr_firmware_load(struct fpga_manager *mgr,
- struct fpga_image_info *info,
- const char *image_name)
+static int fpga_mgr_firmware_load(struct fpga_manager *mgr,
+ struct fpga_image_info *info,
+ const char *image_name)
{
struct device *dev = &mgr->dev;
const struct firmware *fw;
@@ -307,7 +342,18 @@ int fpga_mgr_firmware_load(struct fpga_manager *mgr,

return ret;
}
-EXPORT_SYMBOL_GPL(fpga_mgr_firmware_load);
+
+int fpga_mgr_load(struct fpga_manager *mgr, struct fpga_image_info *info)
+{
+ if (info->sgt)
+ return fpga_mgr_buf_load_sg(mgr, info, info->sgt);
+ if (info->buf && info->count)
+ return fpga_mgr_buf_load(mgr, info, info->buf, info->count);
+ if (info->firmware_name)
+ return fpga_mgr_firmware_load(mgr, info, info->firmware_name);
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(fpga_mgr_load);

static const char * const state_str[] = {
[FPGA_MGR_STATE_UNKNOWN] = "unknown",
@@ -578,7 +624,7 @@ static void __exit fpga_mgr_class_exit(void)
ida_destroy(&fpga_mgr_ida);
}

-MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
+MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
MODULE_DESCRIPTION("FPGA manager framework");
MODULE_LICENSE("GPL v2");

diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
index 91755562..120c496 100644
--- a/drivers/fpga/fpga-region.c
+++ b/drivers/fpga/fpga-region.c
@@ -226,14 +226,11 @@ static int fpga_region_get_bridges(struct fpga_region *region,
/**
* fpga_region_program_fpga - program FPGA
* @region: FPGA region
- * @firmware_name: name of FPGA image firmware file
* @overlay: device node of the overlay
- * Program an FPGA using information in the device tree.
- * Function assumes that there is a firmware-name property.
+ * Program an FPGA using information in the region's fpga image info.
* Return 0 for success or negative error code.
*/
static int fpga_region_program_fpga(struct fpga_region *region,
- const char *firmware_name,
struct device_node *overlay)
{
struct fpga_manager *mgr;
@@ -264,7 +261,7 @@ static int fpga_region_program_fpga(struct fpga_region *region,
goto err_put_br;
}

- ret = fpga_mgr_firmware_load(mgr, region->info, firmware_name);
+ ret = fpga_mgr_load(mgr, region->info);
if (ret) {
pr_err("failed to load fpga image\n");
goto err_put_br;
@@ -357,16 +354,15 @@ static int child_regions_with_firmware(struct device_node *overlay)
static int fpga_region_notify_pre_apply(struct fpga_region *region,
struct of_overlay_notify_data *nd)
{
- const char *firmware_name = NULL;
+ struct device *dev = &region->dev;
struct fpga_image_info *info;
+ const char *firmware_name;
int ret;

- info = devm_kzalloc(&region->dev, sizeof(*info), GFP_KERNEL);
+ info = fpga_image_info_alloc(dev);
if (!info)
return -ENOMEM;

- region->info = info;
-
/* Reject overlay if child FPGA Regions have firmware-name property */
ret = child_regions_with_firmware(nd->overlay);
if (ret)
@@ -382,7 +378,13 @@ static int fpga_region_notify_pre_apply(struct fpga_region *region,
if (of_property_read_bool(nd->overlay, "encrypted-fpga-config"))
info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;

- of_property_read_string(nd->overlay, "firmware-name", &firmware_name);
+ if (!of_property_read_string(nd->overlay, "firmware-name",
+ &firmware_name)) {
+ info->firmware_name = devm_kstrdup(dev, firmware_name,
+ GFP_KERNEL);
+ if (!info->firmware_name)
+ return -ENOMEM;
+ }

of_property_read_u32(nd->overlay, "region-unfreeze-timeout-us",
&info->enable_timeout_us);
@@ -394,22 +396,33 @@ static int fpga_region_notify_pre_apply(struct fpga_region *region,
&info->config_complete_timeout_us);

/* If FPGA was externally programmed, don't specify firmware */
- if ((info->flags & FPGA_MGR_EXTERNAL_CONFIG) && firmware_name) {
+ if ((info->flags & FPGA_MGR_EXTERNAL_CONFIG) && info->firmware_name) {
pr_err("error: specified firmware and external-fpga-config");
+ fpga_image_info_free(info);
return -EINVAL;
}

/* FPGA is already configured externally. We're done. */
- if (info->flags & FPGA_MGR_EXTERNAL_CONFIG)
+ if (info->flags & FPGA_MGR_EXTERNAL_CONFIG) {
+ fpga_image_info_free(info);
return 0;
+ }

/* If we got this far, we should be programming the FPGA */
- if (!firmware_name) {
+ if (!info->firmware_name) {
pr_err("should specify firmware-name or external-fpga-config\n");
+ fpga_image_info_free(info);
return -EINVAL;
}

- return fpga_region_program_fpga(region, firmware_name, nd->overlay);
+ region->info = info;
+ ret = fpga_region_program_fpga(region, nd->overlay);
+ if (ret) {
+ fpga_image_info_free(info);
+ region->info = NULL;
+ }
+
+ return ret;
}

/**
@@ -426,7 +439,7 @@ static void fpga_region_notify_post_remove(struct fpga_region *region,
{
fpga_bridges_disable(&region->bridge_list);
fpga_bridges_put(&region->bridge_list);
- devm_kfree(&region->dev, region->info);
+ fpga_image_info_free(region->info);
region->info = NULL;
}

diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
index bfa14bc..be371e6 100644
--- a/include/linux/fpga/fpga-mgr.h
+++ b/include/linux/fpga/fpga-mgr.h
@@ -1,7 +1,8 @@
/*
* FPGA Framework
*
- * Copyright (C) 2013-2015 Altera Corporation
+ * Copyright (C) 2013-2016 Altera Corporation
+ * Copyright (C) 2017 Intel Corporation
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
@@ -83,12 +84,22 @@ enum fpga_mgr_states {
* @disable_timeout_us: maximum time to disable traffic through bridge (uSec)
* @config_complete_timeout_us: maximum time for FPGA to switch to operating
* status in the write_complete op.
+ * @firmware_name: name of FPGA image firmware file
+ * @sgt: scatter/gather table containing FPGA image
+ * @buf: contiguous buffer containing FPGA image
+ * @count: size of buf
+ * @dev: device that owns this
*/
struct fpga_image_info {
u32 flags;
u32 enable_timeout_us;
u32 disable_timeout_us;
u32 config_complete_timeout_us;
+ char *firmware_name;
+ struct sg_table *sgt;
+ const char *buf;
+ size_t count;
+ struct device *dev;
};

/**
@@ -138,14 +149,11 @@ struct fpga_manager {

#define to_fpga_manager(d) container_of(d, struct fpga_manager, dev)

-int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info,
- const char *buf, size_t count);
-int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info,
- struct sg_table *sgt);
+struct fpga_image_info *fpga_image_info_alloc(struct device *dev);

-int fpga_mgr_firmware_load(struct fpga_manager *mgr,
- struct fpga_image_info *info,
- const char *image_name);
+void fpga_image_info_free(struct fpga_image_info *info);
+
+int fpga_mgr_load(struct fpga_manager *mgr, struct fpga_image_info *info);

struct fpga_manager *of_fpga_mgr_get(struct device_node *node);

--
2.7.4
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