Re: [RFC PATCH] fpga: Introduce new fpga subsystem

[Jason Cooper]

+ Jason Gunthorpe

On Wed, Sep 18, 2013 at 05:56:39PM +0200, Michal Simek wrote:
> This new subsystem should unify all fpga drivers which
> do the same things. Load configuration data to fpga
> or another programmable logic through common interface.
> It doesn't matter if it is MMIO device, gpio bitbanging,
> etc. connection. The point is to have the same
> inteface for these drivers.
> 
> Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
> 
> ---
>  MAINTAINERS             |   7 +
>  drivers/Kconfig         |   2 +
>  drivers/Makefile        |   1 +
>  drivers/fpga/Kconfig    |  18 ++
>  drivers/fpga/Makefile   |   5 +
>  drivers/fpga/fpga-mgr.c | 433 ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/fpga.h    | 105 ++++++++++++
>  7 files changed, 571 insertions(+)
>  create mode 100644 drivers/fpga/Kconfig
>  create mode 100644 drivers/fpga/Makefile
>  create mode 100644 drivers/fpga/fpga-mgr.c
>  create mode 100644 include/linux/fpga.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e61c2e8..5c7597b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -3427,6 +3427,13 @@ F:	include/linux/fmc*.h
>  F:	include/linux/ipmi-fru.h
>  K:	fmc_d.*register
> 
> +FPGA SUBSYSTEM
> +M:	Michal Simek <michal.simek@xxxxxxxxxx>
> +T:	git git://git.xilinx.com/linux-xlnx.git
> +S:	Supported
> +F:	drivers/fpga/
> +F:	include/linux/fpga.h
> +
>  FPU EMULATOR
>  M:	Bill Metzenthen <billm@xxxxxxxxxxxxx>
>  W:	http://floatingpoint.sourceforge.net/emulator/index.html
> diff --git a/drivers/Kconfig b/drivers/Kconfig
> index aa43b91..17f3caa 100644
> --- a/drivers/Kconfig
> +++ b/drivers/Kconfig
> @@ -166,4 +166,6 @@ source "drivers/reset/Kconfig"
> 
>  source "drivers/fmc/Kconfig"
> 
> +source "drivers/fpga/Kconfig"
> +
>  endmenu
> diff --git a/drivers/Makefile b/drivers/Makefile
> index ab93de8..2b5e73b 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -152,3 +152,4 @@ obj-$(CONFIG_VME_BUS)		+= vme/
>  obj-$(CONFIG_IPACK_BUS)		+= ipack/
>  obj-$(CONFIG_NTB)		+= ntb/
>  obj-$(CONFIG_FMC)		+= fmc/
> +obj-$(CONFIG_FPGA)		+= fpga/
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> new file mode 100644
> index 0000000..5357645
> --- /dev/null
> +++ b/drivers/fpga/Kconfig
> @@ -0,0 +1,18 @@
> +#
> +# FPGA framework configuration
> +#
> +
> +menu "FPGA devices"
> +
> +config FPGA
> +	tristate "FPGA Framework"
> +	help
> +	  Say Y here if you want support for configuring FPGAs from the
> +	  kernel.  The FPGA framework adds a FPGA manager class and FPGA
> +	  manager drivers.
> +
> +if FPGA
> +
> +endif
> +
> +endmenu
> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> new file mode 100644
> index 0000000..3c7f29b
> --- /dev/null
> +++ b/drivers/fpga/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for the fpga framework and fpga manager drivers.
> +#
> +
> +obj-$(CONFIG_FPGA)			+= fpga-mgr.o
> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
> new file mode 100644
> index 0000000..7312efd
> --- /dev/null
> +++ b/drivers/fpga/fpga-mgr.c
> @@ -0,0 +1,433 @@
> +/*
> + * FPGA Framework
> + *
> + * Copyright (C) 2013 Xilinx, Inc.
> + *
> + * based on origin code from
> + * Copyright (C) 2013 Altera Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/firmware.h>
> +#include <linux/fpga.h>
> +#include <linux/fs.h>
> +#include <linux/idr.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +
> +static struct idr fpga_mgr_idr;
> +static spinlock_t fpga_mgr_idr_lock;
> +static struct class *fpga_mgr_class;
> +
> +/**
> + * fpga_mgr_name_show - Show fpga manager name
> + * @dev: Pointer to the device structure
> + * @attr: Pointer to the device attribute structure
> + * @buf: Pointer to the buffer location
> + *
> + * Returns the number of bytes copied to @buf, a negative error number otherwise
> + */
> +static ssize_t fpga_mgr_name_show(struct device *dev,
> +				  struct device_attribute *attr, char *buf)
> +{
> +	struct fpga_manager *mgr = dev_get_drvdata(dev);
> +
> +	if (!mgr)
> +		return -ENODEV;
> +
> +	return snprintf(buf, sizeof(mgr->name), "%s\n", mgr->name);
> +}
> +
> +/**
> + * fpga_mgr_status_show - Show fpga manager status
> + * @dev: Pointer to the device structure
> + * @attr: Pointer to the device attribute structure
> + * @buf: Pointer to the buffer location
> + *
> + * Returns the number of bytes copied to @buf, a negative error number otherwise
> + */
> +static ssize_t fpga_mgr_status_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	struct fpga_manager *mgr = dev_get_drvdata(dev);
> +
> +	if (!mgr || !mgr->mops || !mgr->mops->status)
> +		return -ENODEV;
> +
> +	return mgr->mops->status(mgr, buf);
> +}
> +
> +/**
> + * fpga_mgr_read - Read data from fpga
> + * @mgr: Pointer to the fpga manager structure
> + * @buf: Pointer to the buffer location
> + * @count: Pointer to the number of copied bytes
> + *
> + * Function reads fpga bitstream and copy them to output buffer.
> + *
> + * Returns the number of bytes copied to @buf, a negative error number otherwise
> + */
> +static int fpga_mgr_read(struct fpga_manager *mgr, char *buf, ssize_t *count)
> +{
> +	int ret;
> +
> +	if (test_and_set_bit_lock(FPGA_MGR_DEV_BUSY, &mgr->flags))
> +		return -EBUSY;
> +
> +	if (!mgr->mops || !mgr->mops->read) {
> +		dev_err(mgr->dev,
> +			"Controller doesn't support read operations!\n");
> +		return -EPERM;
> +	}
> +
> +	if (mgr->mops->read_init) {
> +		ret = mgr->mops->read_init(mgr);
> +		if (ret) {
> +			dev_err(mgr->dev, "Failed in read-init!\n");
> +			return ret;
> +		}
> +	}
> +
> +	if (mgr->mops->read) {
> +		ret = mgr->mops->read(mgr, buf, count);
> +		if (ret) {
> +			dev_err(mgr->dev, "Failed to read firmware!\n");
> +			return ret;
> +		}
> +	}
> +
> +	if (mgr->mops->read_complete) {
> +		ret = mgr->mops->read_complete(mgr);
> +		if (ret) {
> +			dev_err(mgr->dev, "Failed in read-complete!\n");
> +			return ret;
> +		}
> +	}
> +
> +	clear_bit_unlock(FPGA_MGR_DEV_BUSY, &mgr->flags);
> +
> +	return 0;
> +}
> +
> +/**
> + * fpga_mgr_attr_read - Read data from fpga
> + * @dev: Pointer to the device structure
> + * @attr: Pointer to the device attribute structure
> + * @buf: Pointer to the buffer location
> + *
> + * Function reads fpga bitstream and copy them to output buffer
> + *
> + * Returns the number of bytes copied to @buf, a negative error number otherwise
> + */
> +static ssize_t fpga_mgr_attr_read(struct device *dev,
> +				   struct device_attribute *attr, char *buf)
> +{
> +	struct fpga_manager *mgr = dev_get_drvdata(dev);
> +	ssize_t count;
> +	int ret;
> +
> +	if (mgr && mgr->fpga_read)
> +		ret = mgr->fpga_read(mgr, buf, &count);
> +
> +	return ret == 0 ? count : -EPERM;
> +}
> +
> +/**
> + * fpga_mgr_write - Write data to fpga
> + * @mgr: Pointer to the fpga manager structure
> + * @fw_name: Pointer to the buffer location with bistream firmware filename
> + *
> + * @buf contains firmware filename which is loading through firmware
> + * interface and passed to the fpga driver.
> + *
> + * Returns string lenght added to @fw_name, a negative error number otherwise
> + */
> +static int fpga_mgr_write(struct fpga_manager *mgr, const char *fw_name)
> +{
> +	int ret = 0;
> +	const struct firmware *fw;
> +
> +	if (!fw_name || !strlen(fw_name)) {
> +		dev_err(mgr->dev, "Firmware name is not specified!\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!mgr->mops || !mgr->mops->write) {
> +		dev_err(mgr->dev,
> +			"Controller doesn't support write operations!\n");
> +		return -EPERM;
> +	}
> +
> +	ret = request_firmware(&fw, fw_name, mgr->dev);
> +	if (ret) {
> +		dev_err(mgr->dev, "Failed to load firmware %s!\n", fw_name);
> +		return ret;
> +	}
> +
> +	if (test_and_set_bit_lock(FPGA_MGR_DEV_BUSY, &mgr->flags))
> +		return -EBUSY;
> +
> +	/* Init controller */
> +	if (mgr->mops->write_init) {
> +		ret = mgr->mops->write_init(mgr);
> +		if (ret) {
> +			dev_err(mgr->dev, "Failed to write_init!\n");
> +			return ret;
> +		}
> +	}
> +
> +	/* Do write */
> +	ret = mgr->mops->write(mgr, (void *)fw->data, fw->size);
> +	if (ret) {
> +		dev_err(mgr->dev, "Failed to write data!\n");
> +		return ret;
> +	}
> +
> +	if (mgr->mops->write_complete) {
> +		ret = mgr->mops->write_complete(mgr);
> +		if (ret) {
> +			dev_err(mgr->dev, "Failed to write_init!\n");
> +			return ret;
> +		}
> +	}
> +
> +	release_firmware(fw);
> +
> +	clear_bit_unlock(FPGA_MGR_DEV_BUSY, &mgr->flags);
> +
> +	return 0;
> +}
> +
> +/**
> + * fpga_mgr_attr_write - Write data to fpga
> + * @dev: Pointer to the device structure
> + * @attr: Pointer to the device attribute structure
> + * @buf: Pointer to the buffer location with bistream firmware filename
> + * @count: Number of characters in @buf
> + *
> + * @buf contains firmware filename which is loading through firmware
> + * interface and passed to the fpga driver.
> + *
> + * Returns string lenght added to @buf, a negative error number otherwise
> + */
> +static ssize_t fpga_mgr_attr_write(struct device *dev,
> +				   struct device_attribute *attr,
> +				   const char *buf, size_t count)
> +{
> +	struct fpga_manager *mgr = dev_get_drvdata(dev);
> +	int ret;
> +
> +	if (mgr && mgr->fpga_write)
> +		ret = mgr->fpga_write(mgr, buf);
> +
> +	return ret == 0 ? strlen(buf) : -EPERM;
> +}
> +
> +static struct device_attribute fpga_mgr_attrs[] = {
> +	__ATTR(name, S_IRUGO, fpga_mgr_name_show, NULL),
> +	__ATTR(status, S_IRUGO, fpga_mgr_status_show, NULL),
> +	__ATTR(fpga, S_IRUGO | S_IWUGO, fpga_mgr_attr_read,
> +	       fpga_mgr_attr_write),
> +	__ATTR_NULL
> +};
> +
> +/**
> + * fpga_mgr_register: Register new fpga manager
> + * @pdev: Pointer to the platform device of fpga manager
> + * @mops: Pointer to the fpga manager operations
> + * @name: Name of fpga manager
> + * @priv: Pointer to the fpga manager private data
> + *
> + * Function register fpga manager with uniq ID and create device
> + * for accessing the device.
> + *
> + * Returns 0 on success, a negative error number otherwise
> + */
> +int fpga_mgr_register(struct platform_device *pdev,
> +		      struct fpga_manager_ops *mops, char *name, void *priv)
> +{
> +	struct fpga_manager *mgr;
> +	int ret;
> +
> +	if (!mops) {
> +		dev_err(&pdev->dev, "Register failed: NO fpga_manager_ops!\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!name || !strlen(name)) {
> +		dev_err(&pdev->dev, "Register failed: NO name specific!\n");
> +		return -EINVAL;
> +	}
> +
> +	mgr = devm_kzalloc(&pdev->dev, sizeof(*mgr), GFP_KERNEL);
> +	if (!mgr) {
> +		dev_err(&pdev->dev, "Failed to alloc mgr struct!\n");
> +		return -ENOMEM;
> +	}
> +
> +	/* Get unique number */
> +	idr_preload(GFP_KERNEL);
> +	spin_lock(&fpga_mgr_idr_lock);
> +	ret = idr_alloc(&fpga_mgr_idr, mgr, 0, 0, GFP_NOWAIT);
> +	if (ret >= 0)
> +		mgr->nr = ret;
> +	spin_unlock(&fpga_mgr_idr_lock);
> +	idr_preload_end();
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Setup all necessary information */
> +	mgr->dev = &pdev->dev;
> +	mgr->mops = mops;
> +	mgr->priv = priv;
> +	mgr->fpga_read = fpga_mgr_read;
> +	mgr->fpga_write = fpga_mgr_write;
> +	strlcpy(mgr->name, name, sizeof(mgr->name));
> +
> +	mgr->dev = device_create(fpga_mgr_class, get_device(&pdev->dev),
> +				 MKDEV(0, 0), mgr, "fpga%d", mgr->nr);
> +	if (IS_ERR(mgr->dev)) {
> +		spin_lock(&fpga_mgr_idr_lock);
> +		idr_remove(&fpga_mgr_idr, mgr->nr);
> +		spin_unlock(&fpga_mgr_idr_lock);
> +
> +		dev_err(&pdev->dev, "Failed to create device!\n");
> +		return PTR_ERR(mgr->dev);
> +	}
> +
> +	platform_set_drvdata(pdev, mgr);
> +
> +	dev_info(&pdev->dev, "Fpga manager [%s] registered as minor %d\n",
> +		 mgr->name, mgr->nr);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(fpga_mgr_register);
> +
> +/**
> + * fpga_mgr_unregister: Remove fpga manager
> + * @pdev: Pointer to the platform device of fpga manager
> + *
> + * Function unregister fpga manager and release all temporary structures
> + *
> + * Returns 0 for all cases
> + */
> +int fpga_mgr_unregister(struct platform_device *pdev)
> +{
> +	struct fpga_manager *mgr = platform_get_drvdata(pdev);
> +
> +	if (mgr && mgr->mops && mgr->mops->fpga_remove)
> +		mgr->mops->fpga_remove(mgr);
> +
> +	device_unregister(mgr->dev);
> +
> +	spin_lock(&fpga_mgr_idr_lock);
> +	idr_remove(&fpga_mgr_idr, mgr->nr);
> +	spin_unlock(&fpga_mgr_idr_lock);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(fpga_mgr_unregister);
> +
> +/**
> + * of_dev_node_match: Compare associated device tree node with
> + * @dev: Pointer to the device
> + * @data: Pointer to the device tree node
> + *
> + * Returns 1 on success
> + */
> +static int of_dev_node_match(struct device *dev, void *data)
> +{
> +	return dev->of_node == data;
> +}
> +
> +/**
> + * of_find_fpga_mgr_by_node - Find the fpga_manager associated with a node
> + * @node: Pointer to the device tree node
> + *
> + * Returns fpga_manager pointer, or NULL if not found
> + */
> +struct fpga_manager *of_find_fpga_mgr_by_node(struct device_node *node)
> +{
> +	struct device *dev;
> +	struct fpga_manager *mgr;
> +
> +	dev = bus_find_device(&platform_bus_type, NULL, node,
> +			      of_dev_node_match);
> +	if (!dev)
> +		return NULL;
> +
> +	mgr = dev_get_drvdata(dev);
> +
> +	return mgr ? mgr : NULL;
> +}
> +EXPORT_SYMBOL(of_find_fpga_mgr_by_node);
> +
> +/**
> + * of_find_fpga_mgr_by_phandle - Find the fpga_manager associated with a node
> + * @node: Pointer to the device tree node
> + * @phandle_name: Pointer to the phandle_name
> + *
> + * Returns fpga_manager pointer, or NULL if not found
> + */
> +struct fpga_manager *of_find_fpga_mgr_by_phandle(struct device_node *node,
> +						 const char *phandle_name)
> +{
> +	struct device_node *fpga_node;
> +
> +	fpga_node = of_parse_phandle(node, phandle_name, 0);
> +	if (!fpga_node) {
> +		pr_err("Phandle not found\n");
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	return of_find_fpga_mgr_by_node(fpga_node);
> +}
> +EXPORT_SYMBOL(of_find_fpga_mgr_by_phandle);
> +
> +/**
> + * fpga_mgr_init: Create fpga class
> + */
> +static int __init fpga_mgr_init(void)
> +{
> +	pr_info("FPGA Manager framework driver\n");
> +
> +	fpga_mgr_class = class_create(THIS_MODULE, "fpga");
> +	if (IS_ERR(fpga_mgr_class))
> +		return PTR_ERR(fpga_mgr_class);
> +
> +	idr_init(&fpga_mgr_idr);
> +	spin_lock_init(&fpga_mgr_idr_lock);
> +
> +	fpga_mgr_class->dev_attrs = fpga_mgr_attrs;
> +
> +	return 0;
> +}
> +subsys_initcall(fpga_mgr_init);
> +
> +/**
> + * fpga_mgr_exit: Destroy fpga class
> + */
> +static void __exit fpga_mgr_exit(void)
> +{
> +	class_destroy(fpga_mgr_class);
> +	idr_destroy(&fpga_mgr_idr);
> +}
> +module_exit(fpga_mgr_exit);
> +
> +MODULE_AUTHOR("Xilinx, Inc.");
> +MODULE_DESCRIPTION("FPGA Manager framework driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/fpga.h b/include/linux/fpga.h
> new file mode 100644
> index 0000000..970c42e
> --- /dev/null
> +++ b/include/linux/fpga.h
> @@ -0,0 +1,105 @@
> +/*
> + * FPGA Framework
> + *
> + * Copyright (C) 2013 Xilinx, Inc.
> + *
> + * based on origin code from
> + * Copyright (C) 2013 Altera Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/of.h>
> +
> +#ifndef _LINUX_FPGA_H
> +#define _LINUX_FPGA_H
> +
> +struct fpga_manager;
> +
> +/**
> + * struct fpga_manager_ops - FPGA manager driver operations
> + *
> + * @status: The function to call for getting fpga manager status.
> + *	    Returns number of characters written to the @buf and
> + *	    a string of the FPGA's status in @bug.
> + * @read_init: The function to call for preparing the FPGA for reading
> + *	       its confuration data. Returns 0 on success, a negative error
> + *	       number otherwise.
> + * @read: Read configuration data from the FPGA. Return 0 on success,
> + *	  a negative error number otherwise.
> + * @read_complete: Return FPGA to a default state after reading is done.
> + *		   Return 0 on success, a negative error number otherwise.
> + * @write_init: Prepare the FPGA to receive configuration data.
> + *		Return 0 on success, a negative error number otherwise.
> + * @write: Write count bytes of configuration data to the FPGA placed in @buf.
> + *	   Return 0 on success, a negative error number otherwise.
> + * @write_complete: Return FPGA to default state after writing is done.
> + *		    Return 0 on success, a negative error number otherwise.
> + * @fpga_remove: Set FPGA into a specific state during driver remove.
> + *
> + * fpga_manager_ops are the low level functions implemented by a specific
> + * fpga manager driver. Leaving any of these out that aren't needed is fine
> + * as they are all tested for NULL before being called.
> + */
> +struct fpga_manager_ops {
> +	int (*status)(struct fpga_manager *mgr, char *buf);
> +	int (*read_init)(struct fpga_manager *mgr);
> +	int (*read)(struct fpga_manager *mgr, char *buf, ssize_t *count);
> +	int (*read_complete)(struct fpga_manager *mgr);
> +	int (*write_init)(struct fpga_manager *mgr);
> +	int (*write)(struct fpga_manager *mgr, char *buf, ssize_t count);
> +	int (*write_complete)(struct fpga_manager *mgr);
> +	void (*fpga_remove)(struct fpga_manager *mgr);
> +};
> +
> +/* flag bits */
> +#define FPGA_MGR_DEV_BUSY 0
> +
> +/**
> + * struct fpga_manager - FPGA manager driver structure
> + *
> + * @name: Name of fpga manager
> + * @dev: Pointer to the device structure
> + * @mops: Pointer to the fpga manager operations
> + * @priv: Pointer to fpga manager private data
> + * @nr: Unique manager number in the system
> + * @flags: For saving temporary
> + * @fpga_read: The function to call for reading configuration data from
> + *	       the FPGA.
> + * @fpga_write: The function to call for writing configuration data to the FPGA.
> + */
> +struct fpga_manager {
> +	char name[48];
> +	struct device *dev;
> +	struct fpga_manager_ops *mops;
> +	void *priv;
> +	unsigned int nr;
> +	unsigned long flags;
> +	int (*fpga_read)(struct fpga_manager *mgr, char *buf,
> +			 ssize_t *count);
> +	int (*fpga_write)(struct fpga_manager *mgr, const char *fw_name);
> +};
> +
> +int fpga_mgr_register(struct platform_device *pdev,
> +		      struct fpga_manager_ops *mops, char *name, void *priv);
> +
> +int fpga_mgr_unregister(struct platform_device *pdev);
> +
> +struct fpga_manager *of_find_fpga_mgr_by_node(struct device_node *node);
> +struct fpga_manager *of_find_fpga_mgr_by_phandle(struct device_node *node,
> +						 const char *phandle_name);
> +
> +#endif /*_LINUX_FPGA_H */
> --
> 1.8.2.3
> 


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