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    Subject[PATCH v2 3/3] fpga manager: bus driver
    Date
    From: Alan Tull <atull@opensource.altera.com>

    Support programming the fpga from device tree overlays.

    This patch adds one exported function to the core
    (fpga-mgr.c): of_fpga_mgr_dev_lookup
    Get pointer to fpga manager struct given a phandle.

    This code is dependent on Pantelis Antoniou's current work
    on Device Tree overlays, a method of dynamically altering
    the kernel's live Device Tree. The rest of the patchset was
    tested with recent for-next, but this 'bus driver' patch was
    tested with Pantelis's and Grant Likely's stuff that is in git
    (his git repo https://github.com/pantoniou/linux-beagle-track-mainline
    v3.17-rc2-115-gbc778b8 == dt-ng/bbb) plus some dtc fixups
    for compiling overlays.

    Here's a simple example. Start with:
    * the altera-gpio driver built in to the kernel but not in the
    device tree.
    * raw fpga image at /lib/firmware/soc_system.rbf
    * Load appropriate device tree overlay in configfs by doing
    $ mkdir /config/device-tree/overlays/1
    $ echo socfpga_overlay.dtbo > /config/device-tree/overlays/1/path
    * This results in the FPGA getting programmed and the altera
    gpio driver getting probed.
    * To remove/clear FPGA image by putting the FPGA in reset,
    remove device tree overlay by doing:
    $ rmdir /config/device-tree/overlays/1

    Device tree overlay looks like this:
    /dts-v1/;
    /plugin/;
    / {
    fragment@0 {
    target-path="/soc";
    __overlay__ {
    #address-cells = <1>;
    #size-cells = <1>;

    bridge@0xff200000 {
    compatible = "fpga-mgr-bus", "simple-bus";
    reg = <0xff200000 0x200000>;
    clocks = <0x2 0x2>;
    clock-names = "h2f_lw_axi_clock", "f2h_sdram0_clock";
    #address-cells = <0x2>;
    #size-cells = <0x1>;
    ranges = <0x1 0x10040 0xff210040 0x20>;

    fpgamgr = <&hps_0_fpgamgr>;
    fpga-firmware = "soc_system.rbf";

    gpio@0x100010040 {
    compatible = "altr,pio-14.0", "altr,pio-1.0";
    reg = <0x1 0x10040 0x20>;
    clocks = <0x2>;
    altr,gpio-bank-width = <0x4>;
    resetvalue = <0x0>;
    #gpio-cells = <0x2>;
    gpio-controller;
    linux,phandle = <0x2d>;
    };
    };
    };
    };
    };

    Signed-off-by: Alan Tull <atull@opensource.altera.com>

    v2: simplify of_fpga_mgr_dev_lookup to return NULL on failure
    move suspend/resume to fpga-mgr.c core
    support 'rmdir' to remove overlay
    ---
    drivers/fpga/Kconfig | 7 +++
    drivers/fpga/Makefile | 1 +
    drivers/fpga/bus.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++
    drivers/fpga/fpga-mgr.c | 23 +++++++++
    include/linux/fpga-mgr.h | 2 +
    5 files changed, 157 insertions(+)
    create mode 100644 drivers/fpga/bus.c

    diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
    index e775b17..2bd6c83 100644
    --- a/drivers/fpga/Kconfig
    +++ b/drivers/fpga/Kconfig
    @@ -18,4 +18,11 @@ config FPGA_MGR_SYSFS
    help
    FPGA Manager SysFS interface.

    +config FPGA_MGR_BUS
    + bool "FPGA Manager Bus"
    + depends on FPGA
    + help
    + FPGA Manager Bus interface. Allows loading FPGA images
    + from Device Tree or from other drivers.
    +
    endmenu
    diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
    index c8a676f..e39911f 100644
    --- a/drivers/fpga/Makefile
    +++ b/drivers/fpga/Makefile
    @@ -6,5 +6,6 @@ fpga-mgr-core-y += fpga-mgr.o

    # Core FPGA Manager Framework
    obj-$(CONFIG_FPGA) += fpga-mgr-core.o
    +obj-$(CONFIG_FPGA_MGR_BUS) += bus.o

    # FPGA Manager Drivers
    diff --git a/drivers/fpga/bus.c b/drivers/fpga/bus.c
    new file mode 100644
    index 0000000..999346e
    --- /dev/null
    +++ b/drivers/fpga/bus.c
    @@ -0,0 +1,124 @@
    +/*
    + * FPGA Manager Bus Driver
    + *
    + * Copyright (C) 2013-2014 Altera 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,
    + * version 2, as published by the Free Software Foundation.
    + *
    + * This program is distributed in the hope 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/completion.h>
    +#include <linux/fs.h>
    +#include <linux/fpga-mgr.h>
    +#include <linux/io.h>
    +#include <linux/irq.h>
    +#include <linux/kernel.h>
    +#include <linux/list.h>
    +#include <linux/mm.h>
    +#include <linux/module.h>
    +#include <linux/of.h>
    +#include <linux/of_address.h>
    +#include <linux/of_device.h>
    +#include <linux/of_platform.h>
    +#include <linux/pm.h>
    +#include <linux/slab.h>
    +#include <linux/string.h>
    +#include <linux/types.h>
    +
    +struct fpga_mgr_bus_priv {
    + struct device *dev;
    + struct device_node *np;
    + struct fpga_manager *mgr;
    + const char *path;
    +};
    +
    +static int fpga_mgr_bus_probe(struct platform_device *pdev)
    +{
    + struct device_node *np = pdev->dev.of_node;
    + struct device *dev = &pdev->dev;
    + struct fpga_mgr_bus_priv *priv;
    + const char *path;
    + struct fpga_manager *mgr;
    + int ret = 0;
    +
    + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
    + if (!priv)
    + return -ENOMEM;
    +
    + /* Find the FPGA Manager to associate with */
    + mgr = of_fpga_mgr_dev_lookup(np, "fpgamgr");
    + if (!mgr) {
    + dev_err(mgr->dev, "%s could not find fpga mgr\n", __func__);
    + return -ENODEV;
    + }
    +
    + /* Find the FPGA image on the firmware path */
    + of_property_read_string(np, "fpga-firmware", &path);
    +
    + ret = fpga_mgr_firmware_write(mgr, path);
    + if (ret != 0) {
    + dev_err(mgr->dev, "%s fpga mgr write failure\n", __func__);
    + return -EIO;
    + }
    +
    + priv->dev = dev;
    + priv->np = np;
    + priv->mgr = mgr;
    + priv->path = path;
    + platform_set_drvdata(pdev, priv);
    +
    + return 0;
    +}
    +
    +/* Called when the Device Tree overlay is removed */
    +static int fpga_mgr_bus_remove(struct platform_device *pdev)
    +{
    + struct fpga_mgr_bus_priv *priv = platform_get_drvdata(pdev);
    + struct fpga_manager *mgr = priv->mgr;
    +
    + return fpga_mgr_reset(mgr);
    +}
    +
    +#ifdef CONFIG_OF
    +static const struct of_device_id fpga_mgr_bus_of_match[] = {
    + { .compatible = "fpga-mgr-bus", },
    + {},
    +};
    +
    +MODULE_DEVICE_TABLE(of, fpga_mgr_bus_of_match);
    +#endif
    +
    +static struct platform_driver fpga_mgr_bus_driver = {
    + .probe = fpga_mgr_bus_probe,
    + .remove = fpga_mgr_bus_remove,
    + .driver = {
    + .name = "fpga_manager_bus",
    + .owner = THIS_MODULE,
    + .of_match_table = of_match_ptr(fpga_mgr_bus_of_match),
    + },
    +};
    +
    +static int __init fpga_mgr_bus_init(void)
    +{
    + return platform_driver_register(&fpga_mgr_bus_driver);
    +}
    +
    +static void __exit fpga_mgr_bus_exit(void)
    +{
    + platform_driver_unregister(&fpga_mgr_bus_driver);
    +}
    +
    +module_init(fpga_mgr_bus_init);
    +module_exit(fpga_mgr_bus_exit);
    +
    +MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
    +MODULE_DESCRIPTION("Altera FPGA Manager Bus");
    +MODULE_LICENSE("GPL v2");
    diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
    index 0c7236a..fed13a6 100644
    --- a/drivers/fpga/fpga-mgr.c
    +++ b/drivers/fpga/fpga-mgr.c
    @@ -350,6 +350,29 @@ const struct attribute_group *fpga_mgr_groups[] = {
    #define fpga_mgr_groups NULL
    #endif /* CONFIG_FPGA_MGR_SYSFS */

    +/* Find the fpga manager that is pointed to by a phandle */
    +struct fpga_manager *of_fpga_mgr_dev_lookup(struct device_node *node,
    + const char *mgr_property)
    +{
    + struct fpga_manager *mgr;
    + struct device_node *mgr_node;
    +
    + mgr_node = of_parse_phandle(node, mgr_property, 0);
    + if (!mgr_node)
    + return NULL;
    +
    + list_for_each_entry(mgr, &fpga_manager_list, list)
    + if (mgr_node == mgr->np) {
    + of_node_put(mgr_node);
    + return mgr;
    + }
    +
    + of_node_put(mgr_node);
    +
    + return NULL;
    +}
    +EXPORT_SYMBOL_GPL(of_fpga_mgr_dev_lookup);
    +
    static int fpga_mgr_suspend(struct device *dev)
    {
    struct fpga_manager *mgr = dev_get_drvdata(dev);
    diff --git a/include/linux/fpga-mgr.h b/include/linux/fpga-mgr.h
    index 97c7e0b..abf2699 100644
    --- a/include/linux/fpga-mgr.h
    +++ b/include/linux/fpga-mgr.h
    @@ -110,6 +110,8 @@ int fpga_mgr_register(struct platform_device *pdev,
    struct fpga_manager_ops *mops,
    const char *name, void *priv);
    void fpga_mgr_remove(struct platform_device *pdev);
    +struct fpga_manager *of_fpga_mgr_dev_lookup(struct device_node *node,
    + const char *mgr_property);

    #endif /* CONFIG_FPGA */
    #endif /*_LINUX_FPGA_MGR_H */
    --
    1.7.9.5


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