230 lines
6.2 KiB
C
230 lines
6.2 KiB
C
/*
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* FPGA to/from HPS Bridge Driver for Altera SoCFPGA Devices
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*
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* Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
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*
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* Includes this patch from the mailing list:
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* fpga: altera-hps2fpga: fix HPS2FPGA bridge visibility to L3 masters
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* Signed-off-by: Anatolij Gustschin <agust@denx.de>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* This driver manages bridges on a Altera SOCFPGA between the ARM host
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* processor system (HPS) and the embedded FPGA.
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*
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* This driver supports enabling and disabling of the configured ports, which
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* allows for safe reprogramming of the FPGA, assuming that the new FPGA image
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* uses the same port configuration. Bridges must be disabled before
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* reprogramming the FPGA and re-enabled after the FPGA has been programmed.
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*/
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#include <linux/clk.h>
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#include <linux/fpga/fpga-bridge.h>
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#include <linux/kernel.h>
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/of_platform.h>
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#include <linux/regmap.h>
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#include <linux/reset.h>
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#include <linux/spinlock.h>
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#define ALT_L3_REMAP_OFST 0x0
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#define ALT_L3_REMAP_MPUZERO_MSK 0x00000001
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#define ALT_L3_REMAP_H2F_MSK 0x00000008
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#define ALT_L3_REMAP_LWH2F_MSK 0x00000010
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#define HPS2FPGA_BRIDGE_NAME "hps2fpga"
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#define LWHPS2FPGA_BRIDGE_NAME "lwhps2fpga"
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#define FPGA2HPS_BRIDGE_NAME "fpga2hps"
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struct altera_hps2fpga_data {
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const char *name;
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struct reset_control *bridge_reset;
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struct regmap *l3reg;
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unsigned int remap_mask;
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struct clk *clk;
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};
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static int alt_hps2fpga_enable_show(struct fpga_bridge *bridge)
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{
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struct altera_hps2fpga_data *priv = bridge->priv;
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return reset_control_status(priv->bridge_reset);
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}
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/* The L3 REMAP register is write only, so keep a cached value. */
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static unsigned int l3_remap_shadow;
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static DEFINE_SPINLOCK(l3_remap_lock);
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static int _alt_hps2fpga_enable_set(struct altera_hps2fpga_data *priv,
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bool enable)
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{
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unsigned long flags;
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int ret;
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/* bring bridge out of reset */
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if (enable)
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ret = reset_control_deassert(priv->bridge_reset);
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else
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ret = reset_control_assert(priv->bridge_reset);
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if (ret)
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return ret;
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/* Allow bridge to be visible to L3 masters or not */
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if (priv->remap_mask) {
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spin_lock_irqsave(&l3_remap_lock, flags);
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l3_remap_shadow |= ALT_L3_REMAP_MPUZERO_MSK;
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if (enable)
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l3_remap_shadow |= priv->remap_mask;
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else
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l3_remap_shadow &= ~priv->remap_mask;
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ret = regmap_write(priv->l3reg, ALT_L3_REMAP_OFST,
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l3_remap_shadow);
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spin_unlock_irqrestore(&l3_remap_lock, flags);
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}
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return ret;
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}
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static int alt_hps2fpga_enable_set(struct fpga_bridge *bridge, bool enable)
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{
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return _alt_hps2fpga_enable_set(bridge->priv, enable);
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}
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static const struct fpga_bridge_ops altera_hps2fpga_br_ops = {
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.enable_set = alt_hps2fpga_enable_set,
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.enable_show = alt_hps2fpga_enable_show,
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};
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static struct altera_hps2fpga_data hps2fpga_data = {
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.name = HPS2FPGA_BRIDGE_NAME,
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.remap_mask = ALT_L3_REMAP_H2F_MSK,
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};
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static struct altera_hps2fpga_data lwhps2fpga_data = {
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.name = LWHPS2FPGA_BRIDGE_NAME,
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.remap_mask = ALT_L3_REMAP_LWH2F_MSK,
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};
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static struct altera_hps2fpga_data fpga2hps_data = {
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.name = FPGA2HPS_BRIDGE_NAME,
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};
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static const struct of_device_id altera_fpga_of_match[] = {
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{ .compatible = "altr,socfpga-hps2fpga-bridge",
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.data = &hps2fpga_data },
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{ .compatible = "altr,socfpga-lwhps2fpga-bridge",
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.data = &lwhps2fpga_data },
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{ .compatible = "altr,socfpga-fpga2hps-bridge",
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.data = &fpga2hps_data },
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{},
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};
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static int alt_fpga_bridge_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct altera_hps2fpga_data *priv;
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const struct of_device_id *of_id;
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u32 enable;
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int ret;
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of_id = of_match_device(altera_fpga_of_match, dev);
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if (!of_id) {
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dev_err(dev, "failed to match device\n");
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return -ENODEV;
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}
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priv = (struct altera_hps2fpga_data *)of_id->data;
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priv->bridge_reset = of_reset_control_get_exclusive_by_index(dev->of_node,
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0);
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if (IS_ERR(priv->bridge_reset)) {
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dev_err(dev, "Could not get %s reset control\n", priv->name);
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return PTR_ERR(priv->bridge_reset);
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}
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if (priv->remap_mask) {
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priv->l3reg = syscon_regmap_lookup_by_compatible("altr,l3regs");
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if (IS_ERR(priv->l3reg)) {
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dev_err(dev, "regmap for altr,l3regs lookup failed\n");
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return PTR_ERR(priv->l3reg);
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}
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}
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priv->clk = devm_clk_get(dev, NULL);
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if (IS_ERR(priv->clk)) {
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dev_err(dev, "no clock specified\n");
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return PTR_ERR(priv->clk);
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}
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ret = clk_prepare_enable(priv->clk);
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if (ret) {
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dev_err(dev, "could not enable clock\n");
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return -EBUSY;
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}
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if (!of_property_read_u32(dev->of_node, "bridge-enable", &enable)) {
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if (enable > 1) {
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dev_warn(dev, "invalid bridge-enable %u > 1\n", enable);
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} else {
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dev_info(dev, "%s bridge\n",
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(enable ? "enabling" : "disabling"));
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ret = _alt_hps2fpga_enable_set(priv, enable);
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if (ret)
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goto err;
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}
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}
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ret = fpga_bridge_register(dev, priv->name, &altera_hps2fpga_br_ops,
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priv);
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err:
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if (ret)
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clk_disable_unprepare(priv->clk);
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return ret;
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}
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static int alt_fpga_bridge_remove(struct platform_device *pdev)
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{
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struct fpga_bridge *bridge = platform_get_drvdata(pdev);
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struct altera_hps2fpga_data *priv = bridge->priv;
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fpga_bridge_unregister(&pdev->dev);
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clk_disable_unprepare(priv->clk);
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return 0;
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}
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MODULE_DEVICE_TABLE(of, altera_fpga_of_match);
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static struct platform_driver alt_fpga_bridge_driver = {
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.probe = alt_fpga_bridge_probe,
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.remove = alt_fpga_bridge_remove,
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.driver = {
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.name = "altera_hps2fpga_bridge",
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.of_match_table = of_match_ptr(altera_fpga_of_match),
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},
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};
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module_platform_driver(alt_fpga_bridge_driver);
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MODULE_DESCRIPTION("Altera SoCFPGA HPS to FPGA Bridge");
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MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
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MODULE_LICENSE("GPL v2");
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