blob: d4eeb74388da97b8bdf0d496ba70207717f32401 [file] [log] [blame]
* FPGA to SDRAM Bridge Driver for Altera SoCFPGA Devices
* Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
* 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 <>.
* This driver manages a bridge between an FPGA and the SDRAM used by the ARM
* host processor system (HPS).
* The bridge contains 4 read ports, 4 write ports, and 6 command ports.
* Reconfiguring these ports requires that no SDRAM transactions occur during
* reconfiguration. The code reconfiguring the ports cannot run out of SDRAM
* nor can the FPGA access the SDRAM during reconfiguration. This driver does
* not support reconfiguring the ports. The ports are configured by code
* running out of on chip ram before Linux is started and the configuration
* is passed in a handoff register in the system manager.
* This driver supports enabling and disabling of the configured ports, which
* allows for safe reprogramming of the FPGA, assuming that the new FPGA image
* uses the same port configuration. Bridges must be disabled before
* reprogramming the FPGA and re-enabled after the FPGA has been programmed.
#include <linux/fpga/fpga-bridge.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/regmap.h>
* From the Cyclone V HPS Memory Map document:
* These registers are used to store handoff information between the
* preloader and the OS. These 8 registers can be used to store any
* information. The contents of these registers have no impact on
* the state of the HPS hardware.
#define F2S_BRIDGE_NAME "fpga2sdram"
struct alt_fpga2sdram_data {
struct device *dev;
struct regmap *sdrctl;
int mask;
static int alt_fpga2sdram_enable_show(struct fpga_bridge *bridge)
struct alt_fpga2sdram_data *priv = bridge->priv;
int value;
regmap_read(priv->sdrctl, ALT_SDR_CTL_FPGAPORTRST_OFST, &value);
return (value & priv->mask) == priv->mask;
static inline int _alt_fpga2sdram_enable_set(struct alt_fpga2sdram_data *priv,
bool enable)
return regmap_update_bits(priv->sdrctl, ALT_SDR_CTL_FPGAPORTRST_OFST,
priv->mask, enable ? priv->mask : 0);
static int alt_fpga2sdram_enable_set(struct fpga_bridge *bridge, bool enable)
return _alt_fpga2sdram_enable_set(bridge->priv, enable);
struct prop_map {
char *prop_name;
u32 *prop_value;
u32 prop_max;
static const struct fpga_bridge_ops altera_fpga2sdram_br_ops = {
.enable_set = alt_fpga2sdram_enable_set,
.enable_show = alt_fpga2sdram_enable_show,
static const struct of_device_id altera_fpga_of_match[] = {
{ .compatible = "altr,socfpga-fpga2sdram-bridge" },
static int alt_fpga_bridge_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct alt_fpga2sdram_data *priv;
u32 enable;
struct regmap *sysmgr;
int ret = 0;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = dev;
priv->sdrctl = syscon_regmap_lookup_by_compatible("altr,sdr-ctl");
if (IS_ERR(priv->sdrctl)) {
dev_err(dev, "regmap for altr,sdr-ctl lookup failed.\n");
return PTR_ERR(priv->sdrctl);
sysmgr = syscon_regmap_lookup_by_compatible("altr,sys-mgr");
if (IS_ERR(sysmgr)) {
dev_err(dev, "regmap for altr,sys-mgr lookup failed.\n");
return PTR_ERR(sysmgr);
/* Get f2s bridge configuration saved in handoff register */
regmap_read(sysmgr, SYSMGR_ISWGRP_HANDOFF3, &priv->mask);
ret = fpga_bridge_register(dev, F2S_BRIDGE_NAME,
&altera_fpga2sdram_br_ops, priv);
if (ret)
return ret;
dev_info(dev, "driver initialized with handoff %08x\n", priv->mask);
if (!of_property_read_u32(dev->of_node, "bridge-enable", &enable)) {
if (enable > 1) {
dev_warn(dev, "invalid bridge-enable %u > 1\n", enable);
} else {
dev_info(dev, "%s bridge\n",
(enable ? "enabling" : "disabling"));
ret = _alt_fpga2sdram_enable_set(priv, enable);
if (ret) {
return ret;
return ret;
static int alt_fpga_bridge_remove(struct platform_device *pdev)
return 0;
MODULE_DEVICE_TABLE(of, altera_fpga_of_match);
static struct platform_driver altera_fpga_driver = {
.probe = alt_fpga_bridge_probe,
.remove = alt_fpga_bridge_remove,
.driver = {
.name = "altera_fpga2sdram_bridge",
.of_match_table = of_match_ptr(altera_fpga_of_match),
MODULE_AUTHOR("Alan Tull <>");