/*
* FPGA to/from HPS Bridge Driver for Altera SoCFPGA Devices
*
* Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
*
* Includes this patch from the mailing list:
* fpga: altera-hps2fpga: fix HPS2FPGA bridge visibility to L3 masters
* Signed-off-by: Anatolij Gustschin <agust@denx.de>
*
* 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/>.
*/
/*
* This driver manages bridges on a Altera SOCFPGA between the ARM host
* processor system (HPS) and the embedded FPGA.
*
* 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/clk.h>
#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>
#include <linux/reset.h>
#include <linux/spinlock.h>
#define ALT_L3_REMAP_OFST 0x0
#define ALT_L3_REMAP_MPUZERO_MSK 0x00000001
#define ALT_L3_REMAP_H2F_MSK 0x00000008
#define ALT_L3_REMAP_LWH2F_MSK 0x00000010
#define HPS2FPGA_BRIDGE_NAME "hps2fpga"
#define LWHPS2FPGA_BRIDGE_NAME "lwhps2fpga"
#define FPGA2HPS_BRIDGE_NAME "fpga2hps"
struct altera_hps2fpga_data {
const char *name;
struct reset_control *bridge_reset;
struct regmap *l3reg;
unsigned int remap_mask;
struct clk *clk;
};
static int alt_hps2fpga_enable_show(struct fpga_bridge *bridge)
{
struct altera_hps2fpga_data *priv = bridge->priv;
return reset_control_status(priv->bridge_reset);
}
/* The L3 REMAP register is write only, so keep a cached value. */
static unsigned int l3_remap_shadow;
static spinlock_t l3_remap_lock;
static int _alt_hps2fpga_enable_set(struct altera_hps2fpga_data *priv,
bool enable)
{
unsigned long flags;
int ret;
/* bring bridge out of reset */
if (enable)
ret = reset_control_deassert(priv->bridge_reset);
else
ret = reset_control_assert(priv->bridge_reset);
if (ret)
return ret;
/* Allow bridge to be visible to L3 masters or not */
if (priv->remap_mask) {
spin_lock_irqsave(&l3_remap_lock, flags);
l3_remap_shadow |= ALT_L3_REMAP_MPUZERO_MSK;
if (enable)
l3_remap_shadow |= priv->remap_mask;
else
l3_remap_shadow &= ~priv->remap_mask;
ret = regmap_write(priv->l3reg, ALT_L3_REMAP_OFST,
l3_remap_shadow);
spin_unlock_irqrestore(&l3_remap_lock, flags);
}
return ret;
}
static int alt_hps2fpga_enable_set(struct fpga_bridge *bridge, bool enable)
{
return _alt_hps2fpga_enable_set(bridge->priv, enable);
}
static const struct fpga_bridge_ops altera_hps2fpga_br_ops = {
.enable_set = alt_hps2fpga_enable_set,
.enable_show = alt_hps2fpga_enable_show,
};
static struct altera_hps2fpga_data hps2fpga_data = {
.name = HPS2FPGA_BRIDGE_NAME,
.remap_mask = ALT_L3_REMAP_H2F_MSK,
};
static struct altera_hps2fpga_data lwhps2fpga_data = {
.name = LWHPS2FPGA_BRIDGE_NAME,
.remap_mask = ALT_L3_REMAP_LWH2F_MSK,
};
static struct altera_hps2fpga_data fpga2hps_data = {
.name = FPGA2HPS_BRIDGE_NAME,
};
static const struct of_device_id altera_fpga_of_match[] = {
{ .compatible = "altr,socfpga-hps2fpga-bridge",
.data = &hps2fpga_data },
{ .compatible = "altr,socfpga-lwhps2fpga-bridge",
.data = &lwhps2fpga_data },
{ .compatible = "altr,socfpga-fpga2hps-bridge",
.data = &fpga2hps_data },
{},
};
static int alt_fpga_bridge_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct altera_hps2fpga_data *priv;
const struct of_device_id *of_id;
u32 enable;
int ret;
of_id = of_match_device(altera_fpga_of_match, dev);
priv = (struct altera_hps2fpga_data *)of_id->data;
priv->bridge_reset = of_reset_control_get_by_index(dev->of_node, 0);
if (IS_ERR(priv->bridge_reset)) {
dev_err(dev, "Could not get %s reset control\n", priv->name);
return PTR_ERR(priv->bridge_reset);
}
if (priv->remap_mask) {
priv->l3reg = syscon_regmap_lookup_by_compatible("altr,l3regs");
if (IS_ERR(priv->l3reg)) {
dev_err(dev, "regmap for altr,l3regs lookup failed\n");
return PTR_ERR(priv->l3reg);
}
}
priv->clk = devm_clk_get(dev, NULL);
if (IS_ERR(priv->clk)) {
dev_err(dev, "no clock specified\n");
return PTR_ERR(priv->clk);
}
ret = clk_prepare_enable(priv->clk);
if (ret) {
dev_err(dev, "could not enable clock\n");
return -EBUSY;
}
spin_lock_init(&l3_remap_lock);
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_hps2fpga_enable_set(priv, enable);
if (ret)
goto err;
}
}
ret = fpga_bridge_register(dev, priv->name, &altera_hps2fpga_br_ops,
priv);
err:
if (ret)
clk_disable_unprepare(priv->clk);
return ret;
}
static int alt_fpga_bridge_remove(struct platform_device *pdev)
{
struct fpga_bridge *bridge = platform_get_drvdata(pdev);
struct altera_hps2fpga_data *priv = bridge->priv;
fpga_bridge_unregister(&pdev->dev);
clk_disable_unprepare(priv->clk);
return 0;
}
MODULE_DEVICE_TABLE(of, altera_fpga_of_match);
static struct platform_driver alt_fpga_bridge_driver = {
.probe = alt_fpga_bridge_probe,
.remove = alt_fpga_bridge_remove,
.driver = {
.name = "altera_hps2fpga_bridge",
.of_match_table = of_match_ptr(altera_fpga_of_match),
},
};
module_platform_driver(alt_fpga_bridge_driver);
MODULE_DESCRIPTION("Altera SoCFPGA HPS to FPGA Bridge");
MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
MODULE_LICENSE("GPL v2");
