linux/drivers/fpga/altera-fpga2sdram.c
Uwe Kleine-König d6c10a46b4
fpga: altera-fpga2sdram: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/017b9e17a0c88b2a633467633d304639e7765926.1703006638.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
2023-12-21 22:30:42 +08:00

173 lines
4.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* FPGA to SDRAM Bridge Driver for Altera SoCFPGA Devices
*
* Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
*/
/*
* 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.h>
#include <linux/regmap.h>
#define ALT_SDR_CTL_FPGAPORTRST_OFST 0x80
#define ALT_SDR_CTL_FPGAPORTRST_PORTRSTN_MSK 0x00003fff
#define ALT_SDR_CTL_FPGAPORTRST_RD_SHIFT 0
#define ALT_SDR_CTL_FPGAPORTRST_WR_SHIFT 4
#define ALT_SDR_CTL_FPGAPORTRST_CTRL_SHIFT 8
/*
* 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 SYSMGR_ISWGRP_HANDOFF3 (0x8C)
#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;
struct fpga_bridge *br;
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);
br = fpga_bridge_register(dev, F2S_BRIDGE_NAME,
&altera_fpga2sdram_br_ops, priv);
if (IS_ERR(br))
return PTR_ERR(br);
platform_set_drvdata(pdev, br);
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) {
fpga_bridge_unregister(br);
return ret;
}
}
}
return ret;
}
static void alt_fpga_bridge_remove(struct platform_device *pdev)
{
struct fpga_bridge *br = platform_get_drvdata(pdev);
fpga_bridge_unregister(br);
}
MODULE_DEVICE_TABLE(of, altera_fpga_of_match);
static struct platform_driver altera_fpga_driver = {
.probe = alt_fpga_bridge_probe,
.remove_new = alt_fpga_bridge_remove,
.driver = {
.name = "altera_fpga2sdram_bridge",
.of_match_table = of_match_ptr(altera_fpga_of_match),
},
};
module_platform_driver(altera_fpga_driver);
MODULE_DESCRIPTION("Altera SoCFPGA FPGA to SDRAM Bridge");
MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
MODULE_LICENSE("GPL v2");