diff options
Diffstat (limited to 'drivers/fpga/altera-fpga2sdram.c')
| -rw-r--r-- | drivers/fpga/altera-fpga2sdram.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/drivers/fpga/altera-fpga2sdram.c b/drivers/fpga/altera-fpga2sdram.c new file mode 100644 index 000000000000..d4eeb74388da --- /dev/null +++ b/drivers/fpga/altera-fpga2sdram.c @@ -0,0 +1,180 @@ +/* + * 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 <http://www.gnu.org/licenses/>. + */ + +/* + * 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> + +#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; + 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) { + fpga_bridge_unregister(&pdev->dev); + return ret; + } + } + } + + return ret; +} + +static int alt_fpga_bridge_remove(struct platform_device *pdev) +{ + fpga_bridge_unregister(&pdev->dev); + + 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_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"); |