diff options
Diffstat (limited to 'drivers/fpga/altera-hps2fpga.c')
| -rw-r--r-- | drivers/fpga/altera-hps2fpga.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/drivers/fpga/altera-hps2fpga.c b/drivers/fpga/altera-hps2fpga.c new file mode 100644 index 000000000000..4b354c79be31 --- /dev/null +++ b/drivers/fpga/altera-hps2fpga.c @@ -0,0 +1,222 @@ +/* + * 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 <[email protected]> + * + * 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) { + fpga_bridge_unregister(&pdev->dev); + return ret; + } + } + } + + return fpga_bridge_register(dev, priv->name, &altera_hps2fpga_br_ops, + priv); +} + +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 <[email protected]>"); +MODULE_LICENSE("GPL v2"); |