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..7ab358ed6c76
--- /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(priv->sdrctl)) {
+                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");