1 files changed, 279 insertions, 0 deletions
diff --git a/drivers/fpga/altera-freeze-bridge.c b/drivers/fpga/altera-freeze-bridge.c
new file mode 100644
index 000000000..dd58c4aea
--- /dev/null
+++ b/drivers/fpga/altera-freeze-bridge.c
@@ -0,0 +1,279 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * FPGA Freeze Bridge Controller
+ *
+ *  Copyright (C) 2016 Altera Corporation. All rights reserved.
+ */
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of_device.h>
+#include <linux/module.h>
+#include <linux/fpga/fpga-bridge.h>
+
+#define FREEZE_CSR_STATUS_OFFSET		0
+#define FREEZE_CSR_CTRL_OFFSET			4
+#define FREEZE_CSR_ILLEGAL_REQ_OFFSET		8
+#define FREEZE_CSR_REG_VERSION			12
+
+#define FREEZE_CSR_SUPPORTED_VERSION		2
+#define FREEZE_CSR_OFFICIAL_VERSION		0xad000003
+
+#define FREEZE_CSR_STATUS_FREEZE_REQ_DONE	BIT(0)
+#define FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE	BIT(1)
+
+#define FREEZE_CSR_CTRL_FREEZE_REQ		BIT(0)
+#define FREEZE_CSR_CTRL_RESET_REQ		BIT(1)
+#define FREEZE_CSR_CTRL_UNFREEZE_REQ		BIT(2)
+
+#define FREEZE_BRIDGE_NAME			"freeze"
+
+struct altera_freeze_br_data {
+	struct device *dev;
+	void __iomem *base_addr;
+	bool enable;
+};
+
+/*
+ * Poll status until status bit is set or we have a timeout.
+ */
+static int altera_freeze_br_req_ack(struct altera_freeze_br_data *priv,
+				    u32 timeout, u32 req_ack)
+{
+	struct device *dev = priv->dev;
+	void __iomem *csr_illegal_req_addr = priv->base_addr +
+					     FREEZE_CSR_ILLEGAL_REQ_OFFSET;
+	u32 status, illegal, ctrl;
+	int ret = -ETIMEDOUT;
+
+	do {
+		illegal = readl(csr_illegal_req_addr);
+		if (illegal) {
+			dev_err(dev, "illegal request detected 0x%x", illegal);
+
+			writel(1, csr_illegal_req_addr);
+
+			illegal = readl(csr_illegal_req_addr);
+			if (illegal)
+				dev_err(dev, "illegal request not cleared 0x%x",
+					illegal);
+
+			ret = -EINVAL;
+			break;
+		}
+
+		status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);
+		dev_dbg(dev, "%s %x %x\n", __func__, status, req_ack);
+		status &= req_ack;
+		if (status) {
+			ctrl = readl(priv->base_addr + FREEZE_CSR_CTRL_OFFSET);
+			dev_dbg(dev, "%s request %x acknowledged %x %x\n",
+				__func__, req_ack, status, ctrl);
+			ret = 0;
+			break;
+		}
+
+		udelay(1);
+	} while (timeout--);
+
+	if (ret == -ETIMEDOUT)
+		dev_err(dev, "%s timeout waiting for 0x%x\n",
+			__func__, req_ack);
+
+	return ret;
+}
+
+static int altera_freeze_br_do_freeze(struct altera_freeze_br_data *priv,
+				      u32 timeout)
+{
+	struct device *dev = priv->dev;
+	void __iomem *csr_ctrl_addr = priv->base_addr +
+				      FREEZE_CSR_CTRL_OFFSET;
+	u32 status;
+	int ret;
+
+	status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);
+
+	dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr));
+
+	if (status & FREEZE_CSR_STATUS_FREEZE_REQ_DONE) {
+		dev_dbg(dev, "%s bridge already disabled %d\n",
+			__func__, status);
+		return 0;
+	} else if (!(status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE)) {
+		dev_err(dev, "%s bridge not enabled %d\n", __func__, status);
+		return -EINVAL;
+	}
+
+	writel(FREEZE_CSR_CTRL_FREEZE_REQ, csr_ctrl_addr);
+
+	ret = altera_freeze_br_req_ack(priv, timeout,
+				       FREEZE_CSR_STATUS_FREEZE_REQ_DONE);
+
+	if (ret)
+		writel(0, csr_ctrl_addr);
+	else
+		writel(FREEZE_CSR_CTRL_RESET_REQ, csr_ctrl_addr);
+
+	return ret;
+}
+
+static int altera_freeze_br_do_unfreeze(struct altera_freeze_br_data *priv,
+					u32 timeout)
+{
+	struct device *dev = priv->dev;
+	void __iomem *csr_ctrl_addr = priv->base_addr +
+				      FREEZE_CSR_CTRL_OFFSET;
+	u32 status;
+	int ret;
+
+	writel(0, csr_ctrl_addr);
+
+	status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);
+
+	dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr));
+
+	if (status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE) {
+		dev_dbg(dev, "%s bridge already enabled %d\n",
+			__func__, status);
+		return 0;
+	} else if (!(status & FREEZE_CSR_STATUS_FREEZE_REQ_DONE)) {
+		dev_err(dev, "%s bridge not frozen %d\n", __func__, status);
+		return -EINVAL;
+	}
+
+	writel(FREEZE_CSR_CTRL_UNFREEZE_REQ, csr_ctrl_addr);
+
+	ret = altera_freeze_br_req_ack(priv, timeout,
+				       FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE);
+
+	status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);
+
+	dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr));
+
+	writel(0, csr_ctrl_addr);
+
+	return ret;
+}
+
+/*
+ * enable = 1 : allow traffic through the bridge
+ * enable = 0 : disable traffic through the bridge
+ */
+static int altera_freeze_br_enable_set(struct fpga_bridge *bridge,
+				       bool enable)
+{
+	struct altera_freeze_br_data *priv = bridge->priv;
+	struct fpga_image_info *info = bridge->info;
+	u32 timeout = 0;
+	int ret;
+
+	if (enable) {
+		if (info)
+			timeout = info->enable_timeout_us;
+
+		ret = altera_freeze_br_do_unfreeze(bridge->priv, timeout);
+	} else {
+		if (info)
+			timeout = info->disable_timeout_us;
+
+		ret = altera_freeze_br_do_freeze(bridge->priv, timeout);
+	}
+
+	if (!ret)
+		priv->enable = enable;
+
+	return ret;
+}
+
+static int altera_freeze_br_enable_show(struct fpga_bridge *bridge)
+{
+	struct altera_freeze_br_data *priv = bridge->priv;
+
+	return priv->enable;
+}
+
+static const struct fpga_bridge_ops altera_freeze_br_br_ops = {
+	.enable_set = altera_freeze_br_enable_set,
+	.enable_show = altera_freeze_br_enable_show,
+};
+
+static const struct of_device_id altera_freeze_br_of_match[] = {
+	{ .compatible = "altr,freeze-bridge-controller", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, altera_freeze_br_of_match);
+
+static int altera_freeze_br_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node;
+	void __iomem *base_addr;
+	struct altera_freeze_br_data *priv;
+	struct fpga_bridge *br;
+	struct resource *res;
+	u32 status, revision;
+
+	if (!np)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base_addr = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base_addr))
+		return PTR_ERR(base_addr);
+
+	revision = readl(base_addr + FREEZE_CSR_REG_VERSION);
+	if ((revision != FREEZE_CSR_SUPPORTED_VERSION) &&
+	    (revision != FREEZE_CSR_OFFICIAL_VERSION)) {
+		dev_err(dev,
+			"%s unexpected revision 0x%x != 0x%x != 0x%x\n",
+			__func__, revision, FREEZE_CSR_SUPPORTED_VERSION,
+			FREEZE_CSR_OFFICIAL_VERSION);
+		return -EINVAL;
+	}
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+
+	status = readl(base_addr + FREEZE_CSR_STATUS_OFFSET);
+	if (status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE)
+		priv->enable = 1;
+
+	priv->base_addr = base_addr;
+
+	br = devm_fpga_bridge_create(dev, FREEZE_BRIDGE_NAME,
+				     &altera_freeze_br_br_ops, priv);
+	if (!br)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, br);
+
+	return fpga_bridge_register(br);
+}
+
+static int altera_freeze_br_remove(struct platform_device *pdev)
+{
+	struct fpga_bridge *br = platform_get_drvdata(pdev);
+
+	fpga_bridge_unregister(br);
+
+	return 0;
+}
+
+static struct platform_driver altera_freeze_br_driver = {
+	.probe = altera_freeze_br_probe,
+	.remove = altera_freeze_br_remove,
+	.driver = {
+		.name	= "altera_freeze_br",
+		.of_match_table = of_match_ptr(altera_freeze_br_of_match),
+	},
+};
+
+module_platform_driver(altera_freeze_br_driver);
+
+MODULE_DESCRIPTION("Altera Freeze Bridge");
+MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
+MODULE_LICENSE("GPL v2");