[linux-block.git] / drivers / fpga / altera-freeze-bridge.c

// 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,
};

#ifdef CONFIG_OF
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);
#endif

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 = fpga_bridge_register(dev, FREEZE_BRIDGE_NAME,
				  &altera_freeze_br_br_ops, priv);
	if (IS_ERR(br))
		return PTR_ERR(br);

	platform_set_drvdata(pdev, br);

	return 0;
}

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");
Commit	Line	Data
473f01f7	1	// SPDX-License-Identifier: GPL-2.0
ca24a648 AT	2	/*
	3	* FPGA Freeze Bridge Controller
	4	*
	5	* Copyright (C) 2016 Altera Corporation. All rights reserved.
ca24a648 AT	6	*/
	7	#include <linux/delay.h>
	8	#include <linux/io.h>
	9	#include <linux/kernel.h>
	10	#include <linux/of_device.h>
	11	#include <linux/module.h>
	12	#include <linux/fpga/fpga-bridge.h>
	13
	14	#define FREEZE_CSR_STATUS_OFFSET 0
	15	#define FREEZE_CSR_CTRL_OFFSET 4
	16	#define FREEZE_CSR_ILLEGAL_REQ_OFFSET 8
	17	#define FREEZE_CSR_REG_VERSION 12
	18
	19	#define FREEZE_CSR_SUPPORTED_VERSION 2
dd17cc7b	20	#define FREEZE_CSR_OFFICIAL_VERSION 0xad000003
ca24a648 AT	21
	22	#define FREEZE_CSR_STATUS_FREEZE_REQ_DONE BIT(0)
	23	#define FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE BIT(1)
	24
	25	#define FREEZE_CSR_CTRL_FREEZE_REQ BIT(0)
	26	#define FREEZE_CSR_CTRL_RESET_REQ BIT(1)
	27	#define FREEZE_CSR_CTRL_UNFREEZE_REQ BIT(2)
	28
	29	#define FREEZE_BRIDGE_NAME "freeze"
	30
	31	struct altera_freeze_br_data {
	32	struct device *dev;
	33	void __iomem *base_addr;
	34	bool enable;
	35	};
	36
	37	/*
	38	* Poll status until status bit is set or we have a timeout.
	39	*/
	40	static int altera_freeze_br_req_ack(struct altera_freeze_br_data *priv,
	41	u32 timeout, u32 req_ack)
	42	{
	43	struct device *dev = priv->dev;
	44	void __iomem *csr_illegal_req_addr = priv->base_addr +
	45	FREEZE_CSR_ILLEGAL_REQ_OFFSET;
	46	u32 status, illegal, ctrl;
	47	int ret = -ETIMEDOUT;
	48
	49	do {
	50	illegal = readl(csr_illegal_req_addr);
	51	if (illegal) {
	52	dev_err(dev, "illegal request detected 0x%x", illegal);
	53
	54	writel(1, csr_illegal_req_addr);
	55
	56	illegal = readl(csr_illegal_req_addr);
	57	if (illegal)
	58	dev_err(dev, "illegal request not cleared 0x%x",
	59	illegal);
	60
	61	ret = -EINVAL;
	62	break;
	63	}
	64
	65	status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);
	66	dev_dbg(dev, "%s %x %x\n", __func__, status, req_ack);
	67	status &= req_ack;
	68	if (status) {
	69	ctrl = readl(priv->base_addr + FREEZE_CSR_CTRL_OFFSET);
	70	dev_dbg(dev, "%s request %x acknowledged %x %x\n",
	71	__func__, req_ack, status, ctrl);
	72	ret = 0;
	73	break;
	74	}
	75
	76	udelay(1);
	77	} while (timeout--);
	78
	79	if (ret == -ETIMEDOUT)
	80	dev_err(dev, "%s timeout waiting for 0x%x\n",
	81	__func__, req_ack);
	82
	83	return ret;
	84	}
85
86	static int altera_freeze_br_do_freeze(struct altera_freeze_br_data *priv,
87	u32 timeout)
88	{
89	struct device *dev = priv->dev;
90	void __iomem *csr_ctrl_addr = priv->base_addr +
91	FREEZE_CSR_CTRL_OFFSET;
92	u32 status;
93	int ret;
94
95	status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);
96
97	dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr));
98
99	if (status & FREEZE_CSR_STATUS_FREEZE_REQ_DONE) {
100	dev_dbg(dev, "%s bridge already disabled %d\n",
101	__func__, status);
102	return 0;
103	} else if (!(status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE)) {
104	dev_err(dev, "%s bridge not enabled %d\n", __func__, status);
105	return -EINVAL;
106	}
107
108	writel(FREEZE_CSR_CTRL_FREEZE_REQ, csr_ctrl_addr);
109
110	ret = altera_freeze_br_req_ack(priv, timeout,
111	FREEZE_CSR_STATUS_FREEZE_REQ_DONE);
112
113	if (ret)
114	writel(0, csr_ctrl_addr);
115	else
116	writel(FREEZE_CSR_CTRL_RESET_REQ, csr_ctrl_addr);
117
118	return ret;
119	}
120
121	static int altera_freeze_br_do_unfreeze(struct altera_freeze_br_data *priv,
122	u32 timeout)
123	{
124	struct device *dev = priv->dev;
125	void __iomem *csr_ctrl_addr = priv->base_addr +
126	FREEZE_CSR_CTRL_OFFSET;
127	u32 status;
128	int ret;
129
130	writel(0, csr_ctrl_addr);
131
132	status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);
133
134	dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr));
135
136	if (status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE) {
137	dev_dbg(dev, "%s bridge already enabled %d\n",
138	__func__, status);
139	return 0;
140	} else if (!(status & FREEZE_CSR_STATUS_FREEZE_REQ_DONE)) {
141	dev_err(dev, "%s bridge not frozen %d\n", __func__, status);
142	return -EINVAL;
143	}
144
145	writel(FREEZE_CSR_CTRL_UNFREEZE_REQ, csr_ctrl_addr);
146
147	ret = altera_freeze_br_req_ack(priv, timeout,
148	FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE);
149
150	status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);
151
152	dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr));
153
154	writel(0, csr_ctrl_addr);
155
156	return ret;
157	}
158
159	/*
160	* enable = 1 : allow traffic through the bridge
161	* enable = 0 : disable traffic through the bridge
162	*/
163	static int altera_freeze_br_enable_set(struct fpga_bridge *bridge,
164	bool enable)
165	{
166	struct altera_freeze_br_data *priv = bridge->priv;
167	struct fpga_image_info *info = bridge->info;
168	u32 timeout = 0;
169	int ret;
170
171	if (enable) {
172	if (info)
173	timeout = info->enable_timeout_us;
174
175	ret = altera_freeze_br_do_unfreeze(bridge->priv, timeout);
176	} else {
177	if (info)
178	timeout = info->disable_timeout_us;
179
180	ret = altera_freeze_br_do_freeze(bridge->priv, timeout);
181	}
182
183	if (!ret)
184	priv->enable = enable;
185
186	return ret;
187	}
188
189	static int altera_freeze_br_enable_show(struct fpga_bridge *bridge)
190	{
191	struct altera_freeze_br_data *priv = bridge->priv;
192
193	return priv->enable;
194	}
195
6b539d27	196	static const struct fpga_bridge_ops altera_freeze_br_br_ops = {
ca24a648 AT	197	.enable_set = altera_freeze_br_enable_set,
	198	.enable_show = altera_freeze_br_enable_show,
	199	};
	200
e3fd0cfb	201	#ifdef CONFIG_OF
ca24a648 AT	202	static const struct of_device_id altera_freeze_br_of_match[] = {
	203	{ .compatible = "altr,freeze-bridge-controller", },
	204	{},
	205	};
	206	MODULE_DEVICE_TABLE(of, altera_freeze_br_of_match);
e3fd0cfb	207	#endif
ca24a648 AT	208
	209	static int altera_freeze_br_probe(struct platform_device *pdev)
	210	{
	211	struct device *dev = &pdev->dev;
	212	struct device_node *np = pdev->dev.of_node;
dd17cc7b	213	void __iomem *base_addr;
ca24a648	214	struct altera_freeze_br_data *priv;
371cd1b1	215	struct fpga_bridge *br;
ca24a648 AT	216	struct resource *res;
	217	u32 status, revision;
	218
	219	if (!np)
	220	return -ENODEV;
	221
dd17cc7b MG	222	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	223	base_addr = devm_ioremap_resource(dev, res);
	224	if (IS_ERR(base_addr))
	225	return PTR_ERR(base_addr);
	226
	227	revision = readl(base_addr + FREEZE_CSR_REG_VERSION);
	228	if ((revision != FREEZE_CSR_SUPPORTED_VERSION) &&
	229	(revision != FREEZE_CSR_OFFICIAL_VERSION)) {
	230	dev_err(dev,
	231	"%s unexpected revision 0x%x != 0x%x != 0x%x\n",
	232	__func__, revision, FREEZE_CSR_SUPPORTED_VERSION,
	233	FREEZE_CSR_OFFICIAL_VERSION);
	234	return -EINVAL;
	235	}
	236
ca24a648 AT	237	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	238	if (!priv)
	239	return -ENOMEM;
	240
	241	priv->dev = dev;
	242
dd17cc7b	243	status = readl(base_addr + FREEZE_CSR_STATUS_OFFSET);
ca24a648 AT	244	if (status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE)
	245	priv->enable = 1;
	246
dd17cc7b	247	priv->base_addr = base_addr;
ca24a648	248
0d70af3c RW	249	br = fpga_bridge_register(dev, FREEZE_BRIDGE_NAME,
	250	&altera_freeze_br_br_ops, priv);
	251	if (IS_ERR(br))
	252	return PTR_ERR(br);
371cd1b1 AT	253
	254	platform_set_drvdata(pdev, br);
	255
0d70af3c	256	return 0;
ca24a648 AT	257	}
	258
	259	static int altera_freeze_br_remove(struct platform_device *pdev)
	260	{
371cd1b1 AT	261	struct fpga_bridge *br = platform_get_drvdata(pdev);
	262
	263	fpga_bridge_unregister(br);
ca24a648 AT	264
	265	return 0;
	266	}
	267
	268	static struct platform_driver altera_freeze_br_driver = {
	269	.probe = altera_freeze_br_probe,
	270	.remove = altera_freeze_br_remove,
	271	.driver = {
	272	.name = "altera_freeze_br",
	273	.of_match_table = of_match_ptr(altera_freeze_br_of_match),
	274	},
	275	};
	276
	277	module_platform_driver(altera_freeze_br_driver);
	278
	279	MODULE_DESCRIPTION("Altera Freeze Bridge");
	280	MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
	281	MODULE_LICENSE("GPL v2");