[mirror_ubuntu-bionic-kernel.git] / drivers / misc / aspeed-lpc-ctrl.c

/*
 * Copyright 2017 IBM Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/mfd/syscon.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/poll.h>
#include <linux/regmap.h>

#include <linux/aspeed-lpc-ctrl.h>

#define DEVICE_NAME	"aspeed-lpc-ctrl"

#define HICR7 0x8
#define HICR8 0xc

struct aspeed_lpc_ctrl {
	struct miscdevice	miscdev;
	struct regmap		*regmap;
	phys_addr_t		mem_base;
	resource_size_t		mem_size;
	u32		pnor_size;
	u32		pnor_base;
};

static struct aspeed_lpc_ctrl *file_aspeed_lpc_ctrl(struct file *file)
{
	return container_of(file->private_data, struct aspeed_lpc_ctrl,
			miscdev);
}

static int aspeed_lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
	unsigned long vsize = vma->vm_end - vma->vm_start;
	pgprot_t prot = vma->vm_page_prot;

	if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size)
		return -EINVAL;

	/* ast2400/2500 AHB accesses are not cache coherent */
	prot = pgprot_noncached(prot);

	if (remap_pfn_range(vma, vma->vm_start,
		(lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
		vsize, prot))
		return -EAGAIN;

	return 0;
}

static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
		unsigned long param)
{
	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
	void __user *p = (void __user *)param;
	struct aspeed_lpc_ctrl_mapping map;
	u32 addr;
	u32 size;
	long rc;

	if (copy_from_user(&map, p, sizeof(map)))
		return -EFAULT;

	if (map.flags != 0)
		return -EINVAL;

	switch (cmd) {
	case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
		/* The flash windows don't report their size */
		if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
			return -EINVAL;

		/* Support more than one window id in the future */
		if (map.window_id != 0)
			return -EINVAL;

		map.size = lpc_ctrl->mem_size;

		return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
	case ASPEED_LPC_CTRL_IOCTL_MAP:

		/*
		 * The top half of HICR7 is the MSB of the BMC address of the
		 * mapping.
		 * The bottom half of HICR7 is the MSB of the HOST LPC
		 * firmware space address of the mapping.
		 *
		 * The 1 bits in the top of half of HICR8 represent the bits
		 * (in the requested address) that should be ignored and
		 * replaced with those from the top half of HICR7.
		 * The 1 bits in the bottom half of HICR8 represent the bits
		 * (in the requested address) that should be kept and pass
		 * into the BMC address space.
		 */

		/*
		 * It doesn't make sense to talk about a size or offset with
		 * low 16 bits set. Both HICR7 and HICR8 talk about the top 16
		 * bits of addresses and sizes.
		 */

		if ((map.size & 0x0000ffff) || (map.offset & 0x0000ffff))
			return -EINVAL;

		/*
		 * Because of the way the masks work in HICR8 offset has to
		 * be a multiple of size.
		 */
		if (map.offset & (map.size - 1))
			return -EINVAL;

		if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
			addr = lpc_ctrl->pnor_base;
			size = lpc_ctrl->pnor_size;
		} else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
			addr = lpc_ctrl->mem_base;
			size = lpc_ctrl->mem_size;
		} else {
			return -EINVAL;
		}

		/* Check overflow first! */
		if (map.offset + map.size < map.offset ||
			map.offset + map.size > size)
			return -EINVAL;

		if (map.size == 0 || map.size > size)
			return -EINVAL;

		addr += map.offset;

		/*
		 * addr (host lpc address) is safe regardless of values. This
		 * simply changes the address the host has to request on its
		 * side of the LPC bus. This cannot impact the hosts own
		 * memory space by surprise as LPC specific accessors are
		 * required. The only strange thing that could be done is
		 * setting the lower 16 bits but the shift takes care of that.
		 */

		rc = regmap_write(lpc_ctrl->regmap, HICR7,
				(addr | (map.addr >> 16)));
		if (rc)
			return rc;

		return regmap_write(lpc_ctrl->regmap, HICR8,
			(~(map.size - 1)) | ((map.size >> 16) - 1));
	}

	return -EINVAL;
}

static const struct file_operations aspeed_lpc_ctrl_fops = {
	.owner		= THIS_MODULE,
	.mmap		= aspeed_lpc_ctrl_mmap,
	.unlocked_ioctl	= aspeed_lpc_ctrl_ioctl,
};

static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
{
	struct aspeed_lpc_ctrl *lpc_ctrl;
	struct device_node *node;
	struct resource resm;
	struct device *dev;
	int rc;

	dev = &pdev->dev;

	lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
	if (!lpc_ctrl)
		return -ENOMEM;

	node = of_parse_phandle(dev->of_node, "flash", 0);
	if (!node) {
		dev_err(dev, "Didn't find host pnor flash node\n");
		return -ENODEV;
	}

	rc = of_address_to_resource(node, 1, &resm);
	of_node_put(node);
	if (rc) {
		dev_err(dev, "Couldn't address to resource for flash\n");
		return rc;
	}

	lpc_ctrl->pnor_size = resource_size(&resm);
	lpc_ctrl->pnor_base = resm.start;

	dev_set_drvdata(&pdev->dev, lpc_ctrl);

	node = of_parse_phandle(dev->of_node, "memory-region", 0);
	if (!node) {
		dev_err(dev, "Didn't find reserved memory\n");
		return -EINVAL;
	}

	rc = of_address_to_resource(node, 0, &resm);
	of_node_put(node);
	if (rc) {
		dev_err(dev, "Couldn't address to resource for reserved memory\n");
		return -ENOMEM;
	}

	lpc_ctrl->mem_size = resource_size(&resm);
	lpc_ctrl->mem_base = resm.start;

	lpc_ctrl->regmap = syscon_node_to_regmap(
			pdev->dev.parent->of_node);
	if (IS_ERR(lpc_ctrl->regmap)) {
		dev_err(dev, "Couldn't get regmap\n");
		return -ENODEV;
	}

	lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
	lpc_ctrl->miscdev.name = DEVICE_NAME;
	lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
	lpc_ctrl->miscdev.parent = dev;
	rc = misc_register(&lpc_ctrl->miscdev);
	if (rc)
		dev_err(dev, "Unable to register device\n");
	else
		dev_info(dev, "Loaded at %pr\n", &resm);

	return rc;
}

static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
{
	struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);

	misc_deregister(&lpc_ctrl->miscdev);

	return 0;
}

static const struct of_device_id aspeed_lpc_ctrl_match[] = {
	{ .compatible = "aspeed,ast2400-lpc-ctrl" },
	{ .compatible = "aspeed,ast2500-lpc-ctrl" },
	{ },
};

static struct platform_driver aspeed_lpc_ctrl_driver = {
	.driver = {
		.name		= DEVICE_NAME,
		.of_match_table = aspeed_lpc_ctrl_match,
	},
	.probe = aspeed_lpc_ctrl_probe,
	.remove = aspeed_lpc_ctrl_remove,
};

module_platform_driver(aspeed_lpc_ctrl_driver);

MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");
Commit	Line	Data
6c4e9767 CB	1	/*
	2	* Copyright 2017 IBM Corporation
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version
	7	* 2 of the License, or (at your option) any later version.
	8	*/
	9
	10	#include <linux/mfd/syscon.h>
	11	#include <linux/miscdevice.h>
	12	#include <linux/mm.h>
	13	#include <linux/module.h>
	14	#include <linux/of_address.h>
	15	#include <linux/platform_device.h>
	16	#include <linux/poll.h>
	17	#include <linux/regmap.h>
	18
	19	#include <linux/aspeed-lpc-ctrl.h>
	20
	21	#define DEVICE_NAME "aspeed-lpc-ctrl"
	22
	23	#define HICR7 0x8
	24	#define HICR8 0xc
	25
	26	struct aspeed_lpc_ctrl {
	27	struct miscdevice miscdev;
	28	struct regmap *regmap;
	29	phys_addr_t mem_base;
	30	resource_size_t mem_size;
	31	u32 pnor_size;
	32	u32 pnor_base;
	33	};
	34
	35	static struct aspeed_lpc_ctrl file_aspeed_lpc_ctrl(struct file file)
	36	{
	37	return container_of(file->private_data, struct aspeed_lpc_ctrl,
	38	miscdev);
	39	}
	40
	41	static int aspeed_lpc_ctrl_mmap(struct file file, struct vm_area_struct vma)
	42	{
	43	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
	44	unsigned long vsize = vma->vm_end - vma->vm_start;
	45	pgprot_t prot = vma->vm_page_prot;
	46
	47	if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size)
	48	return -EINVAL;
	49
	50	/* ast2400/2500 AHB accesses are not cache coherent */
132c93d4	51	prot = pgprot_noncached(prot);
6c4e9767 CB	52
	53	if (remap_pfn_range(vma, vma->vm_start,
	54	(lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
	55	vsize, prot))
	56	return -EAGAIN;
	57
	58	return 0;
	59	}
	60
	61	static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
	62	unsigned long param)
	63	{
	64	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
	65	void __user p = (void __user )param;
	66	struct aspeed_lpc_ctrl_mapping map;
	67	u32 addr;
	68	u32 size;
	69	long rc;
	70
	71	if (copy_from_user(&map, p, sizeof(map)))
	72	return -EFAULT;
	73
	74	if (map.flags != 0)
	75	return -EINVAL;
	76
	77	switch (cmd) {
	78	case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
	79	/* The flash windows don't report their size */
	80	if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
	81	return -EINVAL;
	82
	83	/* Support more than one window id in the future */
	84	if (map.window_id != 0)
	85	return -EINVAL;
	86
	87	map.size = lpc_ctrl->mem_size;
	88
	89	return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
	90	case ASPEED_LPC_CTRL_IOCTL_MAP:
	91
	92	/*
	93	* The top half of HICR7 is the MSB of the BMC address of the
	94	* mapping.
	95	* The bottom half of HICR7 is the MSB of the HOST LPC
	96	* firmware space address of the mapping.
	97	*
	98	* The 1 bits in the top of half of HICR8 represent the bits
	99	* (in the requested address) that should be ignored and
	100	* replaced with those from the top half of HICR7.
	101	* The 1 bits in the bottom half of HICR8 represent the bits
	102	* (in the requested address) that should be kept and pass
	103	* into the BMC address space.
	104	*/
	105
	106	/*
	107	* It doesn't make sense to talk about a size or offset with
	108	* low 16 bits set. Both HICR7 and HICR8 talk about the top 16
	109	* bits of addresses and sizes.
	110	*/
	111
	112	if ((map.size & 0x0000ffff) \|\| (map.offset & 0x0000ffff))
	113	return -EINVAL;
	114
	115	/*
116	* Because of the way the masks work in HICR8 offset has to
117	* be a multiple of size.
118	*/
119	if (map.offset & (map.size - 1))
120	return -EINVAL;
121
122	if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
123	addr = lpc_ctrl->pnor_base;
124	size = lpc_ctrl->pnor_size;
125	} else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
126	addr = lpc_ctrl->mem_base;
127	size = lpc_ctrl->mem_size;
128	} else {
129	return -EINVAL;
130	}
131
132	/* Check overflow first! */
133	if (map.offset + map.size < map.offset \|\|
134	map.offset + map.size > size)
135	return -EINVAL;
136
137	if (map.size == 0 \|\| map.size > size)
138	return -EINVAL;
139
140	addr += map.offset;
141
142	/*
143	* addr (host lpc address) is safe regardless of values. This
144	* simply changes the address the host has to request on its
145	* side of the LPC bus. This cannot impact the hosts own
146	* memory space by surprise as LPC specific accessors are
147	* required. The only strange thing that could be done is
148	* setting the lower 16 bits but the shift takes care of that.
149	*/
150
151	rc = regmap_write(lpc_ctrl->regmap, HICR7,
152	(addr \| (map.addr >> 16)));
153	if (rc)
154	return rc;
155
156	return regmap_write(lpc_ctrl->regmap, HICR8,
157	(~(map.size - 1)) \| ((map.size >> 16) - 1));
158	}
159
160	return -EINVAL;
161	}
162
163	static const struct file_operations aspeed_lpc_ctrl_fops = {
164	.owner = THIS_MODULE,
165	.mmap = aspeed_lpc_ctrl_mmap,
166	.unlocked_ioctl = aspeed_lpc_ctrl_ioctl,
167	};
168
169	static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
170	{
171	struct aspeed_lpc_ctrl *lpc_ctrl;
172	struct device_node *node;
173	struct resource resm;
174	struct device *dev;
175	int rc;
176
177	dev = &pdev->dev;
178
179	lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
180	if (!lpc_ctrl)
181	return -ENOMEM;
182
183	node = of_parse_phandle(dev->of_node, "flash", 0);
184	if (!node) {
185	dev_err(dev, "Didn't find host pnor flash node\n");
186	return -ENODEV;
187	}
188
189	rc = of_address_to_resource(node, 1, &resm);
190	of_node_put(node);
191	if (rc) {
192	dev_err(dev, "Couldn't address to resource for flash\n");
193	return rc;
194	}
195
196	lpc_ctrl->pnor_size = resource_size(&resm);
197	lpc_ctrl->pnor_base = resm.start;
198
199	dev_set_drvdata(&pdev->dev, lpc_ctrl);
200
201	node = of_parse_phandle(dev->of_node, "memory-region", 0);
202	if (!node) {
203	dev_err(dev, "Didn't find reserved memory\n");
204	return -EINVAL;
205	}
206
207	rc = of_address_to_resource(node, 0, &resm);
208	of_node_put(node);
209	if (rc) {
210	dev_err(dev, "Couldn't address to resource for reserved memory\n");
211	return -ENOMEM;
212	}
213
214	lpc_ctrl->mem_size = resource_size(&resm);
215	lpc_ctrl->mem_base = resm.start;
216
217	lpc_ctrl->regmap = syscon_node_to_regmap(
218	pdev->dev.parent->of_node);
219	if (IS_ERR(lpc_ctrl->regmap)) {
220	dev_err(dev, "Couldn't get regmap\n");
221	return -ENODEV;
222	}
223
224	lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
225	lpc_ctrl->miscdev.name = DEVICE_NAME;
226	lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
227	lpc_ctrl->miscdev.parent = dev;
228	rc = misc_register(&lpc_ctrl->miscdev);
229	if (rc)
230	dev_err(dev, "Unable to register device\n");
231	else
8ff0c566	232	dev_info(dev, "Loaded at %pr\n", &resm);
6c4e9767 CB	233
	234	return rc;
	235	}
	236
	237	static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
	238	{
	239	struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);
	240
	241	misc_deregister(&lpc_ctrl->miscdev);
	242
	243	return 0;
	244	}
	245
	246	static const struct of_device_id aspeed_lpc_ctrl_match[] = {
	247	{ .compatible = "aspeed,ast2400-lpc-ctrl" },
	248	{ .compatible = "aspeed,ast2500-lpc-ctrl" },
	249	{ },
	250	};
	251
	252	static struct platform_driver aspeed_lpc_ctrl_driver = {
	253	.driver = {
	254	.name = DEVICE_NAME,
	255	.of_match_table = aspeed_lpc_ctrl_match,
	256	},
	257	.probe = aspeed_lpc_ctrl_probe,
	258	.remove = aspeed_lpc_ctrl_remove,
	259	};
	260
	261	module_platform_driver(aspeed_lpc_ctrl_driver);
	262
	263	MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
	264	MODULE_LICENSE("GPL");
	265	MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
	266	MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");