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/clk.h>
 11#include <linux/mfd/syscon.h>
 12#include <linux/miscdevice.h>
 13#include <linux/mm.h>
 14#include <linux/module.h>
 15#include <linux/of_address.h>
 16#include <linux/platform_device.h>
 17#include <linux/poll.h>
 18#include <linux/regmap.h>
 19
 20#include <linux/aspeed-lpc-ctrl.h>
 21
 22#define DEVICE_NAME	"aspeed-lpc-ctrl"
 23
 24#define HICR5 0x0
 25#define HICR5_ENL2H	BIT(8)
 26#define HICR5_ENFWH	BIT(10)
 27
 28#define HICR7 0x8
 29#define HICR8 0xc
 30
 31struct aspeed_lpc_ctrl {
 32	struct miscdevice	miscdev;
 33	struct regmap		*regmap;
 34	struct clk		*clk;
 35	phys_addr_t		mem_base;
 36	resource_size_t		mem_size;
 37	u32		pnor_size;
 38	u32		pnor_base;
 39};
 40
 41static struct aspeed_lpc_ctrl *file_aspeed_lpc_ctrl(struct file *file)
 42{
 43	return container_of(file->private_data, struct aspeed_lpc_ctrl,
 44			miscdev);
 45}
 46
 47static int aspeed_lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma)
 48{
 49	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
 50	unsigned long vsize = vma->vm_end - vma->vm_start;
 51	pgprot_t prot = vma->vm_page_prot;
 52
 53	if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size)
 54		return -EINVAL;
 55
 56	/* ast2400/2500 AHB accesses are not cache coherent */
 57	prot = pgprot_noncached(prot);
 58
 59	if (remap_pfn_range(vma, vma->vm_start,
 60		(lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
 61		vsize, prot))
 62		return -EAGAIN;
 63
 64	return 0;
 65}
 66
 67static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
 68		unsigned long param)
 69{
 70	struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
 71	void __user *p = (void __user *)param;
 72	struct aspeed_lpc_ctrl_mapping map;
 73	u32 addr;
 74	u32 size;
 75	long rc;
 76
 77	if (copy_from_user(&map, p, sizeof(map)))
 78		return -EFAULT;
 79
 80	if (map.flags != 0)
 81		return -EINVAL;
 82
 83	switch (cmd) {
 84	case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
 85		/* The flash windows don't report their size */
 86		if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
 87			return -EINVAL;
 88
 89		/* Support more than one window id in the future */
 90		if (map.window_id != 0)
 91			return -EINVAL;
 92
 93		map.size = lpc_ctrl->mem_size;
 94
 95		return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
 96	case ASPEED_LPC_CTRL_IOCTL_MAP:
 97
 98		/*
 99		 * The top half of HICR7 is the MSB of the BMC address of the
100		 * mapping.
101		 * The bottom half of HICR7 is the MSB of the HOST LPC
102		 * firmware space address of the mapping.
103		 *
104		 * The 1 bits in the top of half of HICR8 represent the bits
105		 * (in the requested address) that should be ignored and
106		 * replaced with those from the top half of HICR7.
107		 * The 1 bits in the bottom half of HICR8 represent the bits
108		 * (in the requested address) that should be kept and pass
109		 * into the BMC address space.
110		 */
111
112		/*
113		 * It doesn't make sense to talk about a size or offset with
114		 * low 16 bits set. Both HICR7 and HICR8 talk about the top 16
115		 * bits of addresses and sizes.
116		 */
117
118		if ((map.size & 0x0000ffff) || (map.offset & 0x0000ffff))
119			return -EINVAL;
120
121		/*
122		 * Because of the way the masks work in HICR8 offset has to
123		 * be a multiple of size.
124		 */
125		if (map.offset & (map.size - 1))
126			return -EINVAL;
127
128		if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
129			addr = lpc_ctrl->pnor_base;
130			size = lpc_ctrl->pnor_size;
131		} else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
132			addr = lpc_ctrl->mem_base;
133			size = lpc_ctrl->mem_size;
134		} else {
135			return -EINVAL;
136		}
137
138		/* Check overflow first! */
139		if (map.offset + map.size < map.offset ||
140			map.offset + map.size > size)
141			return -EINVAL;
142
143		if (map.size == 0 || map.size > size)
144			return -EINVAL;
145
146		addr += map.offset;
147
148		/*
149		 * addr (host lpc address) is safe regardless of values. This
150		 * simply changes the address the host has to request on its
151		 * side of the LPC bus. This cannot impact the hosts own
152		 * memory space by surprise as LPC specific accessors are
153		 * required. The only strange thing that could be done is
154		 * setting the lower 16 bits but the shift takes care of that.
155		 */
156
157		rc = regmap_write(lpc_ctrl->regmap, HICR7,
158				(addr | (map.addr >> 16)));
159		if (rc)
160			return rc;
161
162		rc = regmap_write(lpc_ctrl->regmap, HICR8,
163				(~(map.size - 1)) | ((map.size >> 16) - 1));
164		if (rc)
165			return rc;
166
167		/*
168		 * Enable LPC FHW cycles. This is required for the host to
169		 * access the regions specified.
170		 */
171		return regmap_update_bits(lpc_ctrl->regmap, HICR5,
172				HICR5_ENFWH | HICR5_ENL2H,
173				HICR5_ENFWH | HICR5_ENL2H);
174	}
175
176	return -EINVAL;
177}
178
179static const struct file_operations aspeed_lpc_ctrl_fops = {
180	.owner		= THIS_MODULE,
181	.mmap		= aspeed_lpc_ctrl_mmap,
182	.unlocked_ioctl	= aspeed_lpc_ctrl_ioctl,
183};
184
185static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
186{
187	struct aspeed_lpc_ctrl *lpc_ctrl;
188	struct device_node *node;
189	struct resource resm;
190	struct device *dev;
191	int rc;
192
193	dev = &pdev->dev;
194
195	lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
196	if (!lpc_ctrl)
197		return -ENOMEM;
198
199	node = of_parse_phandle(dev->of_node, "flash", 0);
200	if (!node) {
201		dev_err(dev, "Didn't find host pnor flash node\n");
202		return -ENODEV;
203	}
204
205	rc = of_address_to_resource(node, 1, &resm);
206	of_node_put(node);
207	if (rc) {
208		dev_err(dev, "Couldn't address to resource for flash\n");
209		return rc;
210	}
211
212	lpc_ctrl->pnor_size = resource_size(&resm);
213	lpc_ctrl->pnor_base = resm.start;
214
215	dev_set_drvdata(&pdev->dev, lpc_ctrl);
216
217	node = of_parse_phandle(dev->of_node, "memory-region", 0);
218	if (!node) {
219		dev_err(dev, "Didn't find reserved memory\n");
220		return -EINVAL;
221	}
222
223	rc = of_address_to_resource(node, 0, &resm);
224	of_node_put(node);
225	if (rc) {
226		dev_err(dev, "Couldn't address to resource for reserved memory\n");
227		return -ENOMEM;
228	}
229
230	lpc_ctrl->mem_size = resource_size(&resm);
231	lpc_ctrl->mem_base = resm.start;
232
233	lpc_ctrl->regmap = syscon_node_to_regmap(
234			pdev->dev.parent->of_node);
235	if (IS_ERR(lpc_ctrl->regmap)) {
236		dev_err(dev, "Couldn't get regmap\n");
237		return -ENODEV;
238	}
239
240	lpc_ctrl->clk = devm_clk_get(dev, NULL);
241	if (IS_ERR(lpc_ctrl->clk)) {
242		dev_err(dev, "couldn't get clock\n");
243		return PTR_ERR(lpc_ctrl->clk);
244	}
245	rc = clk_prepare_enable(lpc_ctrl->clk);
246	if (rc) {
247		dev_err(dev, "couldn't enable clock\n");
248		return rc;
249	}
250
251	lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
252	lpc_ctrl->miscdev.name = DEVICE_NAME;
253	lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
254	lpc_ctrl->miscdev.parent = dev;
255	rc = misc_register(&lpc_ctrl->miscdev);
256	if (rc) {
257		dev_err(dev, "Unable to register device\n");
258		goto err;
259	}
260
261	dev_info(dev, "Loaded at %pr\n", &resm);
262
263	return 0;
264
265err:
266	clk_disable_unprepare(lpc_ctrl->clk);
267	return rc;
268}
269
270static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
271{
272	struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);
273
274	misc_deregister(&lpc_ctrl->miscdev);
275	clk_disable_unprepare(lpc_ctrl->clk);
276
277	return 0;
278}
279
280static const struct of_device_id aspeed_lpc_ctrl_match[] = {
281	{ .compatible = "aspeed,ast2400-lpc-ctrl" },
282	{ .compatible = "aspeed,ast2500-lpc-ctrl" },
283	{ },
284};
285
286static struct platform_driver aspeed_lpc_ctrl_driver = {
287	.driver = {
288		.name		= DEVICE_NAME,
289		.of_match_table = aspeed_lpc_ctrl_match,
290	},
291	.probe = aspeed_lpc_ctrl_probe,
292	.remove = aspeed_lpc_ctrl_remove,
293};
294
295module_platform_driver(aspeed_lpc_ctrl_driver);
296
297MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
298MODULE_LICENSE("GPL");
299MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
300MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");