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
31 struct 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
file_aspeed_lpc_ctrl(struct file * file)41 static 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
aspeed_lpc_ctrl_mmap(struct file * file,struct vm_area_struct * vma)47 static 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 + vma_pages(vma) > lpc_ctrl->mem_size >> PAGE_SHIFT)
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
aspeed_lpc_ctrl_ioctl(struct file * file,unsigned int cmd,unsigned long param)67 static 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
179 static 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
aspeed_lpc_ctrl_probe(struct platform_device * pdev)185 static 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
265 err:
266 clk_disable_unprepare(lpc_ctrl->clk);
267 return rc;
268 }
269
aspeed_lpc_ctrl_remove(struct platform_device * pdev)270 static 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
280 static const struct of_device_id aspeed_lpc_ctrl_match[] = {
281 { .compatible = "aspeed,ast2400-lpc-ctrl" },
282 { .compatible = "aspeed,ast2500-lpc-ctrl" },
283 { },
284 };
285
286 static 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
295 module_platform_driver(aspeed_lpc_ctrl_driver);
296
297 MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
298 MODULE_LICENSE("GPL");
299 MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
300 MODULE_DESCRIPTION("Control for aspeed 2400/2500 LPC HOST to BMC mappings");
301