1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2017 IBM Corporation
4 */
5
6 #include <linux/clk.h>
7 #include <linux/log2.h>
8 #include <linux/mfd/syscon.h>
9 #include <linux/miscdevice.h>
10 #include <linux/mm.h>
11 #include <linux/module.h>
12 #include <linux/of_address.h>
13 #include <linux/platform_device.h>
14 #include <linux/poll.h>
15 #include <linux/regmap.h>
16
17 #include <linux/aspeed-lpc-ctrl.h>
18
19 #define DEVICE_NAME "aspeed-lpc-ctrl"
20
21 #define HICR5 0x80
22 #define HICR5_ENL2H BIT(8)
23 #define HICR5_ENFWH BIT(10)
24
25 #define HICR6 0x84
26 #define SW_FWH2AHB BIT(17)
27
28 #define HICR7 0x88
29 #define HICR8 0x8c
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 bool fwh2ahb;
40 struct regmap *scu;
41 };
42
file_aspeed_lpc_ctrl(struct file * file)43 static struct aspeed_lpc_ctrl *file_aspeed_lpc_ctrl(struct file *file)
44 {
45 return container_of(file->private_data, struct aspeed_lpc_ctrl,
46 miscdev);
47 }
48
aspeed_lpc_ctrl_mmap(struct file * file,struct vm_area_struct * vma)49 static int aspeed_lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma)
50 {
51 struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
52 unsigned long vsize = vma->vm_end - vma->vm_start;
53 pgprot_t prot = vma->vm_page_prot;
54
55 if (vma->vm_pgoff + vma_pages(vma) > lpc_ctrl->mem_size >> PAGE_SHIFT)
56 return -EINVAL;
57
58 /* ast2400/2500 AHB accesses are not cache coherent */
59 prot = pgprot_noncached(prot);
60
61 if (remap_pfn_range(vma, vma->vm_start,
62 (lpc_ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
63 vsize, prot))
64 return -EAGAIN;
65
66 return 0;
67 }
68
aspeed_lpc_ctrl_ioctl(struct file * file,unsigned int cmd,unsigned long param)69 static long aspeed_lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
70 unsigned long param)
71 {
72 struct aspeed_lpc_ctrl *lpc_ctrl = file_aspeed_lpc_ctrl(file);
73 struct device *dev = file->private_data;
74 void __user *p = (void __user *)param;
75 struct aspeed_lpc_ctrl_mapping map;
76 u32 addr;
77 u32 size;
78 long rc;
79
80 if (copy_from_user(&map, p, sizeof(map)))
81 return -EFAULT;
82
83 if (map.flags != 0)
84 return -EINVAL;
85
86 switch (cmd) {
87 case ASPEED_LPC_CTRL_IOCTL_GET_SIZE:
88 /* The flash windows don't report their size */
89 if (map.window_type != ASPEED_LPC_CTRL_WINDOW_MEMORY)
90 return -EINVAL;
91
92 /* Support more than one window id in the future */
93 if (map.window_id != 0)
94 return -EINVAL;
95
96 /* If memory-region is not described in device tree */
97 if (!lpc_ctrl->mem_size) {
98 dev_dbg(dev, "Didn't find reserved memory\n");
99 return -ENXIO;
100 }
101
102 map.size = lpc_ctrl->mem_size;
103
104 return copy_to_user(p, &map, sizeof(map)) ? -EFAULT : 0;
105 case ASPEED_LPC_CTRL_IOCTL_MAP:
106
107 /*
108 * The top half of HICR7 is the MSB of the BMC address of the
109 * mapping.
110 * The bottom half of HICR7 is the MSB of the HOST LPC
111 * firmware space address of the mapping.
112 *
113 * The 1 bits in the top of half of HICR8 represent the bits
114 * (in the requested address) that should be ignored and
115 * replaced with those from the top half of HICR7.
116 * The 1 bits in the bottom half of HICR8 represent the bits
117 * (in the requested address) that should be kept and pass
118 * into the BMC address space.
119 */
120
121 /*
122 * It doesn't make sense to talk about a size or offset with
123 * low 16 bits set. Both HICR7 and HICR8 talk about the top 16
124 * bits of addresses and sizes.
125 */
126
127 if ((map.size & 0x0000ffff) || (map.offset & 0x0000ffff))
128 return -EINVAL;
129
130 /*
131 * Because of the way the masks work in HICR8 offset has to
132 * be a multiple of size.
133 */
134 if (map.offset & (map.size - 1))
135 return -EINVAL;
136
137 if (map.window_type == ASPEED_LPC_CTRL_WINDOW_FLASH) {
138 if (!lpc_ctrl->pnor_size) {
139 dev_dbg(dev, "Didn't find host pnor flash\n");
140 return -ENXIO;
141 }
142 addr = lpc_ctrl->pnor_base;
143 size = lpc_ctrl->pnor_size;
144 } else if (map.window_type == ASPEED_LPC_CTRL_WINDOW_MEMORY) {
145 /* If memory-region is not described in device tree */
146 if (!lpc_ctrl->mem_size) {
147 dev_dbg(dev, "Didn't find reserved memory\n");
148 return -ENXIO;
149 }
150 addr = lpc_ctrl->mem_base;
151 size = lpc_ctrl->mem_size;
152 } else {
153 return -EINVAL;
154 }
155
156 /* Check overflow first! */
157 if (map.offset + map.size < map.offset ||
158 map.offset + map.size > size)
159 return -EINVAL;
160
161 if (map.size == 0 || map.size > size)
162 return -EINVAL;
163
164 addr += map.offset;
165
166 /*
167 * addr (host lpc address) is safe regardless of values. This
168 * simply changes the address the host has to request on its
169 * side of the LPC bus. This cannot impact the hosts own
170 * memory space by surprise as LPC specific accessors are
171 * required. The only strange thing that could be done is
172 * setting the lower 16 bits but the shift takes care of that.
173 */
174
175 rc = regmap_write(lpc_ctrl->regmap, HICR7,
176 (addr | (map.addr >> 16)));
177 if (rc)
178 return rc;
179
180 rc = regmap_write(lpc_ctrl->regmap, HICR8,
181 (~(map.size - 1)) | ((map.size >> 16) - 1));
182 if (rc)
183 return rc;
184
185 /*
186 * Switch to FWH2AHB mode, AST2600 only.
187 */
188 if (lpc_ctrl->fwh2ahb) {
189 /*
190 * Enable FWH2AHB in SCU debug control register 2. This
191 * does not turn it on, but makes it available for it
192 * to be configured in HICR6.
193 */
194 regmap_update_bits(lpc_ctrl->scu, 0x0D8, BIT(2), 0);
195
196 /*
197 * The other bits in this register are interrupt status bits
198 * that are cleared by writing 1. As we don't want to clear
199 * them, set only the bit of interest.
200 */
201 regmap_write(lpc_ctrl->regmap, HICR6, SW_FWH2AHB);
202 }
203
204 /*
205 * Enable LPC FHW cycles. This is required for the host to
206 * access the regions specified.
207 */
208 return regmap_update_bits(lpc_ctrl->regmap, HICR5,
209 HICR5_ENFWH | HICR5_ENL2H,
210 HICR5_ENFWH | HICR5_ENL2H);
211 }
212
213 return -EINVAL;
214 }
215
216 static const struct file_operations aspeed_lpc_ctrl_fops = {
217 .owner = THIS_MODULE,
218 .mmap = aspeed_lpc_ctrl_mmap,
219 .unlocked_ioctl = aspeed_lpc_ctrl_ioctl,
220 };
221
aspeed_lpc_ctrl_probe(struct platform_device * pdev)222 static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
223 {
224 struct aspeed_lpc_ctrl *lpc_ctrl;
225 struct device_node *node;
226 struct resource resm;
227 struct device *dev;
228 struct device_node *np;
229 int rc;
230
231 dev = &pdev->dev;
232
233 lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
234 if (!lpc_ctrl)
235 return -ENOMEM;
236
237 /* If flash is described in device tree then store */
238 node = of_parse_phandle(dev->of_node, "flash", 0);
239 if (!node) {
240 dev_dbg(dev, "Didn't find host pnor flash node\n");
241 } else {
242 rc = of_address_to_resource(node, 1, &resm);
243 of_node_put(node);
244 if (rc) {
245 dev_err(dev, "Couldn't address to resource for flash\n");
246 return rc;
247 }
248
249 lpc_ctrl->pnor_size = resource_size(&resm);
250 lpc_ctrl->pnor_base = resm.start;
251 }
252
253
254 dev_set_drvdata(&pdev->dev, lpc_ctrl);
255
256 /* If memory-region is described in device tree then store */
257 node = of_parse_phandle(dev->of_node, "memory-region", 0);
258 if (!node) {
259 dev_dbg(dev, "Didn't find reserved memory\n");
260 } else {
261 rc = of_address_to_resource(node, 0, &resm);
262 of_node_put(node);
263 if (rc) {
264 dev_err(dev, "Couldn't address to resource for reserved memory\n");
265 return -ENXIO;
266 }
267
268 lpc_ctrl->mem_size = resource_size(&resm);
269 lpc_ctrl->mem_base = resm.start;
270
271 if (!is_power_of_2(lpc_ctrl->mem_size)) {
272 dev_err(dev, "Reserved memory size must be a power of 2, got %u\n",
273 (unsigned int)lpc_ctrl->mem_size);
274 return -EINVAL;
275 }
276
277 if (!IS_ALIGNED(lpc_ctrl->mem_base, lpc_ctrl->mem_size)) {
278 dev_err(dev, "Reserved memory must be naturally aligned for size %u\n",
279 (unsigned int)lpc_ctrl->mem_size);
280 return -EINVAL;
281 }
282 }
283
284 np = pdev->dev.parent->of_node;
285 if (!of_device_is_compatible(np, "aspeed,ast2400-lpc-v2") &&
286 !of_device_is_compatible(np, "aspeed,ast2500-lpc-v2") &&
287 !of_device_is_compatible(np, "aspeed,ast2600-lpc-v2")) {
288 dev_err(dev, "unsupported LPC device binding\n");
289 return -ENODEV;
290 }
291
292 lpc_ctrl->regmap = syscon_node_to_regmap(np);
293 if (IS_ERR(lpc_ctrl->regmap)) {
294 dev_err(dev, "Couldn't get regmap\n");
295 return -ENODEV;
296 }
297
298 if (of_device_is_compatible(dev->of_node, "aspeed,ast2600-lpc-ctrl")) {
299 lpc_ctrl->fwh2ahb = true;
300
301 lpc_ctrl->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2600-scu");
302 if (IS_ERR(lpc_ctrl->scu)) {
303 dev_err(dev, "couldn't find scu\n");
304 return PTR_ERR(lpc_ctrl->scu);
305 }
306 }
307
308 lpc_ctrl->clk = devm_clk_get(dev, NULL);
309 if (IS_ERR(lpc_ctrl->clk))
310 return dev_err_probe(dev, PTR_ERR(lpc_ctrl->clk),
311 "couldn't get clock\n");
312 rc = clk_prepare_enable(lpc_ctrl->clk);
313 if (rc) {
314 dev_err(dev, "couldn't enable clock\n");
315 return rc;
316 }
317
318 lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
319 lpc_ctrl->miscdev.name = DEVICE_NAME;
320 lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
321 lpc_ctrl->miscdev.parent = dev;
322 rc = misc_register(&lpc_ctrl->miscdev);
323 if (rc) {
324 dev_err(dev, "Unable to register device\n");
325 goto err;
326 }
327
328 return 0;
329
330 err:
331 clk_disable_unprepare(lpc_ctrl->clk);
332 return rc;
333 }
334
aspeed_lpc_ctrl_remove(struct platform_device * pdev)335 static void aspeed_lpc_ctrl_remove(struct platform_device *pdev)
336 {
337 struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);
338
339 misc_deregister(&lpc_ctrl->miscdev);
340 clk_disable_unprepare(lpc_ctrl->clk);
341 }
342
343 static const struct of_device_id aspeed_lpc_ctrl_match[] = {
344 { .compatible = "aspeed,ast2400-lpc-ctrl" },
345 { .compatible = "aspeed,ast2500-lpc-ctrl" },
346 { .compatible = "aspeed,ast2600-lpc-ctrl" },
347 { },
348 };
349
350 static struct platform_driver aspeed_lpc_ctrl_driver = {
351 .driver = {
352 .name = DEVICE_NAME,
353 .of_match_table = aspeed_lpc_ctrl_match,
354 },
355 .probe = aspeed_lpc_ctrl_probe,
356 .remove_new = aspeed_lpc_ctrl_remove,
357 };
358
359 module_platform_driver(aspeed_lpc_ctrl_driver);
360
361 MODULE_DEVICE_TABLE(of, aspeed_lpc_ctrl_match);
362 MODULE_LICENSE("GPL");
363 MODULE_AUTHOR("Cyril Bur <cyrilbur@gmail.com>");
364 MODULE_DESCRIPTION("Control for ASPEED LPC HOST to BMC mappings");
365