1
2
3
4
5
6
7
8
9
10
11
12
13#include <linux/bitops.h>
14#include <linux/clk.h>
15#include <linux/interrupt.h>
16#include <linux/fs.h>
17#include <linux/kfifo.h>
18#include <linux/mfd/syscon.h>
19#include <linux/miscdevice.h>
20#include <linux/module.h>
21#include <linux/of.h>
22#include <linux/of_device.h>
23#include <linux/platform_device.h>
24#include <linux/poll.h>
25#include <linux/regmap.h>
26
27#define DEVICE_NAME "aspeed-lpc-snoop"
28
29#define NUM_SNOOP_CHANNELS 2
30#define SNOOP_FIFO_SIZE 2048
31
32#define HICR5 0x80
33#define HICR5_EN_SNP0W BIT(0)
34#define HICR5_ENINT_SNP0W BIT(1)
35#define HICR5_EN_SNP1W BIT(2)
36#define HICR5_ENINT_SNP1W BIT(3)
37#define HICR6 0x84
38#define HICR6_STR_SNP0W BIT(0)
39#define HICR6_STR_SNP1W BIT(1)
40#define SNPWADR 0x90
41#define SNPWADR_CH0_MASK GENMASK(15, 0)
42#define SNPWADR_CH0_SHIFT 0
43#define SNPWADR_CH1_MASK GENMASK(31, 16)
44#define SNPWADR_CH1_SHIFT 16
45#define SNPWDR 0x94
46#define SNPWDR_CH0_MASK GENMASK(7, 0)
47#define SNPWDR_CH0_SHIFT 0
48#define SNPWDR_CH1_MASK GENMASK(15, 8)
49#define SNPWDR_CH1_SHIFT 8
50#define HICRB 0x100
51#define HICRB_ENSNP0D BIT(14)
52#define HICRB_ENSNP1D BIT(15)
53
54struct aspeed_lpc_snoop_model_data {
55
56
57
58 unsigned int has_hicrb_ensnp;
59};
60
61struct aspeed_lpc_snoop_channel {
62 struct kfifo fifo;
63 wait_queue_head_t wq;
64 struct miscdevice miscdev;
65};
66
67struct aspeed_lpc_snoop {
68 struct regmap *regmap;
69 int irq;
70 struct clk *clk;
71 struct aspeed_lpc_snoop_channel chan[NUM_SNOOP_CHANNELS];
72};
73
74static struct aspeed_lpc_snoop_channel *snoop_file_to_chan(struct file *file)
75{
76 return container_of(file->private_data,
77 struct aspeed_lpc_snoop_channel,
78 miscdev);
79}
80
81static ssize_t snoop_file_read(struct file *file, char __user *buffer,
82 size_t count, loff_t *ppos)
83{
84 struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file);
85 unsigned int copied;
86 int ret = 0;
87
88 if (kfifo_is_empty(&chan->fifo)) {
89 if (file->f_flags & O_NONBLOCK)
90 return -EAGAIN;
91 ret = wait_event_interruptible(chan->wq,
92 !kfifo_is_empty(&chan->fifo));
93 if (ret == -ERESTARTSYS)
94 return -EINTR;
95 }
96 ret = kfifo_to_user(&chan->fifo, buffer, count, &copied);
97 if (ret)
98 return ret;
99
100 return copied;
101}
102
103static __poll_t snoop_file_poll(struct file *file,
104 struct poll_table_struct *pt)
105{
106 struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file);
107
108 poll_wait(file, &chan->wq, pt);
109 return !kfifo_is_empty(&chan->fifo) ? EPOLLIN : 0;
110}
111
112static const struct file_operations snoop_fops = {
113 .owner = THIS_MODULE,
114 .read = snoop_file_read,
115 .poll = snoop_file_poll,
116 .llseek = noop_llseek,
117};
118
119
120static void put_fifo_with_discard(struct aspeed_lpc_snoop_channel *chan, u8 val)
121{
122 if (!kfifo_initialized(&chan->fifo))
123 return;
124 if (kfifo_is_full(&chan->fifo))
125 kfifo_skip(&chan->fifo);
126 kfifo_put(&chan->fifo, val);
127 wake_up_interruptible(&chan->wq);
128}
129
130static irqreturn_t aspeed_lpc_snoop_irq(int irq, void *arg)
131{
132 struct aspeed_lpc_snoop *lpc_snoop = arg;
133 u32 reg, data;
134
135 if (regmap_read(lpc_snoop->regmap, HICR6, ®))
136 return IRQ_NONE;
137
138
139 reg &= (HICR6_STR_SNP0W | HICR6_STR_SNP1W);
140 if (!reg)
141 return IRQ_NONE;
142
143
144 regmap_write(lpc_snoop->regmap, HICR6, reg);
145
146
147 regmap_read(lpc_snoop->regmap, SNPWDR, &data);
148
149 if (reg & HICR6_STR_SNP0W) {
150 u8 val = (data & SNPWDR_CH0_MASK) >> SNPWDR_CH0_SHIFT;
151
152 put_fifo_with_discard(&lpc_snoop->chan[0], val);
153 }
154 if (reg & HICR6_STR_SNP1W) {
155 u8 val = (data & SNPWDR_CH1_MASK) >> SNPWDR_CH1_SHIFT;
156
157 put_fifo_with_discard(&lpc_snoop->chan[1], val);
158 }
159
160 return IRQ_HANDLED;
161}
162
163static int aspeed_lpc_snoop_config_irq(struct aspeed_lpc_snoop *lpc_snoop,
164 struct platform_device *pdev)
165{
166 struct device *dev = &pdev->dev;
167 int rc;
168
169 lpc_snoop->irq = platform_get_irq(pdev, 0);
170 if (!lpc_snoop->irq)
171 return -ENODEV;
172
173 rc = devm_request_irq(dev, lpc_snoop->irq,
174 aspeed_lpc_snoop_irq, IRQF_SHARED,
175 DEVICE_NAME, lpc_snoop);
176 if (rc < 0) {
177 dev_warn(dev, "Unable to request IRQ %d\n", lpc_snoop->irq);
178 lpc_snoop->irq = 0;
179 return rc;
180 }
181
182 return 0;
183}
184
185static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
186 struct device *dev,
187 int channel, u16 lpc_port)
188{
189 int rc = 0;
190 u32 hicr5_en, snpwadr_mask, snpwadr_shift, hicrb_en;
191 const struct aspeed_lpc_snoop_model_data *model_data =
192 of_device_get_match_data(dev);
193
194 init_waitqueue_head(&lpc_snoop->chan[channel].wq);
195
196 rc = kfifo_alloc(&lpc_snoop->chan[channel].fifo,
197 SNOOP_FIFO_SIZE, GFP_KERNEL);
198 if (rc)
199 return rc;
200
201 lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
202 lpc_snoop->chan[channel].miscdev.name =
203 devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
204 lpc_snoop->chan[channel].miscdev.fops = &snoop_fops;
205 lpc_snoop->chan[channel].miscdev.parent = dev;
206 rc = misc_register(&lpc_snoop->chan[channel].miscdev);
207 if (rc)
208 return rc;
209
210
211 switch (channel) {
212 case 0:
213 hicr5_en = HICR5_EN_SNP0W | HICR5_ENINT_SNP0W;
214 snpwadr_mask = SNPWADR_CH0_MASK;
215 snpwadr_shift = SNPWADR_CH0_SHIFT;
216 hicrb_en = HICRB_ENSNP0D;
217 break;
218 case 1:
219 hicr5_en = HICR5_EN_SNP1W | HICR5_ENINT_SNP1W;
220 snpwadr_mask = SNPWADR_CH1_MASK;
221 snpwadr_shift = SNPWADR_CH1_SHIFT;
222 hicrb_en = HICRB_ENSNP1D;
223 break;
224 default:
225 return -EINVAL;
226 }
227
228 regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);
229 regmap_update_bits(lpc_snoop->regmap, SNPWADR, snpwadr_mask,
230 lpc_port << snpwadr_shift);
231 if (model_data->has_hicrb_ensnp)
232 regmap_update_bits(lpc_snoop->regmap, HICRB,
233 hicrb_en, hicrb_en);
234
235 return rc;
236}
237
238static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
239 int channel)
240{
241 switch (channel) {
242 case 0:
243 regmap_update_bits(lpc_snoop->regmap, HICR5,
244 HICR5_EN_SNP0W | HICR5_ENINT_SNP0W,
245 0);
246 break;
247 case 1:
248 regmap_update_bits(lpc_snoop->regmap, HICR5,
249 HICR5_EN_SNP1W | HICR5_ENINT_SNP1W,
250 0);
251 break;
252 default:
253 return;
254 }
255
256 kfifo_free(&lpc_snoop->chan[channel].fifo);
257 misc_deregister(&lpc_snoop->chan[channel].miscdev);
258}
259
260static int aspeed_lpc_snoop_probe(struct platform_device *pdev)
261{
262 struct aspeed_lpc_snoop *lpc_snoop;
263 struct device *dev;
264 struct device_node *np;
265 u32 port;
266 int rc;
267
268 dev = &pdev->dev;
269
270 lpc_snoop = devm_kzalloc(dev, sizeof(*lpc_snoop), GFP_KERNEL);
271 if (!lpc_snoop)
272 return -ENOMEM;
273
274 np = pdev->dev.parent->of_node;
275 if (!of_device_is_compatible(np, "aspeed,ast2400-lpc-v2") &&
276 !of_device_is_compatible(np, "aspeed,ast2500-lpc-v2") &&
277 !of_device_is_compatible(np, "aspeed,ast2600-lpc-v2")) {
278 dev_err(dev, "unsupported LPC device binding\n");
279 return -ENODEV;
280 }
281
282 lpc_snoop->regmap = syscon_node_to_regmap(np);
283 if (IS_ERR(lpc_snoop->regmap)) {
284 dev_err(dev, "Couldn't get regmap\n");
285 return -ENODEV;
286 }
287
288 dev_set_drvdata(&pdev->dev, lpc_snoop);
289
290 rc = of_property_read_u32_index(dev->of_node, "snoop-ports", 0, &port);
291 if (rc) {
292 dev_err(dev, "no snoop ports configured\n");
293 return -ENODEV;
294 }
295
296 lpc_snoop->clk = devm_clk_get(dev, NULL);
297 if (IS_ERR(lpc_snoop->clk)) {
298 rc = PTR_ERR(lpc_snoop->clk);
299 if (rc != -EPROBE_DEFER)
300 dev_err(dev, "couldn't get clock\n");
301 return rc;
302 }
303 rc = clk_prepare_enable(lpc_snoop->clk);
304 if (rc) {
305 dev_err(dev, "couldn't enable clock\n");
306 return rc;
307 }
308
309 rc = aspeed_lpc_snoop_config_irq(lpc_snoop, pdev);
310 if (rc)
311 goto err;
312
313 rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 0, port);
314 if (rc)
315 goto err;
316
317
318 if (of_property_read_u32_index(dev->of_node, "snoop-ports",
319 1, &port) == 0) {
320 rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 1, port);
321 if (rc) {
322 aspeed_lpc_disable_snoop(lpc_snoop, 0);
323 goto err;
324 }
325 }
326
327 return 0;
328
329err:
330 clk_disable_unprepare(lpc_snoop->clk);
331
332 return rc;
333}
334
335static int aspeed_lpc_snoop_remove(struct platform_device *pdev)
336{
337 struct aspeed_lpc_snoop *lpc_snoop = dev_get_drvdata(&pdev->dev);
338
339
340 aspeed_lpc_disable_snoop(lpc_snoop, 0);
341 aspeed_lpc_disable_snoop(lpc_snoop, 1);
342
343 clk_disable_unprepare(lpc_snoop->clk);
344
345 return 0;
346}
347
348static const struct aspeed_lpc_snoop_model_data ast2400_model_data = {
349 .has_hicrb_ensnp = 0,
350};
351
352static const struct aspeed_lpc_snoop_model_data ast2500_model_data = {
353 .has_hicrb_ensnp = 1,
354};
355
356static const struct of_device_id aspeed_lpc_snoop_match[] = {
357 { .compatible = "aspeed,ast2400-lpc-snoop",
358 .data = &ast2400_model_data },
359 { .compatible = "aspeed,ast2500-lpc-snoop",
360 .data = &ast2500_model_data },
361 { .compatible = "aspeed,ast2600-lpc-snoop",
362 .data = &ast2500_model_data },
363 { },
364};
365
366static struct platform_driver aspeed_lpc_snoop_driver = {
367 .driver = {
368 .name = DEVICE_NAME,
369 .of_match_table = aspeed_lpc_snoop_match,
370 },
371 .probe = aspeed_lpc_snoop_probe,
372 .remove = aspeed_lpc_snoop_remove,
373};
374
375module_platform_driver(aspeed_lpc_snoop_driver);
376
377MODULE_DEVICE_TABLE(of, aspeed_lpc_snoop_match);
378MODULE_LICENSE("GPL");
379MODULE_AUTHOR("Robert Lippert <rlippert@google.com>");
380MODULE_DESCRIPTION("Linux driver to control Aspeed LPC snoop functionality");
381
