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13#include <linux/bitops.h>
14#include <linux/interrupt.h>
15#include <linux/fs.h>
16#include <linux/kfifo.h>
17#include <linux/mfd/syscon.h>
18#include <linux/miscdevice.h>
19#include <linux/module.h>
20#include <linux/of.h>
21#include <linux/of_device.h>
22#include <linux/platform_device.h>
23#include <linux/poll.h>
24#include <linux/regmap.h>
25
26#define DEVICE_NAME "aspeed-lpc-snoop"
27
28#define NUM_SNOOP_CHANNELS 2
29#define SNOOP_FIFO_SIZE 2048
30
31#define HICR5 0x0
32#define HICR5_EN_SNP0W BIT(0)
33#define HICR5_ENINT_SNP0W BIT(1)
34#define HICR5_EN_SNP1W BIT(2)
35#define HICR5_ENINT_SNP1W BIT(3)
36
37#define HICR6 0x4
38#define HICR6_STR_SNP0W BIT(0)
39#define HICR6_STR_SNP1W BIT(1)
40#define SNPWADR 0x10
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 0x14
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 0x80
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 aspeed_lpc_snoop_channel chan[NUM_SNOOP_CHANNELS];
71};
72
73static struct aspeed_lpc_snoop_channel *snoop_file_to_chan(struct file *file)
74{
75 return container_of(file->private_data,
76 struct aspeed_lpc_snoop_channel,
77 miscdev);
78}
79
80static ssize_t snoop_file_read(struct file *file, char __user *buffer,
81 size_t count, loff_t *ppos)
82{
83 struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file);
84 unsigned int copied;
85 int ret = 0;
86
87 if (kfifo_is_empty(&chan->fifo)) {
88 if (file->f_flags & O_NONBLOCK)
89 return -EAGAIN;
90 ret = wait_event_interruptible(chan->wq,
91 !kfifo_is_empty(&chan->fifo));
92 if (ret == -ERESTARTSYS)
93 return -EINTR;
94 }
95 ret = kfifo_to_user(&chan->fifo, buffer, count, &copied);
96
97 return ret ? ret : copied;
98}
99
100static __poll_t snoop_file_poll(struct file *file,
101 struct poll_table_struct *pt)
102{
103 struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file);
104
105 poll_wait(file, &chan->wq, pt);
106 return !kfifo_is_empty(&chan->fifo) ? EPOLLIN : 0;
107}
108
109static const struct file_operations snoop_fops = {
110 .owner = THIS_MODULE,
111 .read = snoop_file_read,
112 .poll = snoop_file_poll,
113 .llseek = noop_llseek,
114};
115
116
117static void put_fifo_with_discard(struct aspeed_lpc_snoop_channel *chan, u8 val)
118{
119 if (!kfifo_initialized(&chan->fifo))
120 return;
121 if (kfifo_is_full(&chan->fifo))
122 kfifo_skip(&chan->fifo);
123 kfifo_put(&chan->fifo, val);
124 wake_up_interruptible(&chan->wq);
125}
126
127static irqreturn_t aspeed_lpc_snoop_irq(int irq, void *arg)
128{
129 struct aspeed_lpc_snoop *lpc_snoop = arg;
130 u32 reg, data;
131
132 if (regmap_read(lpc_snoop->regmap, HICR6, ®))
133 return IRQ_NONE;
134
135
136 reg &= (HICR6_STR_SNP0W | HICR6_STR_SNP1W);
137 if (!reg)
138 return IRQ_NONE;
139
140
141 regmap_write(lpc_snoop->regmap, HICR6, reg);
142
143
144 regmap_read(lpc_snoop->regmap, SNPWDR, &data);
145
146 if (reg & HICR6_STR_SNP0W) {
147 u8 val = (data & SNPWDR_CH0_MASK) >> SNPWDR_CH0_SHIFT;
148
149 put_fifo_with_discard(&lpc_snoop->chan[0], val);
150 }
151 if (reg & HICR6_STR_SNP1W) {
152 u8 val = (data & SNPWDR_CH1_MASK) >> SNPWDR_CH1_SHIFT;
153
154 put_fifo_with_discard(&lpc_snoop->chan[1], val);
155 }
156
157 return IRQ_HANDLED;
158}
159
160static int aspeed_lpc_snoop_config_irq(struct aspeed_lpc_snoop *lpc_snoop,
161 struct platform_device *pdev)
162{
163 struct device *dev = &pdev->dev;
164 int rc;
165
166 lpc_snoop->irq = platform_get_irq(pdev, 0);
167 if (!lpc_snoop->irq)
168 return -ENODEV;
169
170 rc = devm_request_irq(dev, lpc_snoop->irq,
171 aspeed_lpc_snoop_irq, IRQF_SHARED,
172 DEVICE_NAME, lpc_snoop);
173 if (rc < 0) {
174 dev_warn(dev, "Unable to request IRQ %d\n", lpc_snoop->irq);
175 lpc_snoop->irq = 0;
176 return rc;
177 }
178
179 return 0;
180}
181
182static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
183 struct device *dev,
184 int channel, u16 lpc_port)
185{
186 int rc = 0;
187 u32 hicr5_en, snpwadr_mask, snpwadr_shift, hicrb_en;
188 const struct aspeed_lpc_snoop_model_data *model_data =
189 of_device_get_match_data(dev);
190
191 init_waitqueue_head(&lpc_snoop->chan[channel].wq);
192
193 rc = kfifo_alloc(&lpc_snoop->chan[channel].fifo,
194 SNOOP_FIFO_SIZE, GFP_KERNEL);
195 if (rc)
196 return rc;
197
198 lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
199 lpc_snoop->chan[channel].miscdev.name =
200 devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
201 lpc_snoop->chan[channel].miscdev.fops = &snoop_fops;
202 lpc_snoop->chan[channel].miscdev.parent = dev;
203 rc = misc_register(&lpc_snoop->chan[channel].miscdev);
204 if (rc)
205 return rc;
206
207
208 switch (channel) {
209 case 0:
210 hicr5_en = HICR5_EN_SNP0W | HICR5_ENINT_SNP0W;
211 snpwadr_mask = SNPWADR_CH0_MASK;
212 snpwadr_shift = SNPWADR_CH0_SHIFT;
213 hicrb_en = HICRB_ENSNP0D;
214 break;
215 case 1:
216 hicr5_en = HICR5_EN_SNP1W | HICR5_ENINT_SNP1W;
217 snpwadr_mask = SNPWADR_CH1_MASK;
218 snpwadr_shift = SNPWADR_CH1_SHIFT;
219 hicrb_en = HICRB_ENSNP1D;
220 break;
221 default:
222 return -EINVAL;
223 }
224
225 regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);
226 regmap_update_bits(lpc_snoop->regmap, SNPWADR, snpwadr_mask,
227 lpc_port << snpwadr_shift);
228 if (model_data->has_hicrb_ensnp)
229 regmap_update_bits(lpc_snoop->regmap, HICRB,
230 hicrb_en, hicrb_en);
231
232 return rc;
233}
234
235static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
236 int channel)
237{
238 switch (channel) {
239 case 0:
240 regmap_update_bits(lpc_snoop->regmap, HICR5,
241 HICR5_EN_SNP0W | HICR5_ENINT_SNP0W,
242 0);
243 break;
244 case 1:
245 regmap_update_bits(lpc_snoop->regmap, HICR5,
246 HICR5_EN_SNP1W | HICR5_ENINT_SNP1W,
247 0);
248 break;
249 default:
250 return;
251 }
252
253 kfifo_free(&lpc_snoop->chan[channel].fifo);
254 misc_deregister(&lpc_snoop->chan[channel].miscdev);
255}
256
257static int aspeed_lpc_snoop_probe(struct platform_device *pdev)
258{
259 struct aspeed_lpc_snoop *lpc_snoop;
260 struct device *dev;
261 u32 port;
262 int rc;
263
264 dev = &pdev->dev;
265
266 lpc_snoop = devm_kzalloc(dev, sizeof(*lpc_snoop), GFP_KERNEL);
267 if (!lpc_snoop)
268 return -ENOMEM;
269
270 lpc_snoop->regmap = syscon_node_to_regmap(
271 pdev->dev.parent->of_node);
272 if (IS_ERR(lpc_snoop->regmap)) {
273 dev_err(dev, "Couldn't get regmap\n");
274 return -ENODEV;
275 }
276
277 dev_set_drvdata(&pdev->dev, lpc_snoop);
278
279 rc = of_property_read_u32_index(dev->of_node, "snoop-ports", 0, &port);
280 if (rc) {
281 dev_err(dev, "no snoop ports configured\n");
282 return -ENODEV;
283 }
284
285 rc = aspeed_lpc_snoop_config_irq(lpc_snoop, pdev);
286 if (rc)
287 return rc;
288
289 rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 0, port);
290 if (rc)
291 return rc;
292
293
294 if (of_property_read_u32_index(dev->of_node, "snoop-ports",
295 1, &port) == 0) {
296 rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 1, port);
297 if (rc)
298 aspeed_lpc_disable_snoop(lpc_snoop, 0);
299 }
300
301 return rc;
302}
303
304static int aspeed_lpc_snoop_remove(struct platform_device *pdev)
305{
306 struct aspeed_lpc_snoop *lpc_snoop = dev_get_drvdata(&pdev->dev);
307
308
309 aspeed_lpc_disable_snoop(lpc_snoop, 0);
310 aspeed_lpc_disable_snoop(lpc_snoop, 1);
311
312 return 0;
313}
314
315static const struct aspeed_lpc_snoop_model_data ast2400_model_data = {
316 .has_hicrb_ensnp = 0,
317};
318
319static const struct aspeed_lpc_snoop_model_data ast2500_model_data = {
320 .has_hicrb_ensnp = 1,
321};
322
323static const struct of_device_id aspeed_lpc_snoop_match[] = {
324 { .compatible = "aspeed,ast2400-lpc-snoop",
325 .data = &ast2400_model_data },
326 { .compatible = "aspeed,ast2500-lpc-snoop",
327 .data = &ast2500_model_data },
328 { },
329};
330
331static struct platform_driver aspeed_lpc_snoop_driver = {
332 .driver = {
333 .name = DEVICE_NAME,
334 .of_match_table = aspeed_lpc_snoop_match,
335 },
336 .probe = aspeed_lpc_snoop_probe,
337 .remove = aspeed_lpc_snoop_remove,
338};
339
340module_platform_driver(aspeed_lpc_snoop_driver);
341
342MODULE_DEVICE_TABLE(of, aspeed_lpc_snoop_match);
343MODULE_LICENSE("GPL");
344MODULE_AUTHOR("Robert Lippert <rlippert@google.com>");
345MODULE_DESCRIPTION("Linux driver to control Aspeed LPC snoop functionality");
346
