1 // SPDX-License-Identifier: GPL-2.0-or-later
5  * Provides a simple driver to control the ASPEED LPC snoop interface which
7  * the host to an arbitrary LPC I/O port.
9  * Typically used by the BMC to "watch" host boot progress via port
26 #define DEVICE_NAME	"aspeed-lpc-snoop"
54 	/* The ast2400 has bits 14 and 15 as reserved, whereas the ast2500
76 	return container_of(file->private_data,  in snoop_file_to_chan()
88 	if (kfifo_is_empty(&chan->fifo)) {  in snoop_file_read()
89 		if (file->f_flags & O_NONBLOCK)  in snoop_file_read()
90 			return -EAGAIN;  in snoop_file_read()
91 		ret = wait_event_interruptible(chan->wq,  in snoop_file_read()
92 				!kfifo_is_empty(&chan->fifo));  in snoop_file_read()
93 		if (ret == -ERESTARTSYS)  in snoop_file_read()
94 			return -EINTR;  in snoop_file_read()
96 	ret = kfifo_to_user(&chan->fifo, buffer, count, &copied);  in snoop_file_read()
108 	poll_wait(file, &chan->wq, pt);  in snoop_file_poll()
109 	return !kfifo_is_empty(&chan->fifo) ? EPOLLIN : 0;  in snoop_file_poll()
122 	if (!kfifo_initialized(&chan->fifo))  in put_fifo_with_discard()
124 	if (kfifo_is_full(&chan->fifo))  in put_fifo_with_discard()
125 		kfifo_skip(&chan->fifo);  in put_fifo_with_discard()
126 	kfifo_put(&chan->fifo, val);  in put_fifo_with_discard()
127 	wake_up_interruptible(&chan->wq);  in put_fifo_with_discard()
135 	if (regmap_read(lpc_snoop->regmap, HICR6, &reg))  in aspeed_lpc_snoop_irq()
144 	regmap_write(lpc_snoop->regmap, HICR6, reg);  in aspeed_lpc_snoop_irq()
147 	regmap_read(lpc_snoop->regmap, SNPWDR, &data);  in aspeed_lpc_snoop_irq()
152 		put_fifo_with_discard(&lpc_snoop->chan[0], val);  in aspeed_lpc_snoop_irq()
157 		put_fifo_with_discard(&lpc_snoop->chan[1], val);  in aspeed_lpc_snoop_irq()
166 	struct device *dev = &pdev->dev;  in aspeed_lpc_snoop_config_irq()
169 	lpc_snoop->irq = platform_get_irq(pdev, 0);  in aspeed_lpc_snoop_config_irq()
170 	if (lpc_snoop->irq < 0)  in aspeed_lpc_snoop_config_irq()
171 		return -ENODEV;  in aspeed_lpc_snoop_config_irq()
173 	rc = devm_request_irq(dev, lpc_snoop->irq,  in aspeed_lpc_snoop_config_irq()
177 		dev_warn(dev, "Unable to request IRQ %d\n", lpc_snoop->irq);  in aspeed_lpc_snoop_config_irq()
178 		lpc_snoop->irq = 0;  in aspeed_lpc_snoop_config_irq()
194 	if (WARN_ON(lpc_snoop->chan[channel].enabled))  in aspeed_lpc_enable_snoop()
195 		return -EBUSY;  in aspeed_lpc_enable_snoop()
197 	init_waitqueue_head(&lpc_snoop->chan[channel].wq);  in aspeed_lpc_enable_snoop()
199 	rc = kfifo_alloc(&lpc_snoop->chan[channel].fifo,  in aspeed_lpc_enable_snoop()
204 	lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;  in aspeed_lpc_enable_snoop()
205 	lpc_snoop->chan[channel].miscdev.name =  in aspeed_lpc_enable_snoop()
207 	if (!lpc_snoop->chan[channel].miscdev.name) {  in aspeed_lpc_enable_snoop()
208 		rc = -ENOMEM;  in aspeed_lpc_enable_snoop()
211 	lpc_snoop->chan[channel].miscdev.fops = &snoop_fops;  in aspeed_lpc_enable_snoop()
212 	lpc_snoop->chan[channel].miscdev.parent = dev;  in aspeed_lpc_enable_snoop()
213 	rc = misc_register(&lpc_snoop->chan[channel].miscdev);  in aspeed_lpc_enable_snoop()
217 	/* Enable LPC snoop channel at requested port */  in aspeed_lpc_enable_snoop()
232 		rc = -EINVAL;  in aspeed_lpc_enable_snoop()
236 	regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);  in aspeed_lpc_enable_snoop()
237 	regmap_update_bits(lpc_snoop->regmap, SNPWADR, snpwadr_mask,  in aspeed_lpc_enable_snoop()
239 	if (model_data->has_hicrb_ensnp)  in aspeed_lpc_enable_snoop()
240 		regmap_update_bits(lpc_snoop->regmap, HICRB,  in aspeed_lpc_enable_snoop()
243 	lpc_snoop->chan[channel].enabled = true;  in aspeed_lpc_enable_snoop()
248 	misc_deregister(&lpc_snoop->chan[channel].miscdev);  in aspeed_lpc_enable_snoop()
250 	kfifo_free(&lpc_snoop->chan[channel].fifo);  in aspeed_lpc_enable_snoop()
257 	if (!lpc_snoop->chan[channel].enabled)  in aspeed_lpc_disable_snoop()
262 		regmap_update_bits(lpc_snoop->regmap, HICR5,  in aspeed_lpc_disable_snoop()
267 		regmap_update_bits(lpc_snoop->regmap, HICR5,  in aspeed_lpc_disable_snoop()
275 	lpc_snoop->chan[channel].enabled = false;  in aspeed_lpc_disable_snoop()
277 	misc_deregister(&lpc_snoop->chan[channel].miscdev);  in aspeed_lpc_disable_snoop()
278 	kfifo_free(&lpc_snoop->chan[channel].fifo);  in aspeed_lpc_disable_snoop()
289 	dev = &pdev->dev;  in aspeed_lpc_snoop_probe()
293 		return -ENOMEM;  in aspeed_lpc_snoop_probe()
295 	np = pdev->dev.parent->of_node;  in aspeed_lpc_snoop_probe()
296 	if (!of_device_is_compatible(np, "aspeed,ast2400-lpc-v2") &&  in aspeed_lpc_snoop_probe()
297 	    !of_device_is_compatible(np, "aspeed,ast2500-lpc-v2") &&  in aspeed_lpc_snoop_probe()
298 	    !of_device_is_compatible(np, "aspeed,ast2600-lpc-v2")) {  in aspeed_lpc_snoop_probe()
299 		dev_err(dev, "unsupported LPC device binding\n");  in aspeed_lpc_snoop_probe()
300 		return -ENODEV;  in aspeed_lpc_snoop_probe()
303 	lpc_snoop->regmap = syscon_node_to_regmap(np);  in aspeed_lpc_snoop_probe()
304 	if (IS_ERR(lpc_snoop->regmap)) {  in aspeed_lpc_snoop_probe()
306 		return -ENODEV;  in aspeed_lpc_snoop_probe()
309 	dev_set_drvdata(&pdev->dev, lpc_snoop);  in aspeed_lpc_snoop_probe()
311 	rc = of_property_read_u32_index(dev->of_node, "snoop-ports", 0, &port);  in aspeed_lpc_snoop_probe()
314 		return -ENODEV;  in aspeed_lpc_snoop_probe()
317 	lpc_snoop->clk = devm_clk_get(dev, NULL);  in aspeed_lpc_snoop_probe()
318 	if (IS_ERR(lpc_snoop->clk)) {  in aspeed_lpc_snoop_probe()
319 		rc = PTR_ERR(lpc_snoop->clk);  in aspeed_lpc_snoop_probe()
320 		if (rc != -EPROBE_DEFER)  in aspeed_lpc_snoop_probe()
324 	rc = clk_prepare_enable(lpc_snoop->clk);  in aspeed_lpc_snoop_probe()
339 	if (of_property_read_u32_index(dev->of_node, "snoop-ports",  in aspeed_lpc_snoop_probe()
351 	clk_disable_unprepare(lpc_snoop->clk);  in aspeed_lpc_snoop_probe()
358 	struct aspeed_lpc_snoop *lpc_snoop = dev_get_drvdata(&pdev->dev);  in aspeed_lpc_snoop_remove()
364 	clk_disable_unprepare(lpc_snoop->clk);  in aspeed_lpc_snoop_remove()
378 	{ .compatible = "aspeed,ast2400-lpc-snoop",
380 	{ .compatible = "aspeed,ast2500-lpc-snoop",
382 	{ .compatible = "aspeed,ast2600-lpc-snoop",
401 MODULE_DESCRIPTION("Linux driver to control Aspeed LPC snoop functionality");