1 // SPDX-License-Identifier: GPL-2.0+
3  *  Serial Port driver for Aspeed VUART device
51  * The VUART is basically two UART 'front ends' connected by their FIFO
62  * to the host on the Host <-> BMC LPC bus. It could be different on a
66 static inline u8 aspeed_vuart_readb(struct aspeed_vuart *vuart, u8 reg)  in aspeed_vuart_readb()  argument
68 	return readb(vuart->port->port.membase + reg);  in aspeed_vuart_readb()
71 static inline void aspeed_vuart_writeb(struct aspeed_vuart *vuart, u8 val, u8 reg)  in aspeed_vuart_writeb()  argument
73 	writeb(val, vuart->port->port.membase + reg);  in aspeed_vuart_writeb()
79 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in lpc_address_show()  local
82 	addr = (aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRH) << 8) |  in lpc_address_show()
83 		(aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRL));  in lpc_address_show()
88 static int aspeed_vuart_set_lpc_address(struct aspeed_vuart *vuart, u32 addr)  in aspeed_vuart_set_lpc_address()  argument
91 		return -EINVAL;  in aspeed_vuart_set_lpc_address()
93 	aspeed_vuart_writeb(vuart, addr >> 8, ASPEED_VUART_ADDRH);  in aspeed_vuart_set_lpc_address()
94 	aspeed_vuart_writeb(vuart, addr >> 0, ASPEED_VUART_ADDRL);  in aspeed_vuart_set_lpc_address()
103 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in lpc_address_store()  local
111 	err = aspeed_vuart_set_lpc_address(vuart, val);  in lpc_address_store()
120 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in sirq_show()  local
123 	reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRB);  in sirq_show()
130 static int aspeed_vuart_set_sirq(struct aspeed_vuart *vuart, u32 sirq)  in aspeed_vuart_set_sirq()  argument
135 		return -EINVAL;  in aspeed_vuart_set_sirq()
140 	reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRB);  in aspeed_vuart_set_sirq()
143 	aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRB);  in aspeed_vuart_set_sirq()
151 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in sirq_store()  local
159 	err = aspeed_vuart_set_sirq(vuart, val);  in sirq_store()
168 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in sirq_polarity_show()  local
171 	reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA);  in sirq_polarity_show()
177 static void aspeed_vuart_set_sirq_polarity(struct aspeed_vuart *vuart,  in aspeed_vuart_set_sirq_polarity()  argument
180 	u8 reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA);  in aspeed_vuart_set_sirq_polarity()
187 	aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA);  in aspeed_vuart_set_sirq_polarity()
194 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in sirq_polarity_store()  local
202 	aspeed_vuart_set_sirq_polarity(vuart, val != 0);  in sirq_polarity_store()
220 static void aspeed_vuart_set_enabled(struct aspeed_vuart *vuart, bool enabled)  in aspeed_vuart_set_enabled()  argument
222 	u8 reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA);  in aspeed_vuart_set_enabled()
229 	aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA);  in aspeed_vuart_set_enabled()
232 static void aspeed_vuart_set_host_tx_discard(struct aspeed_vuart *vuart,  in aspeed_vuart_set_host_tx_discard()  argument
237 	reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA);  in aspeed_vuart_set_host_tx_discard()
245 	aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA);  in aspeed_vuart_set_host_tx_discard()
251 	struct aspeed_vuart *vuart = uart_8250_port->port.private_data;  in aspeed_vuart_startup()  local
258 	aspeed_vuart_set_host_tx_discard(vuart, false);  in aspeed_vuart_startup()
266 	struct aspeed_vuart *vuart = uart_8250_port->port.private_data;  in aspeed_vuart_shutdown()  local
268 	aspeed_vuart_set_host_tx_discard(vuart, true);  in aspeed_vuart_shutdown()
279 	lockdep_assert_held_once(&up->port.lock);  in __aspeed_vuart_set_throttle()
281 	up->ier &= ~irqs;  in __aspeed_vuart_set_throttle()
283 		up->ier |= irqs;  in __aspeed_vuart_set_throttle()
284 	serial_out(up, UART_IER, up->ier);  in __aspeed_vuart_set_throttle()
291 	spin_lock_irqsave(&port->lock, flags);  in aspeed_vuart_set_throttle()
293 	spin_unlock_irqrestore(&port->lock, flags);  in aspeed_vuart_set_throttle()
308 	struct aspeed_vuart *vuart = from_timer(vuart, timer, unthrottle_timer);  in aspeed_vuart_unthrottle_exp()  local
309 	struct uart_8250_port *up = vuart->port;  in aspeed_vuart_unthrottle_exp()
311 	if (!tty_buffer_space_avail(&up->port.state->port)) {  in aspeed_vuart_unthrottle_exp()
312 		mod_timer(&vuart->unthrottle_timer,  in aspeed_vuart_unthrottle_exp()
317 	aspeed_vuart_unthrottle(&up->port);  in aspeed_vuart_unthrottle_exp()
321  * Custom interrupt handler to manage finer-grained flow control. Although we
322  * have throttle/unthrottle callbacks, we've seen that the VUART device can
343 	spin_lock_irqsave(&port->lock, flags);  in aspeed_vuart_handle_irq()
348 		space = tty_buffer_space_avail(&port->state->port);  in aspeed_vuart_handle_irq()
352 			struct aspeed_vuart *vuart = port->private_data;  in aspeed_vuart_handle_irq()  local
355 			if (!timer_pending(&vuart->unthrottle_timer))  in aspeed_vuart_handle_irq()
356 				mod_timer(&vuart->unthrottle_timer,  in aspeed_vuart_handle_irq()
365 				if (--count == 0)  in aspeed_vuart_handle_irq()
369 			tty_flip_buffer_push(&port->state->port);  in aspeed_vuart_handle_irq()
383 	struct aspeed_vuart *vuart, struct device_node *syscon_np,  in aspeed_vuart_auto_configure_sirq_polarity()  argument
391 		dev_warn(vuart->dev,  in aspeed_vuart_auto_configure_sirq_polarity()
392 			 "could not get regmap for aspeed,sirq-polarity-sense\n");  in aspeed_vuart_auto_configure_sirq_polarity()
396 		dev_warn(vuart->dev, "could not read hw strap table\n");  in aspeed_vuart_auto_configure_sirq_polarity()
400 	aspeed_vuart_set_sirq_polarity(vuart, (value & reg_mask) == 0);  in aspeed_vuart_auto_configure_sirq_polarity()
411 		return -EINVAL;  in aspeed_vuart_map_irq_polarity()
419 	struct aspeed_vuart *vuart;  in aspeed_vuart_probe()  local
425 	np = pdev->dev.of_node;  in aspeed_vuart_probe()
427 	vuart = devm_kzalloc(&pdev->dev, sizeof(*vuart), GFP_KERNEL);  in aspeed_vuart_probe()
428 	if (!vuart)  in aspeed_vuart_probe()
429 		return -ENOMEM;  in aspeed_vuart_probe()
431 	vuart->dev = &pdev->dev;  in aspeed_vuart_probe()
432 	timer_setup(&vuart->unthrottle_timer, aspeed_vuart_unthrottle_exp, 0);  in aspeed_vuart_probe()
436 		return -EINVAL;  in aspeed_vuart_probe()
439 	port.port.private_data = vuart;  in aspeed_vuart_probe()
440 	port.port.mapbase = res->start;  in aspeed_vuart_probe()
447 	port.port.dev = &pdev->dev;  in aspeed_vuart_probe()
451 	rc = sysfs_create_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);  in aspeed_vuart_probe()
455 	if (of_property_read_u32(np, "clock-frequency", &clk)) {  in aspeed_vuart_probe()
456 		vuart->clk = devm_clk_get(&pdev->dev, NULL);  in aspeed_vuart_probe()
457 		if (IS_ERR(vuart->clk)) {  in aspeed_vuart_probe()
458 			dev_warn(&pdev->dev,  in aspeed_vuart_probe()
459 				"clk or clock-frequency not defined\n");  in aspeed_vuart_probe()
460 			rc = PTR_ERR(vuart->clk);  in aspeed_vuart_probe()
464 		rc = clk_prepare_enable(vuart->clk);  in aspeed_vuart_probe()
468 		clk = clk_get_rate(vuart->clk);  in aspeed_vuart_probe()
471 	/* If current-speed was set, then try not to change it. */  in aspeed_vuart_probe()
472 	if (of_property_read_u32(np, "current-speed", &prop) == 0)  in aspeed_vuart_probe()
476 	if (of_property_read_u32(np, "reg-offset", &prop) == 0)  in aspeed_vuart_probe()
480 	if (of_property_read_u32(np, "reg-shift", &prop) == 0)  in aspeed_vuart_probe()
484 	if (of_property_read_u32(np, "fifo-size", &prop) == 0)  in aspeed_vuart_probe()
500 	if (of_property_read_bool(np, "no-loopback-test"))  in aspeed_vuart_probe()
506 	if (of_property_read_bool(np, "auto-flow-control"))  in aspeed_vuart_probe()
513 	vuart->line = rc;  in aspeed_vuart_probe()
514 	vuart->port = serial8250_get_port(vuart->line);  in aspeed_vuart_probe()
517 		np, "aspeed,sirq-polarity-sense", 2, 0,  in aspeed_vuart_probe()
520 		dev_dbg(&pdev->dev,  in aspeed_vuart_probe()
521 			"aspeed,sirq-polarity-sense property not found\n");  in aspeed_vuart_probe()
524 			vuart, sirq_polarity_sense_args.np,  in aspeed_vuart_probe()
530 	rc = of_property_read_u32(np, "aspeed,lpc-io-reg", &prop);  in aspeed_vuart_probe()
534 	rc = aspeed_vuart_set_lpc_address(vuart, prop);  in aspeed_vuart_probe()
536 		dev_err(&pdev->dev, "invalid value in aspeed,lpc-io-reg property\n");  in aspeed_vuart_probe()
540 	rc = of_property_read_u32_array(np, "aspeed,lpc-interrupts", sirq, 2);  in aspeed_vuart_probe()
546 	rc = aspeed_vuart_set_sirq(vuart, sirq[0]);  in aspeed_vuart_probe()
548 		dev_err(&pdev->dev, "invalid sirq number in aspeed,lpc-interrupts property\n");  in aspeed_vuart_probe()
554 		dev_err(&pdev->dev, "invalid sirq polarity in aspeed,lpc-interrupts property\n");  in aspeed_vuart_probe()
559 	aspeed_vuart_set_sirq_polarity(vuart, sirq_polarity);  in aspeed_vuart_probe()
561 	aspeed_vuart_set_enabled(vuart, true);  in aspeed_vuart_probe()
562 	aspeed_vuart_set_host_tx_discard(vuart, true);  in aspeed_vuart_probe()
563 	platform_set_drvdata(pdev, vuart);  in aspeed_vuart_probe()
568 	clk_disable_unprepare(vuart->clk);  in aspeed_vuart_probe()
571 	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);  in aspeed_vuart_probe()
577 	struct aspeed_vuart *vuart = platform_get_drvdata(pdev);  in aspeed_vuart_remove()  local
579 	del_timer_sync(&vuart->unthrottle_timer);  in aspeed_vuart_remove()
580 	aspeed_vuart_set_enabled(vuart, false);  in aspeed_vuart_remove()
581 	serial8250_unregister_port(vuart->line);  in aspeed_vuart_remove()
582 	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);  in aspeed_vuart_remove()
583 	clk_disable_unprepare(vuart->clk);  in aspeed_vuart_remove()
589 	{ .compatible = "aspeed,ast2400-vuart" },
590 	{ .compatible = "aspeed,ast2500-vuart" },
596 		.name = "aspeed-vuart",
607 MODULE_DESCRIPTION("Driver for Aspeed VUART device");