1 // SPDX-License-Identifier: GPL-2.0+
3  *  Serial Port driver for Aspeed VUART device
50  * The VUART is basically two UART 'front ends' connected by their FIFO
61  * to the host on the Host <-> BMC LPC bus. It could be different on a
65 static inline u8 aspeed_vuart_readb(struct aspeed_vuart *vuart, u8 reg)  in aspeed_vuart_readb()  argument
67 	return readb(vuart->port->port.membase + reg);  in aspeed_vuart_readb()
70 static inline void aspeed_vuart_writeb(struct aspeed_vuart *vuart, u8 val, u8 reg)  in aspeed_vuart_writeb()  argument
72 	writeb(val, vuart->port->port.membase + reg);  in aspeed_vuart_writeb()
78 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in lpc_address_show()  local
81 	addr = (aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRH) << 8) |  in lpc_address_show()
82 		(aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRL));  in lpc_address_show()
87 static int aspeed_vuart_set_lpc_address(struct aspeed_vuart *vuart, u32 addr)  in aspeed_vuart_set_lpc_address()  argument
90 		return -EINVAL;  in aspeed_vuart_set_lpc_address()
92 	aspeed_vuart_writeb(vuart, addr >> 8, ASPEED_VUART_ADDRH);  in aspeed_vuart_set_lpc_address()
93 	aspeed_vuart_writeb(vuart, addr >> 0, ASPEED_VUART_ADDRL);  in aspeed_vuart_set_lpc_address()
102 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in lpc_address_store()  local
110 	err = aspeed_vuart_set_lpc_address(vuart, val);  in lpc_address_store()
119 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in sirq_show()  local
122 	reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRB);  in sirq_show()
129 static int aspeed_vuart_set_sirq(struct aspeed_vuart *vuart, u32 sirq)  in aspeed_vuart_set_sirq()  argument
134 		return -EINVAL;  in aspeed_vuart_set_sirq()
139 	reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRB);  in aspeed_vuart_set_sirq()
142 	aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRB);  in aspeed_vuart_set_sirq()
150 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in sirq_store()  local
158 	err = aspeed_vuart_set_sirq(vuart, val);  in sirq_store()
167 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in sirq_polarity_show()  local
170 	reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA);  in sirq_polarity_show()
176 static void aspeed_vuart_set_sirq_polarity(struct aspeed_vuart *vuart,  in aspeed_vuart_set_sirq_polarity()  argument
179 	u8 reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA);  in aspeed_vuart_set_sirq_polarity()
186 	aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA);  in aspeed_vuart_set_sirq_polarity()
193 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);  in sirq_polarity_store()  local
201 	aspeed_vuart_set_sirq_polarity(vuart, val != 0);  in sirq_polarity_store()
219 static void aspeed_vuart_set_enabled(struct aspeed_vuart *vuart, bool enabled)  in aspeed_vuart_set_enabled()  argument
221 	u8 reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA);  in aspeed_vuart_set_enabled()
228 	aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA);  in aspeed_vuart_set_enabled()
231 static void aspeed_vuart_set_host_tx_discard(struct aspeed_vuart *vuart,  in aspeed_vuart_set_host_tx_discard()  argument
236 	reg = aspeed_vuart_readb(vuart, ASPEED_VUART_GCRA);  in aspeed_vuart_set_host_tx_discard()
244 	aspeed_vuart_writeb(vuart, reg, ASPEED_VUART_GCRA);  in aspeed_vuart_set_host_tx_discard()
250 	struct aspeed_vuart *vuart = uart_8250_port->port.private_data;  in aspeed_vuart_startup()  local
257 	aspeed_vuart_set_host_tx_discard(vuart, false);  in aspeed_vuart_startup()
265 	struct aspeed_vuart *vuart = uart_8250_port->port.private_data;  in aspeed_vuart_shutdown()  local
267 	aspeed_vuart_set_host_tx_discard(vuart, true);  in aspeed_vuart_shutdown()
278 	lockdep_assert_held_once(&up->port.lock);  in __aspeed_vuart_set_throttle()
280 	up->ier &= ~irqs;  in __aspeed_vuart_set_throttle()
282 		up->ier |= irqs;  in __aspeed_vuart_set_throttle()
283 	serial_out(up, UART_IER, up->ier);  in __aspeed_vuart_set_throttle()
307 	struct aspeed_vuart *vuart = from_timer(vuart, timer, unthrottle_timer);  in aspeed_vuart_unthrottle_exp()  local
308 	struct uart_8250_port *up = vuart->port;  in aspeed_vuart_unthrottle_exp()
310 	if (!tty_buffer_space_avail(&up->port.state->port)) {  in aspeed_vuart_unthrottle_exp()
311 		mod_timer(&vuart->unthrottle_timer,  in aspeed_vuart_unthrottle_exp()
316 	aspeed_vuart_unthrottle(&up->port);  in aspeed_vuart_unthrottle_exp()
320  * Custom interrupt handler to manage finer-grained flow control. Although we
321  * have throttle/unthrottle callbacks, we've seen that the VUART device can
347 		space = tty_buffer_space_avail(&port->state->port);  in aspeed_vuart_handle_irq()
351 			struct aspeed_vuart *vuart = port->private_data;  in aspeed_vuart_handle_irq()  local
354 			if (!timer_pending(&vuart->unthrottle_timer))  in aspeed_vuart_handle_irq()
355 				mod_timer(&vuart->unthrottle_timer,  in aspeed_vuart_handle_irq()
364 				if (--count == 0)  in aspeed_vuart_handle_irq()
368 			tty_flip_buffer_push(&port->state->port);  in aspeed_vuart_handle_irq()
382 	struct aspeed_vuart *vuart, struct device_node *syscon_np,  in aspeed_vuart_auto_configure_sirq_polarity()  argument
390 		dev_warn(vuart->dev,  in aspeed_vuart_auto_configure_sirq_polarity()
391 			 "could not get regmap for aspeed,sirq-polarity-sense\n");  in aspeed_vuart_auto_configure_sirq_polarity()
395 		dev_warn(vuart->dev, "could not read hw strap table\n");  in aspeed_vuart_auto_configure_sirq_polarity()
399 	aspeed_vuart_set_sirq_polarity(vuart, (value & reg_mask) == 0);  in aspeed_vuart_auto_configure_sirq_polarity()
410 		return -EINVAL;  in aspeed_vuart_map_irq_polarity()
417 	struct device *dev = &pdev->dev;  in aspeed_vuart_probe()
419 	struct aspeed_vuart *vuart;  in aspeed_vuart_probe()  local
426 	np = pdev->dev.of_node;  in aspeed_vuart_probe()
428 	vuart = devm_kzalloc(&pdev->dev, sizeof(*vuart), GFP_KERNEL);  in aspeed_vuart_probe()
429 	if (!vuart)  in aspeed_vuart_probe()
430 		return -ENOMEM;  in aspeed_vuart_probe()
432 	vuart->dev = &pdev->dev;  in aspeed_vuart_probe()
433 	timer_setup(&vuart->unthrottle_timer, aspeed_vuart_unthrottle_exp, 0);  in aspeed_vuart_probe()
437 		return -EINVAL;  in aspeed_vuart_probe()
440 	port.port.private_data = vuart;  in aspeed_vuart_probe()
441 	port.port.mapbase = res->start;  in aspeed_vuart_probe()
448 	port.port.dev = &pdev->dev;  in aspeed_vuart_probe()
454 	rc = sysfs_create_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);  in aspeed_vuart_probe()
466 			rc = dev_err_probe(dev, PTR_ERR(vclk), "clk or clock-frequency not defined\n");  in aspeed_vuart_probe()
473 	/* If current-speed was set, then try not to change it. */  in aspeed_vuart_probe()
474 	if (of_property_read_u32(np, "current-speed", &prop) == 0)  in aspeed_vuart_probe()
483 	if (of_property_read_bool(np, "auto-flow-control"))  in aspeed_vuart_probe()
490 	vuart->line = rc;  in aspeed_vuart_probe()
491 	vuart->port = serial8250_get_port(vuart->line);  in aspeed_vuart_probe()
494 		np, "aspeed,sirq-polarity-sense", 2, 0,  in aspeed_vuart_probe()
497 		dev_dbg(&pdev->dev,  in aspeed_vuart_probe()
498 			"aspeed,sirq-polarity-sense property not found\n");  in aspeed_vuart_probe()
501 			vuart, sirq_polarity_sense_args.np,  in aspeed_vuart_probe()
507 	rc = of_property_read_u32(np, "aspeed,lpc-io-reg", &prop);  in aspeed_vuart_probe()
511 	rc = aspeed_vuart_set_lpc_address(vuart, prop);  in aspeed_vuart_probe()
513 		dev_err_probe(dev, rc, "invalid value in aspeed,lpc-io-reg property\n");  in aspeed_vuart_probe()
517 	rc = of_property_read_u32_array(np, "aspeed,lpc-interrupts", sirq, 2);  in aspeed_vuart_probe()
523 	rc = aspeed_vuart_set_sirq(vuart, sirq[0]);  in aspeed_vuart_probe()
525 		dev_err_probe(dev, rc, "invalid sirq number in aspeed,lpc-interrupts property\n");  in aspeed_vuart_probe()
532 				   "invalid sirq polarity in aspeed,lpc-interrupts property\n");  in aspeed_vuart_probe()
536 	aspeed_vuart_set_sirq_polarity(vuart, sirq_polarity);  in aspeed_vuart_probe()
538 	aspeed_vuart_set_enabled(vuart, true);  in aspeed_vuart_probe()
539 	aspeed_vuart_set_host_tx_discard(vuart, true);  in aspeed_vuart_probe()
540 	platform_set_drvdata(pdev, vuart);  in aspeed_vuart_probe()
545 	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);  in aspeed_vuart_probe()
551 	struct aspeed_vuart *vuart = platform_get_drvdata(pdev);  in aspeed_vuart_remove()  local
553 	del_timer_sync(&vuart->unthrottle_timer);  in aspeed_vuart_remove()
554 	aspeed_vuart_set_enabled(vuart, false);  in aspeed_vuart_remove()
555 	serial8250_unregister_port(vuart->line);  in aspeed_vuart_remove()
556 	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);  in aspeed_vuart_remove()
560 	{ .compatible = "aspeed,ast2400-vuart" },
561 	{ .compatible = "aspeed,ast2500-vuart" },
568 		.name = "aspeed-vuart",
579 MODULE_DESCRIPTION("Driver for Aspeed VUART device");