1 // SPDX-License-Identifier: GPL-2.0-only
4  * 8250-core based driver for Broadcom ns16550a UARTs
20 #include <linux/dma-mapping.h>
29 /* Register definitions for UART DMA block. Version 1.1 or later. */
158 #define UDMA_RX_BUFS_REG_OFFSET (UDMA_RX_BUF1_PTR_LO - UDMA_RX_BUF0_PTR_LO)
170 #define UDMA_TX_BUFS_REG_OFFSET (UDMA_TX_BUF1_PTR_LO - UDMA_TX_BUF0_PTR_LO)
250 	return readl(priv->regs[reg_type] + offset);  in udma_readl()
256 	writel(value, priv->regs[reg_type] + offset);  in udma_writel()
262 	void __iomem *reg = priv->regs[reg_type] + offset;  in udma_set()
273 	void __iomem *reg = priv->regs[reg_type] + offset;  in udma_unset()
282  * The UART DMA engine hardware can be used by multiple UARTS, but
284  * the first UART to request the DMA engine will get it and any
304 			if (waits-- == 0)  in brcmuart_arbitration()
338 	daddr = priv->rx_addr;  in brcmuart_init_dma_hardware()
351 	daddr = priv->tx_addr;  in brcmuart_init_dma_hardware()
368 	struct brcmuart_priv *priv = p->port.private_data;  in start_rx_dma()
381 	priv->rx_next_buf = 0;  in start_rx_dma()
384 	priv->rx_running = true;  in start_rx_dma()
389 	struct brcmuart_priv *priv = p->port.private_data;  in stop_rx_dma()
392 	if (priv->rx_running)  in stop_rx_dma()
398 	struct brcmuart_priv *priv = p->port.private_data;  in stop_tx_dma()
405 	priv->tx_running = false;  in stop_tx_dma()
415 	struct brcmuart_priv *priv = p->port.private_data;  in brcmuart_tx_dma()
416 	struct tty_port *tport = &p->port.state->port;  in brcmuart_tx_dma()
419 	if (uart_tx_stopped(&p->port) || priv->tx_running ||  in brcmuart_tx_dma()
420 		kfifo_is_empty(&tport->xmit_fifo)) {  in brcmuart_tx_dma()
424 	priv->dma.tx_err = 0;  in brcmuart_tx_dma()
425 	tx_size = uart_fifo_out(&p->port, priv->tx_buf, UART_XMIT_SIZE);  in brcmuart_tx_dma()
427 	if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)  in brcmuart_tx_dma()
428 		uart_write_wakeup(&p->port);  in brcmuart_tx_dma()
434 	priv->tx_running = true;  in brcmuart_tx_dma()
441 	struct brcmuart_priv *priv = up->private_data;  in brcmuart_rx_buf_done_isr()
442 	struct tty_port *tty_port = &up->state->port;  in brcmuart_rx_buf_done_isr()
452 		dev_err(up->dev, "RX done interrupt but DATA_RDY not found\n");  in brcmuart_rx_buf_done_isr()
459 			up->icount.overrun++;  in brcmuart_rx_buf_done_isr()
460 			dev_warn(up->dev, "RX OVERRUN Error\n");  in brcmuart_rx_buf_done_isr()
463 			up->icount.frame++;  in brcmuart_rx_buf_done_isr()
464 			dev_warn(up->dev, "RX FRAMING Error\n");  in brcmuart_rx_buf_done_isr()
467 			up->icount.parity++;  in brcmuart_rx_buf_done_isr()
468 			dev_warn(up->dev, "RX PARITY Error\n");  in brcmuart_rx_buf_done_isr()
473 		priv->rx_bufs + (index * RX_BUF_SIZE),  in brcmuart_rx_buf_done_isr()
476 		dev_warn(up->dev, "Flip buffer overrun of %d bytes\n",  in brcmuart_rx_buf_done_isr()
477 			 length - copied);  in brcmuart_rx_buf_done_isr()
478 		up->icount.overrun += length - copied;  in brcmuart_rx_buf_done_isr()
480 	up->icount.rx += length;  in brcmuart_rx_buf_done_isr()
482 		priv->dma_rx_partial_buf++;  in brcmuart_rx_buf_done_isr()
488 		priv->rx_missing_close_timeout++;  in brcmuart_rx_buf_done_isr()
490 		priv->dma_rx_full_buf++;  in brcmuart_rx_buf_done_isr()
497 	struct brcmuart_priv *priv = up->private_data;  in brcmuart_rx_isr()
498 	struct device *dev = up->dev;  in brcmuart_rx_isr()
504 		check_isr = UDMA_INTR_RX_READY_BUF0 << priv->rx_next_buf;  in brcmuart_rx_isr()
506 			brcmuart_rx_buf_done_isr(up, priv->rx_next_buf);  in brcmuart_rx_isr()
515 				priv->rx_err++;  in brcmuart_rx_isr()
517 				priv->rx_timeout++;  in brcmuart_rx_isr()
521 				priv->rx_abort++;  in brcmuart_rx_isr()
522 			priv->rx_running = false;  in brcmuart_rx_isr()
524 		/* If not ABORT, re-enable RX buffer */  in brcmuart_rx_isr()
527 				   UDMA_RX_BUFx_STATUS(priv->rx_next_buf),  in brcmuart_rx_isr()
530 		priv->rx_next_buf++;  in brcmuart_rx_isr()
531 		if (priv->rx_next_buf == RX_BUFS_COUNT)  in brcmuart_rx_isr()
532 			priv->rx_next_buf = 0;  in brcmuart_rx_isr()
538 	struct brcmuart_priv *priv = up->private_data;  in brcmuart_tx_isr()
539 	struct device *dev = up->dev;  in brcmuart_tx_isr()
541 	struct tty_port *tport = &port_8250->port.state->port;  in brcmuart_tx_isr()
544 		if (priv->tx_running)  in brcmuart_tx_isr()
548 	priv->tx_running = false;  in brcmuart_tx_isr()
549 	if (!kfifo_is_empty(&tport->xmit_fifo) && !uart_tx_stopped(up))  in brcmuart_tx_isr()
556 	struct device *dev = up->dev;  in brcmuart_isr()
557 	struct brcmuart_priv *priv = up->private_data;  in brcmuart_isr()
589 	struct brcmuart_priv *priv = up->port.private_data;  in brcmuart_startup()
591 	priv->shutdown = false;  in brcmuart_startup()
594 	 * prevent serial8250_do_startup() from allocating non-existent  in brcmuart_startup()
597 	up->dma = NULL;  in brcmuart_startup()
600 	if (!priv->dma_enabled)  in brcmuart_startup()
609 	up->ier &= ~UART_IER_RDI;  in brcmuart_startup()
610 	serial_port_out(port, UART_IER, up->ier);  in brcmuart_startup()
613 	priv->tx_running = false;  in brcmuart_startup()
614 	priv->dma.rx_dma = NULL;  in brcmuart_startup()
615 	priv->dma.tx_dma = brcmuart_tx_dma;  in brcmuart_startup()
616 	up->dma = &priv->dma;  in brcmuart_startup()
626 	struct brcmuart_priv *priv = up->port.private_data;  in brcmuart_shutdown()
630 	priv->shutdown = true;  in brcmuart_shutdown()
631 	if (priv->dma_enabled) {  in brcmuart_shutdown()
643 	up->dma = NULL;  in brcmuart_shutdown()
658 	priv->default_mux_rate = clk_get_rate(priv->baud_mux_clk);  in init_real_clk_rates()
659 	for (x = 0; x < ARRAY_SIZE(priv->real_rates); x++) {  in init_real_clk_rates()
660 		if (priv->rate_table[x] == 0) {  in init_real_clk_rates()
661 			priv->real_rates[x] = 0;  in init_real_clk_rates()
664 		rc = clk_set_rate(priv->baud_mux_clk, priv->rate_table[x]);  in init_real_clk_rates()
667 				priv->rate_table[x]);  in init_real_clk_rates()
668 			priv->real_rates[x] = priv->rate_table[x];  in init_real_clk_rates()
670 			priv->real_rates[x] = clk_get_rate(priv->baud_mux_clk);  in init_real_clk_rates()
673 	clk_set_rate(priv->baud_mux_clk, priv->default_mux_rate);  in init_real_clk_rates()
695 		hires_err = (hires_rate - hires_baud);  in find_quot()
697 		hires_err = (hires_baud - hires_rate);  in find_quot()
721 	if (priv->baud_mux_clk == NULL)  in set_clock_mux()
725 	quot = find_quot(up->dev, priv->default_mux_rate, baud, &percent);  in set_clock_mux()
728 		best_freq = priv->default_mux_rate;  in set_clock_mux()
733 		for (i = 0; i < ARRAY_SIZE(priv->real_rates); i++) {  in set_clock_mux()
734 			freq = priv->real_rates[i];  in set_clock_mux()
735 			if (freq == 0 || freq == priv->default_mux_rate)  in set_clock_mux()
737 			quot = find_quot(up->dev, freq, baud, &percent);  in set_clock_mux()
749 		dev_err(up->dev, "Error, %d BAUD rate is too fast.\n", baud);  in set_clock_mux()
752 	rc = clk_set_rate(priv->baud_mux_clk, best_freq);  in set_clock_mux()
754 		dev_err(up->dev, "Error selecting BAUD MUX clock\n");  in set_clock_mux()
758 		dev_err(up->dev, "Error, baud: %d has %u.%u%% error\n",  in set_clock_mux()
762 	dev_dbg(up->dev, "Selecting BAUD MUX rate: %u\n", best_freq);  in set_clock_mux()
763 	dev_dbg(up->dev, "Requested baud: %u, Actual baud: %u\n",  in set_clock_mux()
769 	priv->char_wait = ns_to_ktime(i);  in set_clock_mux()
771 	up->uartclk = best_freq;  in set_clock_mux()
779 	struct brcmuart_priv *priv = up->private_data;  in brcmstb_set_termios()
781 	if (priv->dma_enabled)  in brcmstb_set_termios()
785 	if (p8250->mcr & UART_MCR_AFE)  in brcmstb_set_termios()
786 		p8250->port.status |= UPSTAT_AUTOCTS;  in brcmstb_set_termios()
787 	if (priv->dma_enabled)  in brcmstb_set_termios()
794 	struct brcmuart_priv *priv = p->private_data;  in brcmuart_handle_irq()
806 	if (((iir & UART_IIR_ID) == UART_IIR_RX_TIMEOUT) && !(priv->shutdown)) {  in brcmuart_handle_irq()
818 			if ((ier & UART_IER_RDI) && (up->mcr & UART_MCR_AFE)) {  in brcmuart_handle_irq()
824 				hrtimer_start(&priv->hrt, priv->char_wait,  in brcmuart_handle_irq()
842 	struct uart_port *p = priv->up;  in brcmuart_hrtimer_func()
847 	if (priv->shutdown)  in brcmuart_hrtimer_func()
859 		priv->rx_bad_timeout_no_char++;  in brcmuart_hrtimer_func()
861 		priv->rx_bad_timeout_late_char++;  in brcmuart_hrtimer_func()
864 	/* re-enable receive unless upper layer has disabled it */  in brcmuart_hrtimer_func()
865 	if ((up->ier & (UART_IER_RLSI | UART_IER_RDI)) ==  in brcmuart_hrtimer_func()
880 		.compatible = "brcm,bcm7278-uart",
884 		.compatible = "brcm,bcm7271-uart",
894 	if (priv->rx_bufs)  in brcmuart_free_bufs()
895 		dma_free_coherent(dev, priv->rx_size, priv->rx_bufs,  in brcmuart_free_bufs()
896 				  priv->rx_addr);  in brcmuart_free_bufs()
897 	if (priv->tx_buf)  in brcmuart_free_bufs()
898 		dma_free_coherent(dev, priv->tx_size, priv->tx_buf,  in brcmuart_free_bufs()
899 				  priv->tx_addr);  in brcmuart_free_bufs()
904 	struct brcmuart_priv *priv = port->private_data;  in brcmuart_throttle()
911 	struct brcmuart_priv *priv = port->private_data;  in brcmuart_unthrottle()
919 	struct brcmuart_priv *priv = s->private;  in debugfs_stats_show()
922 		   priv->rx_err);  in debugfs_stats_show()
924 		   priv->rx_timeout);  in debugfs_stats_show()
926 		   priv->rx_abort);  in debugfs_stats_show()
928 		   priv->rx_bad_timeout_late_char);  in debugfs_stats_show()
930 		   priv->rx_bad_timeout_no_char);  in debugfs_stats_show()
932 		   priv->rx_missing_close_timeout);  in debugfs_stats_show()
933 	if (priv->dma_enabled) {  in debugfs_stats_show()
935 			   priv->dma_rx_partial_buf);  in debugfs_stats_show()
937 			   priv->dma_rx_full_buf);  in debugfs_stats_show()
946 	priv->debugfs_dir = debugfs_create_dir(device, brcmuart_debugfs_root);  in brcmuart_init_debugfs()
947 	debugfs_create_file("stats", 0444, priv->debugfs_dir, priv,  in brcmuart_init_debugfs()
957 	struct device *dev = &pdev->dev;  in brcmuart_probe()
967 		"uart", "dma_rx", "dma_tx", "dma_intr2", "dma_arb"  in brcmuart_probe()
973 		return -ENOMEM;  in brcmuart_probe()
975 	of_id = of_match_node(brcmuart_dt_ids, dev->of_node);  in brcmuart_probe()
976 	if (!of_id || !of_id->data)  in brcmuart_probe()
977 		priv->rate_table = brcmstb_rate_table;  in brcmuart_probe()
979 		priv->rate_table = of_id->data;  in brcmuart_probe()
986 		priv->regs[x] =	devm_ioremap(dev, regs->start,  in brcmuart_probe()
988 		if (!priv->regs[x])  in brcmuart_probe()
989 			return -ENOMEM;  in brcmuart_probe()
991 			mapbase = regs->start;  in brcmuart_probe()
992 			membase = priv->regs[x];  in brcmuart_probe()
996 	/* We should have just the uart base registers or all the registers */  in brcmuart_probe()
998 		return dev_err_probe(dev, -EINVAL, "%s registers not specified\n",  in brcmuart_probe()
1013 				priv->dma_enabled = true;  in brcmuart_probe()
1021 				"Timeout arbitrating for UART DMA hardware\n");  in brcmuart_probe()
1025 	dev_dbg(dev, "DMA is %senabled\n", priv->dma_enabled ? "" : "not ");  in brcmuart_probe()
1051 		priv->baud_mux_clk = baud_mux_clk;  in brcmuart_probe()
1053 		up.port.uartclk = priv->default_mux_rate;  in brcmuart_probe()
1059 	hrtimer_init(&priv->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);  in brcmuart_probe()
1060 	priv->hrt.function = brcmuart_hrtimer_func;  in brcmuart_probe()
1068 	if (priv->dma_enabled) {  in brcmuart_probe()
1069 		priv->rx_size = RX_BUF_SIZE * RX_BUFS_COUNT;  in brcmuart_probe()
1070 		priv->rx_bufs = dma_alloc_coherent(dev,  in brcmuart_probe()
1071 						   priv->rx_size,  in brcmuart_probe()
1072 						   &priv->rx_addr, GFP_KERNEL);  in brcmuart_probe()
1073 		if (!priv->rx_bufs) {  in brcmuart_probe()
1074 			ret = -ENOMEM;  in brcmuart_probe()
1077 		priv->tx_size = UART_XMIT_SIZE;  in brcmuart_probe()
1078 		priv->tx_buf = dma_alloc_coherent(dev,  in brcmuart_probe()
1079 						  priv->tx_size,  in brcmuart_probe()
1080 						  &priv->tx_addr, GFP_KERNEL);  in brcmuart_probe()
1081 		if (!priv->tx_buf) {  in brcmuart_probe()
1082 			ret = -ENOMEM;  in brcmuart_probe()
1092 	priv->line = ret;  in brcmuart_probe()
1094 	priv->up = &new_port->port;  in brcmuart_probe()
1095 	if (priv->dma_enabled) {  in brcmuart_probe()
1102 				IRQF_SHARED, "uart DMA irq", &new_port->port);  in brcmuart_probe()
1109 	brcmuart_init_debugfs(priv, dev_name(&pdev->dev));  in brcmuart_probe()
1113 	serial8250_unregister_port(priv->line);  in brcmuart_probe()
1117 	if (priv->dma_enabled)  in brcmuart_probe()
1126 	debugfs_remove_recursive(priv->debugfs_dir);  in brcmuart_remove()
1127 	hrtimer_cancel(&priv->hrt);  in brcmuart_remove()
1128 	serial8250_unregister_port(priv->line);  in brcmuart_remove()
1129 	brcmuart_free_bufs(&pdev->dev, priv);  in brcmuart_remove()
1130 	if (priv->dma_enabled)  in brcmuart_remove()
1137 	struct uart_8250_port *up = serial8250_get_port(priv->line);  in brcmuart_suspend()
1138 	struct uart_port *port = &up->port;  in brcmuart_suspend()
1146 	priv->saved_mctrl = port->mctrl;  in brcmuart_suspend()
1147 	port->mctrl &= ~TIOCM_RTS;  in brcmuart_suspend()
1150 	serial8250_suspend_port(priv->line);  in brcmuart_suspend()
1151 	clk_disable_unprepare(priv->baud_mux_clk);  in brcmuart_suspend()
1159 	struct uart_8250_port *up = serial8250_get_port(priv->line);  in brcmuart_resume()
1160 	struct uart_port *port = &up->port;  in brcmuart_resume()
1164 	ret = clk_prepare_enable(priv->baud_mux_clk);  in brcmuart_resume()
1172 	ret = clk_set_rate(priv->baud_mux_clk, priv->default_mux_rate);  in brcmuart_resume()
1175 	if (priv->dma_enabled) {  in brcmuart_resume()
1178 			return(-EBUSY);  in brcmuart_resume()
1181 		start_rx_dma(serial8250_get_port(priv->line));  in brcmuart_resume()
1183 	serial8250_resume_port(priv->line);  in brcmuart_resume()
1185 	if (priv->saved_mctrl & TIOCM_RTS) {  in brcmuart_resume()
1188 		port->mctrl |= TIOCM_RTS;  in brcmuart_resume()
1189 		port->ops->set_mctrl(port, port->mctrl);  in brcmuart_resume()
1202 		.name	= "bcm7271-uart",