15 files changed, 341 insertions, 250 deletions
diff --git a/arch/mips/dec/platform.c b/arch/mips/dec/platform.c
index c4fcb8c58e01c..723ce16cbfc0c 100644
--- a/arch/mips/dec/platform.c
+++ b/arch/mips/dec/platform.c
@@ -10,6 +10,14 @@
 #include <linux/mc146818rtc.h>
 #include <linux/platform_device.h>
 
+#include <asm/bootinfo.h>
+
+#include <asm/dec/interrupts.h>
+#include <asm/dec/ioasic_addrs.h>
+#include <asm/dec/kn01.h>
+#include <asm/dec/kn02.h>
+#include <asm/dec/system.h>
+
 static struct resource dec_rtc_resources[] = {
 	{
 		.name = "rtc",
@@ -30,11 +38,110 @@ static struct platform_device dec_rtc_device = {
 	.num_resources = ARRAY_SIZE(dec_rtc_resources),
 };
 
+static struct resource dec_dz_resources[] = {
+	{ .name = "dz", .flags = IORESOURCE_MEM, },
+	{ .name = "dz", .flags = IORESOURCE_IRQ, },
+};
+
+static struct platform_device dec_dz_device = {
+	.name = "dz",
+	.id = PLATFORM_DEVID_NONE,
+	.resource = dec_dz_resources,
+	.num_resources = ARRAY_SIZE(dec_dz_resources),
+};
+
+static struct platform_device *dec_dz_devices[] __initdata = {
+	&dec_dz_device,
+};
+
+static struct resource dec_zs_resources[][2] = {
+	{
+		{ .name = "scc0", .flags = IORESOURCE_MEM, },
+		{ .name = "scc0", .flags = IORESOURCE_IRQ, },
+	},
+	{
+		{ .name = "scc1", .flags = IORESOURCE_MEM, },
+		{ .name = "scc1", .flags = IORESOURCE_IRQ, },
+	},
+};
+
+static struct platform_device dec_zs_device[] = {
+	{
+		.name = "zs",
+		.id = 0,
+		.resource = dec_zs_resources[0],
+		.num_resources = ARRAY_SIZE(dec_zs_resources[0]),
+	},
+	{
+		.name = "zs",
+		.id = 1,
+		.resource = dec_zs_resources[1],
+		.num_resources = ARRAY_SIZE(dec_zs_resources[1]),
+	},
+};
+
 static int __init dec_add_devices(void)
 {
+	struct platform_device *dec_zs_devices[ARRAY_SIZE(dec_zs_device)];
+	int ret1, ret2, ret3;
+	int num_dz, num_zs;
+	int irq, i;
+
 	dec_rtc_resources[0].start = RTC_PORT(0);
 	dec_rtc_resources[0].end = RTC_PORT(0) + dec_kn_slot_size - 1;
-	return platform_device_register(&dec_rtc_device);
+
+	i = 0;
+	irq = dec_interrupt[DEC_IRQ_DZ11];
+	if (IS_ENABLED(CONFIG_32BIT) && irq >= 0) {
+		resource_size_t base;
+
+		switch (mips_machtype) {
+		case MACH_DS23100:
+		case MACH_DS5100:
+			base = dec_kn_slot_base + KN01_DZ11;
+			break;
+		default:
+			base = dec_kn_slot_base + KN02_DZ11;
+			break;
+		}
+		dec_dz_device.resource[0].start = base;
+		dec_dz_device.resource[0].end = base + dec_kn_slot_size - 1;
+		dec_dz_device.resource[1].start = irq;
+		dec_dz_device.resource[1].end = irq;
+		i++;
+	}
+	num_dz = i;
+
+	i = 0;
+	irq = dec_interrupt[DEC_IRQ_SCC0];
+	if (irq >= 0) {
+		resource_size_t base = dec_kn_slot_base + IOASIC_SCC0;
+
+		dec_zs_device[i].resource[0].start = base;
+		dec_zs_device[i].resource[0].end = base + dec_kn_slot_size - 1;
+		dec_zs_device[i].resource[1].start = irq;
+		dec_zs_device[i].resource[1].end = irq;
+		dec_zs_devices[i] = &dec_zs_device[i];
+		i++;
+	}
+	irq = dec_interrupt[DEC_IRQ_SCC1];
+	if (irq >= 0) {
+		resource_size_t base = dec_kn_slot_base + IOASIC_SCC1;
+
+		dec_zs_device[i].resource[0].start = base;
+		dec_zs_device[i].resource[0].end = base + dec_kn_slot_size - 1;
+		dec_zs_device[i].resource[1].start = irq;
+		dec_zs_device[i].resource[1].end = irq;
+		dec_zs_devices[i] = &dec_zs_device[i];
+		i++;
+	}
+	num_zs = i;
+
+	ret1 = platform_device_register(&dec_rtc_device);
+	ret2 = IS_ENABLED(CONFIG_32BIT) ?
+	       platform_add_devices(dec_dz_devices, num_dz) : 0;
+	ret3 = platform_add_devices(dec_zs_devices, num_zs);
+	return ret1 ? ret1 : ret2 ? ret2 : ret3;
 }
 
 device_initcall(dec_add_devices);
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 94beadb4024df..2af0c4d0ad823 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -427,7 +427,7 @@ static int dw8250_handle_irq(struct uart_port *p)
 	unsigned int quirks = d->pdata->quirks;
 	unsigned int status;
 
-	guard(uart_port_lock_irqsave)(p);
+	guard(uart_port_lock_check_sysrq_irqsave)(p);
 
 	switch (FIELD_GET(DW_UART_IIR_IID, iir)) {
 	case UART_IIR_NO_INT:
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index af78cc02f38e7..c66ba714caa5f 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1784,7 +1784,10 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
 }
 
 /*
- * Context: port's lock must be held by the caller.
+ * Context: port's lock must be held by the caller. The caller must
+ * release it via guard(uart_port_lock_check_sysrq_irqsave) or
+ * uart_unlock_and_check_sysrq_irqrestore(), which captures SysRq
+ * character on unlock.
  */
 void serial8250_handle_irq_locked(struct uart_port *port, unsigned int iir)
 {
@@ -1837,7 +1840,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
 	if (iir & UART_IIR_NO_INT)
 		return 0;
 
-	guard(uart_port_lock_irqsave)(port);
+	guard(uart_port_lock_check_sysrq_irqsave)(port);
 	serial8250_handle_irq_locked(port, iir);
 
 	return 1;
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 9aa61c93d7bc6..ec284aceb9093 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -334,7 +334,7 @@ config SERIAL_MAX310X
 	  Say Y here if you want to support this ICs.
 
 config SERIAL_DZ
-	bool "DECstation DZ serial driver"
+	tristate "DECstation DZ serial driver"
 	depends on MACH_DECSTATION && 32BIT
 	select SERIAL_CORE
 	default y
diff --git a/drivers/tty/serial/altera_jtaguart.c b/drivers/tty/serial/altera_jtaguart.c
index d47a62d1c9f7d..20f079fe11d82 100644
--- a/drivers/tty/serial/altera_jtaguart.c
+++ b/drivers/tty/serial/altera_jtaguart.c
@@ -379,6 +379,7 @@ static int altera_jtaguart_probe(struct platform_device *pdev)
 	struct resource *res_mem;
 	int i = pdev->id;
 	int irq;
+	int ret;
 
 	/* -1 emphasizes that the platform must have one port, no .N suffix */
 	if (i == -1)
@@ -418,7 +419,11 @@ static int altera_jtaguart_probe(struct platform_device *pdev)
 	port->flags = UPF_BOOT_AUTOCONF;
 	port->dev = &pdev->dev;
 
-	uart_add_one_port(&altera_jtaguart_driver, port);
+	ret = uart_add_one_port(&altera_jtaguart_driver, port);
+	if (ret) {
+		iounmap(port->membase);
+		return ret;
+	}
 
 	return 0;
 }
diff --git a/drivers/tty/serial/dz.c b/drivers/tty/serial/dz.c
index e53c54353c3e4..39d93e9c2d157 100644
--- a/drivers/tty/serial/dz.c
+++ b/drivers/tty/serial/dz.c
@@ -40,6 +40,7 @@
 #include <linux/kernel.h>
 #include <linux/major.h>
 #include <linux/module.h>
+#include <linux/platform_device.h>
 #include <linux/serial.h>
 #include <linux/serial_core.h>
 #include <linux/sysrq.h>
@@ -48,14 +49,6 @@
 
 #include <linux/atomic.h>
 #include <linux/io.h>
-#include <asm/bootinfo.h>
-
-#include <asm/dec/interrupts.h>
-#include <asm/dec/kn01.h>
-#include <asm/dec/kn02.h>
-#include <asm/dec/machtype.h>
-#include <asm/dec/prom.h>
-#include <asm/dec/system.h>
 
 #include "dz.h"
 
@@ -65,7 +58,9 @@ MODULE_LICENSE("GPL");
 
 
 static char dz_name[] __initdata = "DECstation DZ serial driver version ";
-static char dz_version[] __initdata = "1.04";
+static char dz_version[] __initdata = "1.05";
+
+#define DZ_IO_SIZE 0x20			/* IOMEM space size.  */
 
 struct dz_port {
 	struct dz_mux		*mux;
@@ -81,6 +76,7 @@ struct dz_mux {
 };
 
 static struct dz_mux dz_mux;
+static struct uart_driver dz_reg;
 
 static inline struct dz_port *to_dport(struct uart_port *uport)
 {
@@ -542,14 +538,47 @@ static int dz_encode_baud_rate(unsigned int baud)
 static void dz_reset(struct dz_port *dport)
 {
 	struct dz_mux *mux = dport->mux;
+	unsigned short tcr;
+	int loops = 10000;
 
 	if (mux->initialised)
 		return;
 
+	tcr = dz_in(dport, DZ_TCR);
+
+	/* Do not disturb any ongoing transmissions.  */
+	if (dz_in(dport, DZ_CSR) & DZ_MSE) {
+		unsigned short csr, mask;
+
+		mask = tcr;
+		while ((mask & DZ_LNENB) && loops--) {
+			csr = dz_in(dport, DZ_CSR);
+			if (!(csr & DZ_TRDY))
+				continue;
+			mask &= ~(1 << ((csr & DZ_TLINE) >> 8));
+			dz_out(dport, DZ_TCR, mask);
+			iob();
+			udelay(2);		/* 1.4us TRDY recovery.  */
+		}
+		fsleep(1200);			/* Transmitter drain.  */
+	}
+
 	dz_out(dport, DZ_CSR, DZ_CLR);
 	while (dz_in(dport, DZ_CSR) & DZ_CLR);
 	iob();
 
+	/*
+	 * Set parameters across all lines such as not to interfere
+	 * with the initial PROM-based console.  Otherwise any output
+	 * produced before the console handover would cause the system
+	 * firmware to produce rubbish.
+	 */
+	for (int line = 0; line < DZ_NB_PORT; line++)
+		dz_out(dport, DZ_LPR, DZ_B9600 | DZ_CS8 | line);
+
+	/* Re-enable transmission for the initial PROM-based console.  */
+	dz_out(dport, DZ_TCR, tcr);
+
 	/* Enable scanning.  */
 	dz_out(dport, DZ_CSR, DZ_MSE);
 
@@ -633,26 +662,6 @@ static void dz_set_termios(struct uart_port *uport, struct ktermios *termios,
 	uart_port_unlock_irqrestore(&dport->port, flags);
 }
 
-/*
- * Hack alert!
- * Required solely so that the initial PROM-based console
- * works undisturbed in parallel with this one.
- */
-static void dz_pm(struct uart_port *uport, unsigned int state,
-		  unsigned int oldstate)
-{
-	struct dz_port *dport = to_dport(uport);
-	unsigned long flags;
-
-	uart_port_lock_irqsave(&dport->port, &flags);
-	if (state < 3)
-		dz_start_tx(&dport->port);
-	else
-		dz_stop_tx(&dport->port);
-	uart_port_unlock_irqrestore(&dport->port, flags);
-}
-
-
 static const char *dz_type(struct uart_port *uport)
 {
 	return "DZ";
@@ -668,14 +677,13 @@ static void dz_release_port(struct uart_port *uport)
 
 	map_guard = atomic_add_return(-1, &mux->map_guard);
 	if (!map_guard)
-		release_mem_region(uport->mapbase, dec_kn_slot_size);
+		release_mem_region(uport->mapbase, DZ_IO_SIZE);
 }
 
 static int dz_map_port(struct uart_port *uport)
 {
 	if (!uport->membase)
-		uport->membase = ioremap(uport->mapbase,
-						 dec_kn_slot_size);
+		uport->membase = ioremap(uport->mapbase, DZ_IO_SIZE);
 	if (!uport->membase) {
 		printk(KERN_ERR "dz: Cannot map MMIO\n");
 		return -ENOMEM;
@@ -691,8 +699,7 @@ static int dz_request_port(struct uart_port *uport)
 
 	map_guard = atomic_add_return(1, &mux->map_guard);
 	if (map_guard == 1) {
-		if (!request_mem_region(uport->mapbase, dec_kn_slot_size,
-					"dz")) {
+		if (!request_mem_region(uport->mapbase, DZ_IO_SIZE, "dz")) {
 			atomic_add(-1, &mux->map_guard);
 			printk(KERN_ERR
 			       "dz: Unable to reserve MMIO resource\n");
@@ -703,7 +710,7 @@ static int dz_request_port(struct uart_port *uport)
 	if (ret) {
 		map_guard = atomic_add_return(-1, &mux->map_guard);
 		if (!map_guard)
-			release_mem_region(uport->mapbase, dec_kn_slot_size);
+			release_mem_region(uport->mapbase, DZ_IO_SIZE);
 		return ret;
 	}
 	return 0;
@@ -748,7 +755,6 @@ static const struct uart_ops dz_ops = {
 	.startup	= dz_startup,
 	.shutdown	= dz_shutdown,
 	.set_termios	= dz_set_termios,
-	.pm		= dz_pm,
 	.type		= dz_type,
 	.release_port	= dz_release_port,
 	.request_port	= dz_request_port,
@@ -756,20 +762,15 @@ static const struct uart_ops dz_ops = {
 	.verify_port	= dz_verify_port,
 };
 
-static void __init dz_init_ports(void)
+static int __init dz_probe(struct platform_device *pdev)
 {
-	static int first = 1;
-	unsigned long base;
+	struct resource *mem_resource, *irq_resource;
 	int line;
 
-	if (!first)
-		return;
-	first = 0;
-
-	if (mips_machtype == MACH_DS23100 || mips_machtype == MACH_DS5100)
-		base = dec_kn_slot_base + KN01_DZ11;
-	else
-		base = dec_kn_slot_base + KN02_DZ11;
+	mem_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	irq_resource = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!mem_resource || !irq_resource)
+		return -ENODEV;
 
 	for (line = 0; line < DZ_NB_PORT; line++) {
 		struct dz_port *dport = &dz_mux.dport[line];
@@ -777,14 +778,33 @@ static void __init dz_init_ports(void)
 
 		dport->mux	= &dz_mux;
 
-		uport->irq	= dec_interrupt[DEC_IRQ_DZ11];
+		uport->dev	= &pdev->dev;
+		uport->irq	= irq_resource->start;
 		uport->fifosize	= 1;
 		uport->iotype	= UPIO_MEM;
 		uport->flags	= UPF_BOOT_AUTOCONF;
 		uport->ops	= &dz_ops;
 		uport->line	= line;
-		uport->mapbase	= base;
+		uport->mapbase	= mem_resource->start;
 		uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_DZ_CONSOLE);
+
+		if (uart_add_one_port(&dz_reg, uport))
+			uport->dev = NULL;
+	}
+
+	return 0;
+}
+
+static void __exit dz_remove(struct platform_device *pdev)
+{
+	int line;
+
+	for (line = DZ_NB_PORT - 1; line >= 0; line--) {
+		struct dz_port *dport = &dz_mux.dport[line];
+		struct uart_port *uport = &dport->port;
+
+		if (uport->dev)
+			uart_remove_one_port(&dz_reg, uport);
 	}
 }
 
@@ -867,24 +887,14 @@ static int __init dz_console_setup(struct console *co, char *options)
 	int bits = 8;
 	int parity = 'n';
 	int flow = 'n';
-	int ret;
-
-	ret = dz_map_port(uport);
-	if (ret)
-		return ret;
-
-	spin_lock_init(&dport->port.lock);	/* For dz_pm().  */
-
-	dz_reset(dport);
-	dz_pm(uport, 0, -1);
 
+	if (!dport->mux)
+		return -ENODEV;
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
-
-	return uart_set_options(&dport->port, co, baud, parity, bits, flow);
+	return uart_set_options(uport, co, baud, parity, bits, flow);
 }
 
-static struct uart_driver dz_reg;
 static struct console dz_console = {
 	.name	= "ttyS",
 	.write	= dz_console_print,
@@ -895,18 +905,6 @@ static struct console dz_console = {
 	.data	= &dz_reg,
 };
 
-static int __init dz_serial_console_init(void)
-{
-	if (!IOASIC) {
-		dz_init_ports();
-		register_console(&dz_console);
-		return 0;
-	} else
-		return -ENXIO;
-}
-
-console_initcall(dz_serial_console_init);
-
 #define SERIAL_DZ_CONSOLE	&dz_console
 #else
 #define SERIAL_DZ_CONSOLE	NULL
@@ -922,25 +920,32 @@ static struct uart_driver dz_reg = {
 	.cons			= SERIAL_DZ_CONSOLE,
 };
 
+static struct platform_driver dz_driver = {
+	.remove = __exit_p(dz_remove),
+	.driver = { .name = "dz" },
+};
+
 static int __init dz_init(void)
 {
-	int ret, i;
-
-	if (IOASIC)
-		return -ENXIO;
+	int ret;
 
 	printk("%s%s\n", dz_name, dz_version);
 
-	dz_init_ports();
-
 	ret = uart_register_driver(&dz_reg);
 	if (ret)
 		return ret;
+	ret = platform_driver_probe(&dz_driver, dz_probe);
+	if (ret)
+		uart_unregister_driver(&dz_reg);
 
-	for (i = 0; i < DZ_NB_PORT; i++)
-		uart_add_one_port(&dz_reg, &dz_mux.dport[i].port);
+	return ret;
+}
 
-	return 0;
+static void __exit dz_exit(void)
+{
+	platform_driver_unregister(&dz_driver);
+	uart_unregister_driver(&dz_reg);
 }
 
 module_init(dz_init);
+module_exit(dz_exit);
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 1bd7ec9c81ea4..b7919c05f0fb8 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1379,7 +1379,8 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
 
 	if (!nent) {
 		dev_err(sport->port.dev, "DMA Rx mapping error\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_free_buf;
 	}
 
 	dma_rx_sconfig.src_addr = lpuart_dma_datareg_addr(sport);
@@ -1391,7 +1392,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
 	if (ret < 0) {
 		dev_err(sport->port.dev,
 				"DMA Rx slave config failed, err = %d\n", ret);
-		return ret;
+		goto err_unmap_sg;
 	}
 
 	sport->dma_rx_desc = dmaengine_prep_dma_cyclic(chan,
@@ -1402,7 +1403,8 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
 				 DMA_PREP_INTERRUPT);
 	if (!sport->dma_rx_desc) {
 		dev_err(sport->port.dev, "Cannot prepare cyclic DMA\n");
-		return -EFAULT;
+		ret = -ENOMEM;
+		goto err_unmap_sg;
 	}
 
 	sport->dma_rx_desc->callback = lpuart_dma_rx_complete;
@@ -1426,6 +1428,13 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
 	}
 
 	return 0;
+
+err_unmap_sg:
+	dma_unmap_sg(chan->device->dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+err_free_buf:
+	kfree(ring->buf);
+	ring->buf = NULL;
+	return ret;
 }
 
 static void lpuart_dma_rx_free(struct uart_port *port)
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 6729d8e83c3c5..ba1fcd663fe22 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -689,8 +689,7 @@ static void pch_request_dma(struct uart_port *port)
 	if (!chan) {
 		dev_err(priv->port.dev, "%s:dma_request_channel FAILS(Tx)\n",
 			__func__);
-		pci_dev_put(dma_dev);
-		return;
+		goto err_pci_get;
 	}
 	priv->chan_tx = chan;
 
@@ -704,18 +703,26 @@ static void pch_request_dma(struct uart_port *port)
 	if (!chan) {
 		dev_err(priv->port.dev, "%s:dma_request_channel FAILS(Rx)\n",
 			__func__);
-		dma_release_channel(priv->chan_tx);
-		priv->chan_tx = NULL;
-		pci_dev_put(dma_dev);
-		return;
+		goto err_req_tx;
 	}
 
 	/* Get Consistent memory for DMA */
 	priv->rx_buf_virt = dma_alloc_coherent(port->dev, port->fifosize,
 				    &priv->rx_buf_dma, GFP_KERNEL);
+	if (!priv->rx_buf_virt)
+		goto err_req_rx;
 	priv->chan_rx = chan;
 
 	pci_dev_put(dma_dev);
+	return;
+
+err_req_rx:
+	dma_release_channel(chan);
+err_req_tx:
+	dma_release_channel(priv->chan_tx);
+	priv->chan_tx = NULL;
+err_pci_get:
+	pci_dev_put(dma_dev);
 }
 
 static void pch_dma_rx_complete(void *arg)
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index b365dd5da3cb7..17da115b1e78b 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -50,7 +50,7 @@
 #define TX_STOP_BIT_LEN_2		2
 
 /* SE_UART_RX_TRANS_CFG */
-#define UART_RX_PAR_EN			BIT(3)
+#define UART_RX_PAR_EN			BIT(4)
 
 /* SE_UART_RX_WORD_LEN */
 #define RX_WORD_LEN_MASK		GENMASK(9, 0)
@@ -1031,8 +1031,20 @@ static void qcom_geni_serial_handle_tx_dma(struct uart_port *uport)
 {
 	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	struct tty_port *tport = &uport->state->port;
+	unsigned int fifo_len = kfifo_len(&tport->xmit_fifo);
+
+	/*
+	 * Only advance the kfifo if it still contains the bytes that were
+	 * transferred. uart_flush_buffer() may have run before this IRQ
+	 * fired: it calls kfifo_reset() under the port lock, making
+	 * fifo_len = 0 while tx_remaining remains non-zero. Calling
+	 * uart_xmit_advance() in that case would underflow kfifo->out past
+	 * kfifo->in, making kfifo_len() wrap to UART_XMIT_SIZE - tx_remaining
+	 * and triggering a spurious large DMA transfer of stale data.
+	 */
+	if (fifo_len >= port->tx_remaining)
+		uart_xmit_advance(uport, port->tx_remaining);
 
-	uart_xmit_advance(uport, port->tx_remaining);
 	geni_se_tx_dma_unprep(&port->se, port->tx_dma_addr, port->tx_remaining);
 	port->tx_dma_addr = 0;
 	port->tx_remaining = 0;
diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index e27806bf2cf3e..17cd5bb100b15 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -245,12 +245,9 @@ static bool s3c24xx_serial_txempty_nofifo(const struct uart_port *port)
 static void s3c24xx_serial_rx_enable(struct uart_port *port)
 {
 	struct s3c24xx_uart_port *ourport = to_ourport(port);
-	unsigned long flags;
 	int count = 10000;
 	u32 ucon, ufcon;
 
-	uart_port_lock_irqsave(port, &flags);
-
 	while (--count && !s3c24xx_serial_txempty_nofifo(port))
 		udelay(100);
 
@@ -263,23 +260,18 @@ static void s3c24xx_serial_rx_enable(struct uart_port *port)
 	wr_regl(port, S3C2410_UCON, ucon);
 
 	ourport->rx_enabled = 1;
-	uart_port_unlock_irqrestore(port, flags);
 }
 
 static void s3c24xx_serial_rx_disable(struct uart_port *port)
 {
 	struct s3c24xx_uart_port *ourport = to_ourport(port);
-	unsigned long flags;
 	u32 ucon;
 
-	uart_port_lock_irqsave(port, &flags);
-
 	ucon = rd_regl(port, S3C2410_UCON);
 	ucon &= ~S3C2410_UCON_RXIRQMODE;
 	wr_regl(port, S3C2410_UCON, ucon);
 
 	ourport->rx_enabled = 0;
-	uart_port_unlock_irqrestore(port, flags);
 }
 
 static void s3c24xx_serial_stop_tx(struct uart_port *port)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 6c819b6b24258..54db019a5bfcd 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3025,7 +3025,7 @@ int sci_request_port(struct uart_port *port)
 
 	ret = sci_remap_port(port);
 	if (unlikely(ret != 0)) {
-		release_resource(res);
+		release_mem_region(port->mapbase, sport->reg_size);
 		return ret;
 	}
 
diff --git a/drivers/tty/serial/zs.c b/drivers/tty/serial/zs.c
index 72a3c0d90f409..8f92b4129a385 100644
--- a/drivers/tty/serial/zs.c
+++ b/drivers/tty/serial/zs.c
@@ -56,6 +56,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/major.h>
+#include <linux/platform_device.h>
 #include <linux/serial.h>
 #include <linux/serial_core.h>
 #include <linux/spinlock.h>
@@ -66,10 +67,6 @@
 
 #include <linux/atomic.h>
 
-#include <asm/dec/interrupts.h>
-#include <asm/dec/ioasic_addrs.h>
-#include <asm/dec/system.h>
-
 #include "zs.h"
 
 
@@ -79,7 +76,7 @@ MODULE_LICENSE("GPL");
 
 
 static char zs_name[] __initdata = "DECstation Z85C30 serial driver version ";
-static char zs_version[] __initdata = "0.10";
+static char zs_version[] __initdata = "0.11";
 
 /*
  * It would be nice to dynamically allocate everything that
@@ -98,25 +95,27 @@ static char zs_version[] __initdata = "0.10";
 
 #define to_zport(uport) container_of(uport, struct zs_port, port)
 
-struct zs_parms {
-	resource_size_t scc[ZS_NUM_SCCS];
-	int irq[ZS_NUM_SCCS];
-};
-
 static struct zs_scc zs_sccs[ZS_NUM_SCCS];
+static struct uart_driver zs_reg;
 
+/*
+ * Set parameters in WR5, WR12, WR13 such as not to interfere
+ * with the initial PROM-based console.  Otherwise any output
+ * produced before the console handover would cause the system
+ * firmware to hang (TxENAB) or produce rubbish (Tx8, B9600).
+ */
 static u8 zs_init_regs[ZS_NUM_REGS] __initdata = {
 	0,				/* write 0 */
 	PAR_SPEC,			/* write 1 */
 	0,				/* write 2 */
 	0,				/* write 3 */
 	X16CLK | SB1,			/* write 4 */
-	0,				/* write 5 */
+	Tx8 | TxENAB,			/* write 5 */
 	0, 0, 0,			/* write 6, 7, 8 */
 	MIE | DLC | NV,			/* write 9 */
 	NRZ,				/* write 10 */
 	TCBR | RCBR,			/* write 11 */
-	0, 0,				/* BRG time constant, write 12 + 13 */
+	0x16, 0x00,			/* BRG time constant, write 12 + 13 */
 	BRSRC | BRENABL,		/* write 14 */
 	0,				/* write 15 */
 };
@@ -680,9 +679,9 @@ static void zs_status_handle(struct zs_port *zport, struct zs_port *zport_a)
 			uart_handle_dcd_change(uport,
 					       zport->mctrl & TIOCM_CAR);
 		if (delta & TIOCM_RNG)
-			uport->icount.dsr++;
-		if (delta & TIOCM_DSR)
 			uport->icount.rng++;
+		if (delta & TIOCM_DSR)
+			uport->icount.dsr++;
 
 		if (delta)
 			wake_up_interruptible(&uport->state->port.delta_msr_wait);
@@ -826,22 +825,22 @@ static void zs_shutdown(struct uart_port *uport)
 
 static void zs_reset(struct zs_port *zport)
 {
+	struct zs_port *zport_a = &zport->scc->zport[ZS_CHAN_A];
 	struct zs_scc *scc = zport->scc;
 	int irq;
 	unsigned long flags;
 
 	spin_lock_irqsave(&scc->zlock, flags);
 	irq = !irqs_disabled_flags(flags);
-	if (!scc->initialised) {
-		/* Reset the pointer first, just in case...  */
-		read_zsreg(zport, R0);
-		/* And let the current transmission finish.  */
-		zs_line_drain(zport, irq);
-		write_zsreg(zport, R9, FHWRES);
-		udelay(10);
-		write_zsreg(zport, R9, 0);
-		scc->initialised = 1;
-	}
+
+	/* Reset the pointer first, just in case...  */
+	read_zsreg(zport, R0);
+	/* And let the current transmission finish.  */
+	zs_line_drain(zport, irq);
+	write_zsreg(zport, R9, zport == zport_a ? CHRA : CHRB);
+	udelay(10);
+	write_zsreg(zport, R9, 0);
+
 	load_zsregs(zport, zport->regs, irq);
 	spin_unlock_irqrestore(&scc->zlock, flags);
 }
@@ -956,23 +955,6 @@ static void zs_set_termios(struct uart_port *uport, struct ktermios *termios,
 	spin_unlock_irqrestore(&scc->zlock, flags);
 }
 
-/*
- * Hack alert!
- * Required solely so that the initial PROM-based console
- * works undisturbed in parallel with this one.
- */
-static void zs_pm(struct uart_port *uport, unsigned int state,
-		  unsigned int oldstate)
-{
-	struct zs_port *zport = to_zport(uport);
-
-	if (state < 3)
-		zport->regs[5] |= TxENAB;
-	else
-		zport->regs[5] &= ~TxENAB;
-	write_zsreg(zport, R5, zport->regs[5]);
-}
-
 
 static const char *zs_type(struct uart_port *uport)
 {
@@ -1055,7 +1037,6 @@ static const struct uart_ops zs_ops = {
 	.startup	= zs_startup,
 	.shutdown	= zs_shutdown,
 	.set_termios	= zs_set_termios,
-	.pm		= zs_pm,
 	.type		= zs_type,
 	.release_port	= zs_release_port,
 	.request_port	= zs_request_port,
@@ -1066,63 +1047,62 @@ static const struct uart_ops zs_ops = {
 /*
  * Initialize Z85C30 port structures.
  */
-static int __init zs_probe_sccs(void)
+static int __init zs_probe(struct platform_device *pdev)
 {
-	static int probed;
-	struct zs_parms zs_parms;
-	int chip, side, irq;
-	int n_chips = 0;
+	struct resource *mem_resource, *irq_resource;
+	int chip, side;
 	int i;
 
-	if (probed)
-		return 0;
+	mem_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	irq_resource = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!mem_resource || !irq_resource)
+		return -ENODEV;
 
-	irq = dec_interrupt[DEC_IRQ_SCC0];
-	if (irq >= 0) {
-		zs_parms.scc[n_chips] = IOASIC_SCC0;
-		zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC0];
-		n_chips++;
-	}
-	irq = dec_interrupt[DEC_IRQ_SCC1];
-	if (irq >= 0) {
-		zs_parms.scc[n_chips] = IOASIC_SCC1;
-		zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC1];
-		n_chips++;
-	}
-	if (!n_chips)
-		return -ENXIO;
-
-	probed = 1;
+	chip = pdev->id;
+	spin_lock_init(&zs_sccs[chip].zlock);
+	for (side = 0; side < ZS_NUM_CHAN; side++) {
+		struct zs_port *zport = &zs_sccs[chip].zport[side];
+		struct uart_port *uport = &zport->port;
 
-	for (chip = 0; chip < n_chips; chip++) {
-		spin_lock_init(&zs_sccs[chip].zlock);
-		for (side = 0; side < ZS_NUM_CHAN; side++) {
-			struct zs_port *zport = &zs_sccs[chip].zport[side];
-			struct uart_port *uport = &zport->port;
+		zport->scc	= &zs_sccs[chip];
+		zport->clk_mode	= 16;
 
-			zport->scc	= &zs_sccs[chip];
-			zport->clk_mode	= 16;
+		uport->dev	= &pdev->dev;
+		uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_ZS_CONSOLE);
+		uport->irq	= irq_resource->start;
+		uport->uartclk	= ZS_CLOCK;
+		uport->fifosize	= 1;
+		uport->iotype	= UPIO_MEM;
+		uport->flags	= UPF_BOOT_AUTOCONF;
+		uport->ops	= &zs_ops;
+		uport->line	= chip * ZS_NUM_CHAN + side;
+		uport->mapbase	= mem_resource->start +
+				  (side ^ ZS_CHAN_B) * ZS_CHAN_IO_SIZE;
 
-			uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_ZS_CONSOLE);
-			uport->irq	= zs_parms.irq[chip];
-			uport->uartclk	= ZS_CLOCK;
-			uport->fifosize	= 1;
-			uport->iotype	= UPIO_MEM;
-			uport->flags	= UPF_BOOT_AUTOCONF;
-			uport->ops	= &zs_ops;
-			uport->line	= chip * ZS_NUM_CHAN + side;
-			uport->mapbase	= dec_kn_slot_base +
-					  zs_parms.scc[chip] +
-					  (side ^ ZS_CHAN_B) * ZS_CHAN_IO_SIZE;
+		for (i = 0; i < ZS_NUM_REGS; i++)
+			zport->regs[i] = zs_init_regs[i];
 
-			for (i = 0; i < ZS_NUM_REGS; i++)
-				zport->regs[i] = zs_init_regs[i];
-		}
+		if (uart_add_one_port(&zs_reg, uport))
+			uport->dev = NULL;
 	}
 
 	return 0;
 }
 
+static void __exit zs_remove(struct platform_device *pdev)
+{
+	int chip, side;
+
+	chip = pdev->id;
+	for (side = ZS_NUM_CHAN - 1; side >= 0; side--) {
+		struct zs_port *zport = &zs_sccs[chip].zport[side];
+		struct uart_port *uport = &zport->port;
+
+		if (uport->dev)
+			uart_remove_one_port(&zs_reg, uport);
+	}
+}
+
 
 #ifdef CONFIG_SERIAL_ZS_CONSOLE
 static void zs_console_putchar(struct uart_port *uport, unsigned char ch)
@@ -1203,21 +1183,14 @@ static int __init zs_console_setup(struct console *co, char *options)
 	int bits = 8;
 	int parity = 'n';
 	int flow = 'n';
-	int ret;
-
-	ret = zs_map_port(uport);
-	if (ret)
-		return ret;
-
-	zs_reset(zport);
-	zs_pm(uport, 0, -1);
 
+	if (!zport->scc)
+		return -ENODEV;
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
 	return uart_set_options(uport, co, baud, parity, bits, flow);
 }
 
-static struct uart_driver zs_reg;
 static struct console zs_console = {
 	.name	= "ttyS",
 	.write	= zs_console_write,
@@ -1228,23 +1201,6 @@ static struct console zs_console = {
 	.data	= &zs_reg,
 };
 
-/*
- *	Register console.
- */
-static int __init zs_serial_console_init(void)
-{
-	int ret;
-
-	ret = zs_probe_sccs();
-	if (ret)
-		return ret;
-	register_console(&zs_console);
-
-	return 0;
-}
-
-console_initcall(zs_serial_console_init);
-
 #define SERIAL_ZS_CONSOLE	&zs_console
 #else
 #define SERIAL_ZS_CONSOLE	NULL
@@ -1260,47 +1216,31 @@ static struct uart_driver zs_reg = {
 	.cons			= SERIAL_ZS_CONSOLE,
 };
 
+static struct platform_driver zs_driver = {
+	.remove = __exit_p(zs_remove),
+	.driver = { .name = "zs" },
+};
+
 /* zs_init inits the driver. */
 static int __init zs_init(void)
 {
-	int i, ret;
+	int ret;
 
 	pr_info("%s%s\n", zs_name, zs_version);
 
-	/* Find out how many Z85C30 SCCs we have.  */
-	ret = zs_probe_sccs();
-	if (ret)
-		return ret;
-
 	ret = uart_register_driver(&zs_reg);
 	if (ret)
 		return ret;
+	ret = platform_driver_probe(&zs_driver, zs_probe);
+	if (ret)
+		uart_unregister_driver(&zs_reg);
 
-	for (i = 0; i < ZS_NUM_SCCS * ZS_NUM_CHAN; i++) {
-		struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
-		struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
-		struct uart_port *uport = &zport->port;
-
-		if (zport->scc)
-			uart_add_one_port(&zs_reg, uport);
-	}
-
-	return 0;
+	return ret;
 }
 
 static void __exit zs_exit(void)
 {
-	int i;
-
-	for (i = ZS_NUM_SCCS * ZS_NUM_CHAN - 1; i >= 0; i--) {
-		struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
-		struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
-		struct uart_port *uport = &zport->port;
-
-		if (zport->scc)
-			uart_remove_one_port(&zs_reg, uport);
-	}
-
+	platform_driver_unregister(&zs_driver);
 	uart_unregister_driver(&zs_reg);
 }
 
diff --git a/drivers/tty/serial/zs.h b/drivers/tty/serial/zs.h
index 26ef8eafa1c12..e0d3c189b33f6 100644
--- a/drivers/tty/serial/zs.h
+++ b/drivers/tty/serial/zs.h
@@ -41,7 +41,6 @@ struct zs_scc {
 	struct zs_port	zport[2];
 	spinlock_t	zlock;
 	atomic_t	irq_guard;
-	int		initialised;
 };
 
 #endif /* __KERNEL__ */
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 666430b478997..110ad4e2aef99 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -1275,6 +1275,18 @@ static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port
 #endif	/* CONFIG_MAGIC_SYSRQ_SERIAL */
 
 /*
+ * Variant of guard(uart_port_lock_irqsave) for IRQ handlers that may capture
+ * a SysRq character via uart_prepare_sysrq_char(). The destructor uses the
+ * sysrq-aware unlock helper so that a captured port->sysrq_ch is dispatched
+ * to handle_sysrq() on scope exit. The plain guard variant silently drops
+ * sysrq_ch and must not be used by callers that process RX.
+ */
+DEFINE_LOCK_GUARD_1(uart_port_lock_check_sysrq_irqsave, struct uart_port,
+                    uart_port_lock_irqsave(_T->lock, &_T->flags),
+                    uart_unlock_and_check_sysrq_irqrestore(_T->lock, _T->flags),
+                    unsigned long flags);
+
+/*
  * We do the SysRQ and SAK checking like this...
  */
 static inline int uart_handle_break(struct uart_port *port)
diff --git a/include/linux/tty_port.h b/include/linux/tty_port.h
index d2a7882c0b58b..23cad403bb8f5 100644
--- a/include/linux/tty_port.h
+++ b/include/linux/tty_port.h
@@ -6,10 +6,10 @@
 #include <linux/kref.h>
 #include <linux/mutex.h>
 #include <linux/tty_buffer.h>
+#include <linux/tty_driver.h>
 #include <linux/wait.h>
 
 struct attribute_group;
-struct tty_driver;
 struct tty_port;
 struct tty_struct;