Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 197 insertions, 0 deletions

diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
new file mode 100644
index 000000000..5cd8c36c8
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Early serial console for 8250/16550 devices
+ *
+ * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
+ *	Bjorn Helgaas <bjorn.helgaas@hp.com>
+ *
+ * Based on the 8250.c serial driver, Copyright (C) 2001 Russell King,
+ * and on early_printk.c by Andi Kleen.
+ *
+ * This is for use before the serial driver has initialized, in
+ * particular, before the UARTs have been discovered and named.
+ * Instead of specifying the console device as, e.g., "ttyS0",
+ * we locate the device directly by its MMIO or I/O port address.
+ *
+ * The user can specify the device directly, e.g.,
+ *	earlycon=uart8250,io,0x3f8,9600n8
+ *	earlycon=uart8250,mmio,0xff5e0000,115200n8
+ *	earlycon=uart8250,mmio32,0xff5e0000,115200n8
+ * or
+ *	console=uart8250,io,0x3f8,9600n8
+ *	console=uart8250,mmio,0xff5e0000,115200n8
+ *	console=uart8250,mmio32,0xff5e0000,115200n8
+ */
+
+#include <linux/tty.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/serial_reg.h>
+#include <linux/serial.h>
+#include <linux/serial_8250.h>
+#include <asm/io.h>
+#include <asm/serial.h>
+
+static unsigned int serial8250_early_in(struct uart_port *port, int offset)
+{
+	int reg_offset = offset;
+	offset <<= port->regshift;
+
+	switch (port->iotype) {
+	case UPIO_MEM:
+		return readb(port->membase + offset);
+	case UPIO_MEM16:
+		return readw(port->membase + offset);
+	case UPIO_MEM32:
+		return readl(port->membase + offset);
+	case UPIO_MEM32BE:
+		return ioread32be(port->membase + offset);
+	case UPIO_PORT:
+		return inb(port->iobase + offset);
+	case UPIO_AU:
+		return port->serial_in(port, reg_offset);
+	default:
+		return 0;
+	}
+}
+
+static void serial8250_early_out(struct uart_port *port, int offset, int value)
+{
+	int reg_offset = offset;
+	offset <<= port->regshift;
+
+	switch (port->iotype) {
+	case UPIO_MEM:
+		writeb(value, port->membase + offset);
+		break;
+	case UPIO_MEM16:
+		writew(value, port->membase + offset);
+		break;
+	case UPIO_MEM32:
+		writel(value, port->membase + offset);
+		break;
+	case UPIO_MEM32BE:
+		iowrite32be(value, port->membase + offset);
+		break;
+	case UPIO_PORT:
+		outb(value, port->iobase + offset);
+		break;
+	case UPIO_AU:
+		port->serial_out(port, reg_offset, value);
+		break;
+	}
+}
+
+#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
+
+static void serial_putc(struct uart_port *port, int c)
+{
+	unsigned int status;
+
+	serial8250_early_out(port, UART_TX, c);
+
+	for (;;) {
+		status = serial8250_early_in(port, UART_LSR);
+		if ((status & BOTH_EMPTY) == BOTH_EMPTY)
+			break;
+		cpu_relax();
+	}
+}
+
+static void early_serial8250_write(struct console *console,
+					const char *s, unsigned int count)
+{
+	struct earlycon_device *device = console->data;
+	struct uart_port *port = &device->port;
+
+	uart_console_write(port, s, count, serial_putc);
+}
+
+static void __init init_port(struct earlycon_device *device)
+{
+	struct uart_port *port = &device->port;
+	unsigned int divisor;
+	unsigned char c;
+	unsigned int ier;
+
+	serial8250_early_out(port, UART_LCR, 0x3);	/* 8n1 */
+	ier = serial8250_early_in(port, UART_IER);
+	serial8250_early_out(port, UART_IER, ier & UART_IER_UUE); /* no interrupt */
+	serial8250_early_out(port, UART_FCR, 0);	/* no fifo */
+	serial8250_early_out(port, UART_MCR, 0x3);	/* DTR + RTS */
+
+	if (port->uartclk) {
+		divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud);
+		c = serial8250_early_in(port, UART_LCR);
+		serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB);
+		serial8250_early_out(port, UART_DLL, divisor & 0xff);
+		serial8250_early_out(port, UART_DLM, (divisor >> 8) & 0xff);
+		serial8250_early_out(port, UART_LCR, c & ~UART_LCR_DLAB);
+	}
+}
+
+int __init early_serial8250_setup(struct earlycon_device *device,
+					 const char *options)
+{
+	if (!(device->port.membase || device->port.iobase))
+		return -ENODEV;
+
+	if (!device->baud) {
+		struct uart_port *port = &device->port;
+		unsigned int ier;
+
+		/* assume the device was initialized, only mask interrupts */
+		ier = serial8250_early_in(port, UART_IER);
+		serial8250_early_out(port, UART_IER, ier & UART_IER_UUE);
+	} else
+		init_port(device);
+
+	device->con->write = early_serial8250_write;
+	return 0;
+}
+EARLYCON_DECLARE(uart8250, early_serial8250_setup);
+EARLYCON_DECLARE(uart, early_serial8250_setup);
+OF_EARLYCON_DECLARE(ns16550, "ns16550", early_serial8250_setup);
+OF_EARLYCON_DECLARE(ns16550a, "ns16550a", early_serial8250_setup);
+OF_EARLYCON_DECLARE(uart, "nvidia,tegra20-uart", early_serial8250_setup);
+OF_EARLYCON_DECLARE(uart, "snps,dw-apb-uart", early_serial8250_setup);
+
+#ifdef CONFIG_SERIAL_8250_OMAP
+
+static int __init early_omap8250_setup(struct earlycon_device *device,
+				       const char *options)
+{
+	struct uart_port *port = &device->port;
+
+	if (!(device->port.membase || device->port.iobase))
+		return -ENODEV;
+
+	port->regshift = 2;
+	device->con->write = early_serial8250_write;
+	return 0;
+}
+
+OF_EARLYCON_DECLARE(omap8250, "ti,omap2-uart", early_omap8250_setup);
+OF_EARLYCON_DECLARE(omap8250, "ti,omap3-uart", early_omap8250_setup);
+OF_EARLYCON_DECLARE(omap8250, "ti,omap4-uart", early_omap8250_setup);
+
+#endif
+
+#ifdef CONFIG_SERIAL_8250_RT288X
+
+unsigned int au_serial_in(struct uart_port *p, int offset);
+void au_serial_out(struct uart_port *p, int offset, int value);
+
+static int __init early_au_setup(struct earlycon_device *dev, const char *opt)
+{
+	dev->port.serial_in = au_serial_in;
+	dev->port.serial_out = au_serial_out;
+	dev->port.iotype = UPIO_AU;
+	dev->con->write = early_serial8250_write;
+	return 0;
+}
+OF_EARLYCON_DECLARE(palmchip, "ralink,rt2880-uart", early_au_setup);
+
+#endif