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path: root/drivers/tty/serial/8250/8250_early.c
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Diffstat (limited to 'drivers/tty/serial/8250/8250_early.c')
-rw-r--r--drivers/tty/serial/8250/8250_early.c101
1 files changed, 57 insertions, 44 deletions
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index 82fc48eca1df..dc0371857ecb 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -1,13 +1,10 @@
+// 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>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
* Based on the 8250.c serial driver, Copyright (C) 2001 Russell King,
* and on early_printk.c by Andi Kleen.
*
@@ -30,16 +27,14 @@
#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 __init serial8250_early_in(struct uart_port *port, int offset)
+static unsigned int serial8250_early_in(struct uart_port *port, int offset)
{
- int reg_offset = offset;
offset <<= port->regshift;
switch (port->iotype) {
@@ -51,18 +46,17 @@ static unsigned int __init serial8250_early_in(struct uart_port *port, int offse
return readl(port->membase + offset);
case UPIO_MEM32BE:
return ioread32be(port->membase + offset);
+#ifdef CONFIG_HAS_IOPORT
case UPIO_PORT:
return inb(port->iobase + offset);
- case UPIO_AU:
- return port->serial_in(port, reg_offset);
+#endif
default:
return 0;
}
}
-static void __init serial8250_early_out(struct uart_port *port, int offset, int value)
+static void serial8250_early_out(struct uart_port *port, int offset, int value)
{
- int reg_offset = offset;
offset <<= port->regshift;
switch (port->iotype) {
@@ -78,18 +72,17 @@ static void __init serial8250_early_out(struct uart_port *port, int offset, int
case UPIO_MEM32BE:
iowrite32be(value, port->membase + offset);
break;
+#ifdef CONFIG_HAS_IOPORT
case UPIO_PORT:
outb(value, port->iobase + offset);
break;
- case UPIO_AU:
- port->serial_out(port, reg_offset, value);
+#endif
+ default:
break;
}
}
-#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
-
-static void __init serial_putc(struct uart_port *port, int c)
+static void serial_putc(struct uart_port *port, unsigned char c)
{
unsigned int status;
@@ -97,13 +90,13 @@ static void __init serial_putc(struct uart_port *port, int c)
for (;;) {
status = serial8250_early_in(port, UART_LSR);
- if ((status & BOTH_EMPTY) == BOTH_EMPTY)
+ if (uart_lsr_tx_empty(status))
break;
cpu_relax();
}
}
-static void __init early_serial8250_write(struct console *console,
+static void early_serial8250_write(struct console *console,
const char *s, unsigned int count)
{
struct earlycon_device *device = console->data;
@@ -112,6 +105,28 @@ static void __init early_serial8250_write(struct console *console,
uart_console_write(port, s, count, serial_putc);
}
+#ifdef CONFIG_CONSOLE_POLL
+static int early_serial8250_read(struct console *console,
+ char *s, unsigned int count)
+{
+ struct earlycon_device *device = console->data;
+ struct uart_port *port = &device->port;
+ unsigned int status;
+ int num_read = 0;
+
+ while (num_read < count) {
+ status = serial8250_early_in(port, UART_LSR);
+ if (!(status & UART_LSR_DR))
+ break;
+ s[num_read++] = serial8250_early_in(port, UART_RX);
+ }
+
+ return num_read;
+}
+#else
+#define early_serial8250_read NULL
+#endif
+
static void __init init_port(struct earlycon_device *device)
{
struct uart_port *port = &device->port;
@@ -119,18 +134,20 @@ static void __init init_port(struct earlycon_device *device)
unsigned char c;
unsigned int ier;
- serial8250_early_out(port, UART_LCR, 0x3); /* 8n1 */
+ serial8250_early_out(port, UART_LCR, UART_LCR_WLEN8); /* 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 */
-
- 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);
+ serial8250_early_out(port, UART_MCR, UART_MCR_DTR | UART_MCR_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,
@@ -150,6 +167,7 @@ int __init early_serial8250_setup(struct earlycon_device *device,
init_port(device);
device->con->write = early_serial8250_write;
+ device->con->read = early_serial8250_read;
return 0;
}
EARLYCON_DECLARE(uart8250, early_serial8250_setup);
@@ -159,6 +177,17 @@ 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);
+static int __init early_serial8250_rs2_setup(struct earlycon_device *device,
+ const char *options)
+{
+ device->port.regshift = 2;
+
+ return early_serial8250_setup(device, options);
+}
+OF_EARLYCON_DECLARE(uart, "intel,xscale-uart", early_serial8250_rs2_setup);
+OF_EARLYCON_DECLARE(uart, "mrvl,mmp-uart", early_serial8250_rs2_setup);
+OF_EARLYCON_DECLARE(uart, "mrvl,pxa-uart", early_serial8250_rs2_setup);
+
#ifdef CONFIG_SERIAL_8250_OMAP
static int __init early_omap8250_setup(struct earlycon_device *device,
@@ -177,22 +206,6 @@ static int __init early_omap8250_setup(struct earlycon_device *device,
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);
+OF_EARLYCON_DECLARE(omap8250, "ti,am654-uart", early_omap8250_setup);
#endif
generated by cgit (git 2.34.1) at 2025-12-28 20:06:24 +0000