https://github.com/torvalds/linux
Tip revision: 60cc43fc888428bb2f18f08997432d426a243338 authored by Linus Torvalds on 16 April 2018, 01:24:20 UTC
Linux 4.17-rc1
Linux 4.17-rc1
Tip revision: 60cc43f
early_printk.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/screen_info.h>
#include <linux/usb/ch9.h>
#include <linux/pci_regs.h>
#include <linux/pci_ids.h>
#include <linux/errno.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/fcntl.h>
#include <asm/setup.h>
#include <xen/hvc-console.h>
#include <asm/pci-direct.h>
#include <asm/fixmap.h>
#include <asm/intel-mid.h>
#include <asm/pgtable.h>
#include <linux/usb/ehci_def.h>
#include <linux/usb/xhci-dbgp.h>
#include <linux/efi.h>
#include <asm/efi.h>
#include <asm/pci_x86.h>
/* Simple VGA output */
#define VGABASE (__ISA_IO_base + 0xb8000)
static int max_ypos = 25, max_xpos = 80;
static int current_ypos = 25, current_xpos;
static void early_vga_write(struct console *con, const char *str, unsigned n)
{
char c;
int i, k, j;
while ((c = *str++) != '\0' && n-- > 0) {
if (current_ypos >= max_ypos) {
/* scroll 1 line up */
for (k = 1, j = 0; k < max_ypos; k++, j++) {
for (i = 0; i < max_xpos; i++) {
writew(readw(VGABASE+2*(max_xpos*k+i)),
VGABASE + 2*(max_xpos*j + i));
}
}
for (i = 0; i < max_xpos; i++)
writew(0x720, VGABASE + 2*(max_xpos*j + i));
current_ypos = max_ypos-1;
}
#ifdef CONFIG_KGDB_KDB
if (c == '\b') {
if (current_xpos > 0)
current_xpos--;
} else if (c == '\r') {
current_xpos = 0;
} else
#endif
if (c == '\n') {
current_xpos = 0;
current_ypos++;
} else if (c != '\r') {
writew(((0x7 << 8) | (unsigned short) c),
VGABASE + 2*(max_xpos*current_ypos +
current_xpos++));
if (current_xpos >= max_xpos) {
current_xpos = 0;
current_ypos++;
}
}
}
}
static struct console early_vga_console = {
.name = "earlyvga",
.write = early_vga_write,
.flags = CON_PRINTBUFFER,
.index = -1,
};
/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
static unsigned long early_serial_base = 0x3f8; /* ttyS0 */
#define XMTRDY 0x20
#define DLAB 0x80
#define TXR 0 /* Transmit register (WRITE) */
#define RXR 0 /* Receive register (READ) */
#define IER 1 /* Interrupt Enable */
#define IIR 2 /* Interrupt ID */
#define FCR 2 /* FIFO control */
#define LCR 3 /* Line control */
#define MCR 4 /* Modem control */
#define LSR 5 /* Line Status */
#define MSR 6 /* Modem Status */
#define DLL 0 /* Divisor Latch Low */
#define DLH 1 /* Divisor latch High */
static unsigned int io_serial_in(unsigned long addr, int offset)
{
return inb(addr + offset);
}
static void io_serial_out(unsigned long addr, int offset, int value)
{
outb(value, addr + offset);
}
static unsigned int (*serial_in)(unsigned long addr, int offset) = io_serial_in;
static void (*serial_out)(unsigned long addr, int offset, int value) = io_serial_out;
static int early_serial_putc(unsigned char ch)
{
unsigned timeout = 0xffff;
while ((serial_in(early_serial_base, LSR) & XMTRDY) == 0 && --timeout)
cpu_relax();
serial_out(early_serial_base, TXR, ch);
return timeout ? 0 : -1;
}
static void early_serial_write(struct console *con, const char *s, unsigned n)
{
while (*s && n-- > 0) {
if (*s == '\n')
early_serial_putc('\r');
early_serial_putc(*s);
s++;
}
}
static __init void early_serial_hw_init(unsigned divisor)
{
unsigned char c;
serial_out(early_serial_base, LCR, 0x3); /* 8n1 */
serial_out(early_serial_base, IER, 0); /* no interrupt */
serial_out(early_serial_base, FCR, 0); /* no fifo */
serial_out(early_serial_base, MCR, 0x3); /* DTR + RTS */
c = serial_in(early_serial_base, LCR);
serial_out(early_serial_base, LCR, c | DLAB);
serial_out(early_serial_base, DLL, divisor & 0xff);
serial_out(early_serial_base, DLH, (divisor >> 8) & 0xff);
serial_out(early_serial_base, LCR, c & ~DLAB);
}
#define DEFAULT_BAUD 9600
static __init void early_serial_init(char *s)
{
unsigned divisor;
unsigned long baud = DEFAULT_BAUD;
char *e;
if (*s == ',')
++s;
if (*s) {
unsigned port;
if (!strncmp(s, "0x", 2)) {
early_serial_base = simple_strtoul(s, &e, 16);
} else {
static const int __initconst bases[] = { 0x3f8, 0x2f8 };
if (!strncmp(s, "ttyS", 4))
s += 4;
port = simple_strtoul(s, &e, 10);
if (port > 1 || s == e)
port = 0;
early_serial_base = bases[port];
}
s += strcspn(s, ",");
if (*s == ',')
s++;
}
if (*s) {
baud = simple_strtoull(s, &e, 0);
if (baud == 0 || s == e)
baud = DEFAULT_BAUD;
}
/* Convert from baud to divisor value */
divisor = 115200 / baud;
/* These will always be IO based ports */
serial_in = io_serial_in;
serial_out = io_serial_out;
/* Set up the HW */
early_serial_hw_init(divisor);
}
#ifdef CONFIG_PCI
static void mem32_serial_out(unsigned long addr, int offset, int value)
{
u32 __iomem *vaddr = (u32 __iomem *)addr;
/* shift implied by pointer type */
writel(value, vaddr + offset);
}
static unsigned int mem32_serial_in(unsigned long addr, int offset)
{
u32 __iomem *vaddr = (u32 __iomem *)addr;
/* shift implied by pointer type */
return readl(vaddr + offset);
}
/*
* early_pci_serial_init()
*
* This function is invoked when the early_printk param starts with "pciserial"
* The rest of the param should be ",B:D.F,baud" where B, D & F describe the
* location of a PCI device that must be a UART device.
*/
static __init void early_pci_serial_init(char *s)
{
unsigned divisor;
unsigned long baud = DEFAULT_BAUD;
u8 bus, slot, func;
u32 classcode, bar0;
u16 cmdreg;
char *e;
/*
* First, part the param to get the BDF values
*/
if (*s == ',')
++s;
if (*s == 0)
return;
bus = (u8)simple_strtoul(s, &e, 16);
s = e;
if (*s != ':')
return;
++s;
slot = (u8)simple_strtoul(s, &e, 16);
s = e;
if (*s != '.')
return;
++s;
func = (u8)simple_strtoul(s, &e, 16);
s = e;
/* A baud might be following */
if (*s == ',')
s++;
/*
* Second, find the device from the BDF
*/
cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
/*
* Verify it is a UART type device
*/
if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
(classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
(((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */
return;
/*
* Determine if it is IO or memory mapped
*/
if (bar0 & 0x01) {
/* it is IO mapped */
serial_in = io_serial_in;
serial_out = io_serial_out;
early_serial_base = bar0&0xfffffffc;
write_pci_config(bus, slot, func, PCI_COMMAND,
cmdreg|PCI_COMMAND_IO);
} else {
/* It is memory mapped - assume 32-bit alignment */
serial_in = mem32_serial_in;
serial_out = mem32_serial_out;
/* WARNING! assuming the address is always in the first 4G */
early_serial_base =
(unsigned long)early_ioremap(bar0 & 0xfffffff0, 0x10);
write_pci_config(bus, slot, func, PCI_COMMAND,
cmdreg|PCI_COMMAND_MEMORY);
}
/*
* Lastly, initialize the hardware
*/
if (*s) {
if (strcmp(s, "nocfg") == 0)
/* Sometimes, we want to leave the UART alone
* and assume the BIOS has set it up correctly.
* "nocfg" tells us this is the case, and we
* should do no more setup.
*/
return;
if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
baud = DEFAULT_BAUD;
}
/* Convert from baud to divisor value */
divisor = 115200 / baud;
/* Set up the HW */
early_serial_hw_init(divisor);
}
#endif
static struct console early_serial_console = {
.name = "earlyser",
.write = early_serial_write,
.flags = CON_PRINTBUFFER,
.index = -1,
};
static void early_console_register(struct console *con, int keep_early)
{
if (con->index != -1) {
printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
con->name);
return;
}
early_console = con;
if (keep_early)
early_console->flags &= ~CON_BOOT;
else
early_console->flags |= CON_BOOT;
register_console(early_console);
}
static int __init setup_early_printk(char *buf)
{
int keep;
if (!buf)
return 0;
if (early_console)
return 0;
keep = (strstr(buf, "keep") != NULL);
while (*buf != '\0') {
if (!strncmp(buf, "serial", 6)) {
buf += 6;
early_serial_init(buf);
early_console_register(&early_serial_console, keep);
if (!strncmp(buf, ",ttyS", 5))
buf += 5;
}
if (!strncmp(buf, "ttyS", 4)) {
early_serial_init(buf + 4);
early_console_register(&early_serial_console, keep);
}
#ifdef CONFIG_PCI
if (!strncmp(buf, "pciserial", 9)) {
early_pci_serial_init(buf + 9);
early_console_register(&early_serial_console, keep);
buf += 9; /* Keep from match the above "serial" */
}
#endif
if (!strncmp(buf, "vga", 3) &&
boot_params.screen_info.orig_video_isVGA == 1) {
max_xpos = boot_params.screen_info.orig_video_cols;
max_ypos = boot_params.screen_info.orig_video_lines;
current_ypos = boot_params.screen_info.orig_y;
early_console_register(&early_vga_console, keep);
}
#ifdef CONFIG_EARLY_PRINTK_DBGP
if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
early_console_register(&early_dbgp_console, keep);
#endif
#ifdef CONFIG_HVC_XEN
if (!strncmp(buf, "xen", 3))
early_console_register(&xenboot_console, keep);
#endif
#ifdef CONFIG_EARLY_PRINTK_EFI
if (!strncmp(buf, "efi", 3))
early_console_register(&early_efi_console, keep);
#endif
#ifdef CONFIG_EARLY_PRINTK_USB_XDBC
if (!strncmp(buf, "xdbc", 4))
early_xdbc_parse_parameter(buf + 4);
#endif
buf++;
}
return 0;
}
early_param("earlyprintk", setup_early_printk);