Specify PCI based UART for earlyprintk
Add support for specifying PCI based UARTs for earlyprintk using a syntax like "earlyprintk=pciserial,00:18.1,115200", where 00:18.1 is the BDF of a UART device. [Slightly tidied from Stuart's original patch] Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stuart R. Anderson
Greg Kroah-Hartman
Родитель
d2b6f44779
Коммит
ea9e9d8029
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@ -19,6 +19,7 @@
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#include <linux/usb/ehci_def.h>
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#include <linux/efi.h>
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#include <asm/efi.h>
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#include <asm/pci_x86.h>
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/* Simple VGA output */
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#define VGABASE (__ISA_IO_base + 0xb8000)
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@ -76,7 +77,7 @@ static struct console early_vga_console = {
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/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
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static int early_serial_base = 0x3f8; /* ttyS0 */
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static unsigned long early_serial_base = 0x3f8; /* ttyS0 */
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#define XMTRDY 0x20
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@ -94,13 +95,40 @@ static int early_serial_base = 0x3f8; /* ttyS0 */
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#define DLL 0 /* Divisor Latch Low */
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#define DLH 1 /* Divisor latch High */
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static void mem32_serial_out(unsigned long addr, int offset, int value)
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{
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uint32_t *vaddr = (uint32_t *)addr;
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/* shift implied by pointer type */
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writel(value, vaddr + offset);
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}
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static unsigned int mem32_serial_in(unsigned long addr, int offset)
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{
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uint32_t *vaddr = (uint32_t *)addr;
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/* shift implied by pointer type */
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return readl(vaddr + offset);
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}
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static unsigned int io_serial_in(unsigned long addr, int offset)
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{
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return inb(addr + offset);
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}
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static void io_serial_out(unsigned long addr, int offset, int value)
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{
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outb(value, addr + offset);
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}
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static unsigned int (*serial_in)(unsigned long addr, int offset) = io_serial_in;
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static void (*serial_out)(unsigned long addr, int offset, int value) = io_serial_out;
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static int early_serial_putc(unsigned char ch)
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{
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unsigned timeout = 0xffff;
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while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
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while ((serial_in(early_serial_base, LSR) & XMTRDY) == 0 && --timeout)
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cpu_relax();
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outb(ch, early_serial_base + TXR);
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serial_out(early_serial_base, TXR, ch);
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return timeout ? 0 : -1;
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}
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@ -114,13 +142,28 @@ static void early_serial_write(struct console *con, const char *s, unsigned n)
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}
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}
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static __init void early_serial_hw_init(unsigned divisor)
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{
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unsigned char c;
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serial_out(early_serial_base, LCR, 0x3); /* 8n1 */
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serial_out(early_serial_base, IER, 0); /* no interrupt */
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serial_out(early_serial_base, FCR, 0); /* no fifo */
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serial_out(early_serial_base, MCR, 0x3); /* DTR + RTS */
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c = serial_in(early_serial_base, LCR);
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serial_out(early_serial_base, LCR, c | DLAB);
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serial_out(early_serial_base, DLL, divisor & 0xff);
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serial_out(early_serial_base, DLH, (divisor >> 8) & 0xff);
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serial_out(early_serial_base, LCR, c & ~DLAB);
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}
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#define DEFAULT_BAUD 9600
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static __init void early_serial_init(char *s)
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{
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unsigned char c;
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unsigned divisor;
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unsigned baud = DEFAULT_BAUD;
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unsigned long baud = DEFAULT_BAUD;
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char *e;
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if (*s == ',')
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@ -145,25 +188,125 @@ static __init void early_serial_init(char *s)
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s++;
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}
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outb(0x3, early_serial_base + LCR); /* 8n1 */
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outb(0, early_serial_base + IER); /* no interrupt */
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outb(0, early_serial_base + FCR); /* no fifo */
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outb(0x3, early_serial_base + MCR); /* DTR + RTS */
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if (*s) {
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baud = simple_strtoul(s, &e, 0);
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if (baud == 0 || s == e)
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if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
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baud = DEFAULT_BAUD;
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}
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/* Convert from baud to divisor value */
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divisor = 115200 / baud;
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c = inb(early_serial_base + LCR);
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outb(c | DLAB, early_serial_base + LCR);
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outb(divisor & 0xff, early_serial_base + DLL);
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outb((divisor >> 8) & 0xff, early_serial_base + DLH);
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outb(c & ~DLAB, early_serial_base + LCR);
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/* These will always be IO based ports */
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serial_in = io_serial_in;
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serial_out = io_serial_out;
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/* Set up the HW */
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early_serial_hw_init(divisor);
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}
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#ifdef CONFIG_PCI
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/*
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* early_pci_serial_init()
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*
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* This function is invoked when the early_printk param starts with "pciserial"
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* The rest of the param should be ",B:D.F,baud" where B, D & F describe the
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* location of a PCI device that must be a UART device.
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*/
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static __init void early_pci_serial_init(char *s)
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{
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unsigned divisor;
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unsigned long baud = DEFAULT_BAUD;
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u8 bus, slot, func;
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uint32_t classcode, bar0;
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uint16_t cmdreg;
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char *e;
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/*
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* First, part the param to get the BDF values
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*/
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if (*s == ',')
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++s;
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if (*s == 0)
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return;
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bus = (u8)simple_strtoul(s, &e, 16);
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s = e;
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if (*s != ':')
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return;
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++s;
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slot = (u8)simple_strtoul(s, &e, 16);
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s = e;
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if (*s != '.')
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return;
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++s;
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func = (u8)simple_strtoul(s, &e, 16);
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s = e;
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/* A baud might be following */
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if (*s == ',')
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s++;
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/*
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* Second, find the device from the BDF
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*/
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cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
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classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
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bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
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/*
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* Verify it is a UART type device
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*/
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if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
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(classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
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(((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */
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return;
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/*
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* Determine if it is IO or memory mapped
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*/
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if (bar0 & 0x01) {
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/* it is IO mapped */
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serial_in = io_serial_in;
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serial_out = io_serial_out;
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early_serial_base = bar0&0xfffffffc;
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write_pci_config(bus, slot, func, PCI_COMMAND,
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cmdreg|PCI_COMMAND_IO);
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} else {
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/* It is memory mapped - assume 32-bit alignment */
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serial_in = mem32_serial_in;
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serial_out = mem32_serial_out;
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/* WARNING! assuming the address is always in the first 4G */
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early_serial_base =
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(unsigned long)early_ioremap(bar0 & 0xfffffff0, 0x10);
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write_pci_config(bus, slot, func, PCI_COMMAND,
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cmdreg|PCI_COMMAND_MEMORY);
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}
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/*
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* Lastly, initalize the hardware
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*/
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if (*s) {
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if (strcmp(s, "nocfg") == 0)
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/* Sometimes, we want to leave the UART alone
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* and assume the BIOS has set it up correctly.
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* "nocfg" tells us this is the case, and we
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* should do no more setup.
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*/
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return;
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if (kstrtoul(s, 0, &baud) < 0 || baud == 0)
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baud = DEFAULT_BAUD;
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}
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/* Convert from baud to divisor value */
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divisor = 115200 / baud;
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/* Set up the HW */
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early_serial_hw_init(divisor);
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}
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#endif
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static struct console early_serial_console = {
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.name = "earlyser",
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.write = early_serial_write,
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@ -210,6 +353,13 @@ static int __init setup_early_printk(char *buf)
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early_serial_init(buf + 4);
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early_console_register(&early_serial_console, keep);
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}
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#ifdef CONFIG_PCI
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if (!strncmp(buf, "pciserial", 9)) {
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early_pci_serial_init(buf + 9);
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early_console_register(&early_serial_console, keep);
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buf += 9; /* Keep from match the above "serial" */
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}
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#endif
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if (!strncmp(buf, "vga", 3) &&
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boot_params.screen_info.orig_video_isVGA == 1) {
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max_xpos = boot_params.screen_info.orig_video_cols;
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