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Diffstat (limited to 'arch/x86/kernel/early_printk.c')
-rw-r--r--arch/x86/kernel/early_printk.c398
1 files changed, 398 insertions, 0 deletions
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
new file mode 100644
index 000000000..44f937015
--- /dev/null
+++ b/arch/x86/kernel/early_printk.c
@@ -0,0 +1,398 @@
+// 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 <linux/pgtable.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 <linux/usb/ehci_def.h>
+#include <linux/usb/xhci-dbgp.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 "[force],B:D.F,baud", where B, D & F describe
+ * the location of a PCI device that must be a UART device. "force" is optional
+ * and overrides the use of an UART device with a wrong PCI class code.
+ */
+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;
+ int force = 0;
+
+ if (*s == ',')
+ ++s;
+
+ if (*s == 0)
+ return;
+
+ /* Force the use of an UART device with wrong class code */
+ if (!strncmp(s, "force,", 6)) {
+ force = 1;
+ s += 6;
+ }
+
+ /*
+ * Part the param to get the BDF values
+ */
+ 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++;
+
+ /*
+ * 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 16550-UART type device
+ */
+ if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
+ (classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
+ (((classcode >> 8) & 0xff) != PCI_SERIAL_16550_COMPATIBLE)) {
+ if (!force)
+ return;
+ }
+
+ /*
+ * Determine if it is IO or memory mapped
+ */
+ if ((bar0 & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
+ /* it is IO mapped */
+ serial_in = io_serial_in;
+ serial_out = io_serial_out;
+ early_serial_base = bar0 & PCI_BASE_ADDRESS_IO_MASK;
+ 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 & PCI_BASE_ADDRESS_MEM_MASK, 0x10);
+ write_pci_config(bus, slot, func, PCI_COMMAND,
+ cmdreg|PCI_COMMAND_MEMORY);
+ }
+
+ /*
+ * 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_USB_XDBC
+ if (!strncmp(buf, "xdbc", 4))
+ early_xdbc_parse_parameter(buf + 4, keep);
+#endif
+
+ buf++;
+ }
+ return 0;
+}
+
+early_param("earlyprintk", setup_early_printk);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-24 12:17:18 +0000