xref: /openbmc/linux/drivers/firmware/pcdp.c (revision 1da177e4)
1 /*
2  * Parse the EFI PCDP table to locate the console device.
3  *
4  * (c) Copyright 2002, 2003, 2004 Hewlett-Packard Development Company, L.P.
5  *	Khalid Aziz <khalid.aziz@hp.com>
6  *	Alex Williamson <alex.williamson@hp.com>
7  *	Bjorn Helgaas <bjorn.helgaas@hp.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include <linux/acpi.h>
15 #include <linux/console.h>
16 #include <linux/efi.h>
17 #include <linux/serial.h>
18 #include "pcdp.h"
19 
20 static int __init
21 setup_serial_console(struct pcdp_uart *uart)
22 {
23 #ifdef CONFIG_SERIAL_8250_CONSOLE
24 	int mmio;
25 	static char options[64];
26 
27 	mmio = (uart->addr.address_space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY);
28 	snprintf(options, sizeof(options), "console=uart,%s,0x%lx,%lun%d",
29 		mmio ? "mmio" : "io", uart->addr.address, uart->baud,
30 		uart->bits ? uart->bits : 8);
31 
32 	return early_serial_console_init(options);
33 #else
34 	return -ENODEV;
35 #endif
36 }
37 
38 static int __init
39 setup_vga_console(struct pcdp_vga *vga)
40 {
41 #if defined(CONFIG_VT) && defined(CONFIG_VGA_CONSOLE)
42 	if (efi_mem_type(0xA0000) == EFI_CONVENTIONAL_MEMORY) {
43 		printk(KERN_ERR "PCDP: VGA selected, but frame buffer is not MMIO!\n");
44 		return -ENODEV;
45 	}
46 
47 	conswitchp = &vga_con;
48 	printk(KERN_INFO "PCDP: VGA console\n");
49 	return 0;
50 #else
51 	return -ENODEV;
52 #endif
53 }
54 
55 int __init
56 efi_setup_pcdp_console(char *cmdline)
57 {
58 	struct pcdp *pcdp;
59 	struct pcdp_uart *uart;
60 	struct pcdp_device *dev, *end;
61 	int i, serial = 0;
62 
63 	pcdp = efi.hcdp;
64 	if (!pcdp)
65 		return -ENODEV;
66 
67 	printk(KERN_INFO "PCDP: v%d at 0x%lx\n", pcdp->rev, __pa(pcdp));
68 
69 	if (strstr(cmdline, "console=hcdp")) {
70 		if (pcdp->rev < 3)
71 			serial = 1;
72 	} else if (strstr(cmdline, "console=")) {
73 		printk(KERN_INFO "Explicit \"console=\"; ignoring PCDP\n");
74 		return -ENODEV;
75 	}
76 
77 	if (pcdp->rev < 3 && efi_uart_console_only())
78 		serial = 1;
79 
80 	for (i = 0, uart = pcdp->uart; i < pcdp->num_uarts; i++, uart++) {
81 		if (uart->flags & PCDP_UART_PRIMARY_CONSOLE || serial) {
82 			if (uart->type == PCDP_CONSOLE_UART) {
83 				return setup_serial_console(uart);
84 			}
85 		}
86 	}
87 
88 	end = (struct pcdp_device *) ((u8 *) pcdp + pcdp->length);
89 	for (dev = (struct pcdp_device *) (pcdp->uart + pcdp->num_uarts);
90 	     dev < end;
91 	     dev = (struct pcdp_device *) ((u8 *) dev + dev->length)) {
92 		if (dev->flags & PCDP_PRIMARY_CONSOLE) {
93 			if (dev->type == PCDP_CONSOLE_VGA) {
94 				return setup_vga_console((struct pcdp_vga *) dev);
95 			}
96 		}
97 	}
98 
99 	return -ENODEV;
100 }
101