xref: /kernel/linux/linux-6.6/drivers/firmware/pcdp.c (revision 62306a36)
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Parse the EFI PCDP table to locate the console device.
4 *
5 * (c) Copyright 2002, 2003, 2004 Hewlett-Packard Development Company, L.P.
6 *	Khalid Aziz <khalid.aziz@hp.com>
7 *	Alex Williamson <alex.williamson@hp.com>
8 *	Bjorn Helgaas <bjorn.helgaas@hp.com>
9 */
10
11#include <linux/acpi.h>
12#include <linux/console.h>
13#include <linux/efi.h>
14#include <linux/serial.h>
15#include <linux/serial_core.h>
16#include <asm/vga.h>
17#include "pcdp.h"
18
19static int __init
20setup_serial_console(struct pcdp_uart *uart)
21{
22#ifdef CONFIG_SERIAL_8250_CONSOLE
23	int mmio;
24	static char options[64], *p = options;
25	char parity;
26
27	mmio = (uart->addr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY);
28	p += sprintf(p, "uart8250,%s,0x%llx",
29		mmio ? "mmio" : "io", uart->addr.address);
30	if (uart->baud) {
31		p += sprintf(p, ",%llu", uart->baud);
32		if (uart->bits) {
33			switch (uart->parity) {
34			    case 0x2: parity = 'e'; break;
35			    case 0x3: parity = 'o'; break;
36			    default:  parity = 'n';
37			}
38			p += sprintf(p, "%c%d", parity, uart->bits);
39		}
40	}
41
42	add_preferred_console("uart", 8250, &options[9]);
43	return setup_earlycon(options);
44#else
45	return -ENODEV;
46#endif
47}
48
49static int __init
50setup_vga_console(struct pcdp_device *dev)
51{
52#if defined(CONFIG_VT) && defined(CONFIG_VGA_CONSOLE)
53	u8 *if_ptr;
54
55	if_ptr = ((u8 *)dev + sizeof(struct pcdp_device));
56	if (if_ptr[0] == PCDP_IF_PCI) {
57		struct pcdp_if_pci if_pci;
58
59		/* struct copy since ifptr might not be correctly aligned */
60
61		memcpy(&if_pci, if_ptr, sizeof(if_pci));
62
63		if (if_pci.trans & PCDP_PCI_TRANS_IOPORT)
64			vga_console_iobase = if_pci.ioport_tra;
65
66		if (if_pci.trans & PCDP_PCI_TRANS_MMIO)
67			vga_console_membase = if_pci.mmio_tra;
68	}
69
70	if (efi_mem_type(vga_console_membase + 0xA0000) == EFI_CONVENTIONAL_MEMORY) {
71		printk(KERN_ERR "PCDP: VGA selected, but frame buffer is not MMIO!\n");
72		return -ENODEV;
73	}
74
75	conswitchp = &vga_con;
76	printk(KERN_INFO "PCDP: VGA console\n");
77	return 0;
78#else
79	return -ENODEV;
80#endif
81}
82
83extern unsigned long hcdp_phys;
84
85int __init
86efi_setup_pcdp_console(char *cmdline)
87{
88	struct pcdp *pcdp;
89	struct pcdp_uart *uart;
90	struct pcdp_device *dev, *end;
91	int i, serial = 0;
92	int rc = -ENODEV;
93
94	if (hcdp_phys == EFI_INVALID_TABLE_ADDR)
95		return -ENODEV;
96
97	pcdp = early_memremap(hcdp_phys, 4096);
98	printk(KERN_INFO "PCDP: v%d at 0x%lx\n", pcdp->rev, hcdp_phys);
99
100	if (strstr(cmdline, "console=hcdp")) {
101		if (pcdp->rev < 3)
102			serial = 1;
103	} else if (strstr(cmdline, "console=")) {
104		printk(KERN_INFO "Explicit \"console=\"; ignoring PCDP\n");
105		goto out;
106	}
107
108	if (pcdp->rev < 3 && efi_uart_console_only())
109		serial = 1;
110
111	for (i = 0, uart = pcdp->uart; i < pcdp->num_uarts; i++, uart++) {
112		if (uart->flags & PCDP_UART_PRIMARY_CONSOLE || serial) {
113			if (uart->type == PCDP_CONSOLE_UART) {
114				rc = setup_serial_console(uart);
115				goto out;
116			}
117		}
118	}
119
120	end = (struct pcdp_device *) ((u8 *) pcdp + pcdp->length);
121	for (dev = (struct pcdp_device *) (pcdp->uart + pcdp->num_uarts);
122	     dev < end;
123	     dev = (struct pcdp_device *) ((u8 *) dev + dev->length)) {
124		if (dev->flags & PCDP_PRIMARY_CONSOLE) {
125			if (dev->type == PCDP_CONSOLE_VGA) {
126				rc = setup_vga_console(dev);
127				goto out;
128			}
129		}
130	}
131
132out:
133	early_memunmap(pcdp, 4096);
134	return rc;
135}
136