xref: /openbmc/linux/drivers/firmware/pcdp.c (revision 120540f2)
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 
19 static int __init
setup_serial_console(struct pcdp_uart * uart)20 setup_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 
49 static int __init
setup_vga_console(struct pcdp_device * dev)50 setup_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 
83 extern unsigned long hcdp_phys;
84 
85 int __init
efi_setup_pcdp_console(char * cmdline)86 efi_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 
132 out:
133 	early_memunmap(pcdp, 4096);
134 	return rc;
135 }
136