Commit ff51224c authored by Mark Maule's avatar Mark Maule Committed by Tony Luck
Browse files

[IA64-SGI] set altix preferred console

Fix default VGA console on SN platforms.  Since SN firmware does not pass
enough ACPI information to identify VGA cards and the associated legacy IO/MEM
addresses, we rely on the EFI PCDP table.  Since the linux pcdp driver is
optional (and overridden if console= directives are used) SN duplicates a
portion of the pcdp scan code to identify if there is a usable console VGA
adapter.  Additionally, dup necessary pcdp related structs to avoid dragging
drivers/pcdp.h into a more public location.
Signed-off-by: default avatarMark Maule <>
Signed-off-by: default avatarTony Luck <>
parent 837cd0bd
......@@ -30,6 +30,7 @@
#include <linux/root_dev.h>
#include <linux/nodemask.h>
#include <linux/pm.h>
#include <linux/efi.h>
#include <asm/io.h>
#include <asm/sal.h>
......@@ -242,6 +243,135 @@ static void __init sn_check_for_wars(void)
* Scan the EFI PCDP table (if it exists) for an acceptable VGA console
* output device. If one exists, pick it and set sn_legacy_{io,mem} to
* reflect the bus offsets needed to address it.
* Since pcdp support in SN is not supported in the 2.4 kernel (or at least
* the one lbs is based on) just declare the needed structs here.
* Reference spec
* Returns 0 if no acceptable vga is found, !0 otherwise.
* Note: This stuff is duped here because Altix requires the PCDP to
* locate a usable VGA device due to lack of proper ACPI support. Structures
* could be used from drivers/firmware/pcdp.h, but it was decided that moving
* this file to a more public location just for Altix use was undesireable.
struct hcdp_uart_desc {
u8 pad[45];
struct pcdp {
u8 signature[4]; /* should be 'HCDP' */
u32 length;
u8 rev; /* should be >=3 for pcdp, <3 for hcdp */
u8 sum;
u8 oem_id[6];
u64 oem_tableid;
u32 oem_rev;
u32 creator_id;
u32 creator_rev;
u32 num_type0;
struct hcdp_uart_desc uart[0]; /* num_type0 of these */
/* pcdp descriptors follow */
} __attribute__((packed));
struct pcdp_device_desc {
u8 type;
u8 primary;
u16 length;
u16 index;
/* interconnect specific structure follows */
/* device specific structure follows that */
} __attribute__((packed));
struct pcdp_interface_pci {
u8 type; /* 1 == pci */
u8 reserved;
u16 length;
u8 segment;
u8 bus;
u8 dev;
u8 fun;
u16 devid;
u16 vendid;
u32 acpi_interrupt;
u64 mmio_tra;
u64 ioport_tra;
u8 flags;
u8 translation;
} __attribute__((packed));
struct pcdp_vga_device {
u8 num_eas_desc;
/* ACPI Extended Address Space Desc follows */
} __attribute__((packed));
/* from pcdp_device_desc.primary */
/* from pcdp_device_desc.type */
#define PCDP_CONSOLE_OUT 0x2
#define PCDP_CONSOLE_IN 0x3
/* from pcdp_interface_pci.type */
#define PCDP_IF_PCI 1
/* from pcdp_interface_pci.translation */
#define PCDP_PCI_TRANS_MMIO 0x01
static void
u8 *bp;
struct pcdp *pcdp;
struct pcdp_device_desc device;
struct pcdp_interface_pci if_pci;
extern struct efi efi;
pcdp = efi.hcdp;
if (! pcdp)
return; /* no hcdp/pcdp table */
if (pcdp->rev < 3)
return; /* only support PCDP (rev >= 3) */
for (bp = (u8 *)&pcdp->uart[pcdp->num_type0];
bp < (u8 *)pcdp + pcdp->length;
bp += device.length) {
memcpy(&device, bp, sizeof(device));
if (! (device.primary & PCDP_PRIMARY_CONSOLE))
continue; /* not primary console */
if (device.type != PCDP_CONSOLE_VGA)
continue; /* not VGA descriptor */
memcpy(&if_pci, bp+sizeof(device), sizeof(if_pci));
if (if_pci.type != PCDP_IF_PCI)
continue; /* not PCI interconnect */
if (if_pci.translation & PCDP_PCI_TRANS_IOPORT)
vga_console_iobase =
if_pci.ioport_tra | __IA64_UNCACHED_OFFSET;
if (if_pci.translation & PCDP_PCI_TRANS_MMIO)
vga_console_membase =
if_pci.mmio_tra | __IA64_UNCACHED_OFFSET;
break; /* once we find the primary, we're done */
* sn_setup - SN platform setup routine
* @cmdline_p: kernel command line
......@@ -263,16 +393,35 @@ void __init sn_setup(char **cmdline_p)
#if defined(CONFIG_VT) && defined(CONFIG_VGA_CONSOLE)
* If there was a primary vga adapter identified through the
* EFI PCDP table, make it the preferred console. Otherwise
* zero out conswitchp.
* Handle SN vga console.
* SN systems do not have enough ACPI table information
* being passed from prom to identify VGA adapters and the legacy
* addresses to access them. Until that is done, SN systems rely
* on the PCDP table to identify the primary VGA console if one
* exists.
* However, kernel PCDP support is optional, and even if it is built
* into the kernel, it will not be used if the boot cmdline contains
* console= directives.
* So, to work around this mess, we duplicate some of the PCDP code
* here so that the primary VGA console (as defined by PCDP) will
* work on SN systems even if a different console (e.g. serial) is
* selected on the boot line (or CONFIG_EFI_PCDP is off).
if (! vga_console_membase)
if (vga_console_membase) {
/* usable vga ... make tty0 the preferred default console */
add_preferred_console("tty", 0, NULL);
if (!strstr(*cmdline_p, "console="))
add_preferred_console("tty", 0, NULL);
} else {
printk(KERN_DEBUG "SGI: Disabling VGA console\n");
if (!strstr(*cmdline_p, "console="))
add_preferred_console("ttySG", 0, NULL);
conswitchp = &dummy_con;
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