[PATCH] set altix preferred console

Mark Maule
2005-11-11T17:52:43Z

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: Mark Maule <maule@sgi.com>

Index: vga/arch/ia64/sn/kernel/setup.c
=================================--- vga.orig/arch/ia64/sn/kernel/setup.c 2005-10-12 10:36:40.914797412 -0500
+++ vga/arch/ia64/sn/kernel/setup.c 2005-11-09 11:28:04.181164653 -0600
@@ -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 @@
}
}

+/*
+ * 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 http://www.dig64.org/specifications/DIG64_PCDPv20.pdf
+ *
+ * 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 */
+#define PCDP_PRIMARY_CONSOLE 0x01
+
+/* from pcdp_device_desc.type */
+#define PCDP_CONSOLE_INOUT 0x0
+#define PCDP_CONSOLE_DEBUG 0x1
+#define PCDP_CONSOLE_OUT 0x2
+#define PCDP_CONSOLE_IN 0x3
+#define PCDP_CONSOLE_TYPE_VGA 0x8
+
+#define PCDP_CONSOLE_VGA (PCDP_CONSOLE_TYPE_VGA | PCDP_CONSOLE_OUT)
+
+/* from pcdp_interface_pci.type */
+#define PCDP_IF_PCI 1
+
+/* from pcdp_interface_pci.translation */
+#define PCDP_PCI_TRANS_IOPORT 0x02
+#define PCDP_PCI_TRANS_MMIO 0x01
+
+static void
+sn_scan_pcdp(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 @@

#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)
+ sn_scan_pcdp();
+
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);
#ifdef CONFIG_DUMMY_CONSOLE
conswitchp = &dummy_con;
#else