[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: Mark Maule <maule@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 153 insertions, 4 deletions

diff --git a/arch/ia64/sn/kernel/setup.c b/arch/ia64/sn/kernel/setup.c
index 0fb579ef18c2..e510dce9971f 100644
--- a/arch/ia64/sn/kernel/setup.c
+++ b/arch/ia64/sn/kernel/setup.c
@@ -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 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 @@ 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)
+                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