x86: olpc: add One Laptop Per Child architecture support

This adds support for OLPC XO hardware.  Open Firmware on XOs don't contain
the VSA, so it is necessary to emulate the PCI BARs in the kernel.  This also
adds functionality for running EC commands, and a CONFIG_OLPC.

A number of OLPC drivers depend upon CONFIG_OLPC.

olpc_ec_timeout is a hack to work around Embedded Controller bugs.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: geode_has_vsa build fix]
[akpm@linux-foundation.org: olpc_register_battery_callback doesn't exist]
Signed-off-by: Andres Salomon <dilinger@debian.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

7 files changed, 597 insertions, 1 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d9d874cba59..f70e3e3a9fa7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1504,6 +1504,10 @@ config PCI_GODIRECT
 config PCI_GOANY
         bool "Any"
 
+config PCI_GOOLPC
+        bool "OLPC"
+        depends on OLPC
+
 endchoice
 
 config PCI_BIOS
@@ -1513,12 +1517,17 @@ config PCI_BIOS
 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
 config PCI_DIRECT
         def_bool y
-        depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
+        depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC) || X86_VISWS)
 
 config PCI_MMCONFIG
         def_bool y
         depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
 
+config PCI_OLPC
+        bool
+        depends on PCI && PCI_GOOLPC
+        default y
+
 config PCI_DOMAINS
         def_bool y
         depends on PCI
@@ -1638,6 +1647,13 @@ config GEODE_MFGPT_TIMER
           MFGPTs have a better resolution and max interval than the
           generic PIT, and are suitable for use as high-res timers.
 
+config OLPC
+        bool "One Laptop Per Child support"
+        default n
+        help
+          Add support for detecting the unique features of the OLPC
+          XO hardware.
+
 endif # X86_32
 
 config K8_NB
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index fa19c3819540..350eb1b2a208 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -91,6 +91,8 @@ endif
 obj-$(CONFIG_SCx200)            += scx200.o
 scx200-y                        += scx200_32.o
 
+obj-$(CONFIG_OLPC)              += olpc.o
+
 ###
 # 64 bit specific files
 ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/olpc.c b/arch/x86/kernel/olpc.c
new file mode 100644
index 000000000000..3e6672274807
--- /dev/null
+++ b/arch/x86/kernel/olpc.c
@@ -0,0 +1,260 @@
+/*
+ * Support for the OLPC DCON and OLPC EC access
+ *
+ * Copyright © 2006  Advanced Micro Devices, Inc.
+ * Copyright © 2007-2008  Andres Salomon <dilinger@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/string.h>
+#include <asm/geode.h>
+#include <asm/olpc.h>
+
+#ifdef CONFIG_OPEN_FIRMWARE
+#include <asm/ofw.h>
+#endif
+
+struct olpc_platform_t olpc_platform_info;
+EXPORT_SYMBOL_GPL(olpc_platform_info);
+
+static DEFINE_SPINLOCK(ec_lock);
+
+/* what the timeout *should* be (in ms) */
+#define EC_BASE_TIMEOUT 20
+
+/* the timeout that bugs in the EC might force us to actually use */
+static int ec_timeout = EC_BASE_TIMEOUT;
+
+static int __init olpc_ec_timeout_set(char *str)
+{
+        if (get_option(&str, &ec_timeout) != 1) {
+                ec_timeout = EC_BASE_TIMEOUT;
+                printk(KERN_ERR "olpc-ec:  invalid argument to "
+                                "'olpc_ec_timeout=', ignoring!\n");
+        }
+        printk(KERN_DEBUG "olpc-ec:  using %d ms delay for EC commands.\n",
+                        ec_timeout);
+        return 1;
+}
+__setup("olpc_ec_timeout=", olpc_ec_timeout_set);
+
+/*
+ * These {i,o}bf_status functions return whether the buffers are full or not.
+ */
+
+static inline unsigned int ibf_status(unsigned int port)
+{
+        return !!(inb(port) & 0x02);
+}
+
+static inline unsigned int obf_status(unsigned int port)
+{
+        return inb(port) & 0x01;
+}
+
+#define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
+static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
+{
+        unsigned int timeo;
+        int state = ibf_status(port);
+
+        for (timeo = ec_timeout; state != desired && timeo; timeo--) {
+                mdelay(1);
+                state = ibf_status(port);
+        }
+
+        if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
+                        timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
+                printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for IBF!\n",
+                                line, ec_timeout - timeo);
+        }
+
+        return !(state == desired);
+}
+
+#define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
+static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
+{
+        unsigned int timeo;
+        int state = obf_status(port);
+
+        for (timeo = ec_timeout; state != desired && timeo; timeo--) {
+                mdelay(1);
+                state = obf_status(port);
+        }
+
+        if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
+                        timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
+                printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for OBF!\n",
+                                line, ec_timeout - timeo);
+        }
+
+        return !(state == desired);
+}
+
+/*
+ * This allows the kernel to run Embedded Controller commands.  The EC is
+ * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
+ * available EC commands are here:
+ * <http://wiki.laptop.org/go/Ec_specification>.  Unfortunately, while
+ * OpenFirmware's source is available, the EC's is not.
+ */
+int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
+                unsigned char *outbuf,  size_t outlen)
+{
+        unsigned long flags;
+        int ret = -EIO;
+        int i;
+
+        spin_lock_irqsave(&ec_lock, flags);
+
+        /* Clear OBF */
+        for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
+                inb(0x68);
+        if (i == 10) {
+                printk(KERN_ERR "olpc-ec:  timeout while attempting to "
+                                "clear OBF flag!\n");
+                goto err;
+        }
+
+        if (wait_on_ibf(0x6c, 0)) {
+                printk(KERN_ERR "olpc-ec:  timeout waiting for EC to "
+                                "quiesce!\n");
+                goto err;
+        }
+
+restart:
+        /*
+         * Note that if we time out during any IBF checks, that's a failure;
+         * we have to return.  There's no way for the kernel to clear that.
+         *
+         * If we time out during an OBF check, we can restart the command;
+         * reissuing it will clear the OBF flag, and we should be alright.
+         * The OBF flag will sometimes misbehave due to what we believe
+         * is a hardware quirk..
+         */
+        printk(KERN_DEBUG "olpc-ec:  running cmd 0x%x\n", cmd);
+        outb(cmd, 0x6c);
+
+        if (wait_on_ibf(0x6c, 0)) {
+                printk(KERN_ERR "olpc-ec:  timeout waiting for EC to read "
+                                "command!\n");
+                goto err;
+        }
+
+        if (inbuf && inlen) {
+                /* write data to EC */
+                for (i = 0; i < inlen; i++) {
+                        if (wait_on_ibf(0x6c, 0)) {
+                                printk(KERN_ERR "olpc-ec:  timeout waiting for"
+                                                " EC accept data!\n");
+                                goto err;
+                        }
+                        printk(KERN_DEBUG "olpc-ec:  sending cmd arg 0x%x\n",
+                                        inbuf[i]);
+                        outb(inbuf[i], 0x68);
+                }
+        }
+        if (outbuf && outlen) {
+                /* read data from EC */
+                for (i = 0; i < outlen; i++) {
+                        if (wait_on_obf(0x6c, 1)) {
+                                printk(KERN_ERR "olpc-ec:  timeout waiting for"
+                                                " EC to provide data!\n");
+                                goto restart;
+                        }
+                        outbuf[i] = inb(0x68);
+                        printk(KERN_DEBUG "olpc-ec:  received 0x%x\n",
+                                        outbuf[i]);
+                }
+        }
+
+        ret = 0;
+err:
+        spin_unlock_irqrestore(&ec_lock, flags);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(olpc_ec_cmd);
+
+#ifdef CONFIG_OPEN_FIRMWARE
+static void __init platform_detect(void)
+{
+        size_t propsize;
+        u32 rev;
+
+        if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
+                        &propsize) || propsize != 4) {
+                printk(KERN_ERR "ofw: getprop call failed!\n");
+                rev = 0;
+        }
+        olpc_platform_info.boardrev = be32_to_cpu(rev);
+}
+#else
+static void __init platform_detect(void)
+{
+        /* stopgap until OFW support is added to the kernel */
+        olpc_platform_info.boardrev = be32_to_cpu(0xc2);
+}
+#endif
+
+static int __init olpc_init(void)
+{
+        unsigned char *romsig;
+
+        /* The ioremap check is dangerous; limit what we run it on */
+        if (!is_geode() || geode_has_vsa2())
+                return 0;
+
+        spin_lock_init(&ec_lock);
+
+        romsig = ioremap(0xffffffc0, 16);
+        if (!romsig)
+                return 0;
+
+        if (strncmp(romsig, "CL1   Q", 7))
+                goto unmap;
+        if (strncmp(romsig+6, romsig+13, 3)) {
+                printk(KERN_INFO "OLPC BIOS signature looks invalid.  "
+                                "Assuming not OLPC\n");
+                goto unmap;
+        }
+
+        printk(KERN_INFO "OLPC board with OpenFirmware %.16s\n", romsig);
+        olpc_platform_info.flags |= OLPC_F_PRESENT;
+
+        /* get the platform revision */
+        platform_detect();
+
+        /* assume B1 and above models always have a DCON */
+        if (olpc_board_at_least(olpc_board(0xb1)))
+                olpc_platform_info.flags |= OLPC_F_DCON;
+
+        /* get the EC revision */
+        olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
+                        (unsigned char *) &olpc_platform_info.ecver, 1);
+
+        /* check to see if the VSA exists */
+        if (geode_has_vsa2())
+                olpc_platform_info.flags |= OLPC_F_VSA;
+
+        printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
+                        ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
+                        olpc_platform_info.boardrev >> 4,
+                        olpc_platform_info.ecver);
+
+unmap:
+        iounmap(romsig);
+        return 0;
+}
+
+postcore_initcall(olpc_init);
diff --git a/arch/x86/pci/Makefile_32 b/arch/x86/pci/Makefile_32
index cdd6828b5abb..b859047a6376 100644
--- a/arch/x86/pci/Makefile_32
+++ b/arch/x86/pci/Makefile_32
@@ -3,6 +3,7 @@ obj-y				:= i386.o init.o
 obj-$(CONFIG_PCI_BIOS)          += pcbios.o
 obj-$(CONFIG_PCI_MMCONFIG)      += mmconfig_32.o direct.o mmconfig-shared.o
 obj-$(CONFIG_PCI_DIRECT)        += direct.o
+obj-$(CONFIG_PCI_OLPC)          += olpc.o
 
 pci-y                           := fixup.o
 pci-$(CONFIG_ACPI)              += acpi.o
diff --git a/arch/x86/pci/init.c b/arch/x86/pci/init.c
index 3de9f9ba2da6..0f5f7dd2a620 100644
--- a/arch/x86/pci/init.c
+++ b/arch/x86/pci/init.c
@@ -14,6 +14,9 @@ static __init int pci_access_init(void)
 #ifdef CONFIG_PCI_MMCONFIG
         pci_mmcfg_init(type);
 #endif
+#ifdef CONFIG_PCI_OLPC
+        pci_olpc_init();
+#endif
         if (raw_pci_ops)
                 return 0;
 #ifdef CONFIG_PCI_BIOS
diff --git a/arch/x86/pci/olpc.c b/arch/x86/pci/olpc.c
new file mode 100644
index 000000000000..5e7636558c02
--- /dev/null
+++ b/arch/x86/pci/olpc.c
@@ -0,0 +1,313 @@
+/*
+ * Low-level PCI config space access for OLPC systems who lack the VSA
+ * PCI virtualization software.
+ *
+ * Copyright © 2006  Advanced Micro Devices, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * The AMD Geode chipset (ie: GX2 processor, cs5536 I/O companion device)
+ * has some I/O functions (display, southbridge, sound, USB HCIs, etc)
+ * that more or less behave like PCI devices, but the hardware doesn't
+ * directly implement the PCI configuration space headers.  AMD provides
+ * "VSA" (Virtual System Architecture) software that emulates PCI config
+ * space for these devices, by trapping I/O accesses to PCI config register
+ * (CF8/CFC) and running some code in System Management Mode interrupt state.
+ * On the OLPC platform, we don't want to use that VSA code because
+ * (a) it slows down suspend/resume, and (b) recompiling it requires special
+ * compilers that are hard to get.  So instead of letting the complex VSA
+ * code simulate the PCI config registers for the on-chip devices, we
+ * just simulate them the easy way, by inserting the code into the
+ * pci_write_config and pci_read_config path.  Most of the config registers
+ * are read-only anyway, so the bulk of the simulation is just table lookup.
+ */
+
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <asm/olpc.h>
+#include <asm/geode.h>
+#include "pci.h"
+
+/*
+ * In the tables below, the first two line (8 longwords) are the
+ * size masks that are used when the higher level PCI code determines
+ * the size of the region by writing ~0 to a base address register
+ * and reading back the result.
+ *
+ * The following lines are the values that are read during normal
+ * PCI config access cycles, i.e. not after just having written
+ * ~0 to a base address register.
+ */
+
+static const uint32_t lxnb_hdr[] = {  /* dev 1 function 0 - devfn = 8 */
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+
+        0x281022, 0x2200005, 0x6000021, 0x80f808,       /* AMD Vendor ID */
+        0x0,    0x0,    0x0,    0x0,   /* No virtual registers, hence no BAR */
+        0x0,    0x0,    0x0,    0x28100b,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+};
+
+static const uint32_t gxnb_hdr[] = {  /* dev 1 function 0 - devfn = 8 */
+        0xfffffffd, 0x0, 0x0,   0x0,
+        0x0,    0x0,    0x0,    0x0,
+
+        0x28100b, 0x2200005, 0x6000021, 0x80f808,       /* NSC Vendor ID */
+        0xac1d, 0x0,    0x0,    0x0,  /* I/O BAR - base of virtual registers */
+        0x0,    0x0,    0x0,    0x28100b,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+};
+
+static const uint32_t lxfb_hdr[] = {  /* dev 1 function 1 - devfn = 9 */
+        0xff000008, 0xffffc000, 0xffffc000, 0xffffc000,
+        0xffffc000,     0x0,    0x0,    0x0,
+
+        0x20811022, 0x2200003, 0x3000000, 0x0,          /* AMD Vendor ID */
+        0xfd000000, 0xfe000000, 0xfe004000, 0xfe008000, /* FB, GP, VG, DF */
+        0xfe00c000, 0x0, 0x0,   0x30100b,               /* VIP */
+        0x0,    0x0,    0x0,    0x10e,     /* INTA, IRQ14 for graphics accel */
+        0x0,    0x0,    0x0,    0x0,
+        0x3d0,  0x3c0,  0xa0000, 0x0,       /* VG IO, VG IO, EGA FB, MONO FB */
+        0x0,    0x0,    0x0,    0x0,
+};
+
+static const uint32_t gxfb_hdr[] = {  /* dev 1 function 1 - devfn = 9 */
+        0xff800008, 0xffffc000, 0xffffc000, 0xffffc000,
+        0x0,    0x0,    0x0,    0x0,
+
+        0x30100b, 0x2200003, 0x3000000, 0x0,            /* NSC Vendor ID */
+        0xfd000000, 0xfe000000, 0xfe004000, 0xfe008000, /* FB, GP, VG, DF */
+        0x0,    0x0,    0x0,    0x30100b,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x3d0,  0x3c0,  0xa0000, 0x0,       /* VG IO, VG IO, EGA FB, MONO FB */
+        0x0,    0x0,    0x0,    0x0,
+};
+
+static const uint32_t aes_hdr[] = {     /* dev 1 function 2 - devfn = 0xa */
+        0xffffc000, 0x0, 0x0,   0x0,
+        0x0,    0x0,    0x0,    0x0,
+
+        0x20821022, 0x2a00006, 0x10100000, 0x8,         /* NSC Vendor ID */
+        0xfe010000, 0x0, 0x0,   0x0,                    /* AES registers */
+        0x0,    0x0,    0x0,    0x20821022,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+};
+
+
+static const uint32_t isa_hdr[] = {  /* dev f function 0 - devfn = 78 */
+        0xfffffff9, 0xffffff01, 0xffffffc1, 0xffffffe1,
+        0xffffff81, 0xffffffc1, 0x0, 0x0,
+
+        0x20901022, 0x2a00049, 0x6010003, 0x802000,
+        0x18b1, 0x1001, 0x1801, 0x1881, /* SMB-8   GPIO-256 MFGPT-64  IRQ-32 */
+        0x1401, 0x1841, 0x0,    0x20901022,             /* PMS-128 ACPI-64 */
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0xaa5b,                 /* IRQ steering */
+        0x0,    0x0,    0x0,    0x0,
+};
+
+static const uint32_t ac97_hdr[] = {  /* dev f function 3 - devfn = 7b */
+        0xffffff81, 0x0, 0x0,   0x0,
+        0x0,    0x0,    0x0,    0x0,
+
+        0x20931022, 0x2a00041, 0x4010001, 0x0,
+        0x1481, 0x0,    0x0,    0x0,                    /* I/O BAR-128 */
+        0x0,    0x0,    0x0,    0x20931022,
+        0x0,    0x0,    0x0,    0x205,                  /* IntB, IRQ5 */
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+};
+
+static const uint32_t ohci_hdr[] = {  /* dev f function 4 - devfn = 7c */
+        0xfffff000, 0x0, 0x0,   0x0,
+        0x0,    0x0,    0x0,    0x0,
+
+        0x20941022, 0x2300006, 0xc031002, 0x0,
+        0xfe01a000, 0x0, 0x0,   0x0,                    /* MEMBAR-1000 */
+        0x0,    0x0,    0x0,    0x20941022,
+        0x0,    0x40,   0x0,    0x40a,                  /* CapPtr INT-D, IRQA */
+        0xc8020001, 0x0, 0x0,   0x0,    /* Capabilities - 40 is R/O,
+                                           44 is mask 8103 (power control) */
+        0x0,    0x0,    0x0,    0x0,
+        0x0,    0x0,    0x0,    0x0,
+};
+
+static const uint32_t ehci_hdr[] = {  /* dev f function 4 - devfn = 7d */
+        0xfffff000, 0x0, 0x0,   0x0,
+        0x0,    0x0,    0x0,    0x0,
+
+        0x20951022, 0x2300006, 0xc032002, 0x0,
+        0xfe01b000, 0x0, 0x0,   0x0,                    /* MEMBAR-1000 */
+        0x0,    0x0,    0x0,    0x20951022,
+        0x0,    0x40,   0x0,    0x40a,                  /* CapPtr INT-D, IRQA */
+        0xc8020001, 0x0, 0x0,   0x0,    /* Capabilities - 40 is R/O, 44 is
+                                           mask 8103 (power control) */
+#if 0
+        0x1,    0x40080000, 0x0, 0x0,   /* EECP - see EHCI spec section 2.1.7 */
+#endif
+        0x01000001, 0x0, 0x0,   0x0,    /* EECP - see EHCI spec section 2.1.7 */
+        0x2020, 0x0,    0x0,    0x0,    /* (EHCI page 8) 60 SBRN (R/O),
+                                           61 FLADJ (R/W), PORTWAKECAP  */
+};
+
+static uint32_t ff_loc = ~0;
+static uint32_t zero_loc;
+static int bar_probing;         /* Set after a write of ~0 to a BAR */
+static int is_lx;
+
+#define NB_SLOT 0x1     /* Northbridge - GX chip - Device 1 */
+#define SB_SLOT 0xf     /* Southbridge - CS5536 chip - Device F */
+
+static int is_simulated(unsigned int bus, unsigned int devfn)
+{
+        return (!bus && ((PCI_SLOT(devfn) == NB_SLOT) ||
+                        (PCI_SLOT(devfn) == SB_SLOT)));
+}
+
+static uint32_t *hdr_addr(const uint32_t *hdr, int reg)
+{
+        uint32_t addr;
+
+        /*
+         * This is a little bit tricky.  The header maps consist of
+         * 0x20 bytes of size masks, followed by 0x70 bytes of header data.
+         * In the normal case, when not probing a BAR's size, we want
+         * to access the header data, so we add 0x20 to the reg offset,
+         * thus skipping the size mask area.
+         * In the BAR probing case, we want to access the size mask for
+         * the BAR, so we subtract 0x10 (the config header offset for
+         * BAR0), and don't skip the size mask area.
+         */
+
+        addr = (uint32_t)hdr + reg + (bar_probing ? -0x10 : 0x20);
+
+        bar_probing = 0;
+        return (uint32_t *)addr;
+}
+
+static int pci_olpc_read(unsigned int seg, unsigned int bus,
+                unsigned int devfn, int reg, int len, uint32_t *value)
+{
+        uint32_t *addr;
+
+        /* Use the hardware mechanism for non-simulated devices */
+        if (!is_simulated(bus, devfn))
+                return pci_direct_conf1.read(seg, bus, devfn, reg, len, value);
+
+        /*
+         * No device has config registers past 0x70, so we save table space
+         * by not storing entries for the nonexistent registers
+         */
+        if (reg >= 0x70)
+                addr = &zero_loc;
+        else {
+                switch (devfn) {
+                case  0x8:
+                        addr = hdr_addr(is_lx ? lxnb_hdr : gxnb_hdr, reg);
+                        break;
+                case  0x9:
+                        addr = hdr_addr(is_lx ? lxfb_hdr : gxfb_hdr, reg);
+                        break;
+                case  0xa:
+                        addr = is_lx ? hdr_addr(aes_hdr, reg) : &ff_loc;
+                        break;
+                case 0x78:
+                        addr = hdr_addr(isa_hdr, reg);
+                        break;
+                case 0x7b:
+                        addr = hdr_addr(ac97_hdr, reg);
+                        break;
+                case 0x7c:
+                        addr = hdr_addr(ohci_hdr, reg);
+                        break;
+                case 0x7d:
+                        addr = hdr_addr(ehci_hdr, reg);
+                        break;
+                default:
+                        addr = &ff_loc;
+                        break;
+                }
+        }
+        switch (len) {
+        case 1:
+                *value = *(uint8_t *)addr;
+                break;
+        case 2:
+                *value = *(uint16_t *)addr;
+                break;
+        case 4:
+                *value = *addr;
+                break;
+        default:
+                BUG();
+        }
+
+        return 0;
+}
+
+static int pci_olpc_write(unsigned int seg, unsigned int bus,
+                unsigned int devfn, int reg, int len, uint32_t value)
+{
+        /* Use the hardware mechanism for non-simulated devices */
+        if (!is_simulated(bus, devfn))
+                return pci_direct_conf1.write(seg, bus, devfn, reg, len, value);
+
+        /* XXX we may want to extend this to simulate EHCI power management */
+
+        /*
+         * Mostly we just discard writes, but if the write is a size probe
+         * (i.e. writing ~0 to a BAR), we remember it and arrange to return
+         * the appropriate size mask on the next read.  This is cheating
+         * to some extent, because it depends on the fact that the next
+         * access after such a write will always be a read to the same BAR.
+         */
+
+        if ((reg >= 0x10) && (reg < 0x2c)) {
+                /* write is to a BAR */
+                if (value == ~0)
+                        bar_probing = 1;
+        } else {
+                /*
+                 * No warning on writes to ROM BAR, CMD, LATENCY_TIMER,
+                 * CACHE_LINE_SIZE, or PM registers.
+                 */
+                if ((reg != PCI_ROM_ADDRESS) && (reg != PCI_COMMAND_MASTER) &&
+                                (reg != PCI_LATENCY_TIMER) &&
+                                (reg != PCI_CACHE_LINE_SIZE) && (reg != 0x44))
+                        printk(KERN_WARNING "OLPC PCI: Config write to devfn"
+                                " %x reg %x value %x\n", devfn, reg, value);
+        }
+
+        return 0;
+}
+
+static struct pci_raw_ops pci_olpc_conf = {
+        .read = pci_olpc_read,
+        .write = pci_olpc_write,
+};
+
+void __init pci_olpc_init(void)
+{
+        if (!machine_is_olpc() || olpc_has_vsa())
+                return;
+
+        printk(KERN_INFO "PCI: Using configuration type OLPC\n");
+        raw_pci_ops = &pci_olpc_conf;
+        is_lx = is_geode_lx();
+}
diff --git a/arch/x86/pci/pci.h b/arch/x86/pci/pci.h
index c4bddaeff619..7d84e813e958 100644
--- a/arch/x86/pci/pci.h
+++ b/arch/x86/pci/pci.h
@@ -98,6 +98,7 @@ extern int pci_direct_probe(void);
 extern void pci_direct_init(int type);
 extern void pci_pcbios_init(void);
 extern void pci_mmcfg_init(int type);
+extern void pci_olpc_init(void);
 
 /* pci-mmconfig.c */