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>

2 files changed, 262 insertions, 0 deletions

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index fa19c381954..350eb1b2a20 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 00000000000..3e667227480
--- /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);