/*
* 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;
__be32 rev;
if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
&propsize) || propsize != 4) {
printk(KERN_ERR "ofw: getprop call failed!\n");
rev = cpu_to_be32(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 = 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);
