diff options
Diffstat (limited to 'arch/x86/kernel/olpc.c')
| -rw-r--r-- | arch/x86/kernel/olpc.c | 260 |
1 files changed, 260 insertions, 0 deletions
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); |