/* * 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);