diff options
Diffstat (limited to 'drivers/platform/x86/thinkpad_ec.c')
| -rw-r--r-- | drivers/platform/x86/thinkpad_ec.c | 513 |
1 files changed, 513 insertions, 0 deletions
diff --git a/drivers/platform/x86/thinkpad_ec.c b/drivers/platform/x86/thinkpad_ec.c new file mode 100644 index 000000000..ca34fed2d --- /dev/null +++ b/drivers/platform/x86/thinkpad_ec.c @@ -0,0 +1,513 @@ +/* + * thinkpad_ec.c - ThinkPad embedded controller LPC3 functions + * + * The embedded controller on ThinkPad laptops has a non-standard interface, + * where LPC channel 3 of the H8S EC chip is hooked up to IO ports + * 0x1600-0x161F and implements (a special case of) the H8S LPC protocol. + * The EC LPC interface provides various system management services (currently + * known: battery information and accelerometer readouts). This driver + * provides access and mutual exclusion for the EC interface. +* + * The LPC protocol and terminology are documented here: + * "H8S/2104B Group Hardware Manual", + * http://documentation.renesas.com/eng/products/mpumcu/rej09b0300_2140bhm.pdf + * + * Copyright (C) 2006-2007 Shem Multinymous <multinymous@gmail.com> + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/dmi.h> +#include <linux/ioport.h> +#include <linux/delay.h> +#include <linux/thinkpad_ec.h> +#include <linux/jiffies.h> +#include <asm/io.h> + +#include <linux/version.h> +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26) + #include <asm/semaphore.h> +#else + #include <linux/semaphore.h> +#endif + +#define TP_VERSION "0.41" + +MODULE_AUTHOR("Shem Multinymous"); +MODULE_DESCRIPTION("ThinkPad embedded controller hardware access"); +MODULE_VERSION(TP_VERSION); +MODULE_LICENSE("GPL"); + +/* IO ports used by embedded controller LPC channel 3: */ +#define TPC_BASE_PORT 0x1600 +#define TPC_NUM_PORTS 0x20 +#define TPC_STR3_PORT 0x1604 /* Reads H8S EC register STR3 */ +#define TPC_TWR0_PORT 0x1610 /* Mapped to H8S EC register TWR0MW/SW */ +#define TPC_TWR15_PORT 0x161F /* Mapped to H8S EC register TWR15. */ + /* (and port TPC_TWR0_PORT+i is mapped to H8S reg TWRi for 0<i<16) */ + +/* H8S STR3 status flags (see "H8S/2104B Group Hardware Manual" p.549) */ +#define H8S_STR3_IBF3B 0x80 /* Bidi. Data Register Input Buffer Full */ +#define H8S_STR3_OBF3B 0x40 /* Bidi. Data Register Output Buffer Full */ +#define H8S_STR3_MWMF 0x20 /* Master Write Mode Flag */ +#define H8S_STR3_SWMF 0x10 /* Slave Write Mode Flag */ +#define H8S_STR3_MASK 0xF0 /* All bits we care about in STR3 */ + +/* Timeouts and retries */ +#define TPC_READ_RETRIES 150 +#define TPC_READ_NDELAY 500 +#define TPC_REQUEST_RETRIES 1000 +#define TPC_REQUEST_NDELAY 10 +#define TPC_PREFETCH_TIMEOUT (HZ/10) /* invalidate prefetch after 0.1sec */ + +/* A few macros for printk()ing: */ +#define MSG_FMT(fmt, args...) \ + "thinkpad_ec: %s: " fmt "\n", __func__, ## args +#define REQ_FMT(msg, code) \ + MSG_FMT("%s: (0x%02x:0x%02x)->0x%02x", \ + msg, args->val[0x0], args->val[0xF], code) + +/* State of request prefetching: */ +static u8 prefetch_arg0, prefetch_argF; /* Args of last prefetch */ +static u64 prefetch_jiffies; /* time of prefetch, or: */ +#define TPC_PREFETCH_NONE INITIAL_JIFFIES /* No prefetch */ +#define TPC_PREFETCH_JUNK (INITIAL_JIFFIES+1) /* Ignore prefetch */ + +/* Locking: */ +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37) +static DECLARE_MUTEX(thinkpad_ec_mutex); +#else +static DEFINE_SEMAPHORE(thinkpad_ec_mutex); +#endif + +/* Kludge in case the ACPI DSDT reserves the ports we need. */ +static bool force_io; /* Willing to do IO to ports we couldn't reserve? */ +static int reserved_io; /* Successfully reserved the ports? */ +module_param_named(force_io, force_io, bool, 0600); +MODULE_PARM_DESC(force_io, "Force IO even if region already reserved (0=off, 1=on)"); + +/** + * thinkpad_ec_lock - get lock on the ThinkPad EC + * + * Get exclusive lock for accesing the ThinkPad embedded controller LPC3 + * interface. Returns 0 iff lock acquired. + */ +int thinkpad_ec_lock(void) +{ + int ret; + ret = down_interruptible(&thinkpad_ec_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_lock); + +/** + * thinkpad_ec_try_lock - try getting lock on the ThinkPad EC + * + * Try getting an exclusive lock for accesing the ThinkPad embedded + * controller LPC3. Returns immediately if lock is not available; neither + * blocks nor sleeps. Returns 0 iff lock acquired . + */ +int thinkpad_ec_try_lock(void) +{ + return down_trylock(&thinkpad_ec_mutex); +} +EXPORT_SYMBOL_GPL(thinkpad_ec_try_lock); + +/** + * thinkpad_ec_unlock - release lock on ThinkPad EC + * + * Release a previously acquired exclusive lock on the ThinkPad ebmedded + * controller LPC3 interface. + */ +void thinkpad_ec_unlock(void) +{ + up(&thinkpad_ec_mutex); +} +EXPORT_SYMBOL_GPL(thinkpad_ec_unlock); + +/** + * thinkpad_ec_request_row - tell embedded controller to prepare a row + * @args Input register arguments + * + * Requests a data row by writing to H8S LPC registers TRW0 through TWR15 (or + * a subset thereof) following the protocol prescribed by the "H8S/2104B Group + * Hardware Manual". Does sanity checks via status register STR3. + */ +static int thinkpad_ec_request_row(const struct thinkpad_ec_row *args) +{ + u8 str3; + int i; + + /* EC protocol requires write to TWR0 (function code): */ + if (!(args->mask & 0x0001)) { + printk(KERN_ERR MSG_FMT("bad args->mask=0x%02x", args->mask)); + return -EINVAL; + } + + /* Check initial STR3 status: */ + str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + if (str3 & H8S_STR3_OBF3B) { /* data already pending */ + inb(TPC_TWR15_PORT); /* marks end of previous transaction */ + if (prefetch_jiffies == TPC_PREFETCH_NONE) + printk(KERN_WARNING REQ_FMT( + "EC has result from unrequested transaction", + str3)); + return -EBUSY; /* EC will be ready in a few usecs */ + } else if (str3 == H8S_STR3_SWMF) { /* busy with previous request */ + if (prefetch_jiffies == TPC_PREFETCH_NONE) + printk(KERN_WARNING REQ_FMT( + "EC is busy with unrequested transaction", + str3)); + return -EBUSY; /* data will be pending in a few usecs */ + } else if (str3 != 0x00) { /* unexpected status? */ + printk(KERN_WARNING REQ_FMT("unexpected initial STR3", str3)); + return -EIO; + } + + /* Send TWR0MW: */ + outb(args->val[0], TPC_TWR0_PORT); + str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + if (str3 != H8S_STR3_MWMF) { /* not accepted? */ + printk(KERN_WARNING REQ_FMT("arg0 rejected", str3)); + return -EIO; + } + + /* Send TWR1 through TWR14: */ + for (i = 1; i < TP_CONTROLLER_ROW_LEN-1; i++) + if ((args->mask>>i)&1) + outb(args->val[i], TPC_TWR0_PORT+i); + + /* Send TWR15 (default to 0x01). This marks end of command. */ + outb((args->mask & 0x8000) ? args->val[0xF] : 0x01, TPC_TWR15_PORT); + + /* Wait until EC starts writing its reply (~60ns on average). + * Releasing locks before this happens may cause an EC hang + * due to firmware bug! + */ + for (i = 0; i < TPC_REQUEST_RETRIES; i++) { + str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + if (str3 & H8S_STR3_SWMF) /* EC started replying */ + return 0; + else if (!(str3 & ~(H8S_STR3_IBF3B|H8S_STR3_MWMF))) + /* Normal progress (the EC hasn't seen the request + * yet, or is processing it). Wait it out. */ + ndelay(TPC_REQUEST_NDELAY); + else { /* weird EC status */ + printk(KERN_WARNING + REQ_FMT("bad end STR3", str3)); + return -EIO; + } + } + printk(KERN_WARNING REQ_FMT("EC is mysteriously silent", str3)); + return -EIO; +} + +/** + * thinkpad_ec_read_data - read pre-requested row-data from EC + * @args Input register arguments of pre-requested rows + * @data Output register values + * + * Reads current row data from the controller, assuming it's already + * requested. Follows the H8S spec for register access and status checks. + */ +static int thinkpad_ec_read_data(const struct thinkpad_ec_row *args, + struct thinkpad_ec_row *data) +{ + int i; + u8 str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + /* Once we make a request, STR3 assumes the sequence of values listed + * in the following 'if' as it reads the request and writes its data. + * It takes about a few dozen nanosecs total, with very high variance. + */ + if (str3 == (H8S_STR3_IBF3B|H8S_STR3_MWMF) || + str3 == 0x00 || /* the 0x00 is indistinguishable from idle EC! */ + str3 == H8S_STR3_SWMF) + return -EBUSY; /* not ready yet */ + /* Finally, the EC signals output buffer full: */ + if (str3 != (H8S_STR3_OBF3B|H8S_STR3_SWMF)) { + printk(KERN_WARNING + REQ_FMT("bad initial STR3", str3)); + return -EIO; + } + + /* Read first byte (signals start of read transactions): */ + data->val[0] = inb(TPC_TWR0_PORT); + /* Optionally read 14 more bytes: */ + for (i = 1; i < TP_CONTROLLER_ROW_LEN-1; i++) + if ((data->mask >> i)&1) + data->val[i] = inb(TPC_TWR0_PORT+i); + /* Read last byte from 0x161F (signals end of read transaction): */ + data->val[0xF] = inb(TPC_TWR15_PORT); + + /* Readout still pending? */ + str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + if (str3 & H8S_STR3_OBF3B) + printk(KERN_WARNING + REQ_FMT("OBF3B=1 after read", str3)); + /* If port 0x161F returns 0x80 too often, the EC may lock up. Warn: */ + if (data->val[0xF] == 0x80) + printk(KERN_WARNING + REQ_FMT("0x161F reports error", data->val[0xF])); + return 0; +} + +/** + * thinkpad_ec_is_row_fetched - is the given row currently prefetched? + * + * To keep things simple we compare only the first and last args; + * this suffices for all known cases. + */ +static int thinkpad_ec_is_row_fetched(const struct thinkpad_ec_row *args) +{ + return (prefetch_jiffies != TPC_PREFETCH_NONE) && + (prefetch_jiffies != TPC_PREFETCH_JUNK) && + (prefetch_arg0 == args->val[0]) && + (prefetch_argF == args->val[0xF]) && + (get_jiffies_64() < prefetch_jiffies + TPC_PREFETCH_TIMEOUT); +} + +/** + * thinkpad_ec_read_row - request and read data from ThinkPad EC + * @args Input register arguments + * @data Output register values + * + * Read a data row from the ThinkPad embedded controller LPC3 interface. + * Does fetching and retrying if needed. The row is specified by an + * array of 16 bytes, some of which may be undefined (but the first is + * mandatory). These bytes are given in @args->val[], where @args->val[i] is + * used iff (@args->mask>>i)&1). The resulting row data is stored in + * @data->val[], but is only guaranteed to be valid for indices corresponding + * to set bit in @data->mask. That is, if @data->mask&(1<<i)==0 then + * @data->val[i] is undefined. + * + * Returns -EBUSY on transient error and -EIO on abnormal condition. + * Caller must hold controller lock. + */ +int thinkpad_ec_read_row(const struct thinkpad_ec_row *args, + struct thinkpad_ec_row *data) +{ + int retries, ret; + + if (thinkpad_ec_is_row_fetched(args)) + goto read_row; /* already requested */ + + /* Request the row */ + for (retries = 0; retries < TPC_READ_RETRIES; ++retries) { + ret = thinkpad_ec_request_row(args); + if (!ret) + goto read_row; + if (ret != -EBUSY) + break; + ndelay(TPC_READ_NDELAY); + } + printk(KERN_ERR REQ_FMT("failed requesting row", ret)); + goto out; + +read_row: + /* Read the row's data */ + for (retries = 0; retries < TPC_READ_RETRIES; ++retries) { + ret = thinkpad_ec_read_data(args, data); + if (!ret) + goto out; + if (ret != -EBUSY) + break; + ndelay(TPC_READ_NDELAY); + } + + printk(KERN_ERR REQ_FMT("failed waiting for data", ret)); + +out: + prefetch_jiffies = TPC_PREFETCH_JUNK; + return ret; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_read_row); + +/** + * thinkpad_ec_try_read_row - try reading prefetched data from ThinkPad EC + * @args Input register arguments + * @data Output register values + * + * Try reading a data row from the ThinkPad embedded controller LPC3 + * interface, if this raw was recently prefetched using + * thinkpad_ec_prefetch_row(). Does not fetch, retry or block. + * The parameters have the same meaning as in thinkpad_ec_read_row(). + * + * Returns -EBUSY is data not ready and -ENODATA if row not prefetched. + * Caller must hold controller lock. + */ +int thinkpad_ec_try_read_row(const struct thinkpad_ec_row *args, + struct thinkpad_ec_row *data) +{ + int ret; + if (!thinkpad_ec_is_row_fetched(args)) { + ret = -ENODATA; + } else { + ret = thinkpad_ec_read_data(args, data); + if (!ret) + prefetch_jiffies = TPC_PREFETCH_NONE; /* eaten up */ + } + return ret; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_try_read_row); + +/** + * thinkpad_ec_prefetch_row - prefetch data from ThinkPad EC + * @args Input register arguments + * + * Prefetch a data row from the ThinkPad embedded controller LCP3 + * interface. A subsequent call to thinkpad_ec_read_row() with the + * same arguments will be faster, and a subsequent call to + * thinkpad_ec_try_read_row() stands a good chance of succeeding if + * done neither too soon nor too late. See + * thinkpad_ec_read_row() for the meaning of @args. + * + * Returns -EBUSY on transient error and -EIO on abnormal condition. + * Caller must hold controller lock. + */ +int thinkpad_ec_prefetch_row(const struct thinkpad_ec_row *args) +{ + int ret; + ret = thinkpad_ec_request_row(args); + if (ret) { + prefetch_jiffies = TPC_PREFETCH_JUNK; + } else { + prefetch_jiffies = get_jiffies_64(); + prefetch_arg0 = args->val[0x0]; + prefetch_argF = args->val[0xF]; + } + return ret; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_prefetch_row); + +/** + * thinkpad_ec_invalidate - invalidate prefetched ThinkPad EC data + * + * Invalidate the data prefetched via thinkpad_ec_prefetch_row() from the + * ThinkPad embedded controller LPC3 interface. + * Must be called before unlocking by any code that accesses the controller + * ports directly. + */ +void thinkpad_ec_invalidate(void) +{ + prefetch_jiffies = TPC_PREFETCH_JUNK; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_invalidate); + + +/*** Checking for EC hardware ***/ + +/** + * thinkpad_ec_test - verify the EC is present and follows protocol + * + * Ensure the EC LPC3 channel really works on this machine by making + * an EC request and seeing if the EC follows the documented H8S protocol. + * The requested row just reads battery status, so it should be harmless to + * access it (on a correct EC). + * This test writes to IO ports, so execute only after checking DMI. + */ +static int __init thinkpad_ec_test(void) +{ + int ret; + const struct thinkpad_ec_row args = /* battery 0 basic status */ + { .mask = 0x8001, .val = {0x01,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0x00} }; + struct thinkpad_ec_row data = { .mask = 0x0000 }; + ret = thinkpad_ec_lock(); + if (ret) + return ret; + ret = thinkpad_ec_read_row(&args, &data); + thinkpad_ec_unlock(); + return ret; +} + +/* Search all DMI device names of a given type for a substring */ +static int __init dmi_find_substring(int type, const char *substr) +{ + const struct dmi_device *dev = NULL; + while ((dev = dmi_find_device(type, NULL, dev))) { + if (strstr(dev->name, substr)) + return 1; + } + return 0; +} + +#define TP_DMI_MATCH(vendor,model) { \ + .ident = vendor " " model, \ + .matches = { \ + DMI_MATCH(DMI_BOARD_VENDOR, vendor), \ + DMI_MATCH(DMI_PRODUCT_VERSION, model) \ + } \ +} + +/* Check DMI for existence of ThinkPad embedded controller */ +static int __init check_dmi_for_ec(void) +{ + /* A few old models that have a good EC but don't report it in DMI */ + struct dmi_system_id tp_whitelist[] = { + TP_DMI_MATCH("IBM", "ThinkPad A30"), + TP_DMI_MATCH("IBM", "ThinkPad T23"), + TP_DMI_MATCH("IBM", "ThinkPad X24"), + TP_DMI_MATCH("LENOVO", "ThinkPad"), + { .ident = NULL } + }; + return dmi_find_substring(DMI_DEV_TYPE_OEM_STRING, + "IBM ThinkPad Embedded Controller") || + dmi_check_system(tp_whitelist); +} + +/*** Init and cleanup ***/ + +static int __init thinkpad_ec_init(void) +{ + if (!check_dmi_for_ec()) { + printk(KERN_WARNING + "thinkpad_ec: no ThinkPad embedded controller!\n"); + return -ENODEV; + } + + if (request_region(TPC_BASE_PORT, TPC_NUM_PORTS, "thinkpad_ec")) { + reserved_io = 1; + } else { + printk(KERN_ERR "thinkpad_ec: cannot claim IO ports %#x-%#x... ", + TPC_BASE_PORT, + TPC_BASE_PORT + TPC_NUM_PORTS - 1); + if (force_io) { + printk("forcing use of unreserved IO ports.\n"); + } else { + printk("consider using force_io=1.\n"); + return -ENXIO; + } + } + prefetch_jiffies = TPC_PREFETCH_JUNK; + if (thinkpad_ec_test()) { + printk(KERN_ERR "thinkpad_ec: initial ec test failed\n"); + if (reserved_io) + release_region(TPC_BASE_PORT, TPC_NUM_PORTS); + return -ENXIO; + } + printk(KERN_INFO "thinkpad_ec: thinkpad_ec " TP_VERSION " loaded.\n"); + return 0; +} + +static void __exit thinkpad_ec_exit(void) +{ + if (reserved_io) + release_region(TPC_BASE_PORT, TPC_NUM_PORTS); + printk(KERN_INFO "thinkpad_ec: unloaded.\n"); +} + +module_init(thinkpad_ec_init); +module_exit(thinkpad_ec_exit); |