drivers/platform/x86/ibm_rtl.c - maze/linux - Git at Google

 /*
  * IBM Real-Time Linux driver
  *
  * 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.
  *
  * Copyright (C) IBM Corporation, 2010
  *
  * Author: Keith Mannthey <kmannth@us.ibm.com>
  *         Vernon Mauery <vernux@us.ibm.com>
  *
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/io.h>
 #include <linux/dmi.h>
 #include <linux/efi.h>
 #include <linux/mutex.h>
 #include <asm/bios_ebda.h>

 #include <asm-generic/io-64-nonatomic-lo-hi.h>

 static bool force;
 module_param(force, bool, 0);
 MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");

 static bool debug;
 module_param(debug, bool, 0644);
 MODULE_PARM_DESC(debug, "Show debug output");

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Keith Mannthey <kmmanth@us.ibm.com>");
 MODULE_AUTHOR("Vernon Mauery <vernux@us.ibm.com>");

 #define RTL_ADDR_TYPE_IO    1
 #define RTL_ADDR_TYPE_MMIO  2

 #define RTL_CMD_ENTER_PRTM  1
 #define RTL_CMD_EXIT_PRTM   2

 /* The RTL table as presented by the EBDA: */
 struct ibm_rtl_table {
 	char signature[5]; /* signature should be "_RTL_" */
 	u8 version;
 	u8 rt_status;
 	u8 command;
 	u8 command_status;
 	u8 cmd_address_type;
 	u8 cmd_granularity;
 	u8 cmd_offset;
 	u16 reserve1;
 	u32 cmd_port_address; /* platform dependent address */
 	u32 cmd_port_value;   /* platform dependent value */
 } __attribute__((packed));

 /* to locate "_RTL_" signature do a masked 5-byte integer compare */
 #define RTL_SIGNATURE 0x0000005f4c54525fULL
 #define RTL_MASK      0x000000ffffffffffULL

 #define RTL_DEBUG(fmt, ...)				\
 do {							\
 	if (debug)					\
 		pr_info(fmt, ##__VA_ARGS__);		\
 } while (0)

 static DEFINE_MUTEX(rtl_lock);
 static struct ibm_rtl_table __iomem *rtl_table;
 static void __iomem *ebda_map;
 static void __iomem *rtl_cmd_addr;
 static u8 rtl_cmd_type;
 static u8 rtl_cmd_width;

 static void __iomem *rtl_port_map(phys_addr_t addr, unsigned long len)
 {
 	if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
 		return ioremap(addr, len);
 	return ioport_map(addr, len);
 }

 static void rtl_port_unmap(void __iomem *addr)
 {
 	if (addr && rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
 		iounmap(addr);
 	else
 		ioport_unmap(addr);
 }

 static int ibm_rtl_write(u8 value)
 {
 	int ret = 0, count = 0;
 	static u32 cmd_port_val;

 	RTL_DEBUG("%s(%d)\n", __func__, value);

 	value = value == 1 ? RTL_CMD_ENTER_PRTM : RTL_CMD_EXIT_PRTM;

 	mutex_lock(&rtl_lock);

 	if (ioread8(&rtl_table->rt_status) != value) {
 		iowrite8(value, &rtl_table->command);

 		switch (rtl_cmd_width) {
 		case 8:
 			cmd_port_val = ioread8(&rtl_table->cmd_port_value);
 			RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
 			iowrite8((u8)cmd_port_val, rtl_cmd_addr);
 			break;
 		case 16:
 			cmd_port_val = ioread16(&rtl_table->cmd_port_value);
 			RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
 			iowrite16((u16)cmd_port_val, rtl_cmd_addr);
 			break;
 		case 32:
 			cmd_port_val = ioread32(&rtl_table->cmd_port_value);
 			RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
 			iowrite32(cmd_port_val, rtl_cmd_addr);
 			break;
 		}

 		while (ioread8(&rtl_table->command)) {
 			msleep(10);
 			if (count++ > 500) {
 				pr_err("Hardware not responding to "
 				       "mode switch request\n");
 				ret = -EIO;
 				break;
 			}

 		}

 		if (ioread8(&rtl_table->command_status)) {
 			RTL_DEBUG("command_status reports failed command\n");
 			ret = -EIO;
 		}
 	}

 	mutex_unlock(&rtl_lock);
 	return ret;
 }

 static ssize_t rtl_show_version(struct device *dev,
                                 struct device_attribute *attr,
                                 char *buf)
 {
 	return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version));
 }

 static ssize_t rtl_show_state(struct device *dev,
                               struct device_attribute *attr,
                               char *buf)
 {
 	return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status));
 }

 static ssize_t rtl_set_state(struct device *dev,
                              struct device_attribute *attr,
                              const char *buf,
                              size_t count)
 {
 	ssize_t ret;

 	if (count < 1 || count > 2)
 		return -EINVAL;

 	switch (buf[0]) {
 	case '0':
 		ret = ibm_rtl_write(0);
 		break;
 	case '1':
 		ret = ibm_rtl_write(1);
 		break;
 	default:
 		ret = -EINVAL;
 	}
 	if (ret >= 0)
 		ret = count;

 	return ret;
 }

 static struct bus_type rtl_subsys = {
 	.name = "ibm_rtl",
 	.dev_name = "ibm_rtl",
 };

 static DEVICE_ATTR(version, S_IRUGO, rtl_show_version, NULL);
 static DEVICE_ATTR(state, 0600, rtl_show_state, rtl_set_state);

 static struct device_attribute *rtl_attributes[] = {
 	&dev_attr_version,
 	&dev_attr_state,
 	NULL
 };


 static int rtl_setup_sysfs(void) {
 	int ret, i;

 	ret = subsys_system_register(&rtl_subsys, NULL);
 	if (!ret) {
 		for (i = 0; rtl_attributes[i]; i ++)
 			device_create_file(rtl_subsys.dev_root, rtl_attributes[i]);
 	}
 	return ret;
 }

 static void rtl_teardown_sysfs(void) {
 	int i;
 	for (i = 0; rtl_attributes[i]; i ++)
 		device_remove_file(rtl_subsys.dev_root, rtl_attributes[i]);
 	bus_unregister(&rtl_subsys);
 }


 static struct dmi_system_id __initdata ibm_rtl_dmi_table[] = {
 	{                                                  \
 		.matches = {                               \
 			DMI_MATCH(DMI_SYS_VENDOR, "IBM"),  \
 		},                                         \
 	},
 	{ }
 };

 static int __init ibm_rtl_init(void) {
 	unsigned long ebda_addr, ebda_size;
 	unsigned int ebda_kb;
 	int ret = -ENODEV, i;

 	if (force)
 		pr_warn("module loaded by force\n");
 	/* first ensure that we are running on IBM HW */
 	else if (efi_enabled || !dmi_check_system(ibm_rtl_dmi_table))
 		return -ENODEV;

 	/* Get the address for the Extended BIOS Data Area */
 	ebda_addr = get_bios_ebda();
 	if (!ebda_addr) {
 		RTL_DEBUG("no BIOS EBDA found\n");
 		return -ENODEV;
 	}

 	ebda_map = ioremap(ebda_addr, 4);
 	if (!ebda_map)
 		return -ENOMEM;

 	/* First word in the EDBA is the Size in KB */
 	ebda_kb = ioread16(ebda_map);
 	RTL_DEBUG("EBDA is %d kB\n", ebda_kb);

 	if (ebda_kb == 0)
 		goto out;

 	iounmap(ebda_map);
 	ebda_size = ebda_kb*1024;

 	/* Remap the whole table */
 	ebda_map = ioremap(ebda_addr, ebda_size);
 	if (!ebda_map)
 		return -ENOMEM;

 	/* search for the _RTL_ signature at the start of the table */
 	for (i = 0 ; i < ebda_size/sizeof(unsigned int); i++) {
 		struct ibm_rtl_table __iomem * tmp;
 		tmp = (struct ibm_rtl_table __iomem *) (ebda_map+i);
 		if ((readq(&tmp->signature) & RTL_MASK) == RTL_SIGNATURE) {
 			phys_addr_t addr;
 			unsigned int plen;
 			RTL_DEBUG("found RTL_SIGNATURE at %p\n", tmp);
 			rtl_table = tmp;
 			/* The address, value, width and offset are platform
 			 * dependent and found in the ibm_rtl_table */
 			rtl_cmd_width = ioread8(&rtl_table->cmd_granularity);
 			rtl_cmd_type = ioread8(&rtl_table->cmd_address_type);
 			RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n",
 				  rtl_cmd_width, rtl_cmd_type);
 			addr = ioread32(&rtl_table->cmd_port_address);
 			RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr);
 			plen = rtl_cmd_width/sizeof(char);
 			rtl_cmd_addr = rtl_port_map(addr, plen);
 			RTL_DEBUG("rtl_cmd_addr = %p\n", rtl_cmd_addr);
 			if (!rtl_cmd_addr) {
 				ret = -ENOMEM;
 				break;
 			}
 			ret = rtl_setup_sysfs();
 			break;
 		}
 	}

 out:
 	if (ret) {
 		iounmap(ebda_map);
 		rtl_port_unmap(rtl_cmd_addr);
 	}

 	return ret;
 }

 static void __exit ibm_rtl_exit(void)
 {
 	if (rtl_table) {
 		RTL_DEBUG("cleaning up");
 		/* do not leave the machine in SMI-free mode */
 		ibm_rtl_write(0);
 		/* unmap, unlink and remove all traces */
 		rtl_teardown_sysfs();
 		iounmap(ebda_map);
 		rtl_port_unmap(rtl_cmd_addr);
 	}
 }

 module_init(ibm_rtl_init);
 module_exit(ibm_rtl_exit);
	/*
	* IBM Real-Time Linux driver
	*
	* 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.
	*
	* Copyright (C) IBM Corporation, 2010
	*
	* Author: Keith Mannthey <kmannth@us.ibm.com>
	* Vernon Mauery <vernux@us.ibm.com>
	*
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/module.h>
	#include <linux/io.h>
	#include <linux/dmi.h>
	#include <linux/efi.h>
	#include <linux/mutex.h>
	#include <asm/bios_ebda.h>

	#include <asm-generic/io-64-nonatomic-lo-hi.h>

	static bool force;
	module_param(force, bool, 0);
	MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");

	static bool debug;
	module_param(debug, bool, 0644);
	MODULE_PARM_DESC(debug, "Show debug output");

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Keith Mannthey <kmmanth@us.ibm.com>");
	MODULE_AUTHOR("Vernon Mauery <vernux@us.ibm.com>");

	#define RTL_ADDR_TYPE_IO 1
	#define RTL_ADDR_TYPE_MMIO 2

	#define RTL_CMD_ENTER_PRTM 1
	#define RTL_CMD_EXIT_PRTM 2

	/* The RTL table as presented by the EBDA: */
	struct ibm_rtl_table {
	char signature[5]; /* signature should be "_RTL_" */
	u8 version;
	u8 rt_status;
	u8 command;
	u8 command_status;
	u8 cmd_address_type;
	u8 cmd_granularity;
	u8 cmd_offset;
	u16 reserve1;
	u32 cmd_port_address; /* platform dependent address */
	u32 cmd_port_value; /* platform dependent value */
	} __attribute__((packed));

	/* to locate "_RTL_" signature do a masked 5-byte integer compare */
	#define RTL_SIGNATURE 0x0000005f4c54525fULL
	#define RTL_MASK 0x000000ffffffffffULL

	#define RTL_DEBUG(fmt, ...) \
	do { \
	if (debug) \
	pr_info(fmt, ##__VA_ARGS__); \
	} while (0)

	static DEFINE_MUTEX(rtl_lock);
	static struct ibm_rtl_table __iomem *rtl_table;
	static void __iomem *ebda_map;
	static void __iomem *rtl_cmd_addr;
	static u8 rtl_cmd_type;
	static u8 rtl_cmd_width;

	static void __iomem *rtl_port_map(phys_addr_t addr, unsigned long len)
	{
	if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
	return ioremap(addr, len);
	return ioport_map(addr, len);
	}

	static void rtl_port_unmap(void __iomem *addr)
	{
	if (addr && rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
	iounmap(addr);
	else
	ioport_unmap(addr);
	}

	static int ibm_rtl_write(u8 value)
	{
	int ret = 0, count = 0;
	static u32 cmd_port_val;

	RTL_DEBUG("%s(%d)\n", __func__, value);

	value = value == 1 ? RTL_CMD_ENTER_PRTM : RTL_CMD_EXIT_PRTM;

	mutex_lock(&rtl_lock);

	if (ioread8(&rtl_table->rt_status) != value) {
	iowrite8(value, &rtl_table->command);

	switch (rtl_cmd_width) {
	case 8:
	cmd_port_val = ioread8(&rtl_table->cmd_port_value);
	RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
	iowrite8((u8)cmd_port_val, rtl_cmd_addr);
	break;
	case 16:
	cmd_port_val = ioread16(&rtl_table->cmd_port_value);
	RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
	iowrite16((u16)cmd_port_val, rtl_cmd_addr);
	break;
	case 32:
	cmd_port_val = ioread32(&rtl_table->cmd_port_value);
	RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
	iowrite32(cmd_port_val, rtl_cmd_addr);
	break;
	}

	while (ioread8(&rtl_table->command)) {
	msleep(10);
	if (count++ > 500) {
	pr_err("Hardware not responding to "
	"mode switch request\n");
	ret = -EIO;
	break;
	}

	}

	if (ioread8(&rtl_table->command_status)) {
	RTL_DEBUG("command_status reports failed command\n");
	ret = -EIO;
	}
	}

	mutex_unlock(&rtl_lock);
	return ret;
	}

	static ssize_t rtl_show_version(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version));
	}

	static ssize_t rtl_show_state(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status));
	}

	static ssize_t rtl_set_state(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t count)
	{
	ssize_t ret;

	if (count < 1 \|\| count > 2)
	return -EINVAL;

	switch (buf[0]) {
	case '0':
	ret = ibm_rtl_write(0);
	break;
	case '1':
	ret = ibm_rtl_write(1);
	break;
	default:
	ret = -EINVAL;
	}
	if (ret >= 0)
	ret = count;

	return ret;
	}

	static struct bus_type rtl_subsys = {
	.name = "ibm_rtl",
	.dev_name = "ibm_rtl",
	};

	static DEVICE_ATTR(version, S_IRUGO, rtl_show_version, NULL);
	static DEVICE_ATTR(state, 0600, rtl_show_state, rtl_set_state);

	static struct device_attribute *rtl_attributes[] = {
	&dev_attr_version,
	&dev_attr_state,
	NULL
	};


	static int rtl_setup_sysfs(void) {
	int ret, i;

	ret = subsys_system_register(&rtl_subsys, NULL);
	if (!ret) {
	for (i = 0; rtl_attributes[i]; i ++)
	device_create_file(rtl_subsys.dev_root, rtl_attributes[i]);
	}
	return ret;
	}

	static void rtl_teardown_sysfs(void) {
	int i;
	for (i = 0; rtl_attributes[i]; i ++)
	device_remove_file(rtl_subsys.dev_root, rtl_attributes[i]);
	bus_unregister(&rtl_subsys);
	}


	static struct dmi_system_id __initdata ibm_rtl_dmi_table[] = {
	{ \
	.matches = { \
	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), \
	}, \
	},
	{ }
	};

	static int __init ibm_rtl_init(void) {
	unsigned long ebda_addr, ebda_size;
	unsigned int ebda_kb;
	int ret = -ENODEV, i;

	if (force)
	pr_warn("module loaded by force\n");
	/* first ensure that we are running on IBM HW */
	else if (efi_enabled \|\| !dmi_check_system(ibm_rtl_dmi_table))
	return -ENODEV;

	/* Get the address for the Extended BIOS Data Area */
	ebda_addr = get_bios_ebda();
	if (!ebda_addr) {
	RTL_DEBUG("no BIOS EBDA found\n");
	return -ENODEV;
	}

	ebda_map = ioremap(ebda_addr, 4);
	if (!ebda_map)
	return -ENOMEM;

	/* First word in the EDBA is the Size in KB */
	ebda_kb = ioread16(ebda_map);
	RTL_DEBUG("EBDA is %d kB\n", ebda_kb);

	if (ebda_kb == 0)
	goto out;

	iounmap(ebda_map);
	ebda_size = ebda_kb*1024;

	/* Remap the whole table */
	ebda_map = ioremap(ebda_addr, ebda_size);
	if (!ebda_map)
	return -ENOMEM;

	/* search for the _RTL_ signature at the start of the table */
	for (i = 0 ; i < ebda_size/sizeof(unsigned int); i++) {
	struct ibm_rtl_table __iomem * tmp;
	tmp = (struct ibm_rtl_table __iomem *) (ebda_map+i);
	if ((readq(&tmp->signature) & RTL_MASK) == RTL_SIGNATURE) {
	phys_addr_t addr;
	unsigned int plen;
	RTL_DEBUG("found RTL_SIGNATURE at %p\n", tmp);
	rtl_table = tmp;
	/* The address, value, width and offset are platform
	* dependent and found in the ibm_rtl_table */
	rtl_cmd_width = ioread8(&rtl_table->cmd_granularity);
	rtl_cmd_type = ioread8(&rtl_table->cmd_address_type);
	RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n",
	rtl_cmd_width, rtl_cmd_type);
	addr = ioread32(&rtl_table->cmd_port_address);
	RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr);
	plen = rtl_cmd_width/sizeof(char);
	rtl_cmd_addr = rtl_port_map(addr, plen);
	RTL_DEBUG("rtl_cmd_addr = %p\n", rtl_cmd_addr);
	if (!rtl_cmd_addr) {
	ret = -ENOMEM;
	break;
	}
	ret = rtl_setup_sysfs();
	break;
	}
	}

	out:
	if (ret) {
	iounmap(ebda_map);
	rtl_port_unmap(rtl_cmd_addr);
	}

	return ret;
	}

	static void __exit ibm_rtl_exit(void)
	{
	if (rtl_table) {
	RTL_DEBUG("cleaning up");
	/* do not leave the machine in SMI-free mode */
	ibm_rtl_write(0);
	/* unmap, unlink and remove all traces */
	rtl_teardown_sysfs();
	iounmap(ebda_map);
	rtl_port_unmap(rtl_cmd_addr);
	}
	}

	module_init(ibm_rtl_init);
	module_exit(ibm_rtl_exit);