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linux/drivers/platform/x86/ibm_rtl.c

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/*
* 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/sysdev.h>
#include <linux/dmi.h>
#include <linux/efi.h>
#include <linux/mutex.h>
#include <asm/bios_ebda.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;
x86: remove 32-bit versions of readq()/writeq() The presense of a writeq() implementation on 32-bit x86 that splits the 64-bit write into two 32-bit writes turns out to break the mpt2sas driver (and in general is risky for drivers as was discussed in <http://lkml.kernel.org/r/adaab6c1h7c.fsf@cisco.com>). To fix this, revert 2c5643b1c5c7 ("x86: provide readq()/writeq() on 32-bit too") and follow-on cleanups. This unfortunately leads to pushing non-atomic definitions of readq() and write() to various x86-only drivers that in the meantime started using the definitions in the x86 version of <asm/io.h>. However as discussed exhaustively, this is actually the right thing to do, because the right way to split a 64-bit transaction is hardware dependent and therefore belongs in the hardware driver (eg mpt2sas needs a spinlock to make sure no other accesses occur in between the two halves of the access). Build tested on 32- and 64-bit x86 allmodconfig. Link: http://lkml.kernel.org/r/x86-32-writeq-is-broken@mdm.bga.com Acked-by: Hitoshi Mitake <h.mitake@gmail.com> Cc: Kashyap Desai <Kashyap.Desai@lsi.com> Cc: Len Brown <lenb@kernel.org> Cc: Ravi Anand <ravi.anand@qlogic.com> Cc: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Cc: Matthew Garrett <mjg@redhat.com> Cc: Jason Uhlenkott <juhlenko@akamai.com> Acked-by: James Bottomley <James.Bottomley@parallels.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-24 17:13:09 -07:00
#ifndef readq
static inline __u64 readq(const volatile void __iomem *addr)
{
const volatile u32 __iomem *p = addr;
u32 low, high;
low = readl(p);
high = readl(p + 1);
return low + ((u64)high << 32);
}
#endif
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 sysdev_class * dev,
struct sysdev_class_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version));
}
static ssize_t rtl_show_state(struct sysdev_class *dev,
struct sysdev_class_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status));
}
static ssize_t rtl_set_state(struct sysdev_class *dev,
struct sysdev_class_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 sysdev_class class_rtl = {
.name = "ibm_rtl",
};
static SYSDEV_CLASS_ATTR(version, S_IRUGO, rtl_show_version, NULL);
static SYSDEV_CLASS_ATTR(state, 0600, rtl_show_state, rtl_set_state);
static struct sysdev_class_attribute *rtl_attributes[] = {
&attr_version,
&attr_state,
NULL
};
static int rtl_setup_sysfs(void) {
int ret, i;
ret = sysdev_class_register(&class_rtl);
if (!ret) {
for (i = 0; rtl_attributes[i]; i ++)
sysdev_class_create_file(&class_rtl, rtl_attributes[i]);
}
return ret;
}
static void rtl_teardown_sysfs(void) {
int i;
for (i = 0; rtl_attributes[i]; i ++)
sysdev_class_remove_file(&class_rtl, rtl_attributes[i]);
sysdev_class_unregister(&class_rtl);
}
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);