diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/platform/x86/ibm_rtl.c | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/drivers/platform/x86/ibm_rtl.c b/drivers/platform/x86/ibm_rtl.c new file mode 100644 index 000000000..5fc665f7d --- /dev/null +++ b/drivers/platform/x86/ibm_rtl.c @@ -0,0 +1,314 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IBM Real-Time Linux driver + * + * 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 <linux/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; + 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 const struct dmi_system_id ibm_rtl_dmi_table[] __initconst = { + { \ + .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(EFI_BOOT) || !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); |