/* * 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 * Vernon Mauery * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include 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 "); MODULE_AUTHOR("Vernon Mauery "); #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(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);