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Diffstat (limited to 'drivers/platform/x86/ibm_rtl.c')
-rw-r--r--drivers/platform/x86/ibm_rtl.c314
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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-07 18:21:57 +0000