ACPI: ibm-acpi: Implement direct-ec-access thermal reading modes for up to 16 sensors
This patch extends ibm-acpi to support reading thermal sensors directly
through ACPI EC register access. It uses a DMI match to detect ThinkPads
with a new-style embedded controller, that are known to have forward-
compatible register maps and use 0x00 to fill in non-used registers and
export thermal sensors at EC offsets 0x78-7F and 0xC0-C7.
Direct ACPI EC register access is implemented for 8-sensor and 16-sensor
new-style ThinkPad controller firmwares as an experimental feature. The
code does some limited sanity checks on the temperatures read through EC
access, and will default to the old ACPI TMP0-7 mode if anything is amiss.
Userspace ABI is not changed for 8 sensors, but /proc/acpi/ibm/thermal is
extended for 16 sensors if the firmware supports 16 sensors.
A documentation update is also provided.
The information about the ThinkPad register map was determined by studying
ibm-acpi "ecdump" output from various ThinkPad models, submitted by
subscribers of the linux-thinkpad mailinglist. Futher information was
gathered from the DSDT tables, as they describe the EC register map in
recent ThinkPads.
DSDT source shows that TMP0-7 access and direct register access are
actually the same thing on these firmwares, but unfortunately IBM never
did update their DSDT EC register map to export TMP8-TMP15 for the second
range of sensors.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
index baf9492..1703c61 100644
--- a/drivers/acpi/ibm_acpi.c
+++ b/drivers/acpi/ibm_acpi.c
@@ -80,6 +80,7 @@
#include <linux/proc_fs.h>
#include <linux/backlight.h>
#include <asm/uaccess.h>
+#include <linux/dmi.h>
#include <acpi/acpi_drivers.h>
#include <acpi/acnamesp.h>
@@ -221,13 +222,17 @@
IBMACPI_THERMAL_NONE = 0, /* No thermal support */
IBMACPI_THERMAL_ACPI_TMP07, /* Use ACPI TMP0-7 */
IBMACPI_THERMAL_ACPI_UPDT, /* Use ACPI TMP0-7 with UPDT */
+ IBMACPI_THERMAL_TPEC_8, /* Use ACPI EC regs, 8 sensors */
+ IBMACPI_THERMAL_TPEC_16, /* Use ACPI EC regs, 16 sensors */
};
-#define IBMACPI_MAX_THERMAL_SENSORS 8 /* Max thermal sensors supported */
+#define IBMACPI_MAX_THERMAL_SENSORS 16 /* Max thermal sensors supported */
struct ibm_thermal_sensors_struct {
s32 temp[IBMACPI_MAX_THERMAL_SENSORS];
};
+static int ibm_thinkpad_ec_found;
+
struct ibm_struct {
char *name;
char param[32];
@@ -1290,7 +1295,52 @@
static int thermal_init(void)
{
- if (acpi_evalf(ec_handle, NULL, "TMP7", "qv")) {
+ u8 t, ta1, ta2;
+ int i;
+ int acpi_tmp7 = acpi_evalf(ec_handle, NULL, "TMP7", "qv");
+
+ if (ibm_thinkpad_ec_found && experimental) {
+ /*
+ * Direct EC access mode: sensors at registers
+ * 0x78-0x7F, 0xC0-0xC7. Registers return 0x00 for
+ * non-implemented, thermal sensors return 0x80 when
+ * not available
+ */
+
+ ta1 = ta2 = 0;
+ for (i = 0; i < 8; i++) {
+ if (likely(acpi_ec_read(0x78 + i, &t))) {
+ ta1 |= t;
+ } else {
+ ta1 = 0;
+ break;
+ }
+ if (likely(acpi_ec_read(0xC0 + i, &t))) {
+ ta2 |= t;
+ } else {
+ ta1 = 0;
+ break;
+ }
+ }
+ if (ta1 == 0) {
+ /* This is sheer paranoia, but we handle it anyway */
+ if (acpi_tmp7) {
+ printk(IBM_ERR
+ "ThinkPad ACPI EC access misbehaving, "
+ "falling back to ACPI TMPx access mode\n");
+ thermal_read_mode = IBMACPI_THERMAL_ACPI_TMP07;
+ } else {
+ printk(IBM_ERR
+ "ThinkPad ACPI EC access misbehaving, "
+ "disabling thermal sensors access\n");
+ thermal_read_mode = IBMACPI_THERMAL_NONE;
+ }
+ } else {
+ thermal_read_mode =
+ (ta2 != 0) ?
+ IBMACPI_THERMAL_TPEC_16 : IBMACPI_THERMAL_TPEC_8;
+ }
+ } else if (acpi_tmp7) {
if (acpi_evalf(ec_handle, NULL, "UPDT", "qv")) {
/* 600e/x, 770e, 770x */
thermal_read_mode = IBMACPI_THERMAL_ACPI_UPDT;
@@ -1309,12 +1359,30 @@
static int thermal_get_sensors(struct ibm_thermal_sensors_struct *s)
{
int i, t;
+ s8 tmp;
char tmpi[] = "TMPi";
if (!s)
return -EINVAL;
switch (thermal_read_mode) {
+#if IBMACPI_MAX_THERMAL_SENSORS >= 16
+ case IBMACPI_THERMAL_TPEC_16:
+ for (i = 0; i < 8; i++) {
+ if (!acpi_ec_read(0xC0 + i, &tmp))
+ return -EIO;
+ s->temp[i + 8] = tmp * 1000;
+ }
+ /* fallthrough */
+#endif
+ case IBMACPI_THERMAL_TPEC_8:
+ for (i = 0; i < 8; i++) {
+ if (!acpi_ec_read(0x78 + i, &tmp))
+ return -EIO;
+ s->temp[i] = tmp * 1000;
+ }
+ return (thermal_read_mode == IBMACPI_THERMAL_TPEC_16) ? 16 : 8;
+
case IBMACPI_THERMAL_ACPI_UPDT:
if (!acpi_evalf(ec_handle, NULL, "UPDT", "v"))
return -EIO;
@@ -2052,6 +2120,24 @@
remove_proc_entry(IBM_DIR, acpi_root_dir);
}
+static int __init check_dmi_for_ec(void)
+{
+ struct dmi_device *dev = NULL;
+
+ /*
+ * ThinkPad T23 or newer, A31 or newer, R50e or newer,
+ * X32 or newer, all Z series; Some models must have an
+ * up-to-date BIOS or they will not be detected.
+ *
+ * See http://thinkwiki.org/wiki/List_of_DMI_IDs
+ */
+ while ((dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, dev))) {
+ if (strstr(dev->name, "IBM ThinkPad Embedded Controller"))
+ return 1;
+ }
+ return 0;
+}
+
static int __init acpi_ibm_init(void)
{
int ret, i;
@@ -2071,6 +2157,9 @@
return -ENODEV;
}
+ /* Models with newer firmware report the EC in DMI */
+ ibm_thinkpad_ec_found = check_dmi_for_ec();
+
/* these handles are not required */
IBM_HANDLE_INIT(vid);
IBM_HANDLE_INIT(vid2);