The AppleSMC contains two char[32] keys, OSK0 and OSK1, which are not
reported in the key count and index by default. These keys are used by
the OS X boot sequence, and normally don't matter when running Linux.
This patch creates a sysfs entry which reports the value of these keys
as an ASCII string, to help emulators (such as QEMU) load OS X when
running on genuine Apple hardware.
Signed-off-by: Gabriel L. Somlo <so...@cmu.edu>
---
For extra context: To boot OS X as a guest, QEMU must (among others)
emulate the AppleSMC. To boot successfully, OS X insists on querying
the (emulated) SMC for the value of OSK0 and OSK1. Currently, these
values must be supplied on the QEMU command line as
-device applesmc,osk="...concatenated values of OSK0 and OSK1..."
With the availability of /sys/devices/platform/applesmc.768/osk, the
emulated QEMU AppleSMC could acquire this string directly from the
(Apple-manufactured) host machine.
Thanks,
Gabriel
drivers/hwmon/applesmc.c | 18 ++++++++++++++++++
1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index b41baff..0c7cc71 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -1013,6 +1013,23 @@ static ssize_t applesmc_key_at_index_store(struct device
*dev,
return count;
}
+static ssize_t applesmc_osk_show(struct device *dev,
+ struct device_attribute *attr, char *sysfsbuf)
+{
+ int fail;
+
+ mutex_lock(&smcreg.mutex);
+ fail = read_smc(APPLESMC_READ_CMD, "OSK0", sysfsbuf, 32) ||
+ read_smc(APPLESMC_READ_CMD, "OSK1", sysfsbuf + 32, 32);
+ mutex_unlock(&smcreg.mutex);
+ if (fail)
+ return -1;
+
+ sysfsbuf[64] = '\n';
+ sysfsbuf[65] = '\0';
+ return 65;
+}
+
static struct led_classdev applesmc_backlight = {
.name = "smc::kbd_backlight",
.default_trigger = "nand-disk",
@@ -1027,6 +1044,7 @@ static struct applesmc_node_group info_group[] = {
{ "key_at_index_type", applesmc_key_at_index_type_show },
{ "key_at_index_data_length", applesmc_key_at_index_data_length_show },
{ "key_at_index_data", applesmc_key_at_index_read_show },
+ { "osk", applesmc_osk_show },
{ }
};
--
1.7.7.6
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