mfd: cros_ec: Use a zero-length array for command data
Commit 1b84f2a4cd4a ("mfd: cros_ec: Use fixed size arrays to transfer
data with the EC") modified the struct cros_ec_command fields to not
use pointers for the input and output buffers and use fixed length
arrays instead.
This change was made because the cros_ec ioctl API uses that struct
cros_ec_command to allow user-space to send commands to the EC and
to get data from the EC. So using pointers made the API not 64-bit
safe. Unfortunately this approach was not flexible enough for all
the use-cases since there may be a need to send larger commands
on newer versions of the EC command protocol.
So to avoid to choose a constant length that it may be too big for
most commands and thus wasting memory and CPU cycles on copy from
and to user-space or having a size that is too small for some big
commands, use a zero-length array that is both 64-bit safe and
flexible. The same buffer is used for both output and input data
so the maximum of these values should be used to allocate it.
Suggested-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 8603105..4c7f0df 100644
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -73,8 +73,8 @@
/* Copy data and update checksum */
for (i = 0; i < msg->outsize; i++) {
- outb(msg->outdata[i], EC_LPC_ADDR_HOST_PARAM + i);
- csum += msg->outdata[i];
+ outb(msg->data[i], EC_LPC_ADDR_HOST_PARAM + i);
+ csum += msg->data[i];
}
/* Finalize checksum and write args */
@@ -129,8 +129,8 @@
/* Read response and update checksum */
for (i = 0; i < args.data_size; i++) {
- msg->indata[i] = inb(EC_LPC_ADDR_HOST_PARAM + i);
- csum += msg->indata[i];
+ msg->data[i] = inb(EC_LPC_ADDR_HOST_PARAM + i);
+ csum += msg->data[i];
}
/* Verify checksum */