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authorJavier Martinez Canillas <javier.martinez@collabora.co.uk>2015-06-09 14:04:42 +0300
committerLee Jones <lee.jones@linaro.org>2015-06-15 15:18:19 +0300
commita841178445bb72a3d566b4e6ab9d19e9b002eb47 (patch)
treebdc857e82c9c9e8b49bd5471efa5a954673d58f0 /include/linux/mfd/cros_ec.h
parentbb03ffb96c72418d06e75c7b74ea62e04c78d322 (diff)
downloadlinux-a841178445bb72a3d566b4e6ab9d19e9b002eb47.tar.xz
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>
Diffstat (limited to 'include/linux/mfd/cros_ec.h')
-rw-r--r--include/linux/mfd/cros_ec.h6
1 files changed, 2 insertions, 4 deletions
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 14cf522123dd..7eee38abd02a 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -42,8 +42,7 @@ enum {
* @outsize: Outgoing length in bytes
* @insize: Max number of bytes to accept from EC
* @result: EC's response to the command (separate from communication failure)
- * @outdata: Outgoing data to EC
- * @indata: Where to put the incoming data from EC
+ * @data: Where to put the incoming data from EC and outgoing data to EC
*/
struct cros_ec_command {
uint32_t version;
@@ -51,8 +50,7 @@ struct cros_ec_command {
uint32_t outsize;
uint32_t insize;
uint32_t result;
- uint8_t outdata[EC_PROTO2_MAX_PARAM_SIZE];
- uint8_t indata[EC_PROTO2_MAX_PARAM_SIZE];
+ uint8_t data[0];
};
/**