drm/i915: Deduplicate the code to fill the aux message header

We have two instances of the code to fill out the header for the aux
message. Pull it into a small helper.

v2: Rebase due to txbuf[] changes

Cc: Sean Paul <seanpaul@chromium.org>
Cc: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180222212802.4826-1-ville.syrjala@linux.intel.com
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index a30303c..c722a67 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1238,6 +1238,17 @@ out:
 
 #define BARE_ADDRESS_SIZE      3
 #define HEADER_SIZE            (BARE_ADDRESS_SIZE + 1)
+
+static void
+intel_dp_aux_header(u8 txbuf[HEADER_SIZE],
+                   const struct drm_dp_aux_msg *msg)
+{
+       txbuf[0] = (msg->request << 4) | ((msg->address >> 16) & 0xf);
+       txbuf[1] = (msg->address >> 8) & 0xff;
+       txbuf[2] = msg->address & 0xff;
+       txbuf[3] = msg->size - 1;
+}
+
 static ssize_t
 intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 {
@@ -1246,11 +1257,7 @@ intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
        size_t txsize, rxsize;
        int ret;
 
-       txbuf[0] = (msg->request << 4) |
-               ((msg->address >> 16) & 0xf);
-       txbuf[1] = (msg->address >> 8) & 0xff;
-       txbuf[2] = msg->address & 0xff;
-       txbuf[3] = msg->size - 1;
+       intel_dp_aux_header(txbuf, msg);
 
        switch (msg->request & ~DP_AUX_I2C_MOT) {
        case DP_AUX_NATIVE_WRITE:
@@ -5004,7 +5011,12 @@ int intel_dp_hdcp_write_an_aksv(struct intel_digital_port *intel_dig_port,
                                u8 *an)
 {
        struct intel_dp *intel_dp = enc_to_intel_dp(&intel_dig_port->base.base);
-       uint8_t txbuf[4+5] = {}, rxbuf[2], reply = 0;
+       static const struct drm_dp_aux_msg msg = {
+               .request = DP_AUX_NATIVE_WRITE,
+               .address = DP_AUX_HDCP_AKSV,
+               .size = DRM_HDCP_KSV_LEN,
+       };
+       uint8_t txbuf[HEADER_SIZE + DRM_HDCP_KSV_LEN] = {}, rxbuf[2], reply = 0;
        ssize_t dpcd_ret;
        int ret;
 
@@ -5022,13 +5034,9 @@ int intel_dp_hdcp_write_an_aksv(struct intel_digital_port *intel_dig_port,
         * we were writing the data, and then tickle the hardware to output the
         * data once the header is sent out.
         */
-       txbuf[0] = (DP_AUX_NATIVE_WRITE << 4) |
-                  ((DP_AUX_HDCP_AKSV >> 16) & 0xf);
-       txbuf[1] = (DP_AUX_HDCP_AKSV >> 8) & 0xff;
-       txbuf[2] = DP_AUX_HDCP_AKSV & 0xff;
-       txbuf[3] = DRM_HDCP_KSV_LEN - 1;
+       intel_dp_aux_header(txbuf, &msg);
 
-       ret = intel_dp_aux_xfer(intel_dp, txbuf, sizeof(txbuf),
+       ret = intel_dp_aux_xfer(intel_dp, txbuf, HEADER_SIZE + msg.size,
                                rxbuf, sizeof(rxbuf),
                                DP_AUX_CH_CTL_AUX_AKSV_SELECT);
        if (ret < 0) {