[PATCH v4 09/15] drm/bridge: tc358767: Use reported AUX transfer size

From: Andrey Smirnov
Date: Fri Jun 07 2019 - 00:51:05 EST


Don't assume that requested data transfer size is the same as amount
of data that was transferred. Change the code to get that information
from DP0_AUXSTATUS instead.

Since the check for AUX_BUSY in tc_aux_get_status() is pointless (it
will always called after tc_aux_wait_busy()) and there's only one user
of it, inline its code into tc_aux_transfer() instead of trying to
accommodate the change above.

Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Cc: Andrey Gusakov <andrey.gusakov@xxxxxxxxxxxxxxxxxx>
Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Cc: Cory Tusar <cory.tusar@xxxxxxxx>
Cc: Chris Healy <cphealy@xxxxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/gpu/drm/bridge/tc358767.c | 40 ++++++++++---------------------
1 file changed, 12 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 8b53dc8908d3..7d0fbb12195b 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -152,10 +152,10 @@
#define DP0_AUXWDATA(i) (0x066c + (i) * 4)
#define DP0_AUXRDATA(i) (0x067c + (i) * 4)
#define DP0_AUXSTATUS 0x068c
-#define AUX_STATUS_MASK 0xf0
-#define AUX_STATUS_SHIFT 4
-#define AUX_TIMEOUT BIT(1)
-#define AUX_BUSY BIT(0)
+#define AUX_BYTES GENMASK(15, 8)
+#define AUX_STATUS GENMASK(7, 4)
+#define AUX_TIMEOUT BIT(1)
+#define AUX_BUSY BIT(0)
#define DP0_AUXI2CADR 0x0698

/* Link Training */
@@ -298,29 +298,6 @@ static int tc_aux_wait_busy(struct tc_data *tc, unsigned int timeout_ms)
1000, 1000 * timeout_ms);
}

-static int tc_aux_get_status(struct tc_data *tc, u8 *reply)
-{
- int ret;
- u32 value;
-
- ret = regmap_read(tc->regmap, DP0_AUXSTATUS, &value);
- if (ret < 0)
- return ret;
-
- if (value & AUX_BUSY) {
- dev_err(tc->dev, "aux busy!\n");
- return -EBUSY;
- }
-
- if (value & AUX_TIMEOUT) {
- dev_err(tc->dev, "aux access timeout!\n");
- return -ETIMEDOUT;
- }
-
- *reply = (value & AUX_STATUS_MASK) >> AUX_STATUS_SHIFT;
- return 0;
-}
-
static int tc_aux_write_data(struct tc_data *tc, const void *data,
size_t size)
{
@@ -356,6 +333,7 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
struct tc_data *tc = aux_to_tc(aux);
size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size);
u8 request = msg->request & ~DP_AUX_I2C_MOT;
+ u32 auxstatus;
int ret;

if (size == 0)
@@ -393,10 +371,16 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
if (ret)
return ret;

- ret = tc_aux_get_status(tc, &msg->reply);
+ ret = regmap_read(tc->regmap, DP0_AUXSTATUS, &auxstatus);
if (ret)
return ret;

+ if (auxstatus & AUX_TIMEOUT)
+ return -ETIMEDOUT;
+
+ size = FIELD_GET(AUX_BYTES, auxstatus);
+ msg->reply = FIELD_GET(AUX_STATUS, auxstatus);
+
switch (request) {
case DP_AUX_NATIVE_READ:
case DP_AUX_I2C_READ:
--
2.21.0