Hi,

On 10/14/2016 6:57 PM, Eugeniy Paltsev wrote:
ARC PGU driver starts crashing on initialization after
'commit e12c2f645557 ("drm/i2c: adv7511: Convert to drm_bridge")'
This happenes because in "arcpgu_drm_hdmi_init" function we get pointer
of "drm_i2c_encoder_driver" structure, which doesn't exist after
adv7511 hdmi encoder interface changed from slave encoder to drm bridge.
So, when we call "encoder_init" function from this structure driver
crashes.


The conversion doesn't seem entirely correct. Some comments below.


Bootlog:
------------------------------------->8--------------------------------
[drm] Initialized drm 1.1.0 20060810
arcpgu e0017000.pgu: arc_pgu ID: 0xabbabaab
arcpgu e0017000.pgu: assigned reserved memory node frame_buffer@9e000000
Path: (null)
CPU: 0 PID: 1 Comm: swapper Not tainted 4.8.0-00001-gb5642252fa01-dirty #8
task: 9a058000 task.stack: 9a032000

[ECR   ]: 0x00220100 => Invalid Read @ 0x00000004 by insn @ 0x803934e8
[EFA   ]: 0x00000004
[BLINK ]: drm_atomic_helper_connector_dpms+0xa6/0x230
[ERET  ]: drm_atomic_helper_connector_dpms+0xa4/0x230
[STAT32]: 0x00000846 : K DE       E2 E1
BTA: 0x8016d949  SP: 0x9a033e34  FP: 0x00000000
LPS: 0x8036f6fc LPE: 0x8036f700 LPC: 0x00000000
r00: 0x8063c118 r01: 0x805b98ac r02: 0x00000b11
r03: 0x00000000 r04: 0x9a010f54 r05: 0x00000000
r06: 0x00000001 r07: 0x00000000 r08: 0x00000028
r09: 0x00000001 r10: 0x00000007 r11: 0x00000054
r12: 0x720a3033

Stack Trace:
  drm_atomic_helper_connector_dpms+0xa4/0x230
  arcpgu_drm_hdmi_init+0xbc/0x228
  arcpgu_probe+0x168/0x244
  platform_drv_probe+0x26/0x64
  really_probe+0x1f0/0x32c
  __driver_attach+0xa8/0xd0
  bus_for_each_dev+0x3c/0x74
  bus_add_driver+0xc2/0x184
  driver_register+0x50/0xec
  do_one_initcall+0x3a/0x120
  kernel_init_freeable+0x108/0x1a0
------------------------------------->8--------------------------------

Fix ARC PGU driver to be able work with drm bridge hdmi encoder
interface. The hdmi connector code isn't needed anymore as we expect
the adv7511 bridge driver to create/manage the connector.

Signed-off-by: Eugeniy Paltsev <eugeniy.palt...@synopsys.com>
---
 drivers/gpu/drm/arc/arcpgu_hdmi.c | 144 +++++++++-----------------------------
 1 file changed, 35 insertions(+), 109 deletions(-)

diff --git a/drivers/gpu/drm/arc/arcpgu_hdmi.c 
b/drivers/gpu/drm/arc/arcpgu_hdmi.c
index b7a8b2a..48a6c63 100644
--- a/drivers/gpu/drm/arc/arcpgu_hdmi.c
+++ b/drivers/gpu/drm/arc/arcpgu_hdmi.c
@@ -14,104 +14,54 @@
  *
  */

+#include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_encoder_slave.h>
 #include <drm/drm_atomic_helper.h>

 #include "arcpgu.h"

-struct arcpgu_drm_connector {
-       struct drm_connector connector;
-       struct drm_encoder_slave *encoder_slave;
-};
-
-static int arcpgu_drm_connector_get_modes(struct drm_connector *connector)
+static void arcpgu_drm_i2c_encoder_mode_set(struct drm_encoder *encoder,
+                               struct drm_display_mode *mode,
+                               struct drm_display_mode *adjusted_mode)
 {
-       const struct drm_encoder_slave_funcs *sfuncs;
-       struct drm_encoder_slave *slave;
-       struct arcpgu_drm_connector *con =
-               container_of(connector, struct arcpgu_drm_connector, connector);
-
-       slave = con->encoder_slave;
-       if (slave == NULL) {
-               dev_err(connector->dev->dev,
-                       "connector_get_modes: cannot find slave encoder for 
connector\n");
-               return 0;
-       }
-
-       sfuncs = slave->slave_funcs;
-       if (sfuncs->get_modes == NULL)
-               return 0;
-
-       return sfuncs->get_modes(&slave->base, connector);
-}
-
-static enum drm_connector_status
-arcpgu_drm_connector_detect(struct drm_connector *connector, bool force)
-{
-       enum drm_connector_status status = connector_status_unknown;
-       const struct drm_encoder_slave_funcs *sfuncs;
-       struct drm_encoder_slave *slave;
-
-       struct arcpgu_drm_connector *con =
-               container_of(connector, struct arcpgu_drm_connector, connector);
-
-       slave = con->encoder_slave;
-       if (slave == NULL) {
-               dev_err(connector->dev->dev,
-                       "connector_detect: cannot find slave encoder for 
connector\n");
-               return status;
-       }
+       struct drm_bridge *bridge = encoder->bridge;

-       sfuncs = slave->slave_funcs;
-       if (sfuncs && sfuncs->detect)
-               return sfuncs->detect(&slave->base, connector);
-
-       dev_err(connector->dev->dev, "connector_detect: could not detect slave 
funcs\n");
-       return status;
+       bridge->funcs->mode_set(bridge, mode, adjusted_mode);

The bridge functions shouldn't really be called by the kms driver.
They're called automatically by the drm core for the bridge attached
to the encoder. See mode_fixup in drivers/gpu/drm/drm_atomic_helper.c

 }

-static void arcpgu_drm_connector_destroy(struct drm_connector *connector)
-{
-       drm_connector_unregister(connector);
-       drm_connector_cleanup(connector);
-}
-
-static const struct drm_connector_helper_funcs
-arcpgu_drm_connector_helper_funcs = {
-       .get_modes = arcpgu_drm_connector_get_modes,
-};
-
-static const struct drm_connector_funcs arcpgu_drm_connector_funcs = {
-       .dpms = drm_helper_connector_dpms,
-       .reset = drm_atomic_helper_connector_reset,
-       .detect = arcpgu_drm_connector_detect,
-       .fill_modes = drm_helper_probe_single_connector_modes,
-       .destroy = arcpgu_drm_connector_destroy,
-       .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-       .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
 static struct drm_encoder_helper_funcs arcpgu_drm_encoder_helper_funcs = {
        .dpms = drm_i2c_encoder_dpms,
        .mode_fixup = drm_i2c_encoder_mode_fixup,
-       .mode_set = drm_i2c_encoder_mode_set,
+       .mode_set = arcpgu_drm_i2c_encoder_mode_set,
        .prepare = drm_i2c_encoder_prepare,
        .commit = drm_i2c_encoder_commit,
-       .detect = drm_i2c_encoder_detect,
 };

 static struct drm_encoder_funcs arcpgu_drm_encoder_funcs = {
        .destroy = drm_encoder_cleanup,
 };

+static void arcpgu_drm_i2c_encoder_dpms(struct drm_encoder *encoder, int mode)
+{
+       struct drm_bridge *bridge = encoder->bridge;
+
+       if (mode == DRM_MODE_DPMS_ON)
+               bridge->funcs->enable(bridge);
+       else
+               bridge->funcs->disable(bridge);
+}
+
+static struct drm_encoder_slave_funcs arcpgu_drm_encoder_slave_funcs = {
+       .dpms = arcpgu_drm_i2c_encoder_dpms,
+};
+
 int arcpgu_drm_hdmi_init(struct drm_device *drm, struct device_node *np)
 {
-       struct arcpgu_drm_connector *arcpgu_connector;
-       struct drm_i2c_encoder_driver *driver;
        struct drm_encoder_slave *encoder;

We should get rid of the drm_encoder_slave interface here entirely. A
regular drm_encoder should be created here, with mostly noop funcs so
that it doesn't do anything and lets the bridge manage things.


-       struct drm_connector *connector;
        struct i2c_client *i2c_slave;
+       struct drm_bridge *bridge;
+
        int ret;

        encoder = devm_kzalloc(drm->dev, sizeof(*encoder), GFP_KERNEL);
@@ -129,16 +79,14 @@ int arcpgu_drm_hdmi_init(struct drm_device *drm, struct 
device_node *np)
                return -EPROBE_DEFER;
        }

-       driver =
-           to_drm_i2c_encoder_driver(to_i2c_driver(i2c_slave->dev.driver));
-       ret = driver->encoder_init(i2c_slave, drm, encoder);
-       if (ret) {
-               dev_err(drm->dev, "failed to initialize i2c encoder slave\n");
-               return ret;
-       }
+       /* Locate drm bridge from the hdmi encoder DT node */
+       bridge = of_drm_find_bridge(np);
+       if (!bridge)
+               return -EPROBE_DEFER;

        encoder->base.possible_crtcs = 1;
        encoder->base.possible_clones = 0;
+       encoder->slave_funcs = &arcpgu_drm_encoder_slave_funcs;

This should go away too.

        ret = drm_encoder_init(drm, &encoder->base, &arcpgu_drm_encoder_funcs,
                               DRM_MODE_ENCODER_TMDS, NULL);
        if (ret)
@@ -147,37 +95,15 @@ int arcpgu_drm_hdmi_init(struct drm_device *drm, struct 
device_node *np)
        drm_encoder_helper_add(&encoder->base,
                               &arcpgu_drm_encoder_helper_funcs);

-       arcpgu_connector = devm_kzalloc(drm->dev, sizeof(*arcpgu_connector),
-                                       GFP_KERNEL);
-       if (!arcpgu_connector) {
-               ret = -ENOMEM;
-               goto error_encoder_cleanup;
-       }
+       /* Link drm_bridge to encoder */
+       bridge->encoder = &encoder->base;

This will simply become "bridge->encoder = encoder;"

+       encoder->base.bridge = bridge;

and this "encoder->bridge = bridge;"

You can have a look at the following patches which did the same
for rcar-du driver:

drm: rcar-du: Remove i2c slave encoder interface for hdmi encoder

and

drm: rcar-du: Link HDMI encoder with bridge

Thanks,
Archit


-       connector = &arcpgu_connector->connector;
-       drm_connector_helper_add(connector, &arcpgu_drm_connector_helper_funcs);
-       ret = drm_connector_init(drm, connector, &arcpgu_drm_connector_funcs,
-                       DRM_MODE_CONNECTOR_HDMIA);
-       if (ret < 0) {
-               dev_err(drm->dev, "failed to initialize drm connector\n");
-               goto error_encoder_cleanup;
-       }
-
-       ret = drm_mode_connector_attach_encoder(connector, &encoder->base);
-       if (ret < 0) {
-               dev_err(drm->dev, "could not attach connector to encoder\n");
-               drm_connector_unregister(connector);
-               goto error_connector_cleanup;
+       ret = drm_bridge_attach(drm, bridge);
+       if (ret) {
+               drm_encoder_cleanup(&encoder->base);
+               return ret;
        }

-       arcpgu_connector->encoder_slave = encoder;
-
        return 0;
-
-error_connector_cleanup:
-       drm_connector_cleanup(connector);
-
-error_encoder_cleanup:
-       drm_encoder_cleanup(&encoder->base);
-       return ret;
 }


--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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