Re: [PATCH v2] drm/arcpgu: Accommodate adv7511 switch to DRM bridge

From: Archit Taneja
Date: Wed Oct 19 2016 - 11:11:46 EST




On 10/19/2016 01:16 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.

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.

Looks good now.

Reviewed-by: Archit Taneja <architt@xxxxxxxxxxxxxx>


Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
Changes for v2:
- remove bridge functions call from kms driver
- get rid of drm_encoder_slave interface
- coding style cleanup

drivers/gpu/drm/arc/arcpgu_hdmi.c | 159 ++++----------------------------------
1 file changed, 17 insertions(+), 142 deletions(-)

diff --git a/drivers/gpu/drm/arc/arcpgu_hdmi.c b/drivers/gpu/drm/arc/arcpgu_hdmi.c
index b7a8b2a..b69c66b 100644
--- a/drivers/gpu/drm/arc/arcpgu_hdmi.c
+++ b/drivers/gpu/drm/arc/arcpgu_hdmi.c
@@ -14,170 +14,45 @@
*
*/

-#include <drm/drm_crtc_helper.h>
+#include <drm/drm_crtc.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)
-{
- 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;
- }
-
- 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;
-}
-
-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,
- .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,
};

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;
- struct drm_connector *connector;
- struct i2c_client *i2c_slave;
- int ret;
+ struct drm_encoder *encoder;
+ struct drm_bridge *bridge;
+
+ int ret = 0;

encoder = devm_kzalloc(drm->dev, sizeof(*encoder), GFP_KERNEL);
if (encoder == NULL)
return -ENOMEM;

- i2c_slave = of_find_i2c_device_by_node(np);
- if (!i2c_slave || !i2c_get_clientdata(i2c_slave)) {
- dev_err(drm->dev, "failed to find i2c slave encoder\n");
- return -EPROBE_DEFER;
- }
-
- if (i2c_slave->dev.driver == NULL) {
- dev_err(drm->dev, "failed to find i2c slave driver\n");
+ /* Locate drm bridge from the hdmi encoder DT node */
+ bridge = of_drm_find_bridge(np);
+ if (!bridge)
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;
- }
-
- encoder->base.possible_crtcs = 1;
- encoder->base.possible_clones = 0;
- ret = drm_encoder_init(drm, &encoder->base, &arcpgu_drm_encoder_funcs,
+ encoder->possible_crtcs = 1;
+ encoder->possible_clones = 0;
+ ret = drm_encoder_init(drm, encoder, &arcpgu_drm_encoder_funcs,
DRM_MODE_ENCODER_TMDS, NULL);
if (ret)
return ret;

- 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;
- }
-
- 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;
- }
+ /* Link drm_bridge to encoder */
+ bridge->encoder = encoder;
+ encoder->bridge = bridge;

- 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;
- }
-
- arcpgu_connector->encoder_slave = encoder;
-
- return 0;
-
-error_connector_cleanup:
- drm_connector_cleanup(connector);
+ ret = drm_bridge_attach(drm, bridge);
+ if (ret)
+ drm_encoder_cleanup(encoder);

-error_encoder_cleanup:
- drm_encoder_cleanup(&encoder->base);
return ret;
}


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