Hi Dmitry,
>>>>
>>>> The eDP panel is identified and enumerated during probe of the
>>>> panel-edp driver. The current DP driver triggers this panel-edp
>>>> driver probe while getting the panel-bridge associated with the eDP
>>>> panel from the platform driver bind. If the panel-edp probe is
>>>> deferred, then the whole bunch of MDSS parent and child drivers have
>>>> to defer and
>>> roll back.
>>>
>>> No, MDSS has not been rolled back since 5.19. Please shift your
>>> development on top of the current msm-next.
>>>
>>
>> Okay, I will move to the msm-next tip.
>>
>>>>
>>>> So, we want to move the panel enumeration from bind to probe so that
>>>> the probe defer is easier to handle and also both the drivers appear
>>>> consistent in panel enumeration. This change moves the DP driver
>>>> panel-bridge enumeration to probe.
>>>>
>>>> Signed-off-by: Sankeerth Billakanti <quic_sbillaka@xxxxxxxxxxx>
>>>> ---
>>>> drivers/gpu/drm/msm/dp/dp_aux.c | 149
>>> ++++++++++++++++++++++++++--
>>>> drivers/gpu/drm/msm/dp/dp_catalog.c | 12 +++
>>>> drivers/gpu/drm/msm/dp/dp_catalog.h | 1 +
>>>> drivers/gpu/drm/msm/dp/dp_display.c | 80 ++++++---------
>>>> 4 files changed, 182 insertions(+), 60 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> b/drivers/gpu/drm/msm/dp/dp_aux.c index
>cc3efed593aa..5da95dfdeede
>>>> 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> @@ -110,7 +110,7 @@ static ssize_t dp_aux_write(struct
>>>> dp_aux_private *aux, }
>>>>
>>>> static ssize_t dp_aux_cmd_fifo_tx(struct dp_aux_private *aux,
>>>> - struct drm_dp_aux_msg *msg)
>>>> + struct drm_dp_aux_msg *msg, bool poll)
>>>
>>> What is the reason for working in polled mode rather than always
>>> using the interrupts?
>>>
>>
>> The mdss interrupts will be enabled and can be used after msm_irq_install
>from msm_drm_bind.
>> We want to perform aux transactions during probe. The aux data
>> transmission is followed by an interrupt to indicate successful transmission
>status and reply information.
>
>This is the price of developing on, let me guess, 5.15. Nowadays MDSS
>interrupts are enabled and can be used during dp_display_probe() and
>dp_display_bind(). If they can not for some reason, this is an issue that must
>be fixed. Please reconsider your approach after rebasing onto msm-next or
>6.3-rc1.
>
On the msm-next also, I see the mdss irq is enabled from bind (in msm_drv.c).
msm_drm_bind -> msm_drm_init -> msm_irq_install
Currently, interrupts will not be available during the dp_display_probe.
Is there a patch series which is enabling IRQs during mdss probe?
>>
>> As interrupts are not enabled, I took this polling approach for aux interrupts
>during probe.
>>
>>>> {
>>>> ssize_t ret;
>>>> unsigned long time_left;
>>>> @@ -121,10 +121,16 @@ static ssize_t dp_aux_cmd_fifo_tx(struct
>>> dp_aux_private *aux,
>>>> if (ret < 0)
>>>> return ret;
>>>>
>>>> - time_left = wait_for_completion_timeout(&aux->comp,
>>>> + if (!poll) {
>>>> + time_left = wait_for_completion_timeout(&aux->comp,
>>>> msecs_to_jiffies(250));
>>>> - if (!time_left)
>>>> - return -ETIMEDOUT;
>>>> + if (!time_left)
>>>> + return -ETIMEDOUT;
>>>> + } else {
>>>> + ret = dp_catalog_aux_poll_and_get_hw_interrupt(aux-
>>catalog);
>>>> + if (!ret)
>>>> + dp_aux_isr(&aux->dp_aux);
>>>> + }
>>>>
>>>> return ret;
>>>> }
>>>> @@ -238,7 +244,7 @@ static void
>>> dp_aux_update_offset_and_segment(struct dp_aux_private *aux,
>>>> */
>>>> static void dp_aux_transfer_helper(struct dp_aux_private *aux,
>>>> struct drm_dp_aux_msg *input_msg,
>>>> - bool send_seg)
>>>> + bool send_seg, bool poll)
>>>> {
>>>> struct drm_dp_aux_msg helper_msg;
>>>> u32 message_size = 0x10;
>>>> @@ -278,7 +284,7 @@ static void dp_aux_transfer_helper(struct
>>> dp_aux_private *aux,
>>>> helper_msg.address = segment_address;
>>>> helper_msg.buffer = &aux->segment;
>>>> helper_msg.size = 1;
>>>> - dp_aux_cmd_fifo_tx(aux, &helper_msg);
>>>> + dp_aux_cmd_fifo_tx(aux, &helper_msg, poll);
>>>> }
>>>>
>>>> /*
>>>> @@ -292,7 +298,7 @@ static void dp_aux_transfer_helper(struct
>>> dp_aux_private *aux,
>>>> helper_msg.address = input_msg->address;
>>>> helper_msg.buffer = &aux->offset;
>>>> helper_msg.size = 1;
>>>> - dp_aux_cmd_fifo_tx(aux, &helper_msg);
>>>> + dp_aux_cmd_fifo_tx(aux, &helper_msg, poll);
>>>>
>>>> end:
>>>> aux->offset += message_size; @@ -300,6 +306,122 @@ static
>>>> void dp_aux_transfer_helper(struct
>>> dp_aux_private *aux,
>>>> aux->segment = 0x0; /* reset segment at end of
>>>> block */ }
>>>>
>>>> +/*
>>>> + * This function does the real job to process an AUX transaction.
>>>> + * It will call aux_reset() function to reset the AUX channel,
>>>> + * if the waiting is timeout.
>>>> + */
>>>> +static ssize_t dp_aux_transfer_init(struct drm_dp_aux *dp_aux,
>>>> + struct drm_dp_aux_msg *msg) {
>>>> + ssize_t ret;
>>>> + int const aux_cmd_native_max = 16;
>>>> + int const aux_cmd_i2c_max = 128;
>>>> + struct dp_aux_private *aux;
>>>> +
>>>> + aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
>>>> +
>>>> + aux->native = msg->request & (DP_AUX_NATIVE_WRITE &
>>>> + DP_AUX_NATIVE_READ);
>>>> +
>>>> + /* Ignore address only message */
>>>> + if (msg->size == 0 || !msg->buffer) {
>>>> + msg->reply = aux->native ?
>>>> + DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
>>>> + return msg->size;
>>>> + }
>>>> +
>>>> + /* msg sanity check */
>>>> + if ((aux->native && msg->size > aux_cmd_native_max) ||
>>>> + msg->size > aux_cmd_i2c_max) {
>>>> + DRM_ERROR("%s: invalid msg: size(%zu), request(%x)\n",
>>>> + __func__, msg->size, msg->request);
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> + mutex_lock(&aux->mutex);
>>>> + if (!aux->initted) {
>>>> + ret = -EIO;
>>>> + goto exit;
>>>> + }
>>>> +
>>>> + /*
>>>> + * For eDP it's important to give a reasonably long wait here for HPD
>>>> + * to be asserted. This is because the panel driver may have _just_
>>>> + * turned on the panel and then tried to do an AUX transfer. The
>panel
>>>> + * driver has no way of knowing when the panel is ready, so it's up
>>>> + * to us to wait. For DP we never get into this situation so let's
>>>> + * avoid ever doing the extra long wait for DP.
>>>> + */
>>>> + if (aux->is_edp) {
>>>> + ret = dp_catalog_aux_wait_for_hpd_connect_state(aux-
>>catalog);
>>>> + if (ret) {
>>>> + DRM_DEBUG_DP("Panel not ready for aux transactions\n");
>>>> + goto exit;
>>>> + }
>>>> + }
>>>> +
>>>> + dp_aux_update_offset_and_segment(aux, msg);
>>>> + dp_aux_transfer_helper(aux, msg, true, true);
>>>> +
>>>> + aux->read = msg->request & (DP_AUX_I2C_READ &
>>> DP_AUX_NATIVE_READ);
>>>> + aux->cmd_busy = true;
>>>> +
>>>> + if (aux->read) {
>>>> + aux->no_send_addr = true;
>>>> + aux->no_send_stop = false;
>>>> + } else {
>>>> + aux->no_send_addr = true;
>>>> + aux->no_send_stop = true;
>>>> + }
>>>> +
>>>> + ret = dp_aux_cmd_fifo_tx(aux, msg, true);
>>>> +
>>>> + /* TODO: why is fifo_rx necessary here?
>>>> + * Ideally fifo_rx need not be executed for an aux write
>>>> + */
>>>> + ret = dp_aux_cmd_fifo_rx(aux, msg);
>>>> +
>>>> + if (ret < 0) {
>>>> + if (aux->native) {
>>>> + aux->retry_cnt++;
>>>> + if (!(aux->retry_cnt % MAX_AUX_RETRIES))
>>>> + dp_catalog_aux_update_cfg(aux->catalog);
>>>> + }
>>>> + /* reset aux if link is in connected state */
>>>> + if (dp_catalog_link_is_connected(aux->catalog))
>>>> + dp_catalog_aux_reset(aux->catalog);
>>>> + } else {
>>>> + aux->retry_cnt = 0;
>>>> + switch (aux->aux_error_num) {
>>>> + case DP_AUX_ERR_NONE:
>>>> + if (aux->read)
>>>> + ret = dp_aux_cmd_fifo_rx(aux, msg);
>>>> + msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_ACK :
>>> DP_AUX_I2C_REPLY_ACK;
>>>> + break;
>>>> + case DP_AUX_ERR_DEFER:
>>>> + msg->reply = aux->native ?
>>>> + DP_AUX_NATIVE_REPLY_DEFER :
>>> DP_AUX_I2C_REPLY_DEFER;
>>>> + break;
>>>> + case DP_AUX_ERR_PHY:
>>>> + case DP_AUX_ERR_ADDR:
>>>> + case DP_AUX_ERR_NACK:
>>>> + case DP_AUX_ERR_NACK_DEFER:
>>>> + msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_NACK :
>>> DP_AUX_I2C_REPLY_NACK;
>>>> + break;
>>>> + case DP_AUX_ERR_TOUT:
>>>> + ret = -ETIMEDOUT;
>>>> + break;
>>>> + }
>>>> + }
>>>> +
>>>> + aux->cmd_busy = false;
>>>> +
>>>> +exit:
>>>> + mutex_unlock(&aux->mutex);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> /*
>>>> * This function does the real job to process an AUX transaction.
>>>> * It will call aux_reset() function to reset the AUX channel, @@
>>>> -355,7 +477,7 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux
>>> *dp_aux,
>>>> }
>>>>
>>>> dp_aux_update_offset_and_segment(aux, msg);
>>>> - dp_aux_transfer_helper(aux, msg, true);
>>>> + dp_aux_transfer_helper(aux, msg, true, false);
>>>>
>>>> aux->read = msg->request & (DP_AUX_I2C_READ &
>>> DP_AUX_NATIVE_READ);
>>>> aux->cmd_busy = true;
>>>> @@ -368,7 +490,7 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux
>>> *dp_aux,
>>>> aux->no_send_stop = true;
>>>> }
>>>>
>>>> - ret = dp_aux_cmd_fifo_tx(aux, msg);
>>>> + ret = dp_aux_cmd_fifo_tx(aux, msg, false);
>>>> if (ret < 0) {
>>>> if (aux->native) {
>>>> aux->retry_cnt++; @@ -535,6 +657,15 @@
>>>> struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog
>*catalog,
>>>> aux->catalog = catalog;
>>>> aux->retry_cnt = 0;
>>>>
>>>> + /*
>>>> + * Use the drm_dp_aux_init() to use the aux adapter
>>>> + * before registering aux with the DRM device.
>>>> + */
>>>> + aux->dp_aux.name = "dpu_dp_aux";
>>>> + aux->dp_aux.dev = dev;
>>>> + aux->dp_aux.transfer = dp_aux_transfer_init;
>>>> + drm_dp_aux_init(&aux->dp_aux);
>>>
>>> How do you use the aux adapter? It should not be used before
>>> aux->drm_dev is setup.
>>>
>>
>> The drm_dev registration happens during the bind. But we need to use aux
>during probe.
>>
>> The kernel doc for the drm_dp_aux_init function suggested we can use
>> the adapter before drm_dev registration. So, I used this function to enable
>the aux usage during probe.
>
>Then please also change __drm_printk() to use (drm) ? (drm->dev) : NULL as
>a first argument to dev_##level##type. Otherwise the first AUX transfer error
>before aux->drm_dev is set will oops the kernel. See how
>drm_err() is expanded.
>
Okay, will add this also.
>>
>> /**
>> * drm_dp_aux_init() - minimally initialise an aux channel
>> * @aux: DisplayPort AUX channel
>> *
>> * If you need to use the drm_dp_aux's i2c adapter prior to registering it
>with
>> * the outside world, call drm_dp_aux_init() first.
>>
>>>> +
>>>> return &aux->dp_aux;
>>>> }
>>>>
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c
>>>> b/drivers/gpu/drm/msm/dp/dp_catalog.c
>>>> index 676279d0ca8d..ccf0400176f0 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
>>>> @@ -258,6 +258,18 @@ int
>>> dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog
>>> *dp_catalog)
>>>> 2000, 500000); }
>>>>
>>>> +int dp_catalog_aux_poll_and_get_hw_interrupt(struct dp_catalog
>>>> +*dp_catalog) {
>>>> + u32 aux;
>>>> + struct dp_catalog_private *catalog = container_of(dp_catalog,
>>>> + struct dp_catalog_private,
>>>> +dp_catalog);
>>>> +
>>>> + return readl_poll_timeout(catalog->io->dp_controller.ahb.base +
>>>> + REG_DP_INTR_STATUS,
>>>> + aux, aux & DP_INTERRUPT_STATUS1,
>>>> + 250, 250000); }
>>>> +
>>>> static void dump_regs(void __iomem *base, int len) {
>>>> int i;
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h
>>>> b/drivers/gpu/drm/msm/dp/dp_catalog.h
>>>> index 1f717f45c115..ad4a9e0f71f2 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_catalog.h
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.h
>>>> @@ -87,6 +87,7 @@ void dp_catalog_aux_enable(struct dp_catalog
>>>> *dp_catalog, bool enable); void dp_catalog_aux_update_cfg(struct
>>>> dp_catalog *dp_catalog); int
>>>> dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog
>>>> *dp_catalog);
>>>> u32 dp_catalog_aux_get_irq(struct dp_catalog *dp_catalog);
>>>> +int dp_catalog_aux_poll_and_get_hw_interrupt(struct dp_catalog
>>>> +*dp_catalog);
>>>>
>>>> /* DP Controller APIs */
>>>> void dp_catalog_ctrl_state_ctrl(struct dp_catalog *dp_catalog, u32
>>>> state); diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
>>>> b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> index bde1a7ce442f..a5dcef040b74 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> @@ -275,13 +275,6 @@ static int dp_display_bind(struct device *dev,
>struct
>>> device *master,
>>>> dp->dp_display.drm_dev = drm;
>>>> priv->dp[dp->id] = &dp->dp_display;
>>>>
>>>> - rc = dp->parser->parse(dp->parser);
>>>> - if (rc) {
>>>> - DRM_ERROR("device tree parsing failed\n");
>>>> - goto end;
>>>> - }
>>>> -
>>>> -
>>>> dp->drm_dev = drm;
>>>> dp->aux->drm_dev = drm;
>>>> rc = dp_aux_register(dp->aux); @@ -290,12 +283,6 @@ static int
>>>> dp_display_bind(struct device *dev, struct device *master,
>>>> goto end;
>>>> }
>>>>
>>>> - rc = dp_power_client_init(dp->power);
>>>> - if (rc) {
>>>> - DRM_ERROR("Power client create failed\n");
>>>> - goto end;
>>>> - }
>>>> -
>>>> rc = dp_register_audio_driver(dev, dp->audio);
>>>> if (rc) {
>>>> DRM_ERROR("Audio registration Dp failed\n"); @@ -787,6
>>>> +774,12 @@ static int dp_init_sub_modules(struct dp_display_private
>*dp)
>>>> goto error;
>>>> }
>>>>
>>>> + rc = dp->parser->parse(dp->parser);
>>>> + if (rc) {
>>>> + DRM_ERROR("device tree parsing failed\n");
>>>> + goto error;
>>>> + }
>>>> +
>>>> dp->catalog = dp_catalog_get(dev, &dp->parser->io);
>>>> if (IS_ERR(dp->catalog)) {
>>>> rc = PTR_ERR(dp->catalog); @@ -803,6 +796,12 @@ static
>>>> int dp_init_sub_modules(struct dp_display_private *dp)
>>>> goto error;
>>>> }
>>>>
>>>> + rc = dp_power_client_init(dp->power);
>>>> + if (rc) {
>>>> + DRM_ERROR("Power client create failed\n");
>>>> + goto error;
>>>> + }
>>>> +
>>>> dp->aux = dp_aux_get(dev, dp->catalog, dp->dp_display.is_edp);
>>>> if (IS_ERR(dp->aux)) {
>>>> rc = PTR_ERR(dp->aux); @@ -1338,12 +1337,29 @@ static
>>>> int dp_display_probe(struct platform_device *pdev)
>>>>
>>>> platform_set_drvdata(pdev, &dp->dp_display);
>>>>
>>>> + if (dp->dp_display.is_edp) {
>>>> + dp_display_host_init(dp);
>>>> + dp_display_host_phy_init(dp);
>>>> + dp_catalog_ctrl_hpd_config(dp->catalog);
>>>> +
>>>> + rc = devm_of_dp_aux_populate_bus(dp->aux, NULL);
>>>
>>> You should pass a real done_probing handler here, if you are going to
>refactor
>>> this piece of code. The done_probing should then shut down the
>resources
>>> and bind the component.
>>>
>>
>> I removed the resource enabling part from probe in the next patch where I
>implemented pm_runtime_ops.
>> I moved the host_init, phy_init and hpd_config into runtime_resume and
>calling pm_runtime_get_sync from aux_transfer.
>
>Next patch doesn't exist at this point. So, please, either reorder them,
>or make this patch correct per se.
>
>Also, the key part is a call to component_add(). It should come from
>done_probing callback. AUX bus probing is asynchronous. The kernel
>registers a device and then it might take some time for the correct
>driver to be loaded, etc. We clearly expect dp_display_bind to be used
>only when the panel has been probed.
>
Okay, will add the done_probe function
>>
>>>> +
>>>> + dp_display_host_phy_exit(dp);
>>>> + dp_display_host_deinit(dp);
>>>> +
>>>> + if (rc) {
>>>> + DRM_ERROR("failed to initialize panel, rc = %d\n", rc);
>>>> + goto error;
>>>> + }
>>>> + }
>>>> +
>>>> rc = component_add(&pdev->dev, &dp_display_comp_ops);
>>>> if (rc) {
>>>> DRM_ERROR("component add failed, rc=%d\n", rc);
>>>> dp_display_deinit_sub_modules(dp);
>>>> }
>>>>
>>>> +error:
>>>> return rc;
>>>> }
>>>>
>>>> @@ -1546,40 +1562,8 @@ static int dp_display_get_next_bridge(struct
>>>> msm_dp *dp) {
>>>> int rc;
>>>> struct dp_display_private *dp_priv;
>>>> - struct device_node *aux_bus;
>>>> - struct device *dev;
>>>>
>>>> dp_priv = container_of(dp, struct dp_display_private, dp_display);
>>>> - dev = &dp_priv->pdev->dev;
>>>> - aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
>>>> -
>>>> - if (aux_bus && dp->is_edp) {
>>>> - dp_display_host_init(dp_priv);
>>>> - dp_catalog_ctrl_hpd_config(dp_priv->catalog);
>>>> - dp_display_host_phy_init(dp_priv);
>>>> - enable_irq(dp_priv->irq);
>>>> -
>>>> - /*
>>>> - * The code below assumes that the panel will finish probing
>>>> - * by the time devm_of_dp_aux_populate_ep_devices()
>returns.
>>>> - * This isn't a great assumption since it will fail if the
>>>> - * panel driver is probed asynchronously but is the best we
>>>> - * can do without a bigger driver reorganization.
>>>> - */
>>>> - rc = of_dp_aux_populate_bus(dp_priv->aux, NULL);
>>>> - of_node_put(aux_bus);
>>>> - if (rc)
>>>> - goto error;
>>>> -
>>>> - rc = devm_add_action_or_reset(dp->drm_dev->dev,
>>>> - of_dp_aux_depopulate_bus_void,
>>>> - dp_priv->aux);
>>>> - if (rc)
>>>> - goto error;
>>>> - } else if (dp->is_edp) {
>>>> - DRM_ERROR("eDP aux_bus not found\n");
>>>> - return -ENODEV;
>>>> - }
>>>>
>>>> /*
>>>> * External bridges are mandatory for eDP interfaces: one has
>>>> to @@ -1597,12 +1581,6 @@ static int dp_display_get_next_bridge(struct
>>> msm_dp *dp)
>>>> return 0;
>>>> }
>>>>
>>>> -error:
>>>> - if (dp->is_edp) {
>>>> - disable_irq(dp_priv->irq);
>>>> - dp_display_host_phy_exit(dp_priv);
>>>> - dp_display_host_deinit(dp_priv);
>>>> - }
>>>> return rc;
>>>> }
>>>>
>>>> --
>>>> 2.39.0
>>>>
>>>
>>>
>>> --
>>> With best wishes
>>> Dmitry
>
>--
>With best wishes
>Dmitry
