[PATCH v1 3/4] drm/msm/mdp4: move resource allocation to the _probe function
Abhinav Kumar
quic_abhinavk at quicinc.com
Fri Sep 2 17:48:28 UTC 2022
On 9/1/2022 11:06 PM, Dmitry Baryshkov wrote:
>
>
> On 2 September 2022 03:24:17 GMT+03:00, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>>
>>
>> On 6/20/2022 2:30 PM, Dmitry Baryshkov wrote:
>>> To let the probe function bail early if any of the resources is
>>> unavailable, move resource allocattion from kms_init directly to the
>>> probe callback. While we are at it, replace irq_of_parse_and_map() with
>>> platform_get_irq().
>>>
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>>> ---
>>> drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c | 107 +++++++++++------------
>>> 1 file changed, 51 insertions(+), 56 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
>>> index 41dc60784847..6499713eccf6 100644
>>> --- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
>>> +++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
>>> @@ -139,8 +139,6 @@ static void mdp4_destroy(struct msm_kms *kms)
>>> pm_runtime_disable(dev);
>>> mdp_kms_destroy(&mdp4_kms->base);
>>> -
>>> - kfree(mdp4_kms);
>>> }
>>> static const struct mdp_kms_funcs kms_funcs = {
>>> @@ -383,57 +381,27 @@ static int mdp4_kms_init(struct drm_device *dev)
>>> {
>>> struct platform_device *pdev = to_platform_device(dev->dev);
>>> struct msm_drm_private *priv = dev->dev_private;
>>> - struct mdp4_kms *mdp4_kms;
>>> + struct mdp4_kms *mdp4_kms = to_mdp4_kms(to_mdp_kms(priv->kms));
>>> struct msm_kms *kms = NULL;
>>> struct iommu_domain *iommu;
>>> struct msm_gem_address_space *aspace;
>>> - int irq, ret;
>>> + int ret;
>>> u32 major, minor;
>>> unsigned long max_clk;
>>> /* TODO: Chips that aren't apq8064 have a 200 Mhz max_clk */
>>> max_clk = 266667000;
>>> - mdp4_kms = kzalloc(sizeof(*mdp4_kms), GFP_KERNEL);
>>> - if (!mdp4_kms) {
>>> - DRM_DEV_ERROR(dev->dev, "failed to allocate kms\n");
>>> - return -ENOMEM;
>>> - }
>>> -
>>> ret = mdp_kms_init(&mdp4_kms->base, &kms_funcs);
>>> if (ret) {
>>> DRM_DEV_ERROR(dev->dev, "failed to init kms\n");
>>> goto fail;
>>> }
>>> - priv->kms = &mdp4_kms->base.base;
>>> kms = priv->kms;
>>> mdp4_kms->dev = dev;
>>> - mdp4_kms->mmio = msm_ioremap(pdev, NULL);
>>> - if (IS_ERR(mdp4_kms->mmio)) {
>>> - ret = PTR_ERR(mdp4_kms->mmio);
>>> - goto fail;
>>> - }
>>> -
>>> - irq = platform_get_irq(pdev, 0);
>>> - if (irq < 0) {
>>> - ret = irq;
>>> - DRM_DEV_ERROR(dev->dev, "failed to get irq: %d\n", ret);
>>> - goto fail;
>>> - }
>>> -
>>> - kms->irq = irq;
>>> -
>>> - /* NOTE: driver for this regulator still missing upstream.. use
>>> - * _get_exclusive() and ignore the error if it does not exist
>>> - * (and hope that the bootloader left it on for us)
>>> - */
>>> - mdp4_kms->vdd = devm_regulator_get_exclusive(&pdev->dev, "vdd");
>>> - if (IS_ERR(mdp4_kms->vdd))
>>> - mdp4_kms->vdd = NULL;
>>> -
>>> if (mdp4_kms->vdd) {
>>> ret = regulator_enable(mdp4_kms->vdd);
>>> if (ret) {
>>> @@ -442,24 +410,6 @@ static int mdp4_kms_init(struct drm_device *dev)
>>> }
>>> }
>>> - mdp4_kms->clk = devm_clk_get(&pdev->dev, "core_clk");
>>> - if (IS_ERR(mdp4_kms->clk)) {
>>> - DRM_DEV_ERROR(dev->dev, "failed to get core_clk\n");
>>> - ret = PTR_ERR(mdp4_kms->clk);
>>> - goto fail;
>>> - }
>>> -
>>> - mdp4_kms->pclk = devm_clk_get(&pdev->dev, "iface_clk");
>>> - if (IS_ERR(mdp4_kms->pclk))
>>> - mdp4_kms->pclk = NULL;
>>> -
>>> - mdp4_kms->axi_clk = devm_clk_get(&pdev->dev, "bus_clk");
>>> - if (IS_ERR(mdp4_kms->axi_clk)) {
>>> - DRM_DEV_ERROR(dev->dev, "failed to get axi_clk\n");
>>> - ret = PTR_ERR(mdp4_kms->axi_clk);
>>> - goto fail;
>>> - }
>>> -
>>> clk_set_rate(mdp4_kms->clk, max_clk);
>>> read_mdp_hw_revision(mdp4_kms, &major, &minor);
>>> @@ -474,10 +424,9 @@ static int mdp4_kms_init(struct drm_device *dev)
>>> mdp4_kms->rev = minor;
>>> if (mdp4_kms->rev >= 2) {
>>> - mdp4_kms->lut_clk = devm_clk_get(&pdev->dev, "lut_clk");
>>> - if (IS_ERR(mdp4_kms->lut_clk)) {
>>> + if (!mdp4_kms->lut_clk) {
>>> DRM_DEV_ERROR(dev->dev, "failed to get lut_clk\n");
>>> - ret = PTR_ERR(mdp4_kms->lut_clk);
>>> + ret = -ENODEV;
>>> goto fail;
>>> }
>>> clk_set_rate(mdp4_kms->lut_clk, max_clk);
>>> @@ -560,7 +509,53 @@ static const struct dev_pm_ops mdp4_pm_ops = {
>>> static int mdp4_probe(struct platform_device *pdev)
>>> {
>>> - return msm_drv_probe(&pdev->dev, mdp4_kms_init, NULL);
>>> + struct device *dev = &pdev->dev;
>>> + struct mdp4_kms *mdp4_kms;
>>> + int irq;
>>> +
>>> + mdp4_kms = devm_kzalloc(dev, sizeof(*mdp4_kms), GFP_KERNEL);
>>> + if (!mdp4_kms)
>>> + return dev_err_probe(dev, -ENOMEM, "failed to allocate kms\n");
>>> +
>>> + mdp4_kms->mmio = msm_ioremap(pdev, NULL);
>>> + if (IS_ERR(mdp4_kms->mmio))
>>> + return PTR_ERR(mdp4_kms->mmio);
>>> +
>>> + irq = platform_get_irq(pdev, 0);
>>> + if (irq < 0)
>>> + return dev_err_probe(dev, irq, "failed to get irq\n");
>>> +
>>> + mdp4_kms->base.base.irq = irq;
>>> +
>>> + /* NOTE: driver for this regulator still missing upstream.. use
>>> + * _get_exclusive() and ignore the error if it does not exist
>>> + * (and hope that the bootloader left it on for us)
>>> + */
>>> + mdp4_kms->vdd = devm_regulator_get_exclusive(&pdev->dev, "vdd");
>>> + if (IS_ERR(mdp4_kms->vdd))
>>> + mdp4_kms->vdd = NULL;
>>> +
>>> + mdp4_kms->clk = devm_clk_get(&pdev->dev, "core_clk");
>>> + if (IS_ERR(mdp4_kms->clk))
>>> + return dev_err_probe(dev, PTR_ERR(mdp4_kms->clk), "failed to get core_clk\n");
>>> +
>>> + mdp4_kms->pclk = devm_clk_get(&pdev->dev, "iface_clk");
>>> + if (IS_ERR(mdp4_kms->pclk))
>>> + mdp4_kms->pclk = NULL;
>>> +
>>> + mdp4_kms->axi_clk = devm_clk_get(&pdev->dev, "bus_clk");
>>> + if (IS_ERR(mdp4_kms->axi_clk))
>>> + return dev_err_probe(dev, PTR_ERR(mdp4_kms->axi_clk), "failed to get axi_clk\n");
>>> +
>>> + /*
>>> + * This is required for revn >= 2. Handle errors here and let the kms
>>> + * init bail out if the clock is not provided.
>>> + */
>>> + mdp4_kms->lut_clk = devm_clk_get_optional(&pdev->dev, "lut_clk");
>>> + if (IS_ERR(mdp4_kms->lut_clk))
>>> + return dev_err_probe(dev, PTR_ERR(mdp4_kms->lut_clk), "failed to get lut_clk\n");
>>
>> I can see that you have moved this from init to probe and only rev >=2 needs it.
>>
>> But, your check here will end up returning from probe because you have a return. So I guess you means just having dev_err_probe without the return and let the init fail if the clk is not found because we have the hw_rev only in init.
>
> No. The function called here is the devm_clk_get_optional(). So the driver will get NULL if the clock is not present in the DT and an error only in an error case (e.g. EINVAL, EPROBE_DEFER).
>
> Later on the mdp4_kms_init() will check hw_rev and return -ENODEV if the clock is required, but is set to NULL (not present in DT).
>
Ok, I have understood. But dont you think this is too much convolution
just for this check? Why not leave the lut_clk in the init instead of
trying to move it to probe and add all this?
>
>>
>>> +
>>> + return msm_drv_probe(&pdev->dev, mdp4_kms_init, &mdp4_kms->base.base);
>>> }
>>> static int mdp4_remove(struct platform_device *pdev)
>
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