Re: [PATCH v1 3/4] drm/msm/mdp4: move resource allocation to the _probe function
Dmitry Baryshkov
dmitry.baryshkov at linaro.org
Fri Sep 2 06:06:27 UTC 2022
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).
>
>> +
>> + return msm_drv_probe(&pdev->dev, mdp4_kms_init, &mdp4_kms->base.base);
>> }
>> static int mdp4_remove(struct platform_device *pdev)
--
With best wishes
Dmitry
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