drm/msm/a6xx: Vote for cx gdsc from gpu driver

When a device has multiple power domains, dev->power_domain is left
empty during probe. That didn't cause any issue so far because we are
freeloading on smmu driver's vote on cx gdsc. Instead of that, create
a device_link between cx genpd device and gmu device to keep a vote from
gpu driver.

Before this patch:
localhost ~ # cat /sys/kernel/debug/pm_genpd/pm_genpd_summary
gx_gdsc		on		0
    /devices/genpd:1:3d6a000.gmu		active		0
cx_gdsc		on		0
    /devices/platform/soc@0/3da0000.iommu	active		0

After this patch:
localhost ~ # cat /sys/kernel/debug/pm_genpd/pm_genpd_summary
gx_gdsc		on		0
    /devices/genpd:1:3d6a000.gmu		active		0
cx_gdsc		on		0
    /devices/platform/soc@0/3da0000.iommu	active		0
    /devices/genpd:0:3d6a000.gmu		active		0

Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/516468/
Link: https://lore.kernel.org/r/20230102161757.v5.3.I7f545d8494dcdbe6e96a15fbe8aaf5bb0c003d50@changeid
Signed-off-by: Rob Clark <robdclark@chromium.org>

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 7f5bc73..a3676dc 100644 (file)
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -1482,6 +1482,12 @@ void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu)
 
        pm_runtime_force_suspend(gmu->dev);
 
+       /*
+        * Since cxpd is a virt device, the devlink with gmu-dev will be removed
+        * automatically when we do detach
+        */
+       dev_pm_domain_detach(gmu->cxpd, false);
+
        if (!IS_ERR_OR_NULL(gmu->gxpd)) {
                pm_runtime_disable(gmu->gxpd);
                dev_pm_domain_detach(gmu->gxpd, false);
@@ -1608,8 +1614,10 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
 
        if (adreno_is_a650_family(adreno_gpu)) {
                gmu->rscc = a6xx_gmu_get_mmio(pdev, "rscc");
-               if (IS_ERR(gmu->rscc))
+               if (IS_ERR(gmu->rscc)) {
+                       ret = -ENODEV;
                        goto err_mmio;
+               }
        } else {
                gmu->rscc = gmu->mmio + 0x23000;
        }
@@ -1618,8 +1626,22 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
        gmu->hfi_irq = a6xx_gmu_get_irq(gmu, pdev, "hfi", a6xx_hfi_irq);
        gmu->gmu_irq = a6xx_gmu_get_irq(gmu, pdev, "gmu", a6xx_gmu_irq);
 
-       if (gmu->hfi_irq < 0 || gmu->gmu_irq < 0)
+       if (gmu->hfi_irq < 0 || gmu->gmu_irq < 0) {
+               ret = -ENODEV;
+               goto err_mmio;
+       }
+
+       gmu->cxpd = dev_pm_domain_attach_by_name(gmu->dev, "cx");
+       if (IS_ERR(gmu->cxpd)) {
+               ret = PTR_ERR(gmu->cxpd);
                goto err_mmio;
+       }
+
+       if (!device_link_add(gmu->dev, gmu->cxpd,
+                                       DL_FLAG_PM_RUNTIME)) {
+               ret = -ENODEV;
+               goto detach_cxpd;
+       }
 
        /*
         * Get a link to the GX power domain to reset the GPU in case of GMU
@@ -1637,6 +1659,9 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
 
        return 0;
 
+detach_cxpd:
+       dev_pm_domain_detach(gmu->cxpd, false);
+
 err_mmio:
        iounmap(gmu->mmio);
        if (platform_get_resource_byname(pdev, IORESOURCE_MEM, "rscc"))
@@ -1644,8 +1669,6 @@ err_mmio:
        free_irq(gmu->gmu_irq, gmu);
        free_irq(gmu->hfi_irq, gmu);
 
-       ret = -ENODEV;
-
 err_memory:
        a6xx_gmu_memory_free(gmu);
 err_put_device:

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
index e034935..5a42dd4 100644 (file)
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
@@ -56,6 +56,7 @@ struct a6xx_gmu {
        int gmu_irq;
 
        struct device *gxpd;
+       struct device *cxpd;
 
        int idle_level;