[PATCH 3/5] drm/msm/a6xx: Vote for cx gdsc from gpu driver

From: Akhil P Oommen
Date: Thu Dec 15 2022 - 10:12:33 EST


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@xxxxxxxxxxx>
---

drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 31 +++++++++++++++++++++++++++----
drivers/gpu/drm/msm/adreno/a6xx_gmu.h | 1 +
2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 6484b97c5344..1580d0090f35 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -1479,6 +1479,12 @@ 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);
@@ -1605,8 +1611,10 @@ 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;
}
@@ -1615,8 +1623,22 @@ 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
@@ -1634,6 +1656,9 @@ 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"))
@@ -1641,8 +1666,6 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
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 e034935b3986..5a42dd4dd31f 100644
--- 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;

--
2.7.4