On Tue, Feb 11, 2020 at 11:44 AM Rob Herring <robh+dt@xxxxxxxxxx> wrote: > > +Saravana > > On Thu, Feb 6, 2020 at 11:27 PM Nicolas Boichat <drinkcat@xxxxxxxxxxxx> wrote: > > > > When there is a single power domain per device, the core will > > ensure the power domain is switched on (so it is technically > > equivalent to having not power domain specified at all). > > > > However, when there are multiple domains, as in MT8183 Bifrost > > GPU, we need to handle them in driver code. > > > > Signed-off-by: Nicolas Boichat <drinkcat@xxxxxxxxxxxx> > > > > --- > > > > The downstream driver we use on chromeos-4.19 currently uses 2 > > additional devices in device tree to accomodate for this [1], but > > I believe this solution is cleaner. > > > > [1] https://chromium.googlesource.com/chromiumos/third_party/kernel/+/refs/heads/chromeos-4.19/drivers/gpu/arm/midgard/platform/mediatek/mali_kbase_runtime_pm.c#31 > > > > v4: > > - Match the exact power domain names as specified in the compatible > > struct, instead of just matching the number of power domains. > > [Review: Ulf Hansson] > > - Dropped print and reordered function [Review: Steven Price] > > - nits: Run through latest version of checkpatch: > > - Use WARN instead of BUG_ON. > > - Drop braces for single expression if block. > > v3: > > - Use the compatible matching data to specify the number of power > > domains. Note that setting 0 or 1 in num_pm_domains is equivalent > > as the core will handle these 2 cases in the exact same way > > (automatically, without driver intervention), and there should > > be no adverse consequence in this case (the concern is about > > switching on only some power domains and not others). > > > > drivers/gpu/drm/panfrost/panfrost_device.c | 97 ++++++++++++++++++++-- > > drivers/gpu/drm/panfrost/panfrost_device.h | 11 +++ > > drivers/gpu/drm/panfrost/panfrost_drv.c | 2 + > > 3 files changed, 102 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c > > index 3720d50f6d9f965..8136babd3ba9935 100644 > > --- a/drivers/gpu/drm/panfrost/panfrost_device.c > > +++ b/drivers/gpu/drm/panfrost/panfrost_device.c > > @@ -5,6 +5,7 @@ > > #include <linux/clk.h> > > #include <linux/reset.h> > > #include <linux/platform_device.h> > > +#include <linux/pm_domain.h> > > #include <linux/regulator/consumer.h> > > > > #include "panfrost_device.h" > > @@ -120,6 +121,79 @@ static void panfrost_regulator_fini(struct panfrost_device *pfdev) > > pfdev->regulators); > > } > > > > +static void panfrost_pm_domain_fini(struct panfrost_device *pfdev) > > +{ > > + int i; > > + > > + for (i = 0; i < ARRAY_SIZE(pfdev->pm_domain_devs); i++) { > > + if (!pfdev->pm_domain_devs[i]) > > + break; > > + > > + if (pfdev->pm_domain_links[i]) > > + device_link_del(pfdev->pm_domain_links[i]); > > + > > + dev_pm_domain_detach(pfdev->pm_domain_devs[i], true); > > + } > > +} > > + > > +static int panfrost_pm_domain_init(struct panfrost_device *pfdev) > > +{ > > + int err; > > + int i, num_domains; > > + > > + num_domains = of_count_phandle_with_args(pfdev->dev->of_node, > > + "power-domains", > > + "#power-domain-cells"); > > + > > + /* > > + * Single domain is handled by the core, and, if only a single power > > + * the power domain is requested, the property is optional. > > + */ > > + if (num_domains < 2 && pfdev->comp->num_pm_domains < 2) > > + return 0; > > + > > + if (num_domains != pfdev->comp->num_pm_domains) { > > + dev_err(pfdev->dev, > > + "Incorrect number of power domains: %d provided, %d needed\n", > > + num_domains, pfdev->comp->num_pm_domains); > > + return -EINVAL; > > + } > > + > > + if (WARN(num_domains > ARRAY_SIZE(pfdev->pm_domain_devs), > > + "Too many supplies in compatible structure.\n")) > > + return -EINVAL; > > + > > + for (i = 0; i < num_domains; i++) { > > + pfdev->pm_domain_devs[i] = > > + dev_pm_domain_attach_by_name(pfdev->dev, > > + pfdev->comp->pm_domain_names[i]); > > + if (IS_ERR_OR_NULL(pfdev->pm_domain_devs[i])) { > > + err = PTR_ERR(pfdev->pm_domain_devs[i]) ? : -ENODATA; > > + pfdev->pm_domain_devs[i] = NULL; > > + dev_err(pfdev->dev, > > + "failed to get pm-domain %s(%d): %d\n", > > + pfdev->comp->pm_domain_names[i], i, err); > > + goto err; > > + } > > + > > + pfdev->pm_domain_links[i] = device_link_add(pfdev->dev, > > + pfdev->pm_domain_devs[i], DL_FLAG_PM_RUNTIME | > > + DL_FLAG_STATELESS | DL_FLAG_RPM_ACTIVE); > > We're in the process of adding device links based on DT properties. > Shouldn't we add power domains to that? See drivers/of/property.c for > what's handled. Rob, drivers/of/property.c doesn't enable the RPM_ACTIVE AND PM_RUNTIME flags. Wanted to start off conservative. But adding command line ops to change the default flags shouldn't be difficult. But before I do that, I want to change of_devlink to fw_devlink=<disabled|permissive|enabled>. May be I can extend that to "disabled, permissive, suspend, runtime". Nicholas, And the adding and removing of device links for power domains will be a 2 line change. I've been meaning to add a few more bindings like hwspinlocks and pinctrl. I can roll power domains support into that if you want. -Saravana
