+Ulf to keep me honest on the power domains On Thu, Jan 9, 2020 at 10:08 PM Steven Price <steven.pr...@arm.com> wrote: > > On 08/01/2020 05:23, Nicolas Boichat wrote: > > When there is a single power domain per device, the core will > > ensure the power domains are all switched on. > > > > However, when there are multiple ones, as in MT8183 Bifrost GPU, > > we need to handle them in driver code. > > > > > > Signed-off-by: Nicolas Boichat <drink...@chromium.org> > > --- > > > > 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. > > I'm not sure what is best, but it seems odd to encode this into the Panfrost > driver itself - it doesn't have any knowledge of what to do with these power > domains. The naming of the domains looks suspiciously like someone thought > that e.g. only half of the cores could be powered, but it doesn't look like > that was implemented in the chromeos driver linked and anyway that is *meant* > to be automatic in the hardware! (I.e. if you only power up one cores in one > core stack then the PDC should only enable the power domain for that set of > cores).
This is actually implemented in the Chrome OS driver [1]. IMHO power domains are a bit confusing [2]: i. If there's only 1 power domain in the device, then the core takes care of power on the domain (based on pm_runtime) ii. If there's more than 1 power domain, then the device needs to link the domains manually. So the Chrome OS [1] driver takes approach (i), by creating 3 devices, each with 1 power domain that is switched on/off automatically using pm_runtime. This patch takes approach (ii) with device links to handle the extra domains. I believe the latter is more upstream-friendly, but, as always, suggestions welcome. [2] https://elixir.bootlin.com/linux/latest/source/drivers/base/power/domain.c#L2466 > Steve > > > > > [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 > > > > drivers/gpu/drm/panfrost/panfrost_device.c | 87 ++++++++++++++++++++-- > > drivers/gpu/drm/panfrost/panfrost_device.h | 4 + > > 2 files changed, 83 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c > > b/drivers/gpu/drm/panfrost/panfrost_device.c > > index a0b0a6fef8b4e63..c6e9e059de94a4d 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" > > @@ -131,6 +132,67 @@ static void panfrost_regulator_fini(struct > > panfrost_device *pfdev) > > regulator_disable(pfdev->regulator_sram); > > } > > > > +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 domains are handled by the core. */ > > + if (num_domains < 2) > > + return 0; > > + > > + if (num_domains > ARRAY_SIZE(pfdev->pm_domain_devs)) { > > + dev_err(pfdev->dev, "Too many pm-domains: %d\n", num_domains); > > + return -EINVAL; > > + } > > + > > + for (i = 0; i < num_domains; i++) { > > + pfdev->pm_domain_devs[i] = > > + dev_pm_domain_attach_by_id(pfdev->dev, i); > > + if (IS_ERR(pfdev->pm_domain_devs[i])) { > > + err = PTR_ERR(pfdev->pm_domain_devs[i]); > > + pfdev->pm_domain_devs[i] = NULL; > > + dev_err(pfdev->dev, > > + "failed to get pm-domain %d: %d\n", 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); > > + if (!pfdev->pm_domain_links[i]) { > > + dev_err(pfdev->pm_domain_devs[i], > > + "adding device link failed!\n"); > > + err = -ENODEV; > > + goto err; > > + } > > + } > > + > > + return 0; > > + > > +err: > > + panfrost_pm_domain_fini(pfdev); > > + return err; > > +} > > + > > int panfrost_device_init(struct panfrost_device *pfdev) > > { > > int err; > > @@ -161,37 +223,45 @@ int panfrost_device_init(struct panfrost_device > > *pfdev) > > goto err_out1; > > } > > > > + err = panfrost_pm_domain_init(pfdev); > > + if (err) { > > + dev_err(pfdev->dev, "pm_domain init failed %d\n", err); > > + goto err_out2; > > + } > > + > > res = platform_get_resource(pfdev->pdev, IORESOURCE_MEM, 0); > > pfdev->iomem = devm_ioremap_resource(pfdev->dev, res); > > if (IS_ERR(pfdev->iomem)) { > > dev_err(pfdev->dev, "failed to ioremap iomem\n"); > > err = PTR_ERR(pfdev->iomem); > > - goto err_out2; > > + goto err_out3; > > } > > > > err = panfrost_gpu_init(pfdev); > > if (err) > > - goto err_out2; > > + goto err_out3; > > > > err = panfrost_mmu_init(pfdev); > > if (err) > > - goto err_out3; > > + goto err_out4; > > > > err = panfrost_job_init(pfdev); > > if (err) > > - goto err_out4; > > + goto err_out5; > > > > err = panfrost_perfcnt_init(pfdev); > > if (err) > > - goto err_out5; > > + goto err_out6; > > > > return 0; > > -err_out5: > > +err_out6: > > panfrost_job_fini(pfdev); > > -err_out4: > > +err_out5: > > panfrost_mmu_fini(pfdev); > > -err_out3: > > +err_out4: > > panfrost_gpu_fini(pfdev); > > +err_out3: > > + panfrost_pm_domain_fini(pfdev); > > err_out2: > > panfrost_reset_fini(pfdev); > > err_out1: > > @@ -208,6 +278,7 @@ void panfrost_device_fini(struct panfrost_device *pfdev) > > panfrost_mmu_fini(pfdev); > > panfrost_gpu_fini(pfdev); > > panfrost_reset_fini(pfdev); > > + panfrost_pm_domain_fini(pfdev); > > panfrost_regulator_fini(pfdev); > > panfrost_clk_fini(pfdev); > > } > > diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h > > b/drivers/gpu/drm/panfrost/panfrost_device.h > > index a124334d69e7e93..92d471676fc7823 100644 > > --- a/drivers/gpu/drm/panfrost/panfrost_device.h > > +++ b/drivers/gpu/drm/panfrost/panfrost_device.h > > @@ -19,6 +19,7 @@ struct panfrost_job; > > struct panfrost_perfcnt; > > > > #define NUM_JOB_SLOTS 3 > > +#define MAX_PM_DOMAINS 3 > > > > struct panfrost_features { > > u16 id; > > @@ -62,6 +63,9 @@ struct panfrost_device { > > struct regulator *regulator; > > struct regulator *regulator_sram; > > struct reset_control *rstc; > > + /* pm_domains for devices with more than one. */ > > + struct device *pm_domain_devs[MAX_PM_DOMAINS]; > > + struct device_link *pm_domain_links[MAX_PM_DOMAINS]; > > > > struct panfrost_features features; > > > > > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
