Re: [PATCH] drm/stm: support runtime power management

From: Benjamin Gaignard
Date: Fri Jun 07 2019 - 08:53:09 EST

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In reply to: Philippe CORNU: "Re: [PATCH] drm/stm: support runtime power management"
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Le ven. 7 juin 2019 Ã 13:19, Philippe CORNU <philippe.cornu@xxxxxx> a Ãcrit :
>
> Hi Yannick,
>
> Thank you for your patch
>
> Acked-by: Philippe Cornu <philippe.cornu@xxxxxx>

Applied on drm-misc-next

Thanks,
Benjamin
>
> Philippe :-)
>
> On 6/3/19 10:32 AM, Yannick FertrÃ wrote:
> > This patch enables runtime power management (runtime PM) support for
> > the display controller. pm_runtime_enable() and pm_runtime_disable()
> > are added during ltdc load and unload respectively.
> > pm_runtime_get_sync() and pm_runtime_put_sync() are added for ltdc
> > register access.
> >
> > Signed-off-by: Yannick FertrÃ <yannick.fertre@xxxxxx>
> > ---
> > drivers/gpu/drm/stm/drv.c | 43 +++++++++++++++++++++++------
> > drivers/gpu/drm/stm/ltdc.c | 67 +++++++++++++++++++++++++++++++++++-----------
> > 2 files changed, 86 insertions(+), 24 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
> > index 5834ef5..5659572 100644
> > --- a/drivers/gpu/drm/stm/drv.c
> > +++ b/drivers/gpu/drm/stm/drv.c
> > @@ -12,6 +12,7 @@
> > #include <linux/dma-mapping.h>
> > #include <linux/module.h>
> > #include <linux/of_platform.h>
> > +#include <linux/pm_runtime.h>
> >
> > #include <drm/drm_atomic.h>
> > #include <drm/drm_atomic_helper.h>
> > @@ -135,14 +136,15 @@ static __maybe_unused int drv_suspend(struct device *dev)
> > struct ltdc_device *ldev = ddev->dev_private;
> > struct drm_atomic_state *state;
> >
> > - drm_kms_helper_poll_disable(ddev);
> > + if (WARN_ON(!ldev->suspend_state))
> > + return -ENOENT;
> > +
> > state = drm_atomic_helper_suspend(ddev);
> > - if (IS_ERR(state)) {
> > - drm_kms_helper_poll_enable(ddev);
> > + if (IS_ERR(state))
> > return PTR_ERR(state);
> > - }
> > +
> > ldev->suspend_state = state;
> > - ltdc_suspend(ddev);
> > + pm_runtime_force_suspend(dev);
> >
> > return 0;
> > }
> > @@ -151,16 +153,41 @@ static __maybe_unused int drv_resume(struct device *dev)
> > {
> > struct drm_device *ddev = dev_get_drvdata(dev);
> > struct ltdc_device *ldev = ddev->dev_private;
> > + int ret;
> >
> > - ltdc_resume(ddev);
> > - drm_atomic_helper_resume(ddev, ldev->suspend_state);
> > - drm_kms_helper_poll_enable(ddev);
> > + pm_runtime_force_resume(dev);
> > + ret = drm_atomic_helper_resume(ddev, ldev->suspend_state);
> > + if (ret) {
> > + pm_runtime_force_suspend(dev);
> > + ldev->suspend_state = NULL;
> > + return ret;
> > + }
> >
> > return 0;
> > }
> >
> > +static __maybe_unused int drv_runtime_suspend(struct device *dev)
> > +{
> > + struct drm_device *ddev = dev_get_drvdata(dev);
> > +
> > + DRM_DEBUG_DRIVER("\n");
> > + ltdc_suspend(ddev);
> > +
> > + return 0;
> > +}
> > +
> > +static __maybe_unused int drv_runtime_resume(struct device *dev)
> > +{
> > + struct drm_device *ddev = dev_get_drvdata(dev);
> > +
> > + DRM_DEBUG_DRIVER("\n");
> > + return ltdc_resume(ddev);
> > +}
> > +
> > static const struct dev_pm_ops drv_pm_ops = {
> > SET_SYSTEM_SLEEP_PM_OPS(drv_suspend, drv_resume)
> > + SET_RUNTIME_PM_OPS(drv_runtime_suspend,
> > + drv_runtime_resume, NULL)
> > };
> >
> > static int stm_drm_platform_probe(struct platform_device *pdev)
> > diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> > index ac29890..a40870b 100644
> > --- a/drivers/gpu/drm/stm/ltdc.c
> > +++ b/drivers/gpu/drm/stm/ltdc.c
> > @@ -16,6 +16,7 @@
> > #include <linux/of_address.h>
> > #include <linux/of_graph.h>
> > #include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > #include <linux/reset.h>
> >
> > #include <drm/drm_atomic.h>
> > @@ -444,6 +445,7 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc,
> > struct drm_crtc_state *old_state)
> > {
> > struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> > + struct drm_device *ddev = crtc->dev;
> >
> > DRM_DEBUG_DRIVER("\n");
> >
> > @@ -457,6 +459,8 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc,
> >
> > /* immediately commit disable of layers before switching off LTDC */
> > reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR);
> > +
> > + pm_runtime_put_sync(ddev->dev);
> > }
> >
> > #define CLK_TOLERANCE_HZ 50
> > @@ -505,17 +509,31 @@ static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
> > struct drm_display_mode *adjusted_mode)
> > {
> > struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> > + struct drm_device *ddev = crtc->dev;
> > int rate = mode->clock * 1000;
> > + bool runtime_active;
> > + int ret;
> > +
> > + runtime_active = pm_runtime_active(ddev->dev);
> > +
> > + if (runtime_active)
> > + pm_runtime_put_sync(ddev->dev);
> >
> > - clk_disable(ldev->pixel_clk);
> > if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
> > DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
> > return false;
> > }
> > - clk_enable(ldev->pixel_clk);
> >
> > adjusted_mode->clock = clk_get_rate(ldev->pixel_clk) / 1000;
> >
> > + if (runtime_active) {
> > + ret = pm_runtime_get_sync(ddev->dev);
> > + if (ret) {
> > + DRM_ERROR("Failed to fixup mode, cannot get sync\n");
> > + return false;
> > + }
> > + }
> > +
> > DRM_DEBUG_DRIVER("requested clock %dkHz, adjusted clock %dkHz\n",
> > mode->clock, adjusted_mode->clock);
> >
> > @@ -525,11 +543,21 @@ static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
> > static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
> > {
> > struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> > + struct drm_device *ddev = crtc->dev;
> > struct drm_display_mode *mode = &crtc->state->adjusted_mode;
> > struct videomode vm;
> > u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
> > u32 total_width, total_height;
> > u32 val;
> > + int ret;
> > +
> > + if (!pm_runtime_active(ddev->dev)) {
> > + ret = pm_runtime_get_sync(ddev->dev);
> > + if (ret) {
> > + DRM_ERROR("Failed to set mode, cannot get sync\n");
> > + return;
> > + }
> > + }
> >
> > drm_display_mode_to_videomode(mode, &vm);
> >
> > @@ -590,6 +618,7 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc,
> > struct drm_crtc_state *old_crtc_state)
> > {
> > struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> > + struct drm_device *ddev = crtc->dev;
> > struct drm_pending_vblank_event *event = crtc->state->event;
> >
> > DRM_DEBUG_ATOMIC("\n");
> > @@ -602,12 +631,12 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc,
> > if (event) {
> > crtc->state->event = NULL;
> >
> > - spin_lock_irq(&crtc->dev->event_lock);
> > + spin_lock_irq(&ddev->event_lock);
> > if (drm_crtc_vblank_get(crtc) == 0)
> > drm_crtc_arm_vblank_event(crtc, event);
> > else
> > drm_crtc_send_vblank_event(crtc, event);
> > - spin_unlock_irq(&crtc->dev->event_lock);
> > + spin_unlock_irq(&ddev->event_lock);
> > }
> > }
> >
> > @@ -663,15 +692,19 @@ bool ltdc_crtc_scanoutpos(struct drm_device *ddev, unsigned int pipe,
> > * Computation for the two first cases are identical so we can
> > * simplify the code and only test if line > vactive_end
> > */
> > - line = reg_read(ldev->regs, LTDC_CPSR) & CPSR_CYPOS;
> > - vactive_start = reg_read(ldev->regs, LTDC_BPCR) & BPCR_AVBP;
> > - vactive_end = reg_read(ldev->regs, LTDC_AWCR) & AWCR_AAH;
> > - vtotal = reg_read(ldev->regs, LTDC_TWCR) & TWCR_TOTALH;
> > -
> > - if (line > vactive_end)
> > - *vpos = line - vtotal - vactive_start;
> > - else
> > - *vpos = line - vactive_start;
> > + if (pm_runtime_active(ddev->dev)) {
> > + line = reg_read(ldev->regs, LTDC_CPSR) & CPSR_CYPOS;
> > + vactive_start = reg_read(ldev->regs, LTDC_BPCR) & BPCR_AVBP;
> > + vactive_end = reg_read(ldev->regs, LTDC_AWCR) & AWCR_AAH;
> > + vtotal = reg_read(ldev->regs, LTDC_TWCR) & TWCR_TOTALH;
> > +
> > + if (line > vactive_end)
> > + *vpos = line - vtotal - vactive_start;
> > + else
> > + *vpos = line - vactive_start;
> > + } else {
> > + *vpos = 0;
> > + }
> >
> > *hpos = 0;
> >
> > @@ -1243,8 +1276,11 @@ int ltdc_load(struct drm_device *ddev)
> > /* Allow usage of vblank without having to call drm_irq_install */
> > ddev->irq_enabled = 1;
> >
> > - return 0;
> > + clk_disable_unprepare(ldev->pixel_clk);
> > +
> > + pm_runtime_enable(ddev->dev);
> >
> > + return 0;
> > err:
> > for (i = 0; i < MAX_ENDPOINTS; i++)
> > drm_panel_bridge_remove(bridge[i]);
> > @@ -1256,7 +1292,6 @@ int ltdc_load(struct drm_device *ddev)
> >
> > void ltdc_unload(struct drm_device *ddev)
> > {
> > - struct ltdc_device *ldev = ddev->dev_private;
> > int i;
> >
> > DRM_DEBUG_DRIVER("\n");
> > @@ -1264,7 +1299,7 @@ void ltdc_unload(struct drm_device *ddev)
> > for (i = 0; i < MAX_ENDPOINTS; i++)
> > drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);
> >
> > - clk_disable_unprepare(ldev->pixel_clk);
> > + pm_runtime_disable(ddev->dev);
> > }
> >
> > MODULE_AUTHOR("Philippe Cornu <philippe.cornu@xxxxxx>");
> >
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Next message: Benjamin Gaignard: "Re: [PATCH] drm/stm: ltdc: No message if probe"
Previous message: Jean-Philippe Brucker: "Re: [PATCH v8 26/29] vfio-pci: Register an iommu fault handler"
In reply to: Philippe CORNU: "Re: [PATCH] drm/stm: support runtime power management"
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