Re: [EXT] Re: [PATCH v2 12/15] drm/mxsfb: Improve the axi clock usage
Hi Stefan, On Mi, 2019-08-14 at 13:06 +0200, Stefan Agner wrote: > On 2019-08-14 12:48, Robert Chiras wrote: > > > > Currently, the enable of the axi clock return status is ignored, > > causing > > issues when the enable fails then we try to disable it. Therefore, > > it is > > better to check the return status and disable it only when enable > > succeeded. > Is this actually the case in real world sometimes? Why is it failing? When I noticed that fail, we had some restrictions in SCU firmware, so that the clock cannot be enabled if the power domain was down. Still, at that time I noticed it is redundant to have functions that checks if a clock is NULL or not, since the clk_* functions are already doing this. > > I guess if we do this in one place, we should do it in all places > (e.g. > also in mxsfb_crtc_enable, mxsfb_plane_atomic_update..) I add specific checks only in the vblank functions, because those functions can be called before calling the pipe enable/disable functions which enables the spefic power domain and, at this point, the clock enable/disable calls should not fail. > > -- > Stefan > > > > > Also, remove the helper functions around clk_axi, since we can > > directly > > use the clk API function for enable/disable the clock. Those > > functions > > are already checking for NULL clk and returning 0 if that's the > > case. > > > > > > > Signed-off-by: Robert Chiras > > Acked-by: Leonard Crestez > > --- > > drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 8 > > drivers/gpu/drm/mxsfb/mxsfb_drv.c | 32 +- > > -- > > drivers/gpu/drm/mxsfb/mxsfb_drv.h | 3 --- > > 3 files changed, 17 insertions(+), 26 deletions(-) > > > > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c > > b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c > > index a4ba368..e727f5e 100644 > > --- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c > > +++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c > > @@ -408,7 +408,7 @@ void mxsfb_crtc_enable(struct mxsfb_drm_private > > *mxsfb) > > { > > dma_addr_t paddr; > > > > - mxsfb_enable_axi_clk(mxsfb); > > + clk_prepare_enable(mxsfb->clk_axi); > > writel(0, mxsfb->base + LCDC_CTRL); > > mxsfb_crtc_mode_set_nofb(mxsfb); > > > > @@ -425,7 +425,7 @@ void mxsfb_crtc_enable(struct mxsfb_drm_private > > *mxsfb) > > void mxsfb_crtc_disable(struct mxsfb_drm_private *mxsfb) > > { > > mxsfb_disable_controller(mxsfb); > > - mxsfb_disable_axi_clk(mxsfb); > > + clk_disable_unprepare(mxsfb->clk_axi); > > } > > > > void mxsfb_plane_atomic_update(struct mxsfb_drm_private *mxsfb, > > @@ -451,8 +451,8 @@ void mxsfb_plane_atomic_update(struct > > mxsfb_drm_private *mxsfb, > > > > paddr = mxsfb_get_fb_paddr(mxsfb); > > if (paddr) { > > - mxsfb_enable_axi_clk(mxsfb); > > + clk_prepare_enable(mxsfb->clk_axi); > > writel(paddr, mxsfb->base + mxsfb->devdata- > > >next_buf); > > - mxsfb_disable_axi_clk(mxsfb); > > + clk_disable_unprepare(mxsfb->clk_axi); > > } > > } > > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c > > b/drivers/gpu/drm/mxsfb/mxsfb_drv.c > > index 6dae2bd..694b287 100644 > > --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c > > +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c > > @@ -97,18 +97,6 @@ drm_pipe_to_mxsfb_drm_private(struct > > drm_simple_display_pipe *pipe) > > return container_of(pipe, struct mxsfb_drm_private, pipe); > > } > > > > -void mxsfb_enable_axi_clk(struct mxsfb_drm_private *mxsfb) > > -{ > > - if (mxsfb->clk_axi) > > - clk_prepare_enable(mxsfb->clk_axi); > > -} > > - > > -void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb) > > -{ > > - if (mxsfb->clk_axi) > > - clk_disable_unprepare(mxsfb->clk_axi); > > -} > > - > > /** > > * mxsfb_atomic_helper_check - validate state object > > * @dev: DRM device > > @@ -229,25 +217,31 @@ static void mxsfb_pipe_update(struct > > drm_simple_display_pipe *pipe, > > static int mxsfb_pipe_enable_vblank(struct drm_simple_display_pipe > > *pipe) > > { > > struct mxsfb_drm_private *mxsfb = > > drm_pipe_to_mxsfb_drm_private(pipe); > > + int ret = 0; > > + > > + ret = clk_prepare_enable(mxsfb->clk_axi); > > + if (ret) > > + return ret; > > > > /* Clear and enable VBLANK IRQ */ > > - mxsfb_enable_axi_clk(mxsfb); > > writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + > > REG_CLR); > > writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 > > + REG_SET); > > - mxsfb_disable_axi_clk(mxsfb); > > + clk_disable_unprepare(mxsfb->clk_axi); > > > > - return 0; > > + return ret; > > } > > > > static void mxsfb_pipe_disable_vblank(struct > > drm_simple_display_pipe *pipe) > > { > > struct mxsfb_drm_private *mxsfb = > > drm_pipe_to_mxsfb_drm_private(pipe); > > > > + if (clk_prepare_enable(mxsfb->clk_axi)) > > + return; > > + > > /* Disable and clear VBLANK IRQ */ > > -
Re: [PATCH v2 12/15] drm/mxsfb: Improve the axi clock usage
On 2019-08-14 12:48, Robert Chiras wrote: > Currently, the enable of the axi clock return status is ignored, causing > issues when the enable fails then we try to disable it. Therefore, it is > better to check the return status and disable it only when enable > succeeded. Is this actually the case in real world sometimes? Why is it failing? I guess if we do this in one place, we should do it in all places (e.g. also in mxsfb_crtc_enable, mxsfb_plane_atomic_update..) -- Stefan > Also, remove the helper functions around clk_axi, since we can directly > use the clk API function for enable/disable the clock. Those functions > are already checking for NULL clk and returning 0 if that's the case. > > Signed-off-by: Robert Chiras > Acked-by: Leonard Crestez > --- > drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 8 > drivers/gpu/drm/mxsfb/mxsfb_drv.c | 32 +--- > drivers/gpu/drm/mxsfb/mxsfb_drv.h | 3 --- > 3 files changed, 17 insertions(+), 26 deletions(-) > > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c > b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c > index a4ba368..e727f5e 100644 > --- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c > +++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c > @@ -408,7 +408,7 @@ void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb) > { > dma_addr_t paddr; > > - mxsfb_enable_axi_clk(mxsfb); > + clk_prepare_enable(mxsfb->clk_axi); > writel(0, mxsfb->base + LCDC_CTRL); > mxsfb_crtc_mode_set_nofb(mxsfb); > > @@ -425,7 +425,7 @@ void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb) > void mxsfb_crtc_disable(struct mxsfb_drm_private *mxsfb) > { > mxsfb_disable_controller(mxsfb); > - mxsfb_disable_axi_clk(mxsfb); > + clk_disable_unprepare(mxsfb->clk_axi); > } > > void mxsfb_plane_atomic_update(struct mxsfb_drm_private *mxsfb, > @@ -451,8 +451,8 @@ void mxsfb_plane_atomic_update(struct > mxsfb_drm_private *mxsfb, > > paddr = mxsfb_get_fb_paddr(mxsfb); > if (paddr) { > - mxsfb_enable_axi_clk(mxsfb); > + clk_prepare_enable(mxsfb->clk_axi); > writel(paddr, mxsfb->base + mxsfb->devdata->next_buf); > - mxsfb_disable_axi_clk(mxsfb); > + clk_disable_unprepare(mxsfb->clk_axi); > } > } > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c > b/drivers/gpu/drm/mxsfb/mxsfb_drv.c > index 6dae2bd..694b287 100644 > --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c > +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c > @@ -97,18 +97,6 @@ drm_pipe_to_mxsfb_drm_private(struct > drm_simple_display_pipe *pipe) > return container_of(pipe, struct mxsfb_drm_private, pipe); > } > > -void mxsfb_enable_axi_clk(struct mxsfb_drm_private *mxsfb) > -{ > - if (mxsfb->clk_axi) > - clk_prepare_enable(mxsfb->clk_axi); > -} > - > -void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb) > -{ > - if (mxsfb->clk_axi) > - clk_disable_unprepare(mxsfb->clk_axi); > -} > - > /** > * mxsfb_atomic_helper_check - validate state object > * @dev: DRM device > @@ -229,25 +217,31 @@ static void mxsfb_pipe_update(struct > drm_simple_display_pipe *pipe, > static int mxsfb_pipe_enable_vblank(struct drm_simple_display_pipe *pipe) > { > struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe); > + int ret = 0; > + > + ret = clk_prepare_enable(mxsfb->clk_axi); > + if (ret) > + return ret; > > /* Clear and enable VBLANK IRQ */ > - mxsfb_enable_axi_clk(mxsfb); > writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR); > writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_SET); > - mxsfb_disable_axi_clk(mxsfb); > + clk_disable_unprepare(mxsfb->clk_axi); > > - return 0; > + return ret; > } > > static void mxsfb_pipe_disable_vblank(struct drm_simple_display_pipe *pipe) > { > struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe); > > + if (clk_prepare_enable(mxsfb->clk_axi)) > + return; > + > /* Disable and clear VBLANK IRQ */ > - mxsfb_enable_axi_clk(mxsfb); > writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_CLR); > writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR); > - mxsfb_disable_axi_clk(mxsfb); > + clk_disable_unprepare(mxsfb->clk_axi); > } > > static struct drm_simple_display_pipe_funcs mxsfb_funcs = { > @@ -413,7 +407,7 @@ static irqreturn_t mxsfb_irq_handler(int irq, void *data) > struct mxsfb_drm_private *mxsfb = drm->dev_private; > u32 reg; > > - mxsfb_enable_axi_clk(mxsfb); > + clk_prepare_enable(mxsfb->clk_axi); > > reg = readl(mxsfb->base + LCDC_CTRL1); > > @@ -422,7 +416,7 @@ static irqreturn_t mxsfb_irq_handler(int irq, void *data) > > writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR); > > - mxsfb_disable_axi_clk(mxsfb); > + clk_disable_unprepare(mxsfb->clk_axi); >