diff mbox series

[v12,2/5] media: renesas: vsp1: Add support to deassert/assert reset line

Message ID 20220722164907.16587-3-biju.das.jz@bp.renesas.com (mailing list archive)
State Superseded
Delegated to: Kieran Bingham
Headers show
Series Add support for RZ/G2L VSPD | expand

Commit Message

Biju Das July 22, 2022, 4:49 p.m. UTC 
As the resets DT property is mandatory, and is present in all .dtsi
in mainline, add support to perform deassert/assert using reference
counted reset handle.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v11->v12:
 * Replaced read_poll_timeout_atomic-> udelay(1) as testing on RZ/G1N
   shows this delay is sufficient to avoid lock-up.
 * Removed Rb tags.
v10->v11:
 * To avoid lock-up on R-Car Gen2, added poll for reset status after deassert.
v9->v10:
 * Moved {deassert,assert} calls to vsp1_pm_runtime_{resume,suspend}
v8->v9:
 * No change
v7->v8:
 * No Change
v6->v7:
 * No change
v5->v6:
 * Rebased to media_staging and updated commit header
 * Added Rb tag from Laurent
 * Added forward declaration for struct reset_control
 * Updated vsp1_device_get() with changes suggested by Laurent
 * Updated error message for reset_control_get form ctrl->control.
v4->v5:
 * Added Rb tag from Geert
v3->v4:
 * Restored error check for pm_runtime_resume_and_get and calls
   assert() in case of failure.
v2->v3:
 * Added Rb tag from Philipp
 * If reset_control_deassert() failed, return ret directly. 
v1->v2:
 * Used reference counted reset handle to perform deassert/assert
RFC->v1:
 * Added reset support as separate patch
 * Moved rstc just after the bus_master field in struct vsp1_device
RFC:
 * https://patchwork.kernel.org/project/linux-renesas-soc/patch/20220112174612.10773-21-biju.das.jz@bp.renesas.com/
---
 drivers/media/platform/renesas/vsp1/vsp1.h    |  2 ++
 .../media/platform/renesas/vsp1/vsp1_drv.c    | 29 +++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

Comments

Geert Uytterhoeven Aug. 18, 2022, 8:50 a.m. UTC | #1 
Hi Biju,

On Fri, Jul 22, 2022 at 6:49 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> As the resets DT property is mandatory, and is present in all .dtsi
> in mainline, add support to perform deassert/assert using reference
> counted reset handle.
>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> v11->v12:
>  * Replaced read_poll_timeout_atomic-> udelay(1) as testing on RZ/G1N
>    shows this delay is sufficient to avoid lock-up.
>  * Removed Rb tags.

Thanks for the update!

> --- a/drivers/media/platform/renesas/vsp1/vsp1_drv.c
> +++ b/drivers/media/platform/renesas/vsp1/vsp1_drv.c
> @@ -11,11 +11,13 @@
>  #include <linux/delay.h>
>  #include <linux/device.h>
>  #include <linux/interrupt.h>
> +#include <linux/iopoll.h>

This is no longer needed.

>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
>  #include <linux/videodev2.h>
>
>  #include <media/rcar-fcp.h>

The rest LGTM, so with the above fixed:

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Biju Das Aug. 24, 2022, 8:49 a.m. UTC | #2 
Hi Geert,

Thanks for the feedback.

> Subject: Re: [PATCH v12 2/5] media: renesas: vsp1: Add support to
> deassert/assert reset line
> 
> Hi Biju,
> 
> On Fri, Jul 22, 2022 at 6:49 PM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> > As the resets DT property is mandatory, and is present in all .dtsi in
> > mainline, add support to perform deassert/assert using reference
> > counted reset handle.
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > ---
> > v11->v12:
> >  * Replaced read_poll_timeout_atomic-> udelay(1) as testing on RZ/G1N
> >    shows this delay is sufficient to avoid lock-up.
> >  * Removed Rb tags.
> 
> Thanks for the update!
> 
> > --- a/drivers/media/platform/renesas/vsp1/vsp1_drv.c
> > +++ b/drivers/media/platform/renesas/vsp1/vsp1_drv.c
> > @@ -11,11 +11,13 @@
> >  #include <linux/delay.h>
> >  #include <linux/device.h>
> >  #include <linux/interrupt.h>
> > +#include <linux/iopoll.h>
> 
> This is no longer needed.

Oops, fix it in next version.

Cheers,
Biju

> 
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_device.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/pm_runtime.h>
> > +#include <linux/reset.h>
> >  #include <linux/videodev2.h>
> >
> >  #include <media/rcar-fcp.h>
> 
> The rest LGTM, so with the above fixed:
> 
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-
> m68k.org
> 
> In personal conversations with technical people, I call myself a hacker.
> But when I'm talking to journalists I just say "programmer" or something
> like that.
>                                 -- Linus Torvalds
diff mbox series

Patch

diff --git a/drivers/media/platform/renesas/vsp1/vsp1.h b/drivers/media/platform/renesas/vsp1/vsp1.h
index 37cf33c7e6ca..baf898d577ec 100644
--- a/drivers/media/platform/renesas/vsp1/vsp1.h
+++ b/drivers/media/platform/renesas/vsp1/vsp1.h
@@ -22,6 +22,7 @@ 
 struct clk;
 struct device;
 struct rcar_fcp_device;
+struct reset_control;
 
 struct vsp1_drm;
 struct vsp1_entity;
@@ -79,6 +80,7 @@  struct vsp1_device {
 	void __iomem *mmio;
 	struct rcar_fcp_device *fcp;
 	struct device *bus_master;
+	struct reset_control *rstc;
 
 	struct vsp1_brx *brs;
 	struct vsp1_brx *bru;
diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drv.c b/drivers/media/platform/renesas/vsp1/vsp1_drv.c
index 1f73c48eb738..89cb8080e13e 100644
--- a/drivers/media/platform/renesas/vsp1/vsp1_drv.c
+++ b/drivers/media/platform/renesas/vsp1/vsp1_drv.c
@@ -11,11 +11,13 @@ 
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/interrupt.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/videodev2.h>
 
 #include <media/rcar-fcp.h>
@@ -622,6 +624,7 @@  static int __maybe_unused vsp1_pm_runtime_suspend(struct device *dev)
 	struct vsp1_device *vsp1 = dev_get_drvdata(dev);
 
 	rcar_fcp_disable(vsp1->fcp);
+	reset_control_assert(vsp1->rstc);
 
 	return 0;
 }
@@ -631,13 +634,30 @@  static int __maybe_unused vsp1_pm_runtime_resume(struct device *dev)
 	struct vsp1_device *vsp1 = dev_get_drvdata(dev);
 	int ret;
 
+	ret = reset_control_deassert(vsp1->rstc);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * On R-Car Gen2, vsp1 register access after deassert can cause
+	 * lock-up. It is a special case and needs some delay to avoid
+	 * this lock-up.
+	 */
+	udelay(1);
+
 	if (vsp1->info) {
 		ret = vsp1_device_init(vsp1);
 		if (ret < 0)
-			return ret;
+			goto done;
 	}
 
-	return rcar_fcp_enable(vsp1->fcp);
+	ret = rcar_fcp_enable(vsp1->fcp);
+
+done:
+	if (ret < 0)
+		reset_control_assert(vsp1->rstc);
+
+	return ret;
 }
 
 static const struct dev_pm_ops vsp1_pm_ops = {
@@ -825,6 +845,11 @@  static int vsp1_probe(struct platform_device *pdev)
 	if (irq < 0)
 		return irq;
 
+	vsp1->rstc = devm_reset_control_get_shared(&pdev->dev, NULL);
+	if (IS_ERR(vsp1->rstc))
+		return dev_err_probe(&pdev->dev, PTR_ERR(vsp1->rstc),
+				     "failed to get reset control\n");
+
 	/* FCP (optional). */
 	fcp_node = of_parse_phandle(pdev->dev.of_node, "renesas,fcp", 0);
 	if (fcp_node) {