From: YT Shen <yt.shen@mediatek.com>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: <dri-devel@lists.freedesktop.org>,
Philipp Zabel <p.zabel@pengutronix.de>,
Mark Rutland <mark.rutland@arm.com>, <devicetree@vger.kernel.org>,
"Russell King" <linux@arm.linux.org.uk>,
<srv_heupstream@mediatek.com>, Pawel Moll <pawel.moll@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
<emil.l.velikov@gmail.com>, <linux-kernel@vger.kernel.org>,
Mao Huang <littlecvr@chromium.org>,
Rob Herring <robh+dt@kernel.org>,
<linux-mediatek@lists.infradead.org>,
Kumar Gala <galak@codeaurora.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
<yingjoe.chen@mediatek.com>, Sascha Hauer <kernel@pengutronix.de>,
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC v2 1/5] drm/mediatek: rename macros, add chip suffix
Date: Wed, 1 Jun 2016 17:09:05 +0800 [thread overview]
Message-ID: <1464772145.10410.27.camel@mtksdaap41> (raw)
In-Reply-To: <20160530104129.GA8388@ulmo.ba.sec>
Hi Thierry,
On Mon, 2016-05-30 at 12:41 +0200, Thierry Reding wrote:
> On Fri, May 20, 2016 at 11:05:32PM +0800, yt.shen@mediatek.com wrote:
> > From: YT Shen <yt.shen@mediatek.com>
> >
> > Add MT8173 suffix for hardware related macros.
> >
> > Signed-off-by: YT Shen <yt.shen@mediatek.com>
> > ---
> > drivers/gpu/drm/mediatek/mtk_drm_ddp.c | 62 ++++++++++++++++----------------
> > 1 file changed, 31 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> > index 17ba935..d6aafd4 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> > @@ -36,21 +36,21 @@
> > #define DISP_REG_MUTEX_MOD(n) (0x2c + 0x20 * (n))
> > #define DISP_REG_MUTEX_SOF(n) (0x30 + 0x20 * (n))
> >
> > -#define MUTEX_MOD_DISP_OVL0 BIT(11)
> > -#define MUTEX_MOD_DISP_OVL1 BIT(12)
> > -#define MUTEX_MOD_DISP_RDMA0 BIT(13)
> > -#define MUTEX_MOD_DISP_RDMA1 BIT(14)
> > -#define MUTEX_MOD_DISP_RDMA2 BIT(15)
> > -#define MUTEX_MOD_DISP_WDMA0 BIT(16)
> > -#define MUTEX_MOD_DISP_WDMA1 BIT(17)
> > -#define MUTEX_MOD_DISP_COLOR0 BIT(18)
> > -#define MUTEX_MOD_DISP_COLOR1 BIT(19)
> > -#define MUTEX_MOD_DISP_AAL BIT(20)
> > -#define MUTEX_MOD_DISP_GAMMA BIT(21)
> > -#define MUTEX_MOD_DISP_UFOE BIT(22)
> > -#define MUTEX_MOD_DISP_PWM0 BIT(23)
> > -#define MUTEX_MOD_DISP_PWM1 BIT(24)
> > -#define MUTEX_MOD_DISP_OD BIT(25)
> > +#define MUTEX_MOD_DISP_OVL0_MT8173 BIT(11)
> > +#define MUTEX_MOD_DISP_OVL1_MT8173 BIT(12)
> > +#define MUTEX_MOD_DISP_RDMA0_MT8173 BIT(13)
> > +#define MUTEX_MOD_DISP_RDMA1_MT8173 BIT(14)
> > +#define MUTEX_MOD_DISP_RDMA2_MT8173 BIT(15)
> > +#define MUTEX_MOD_DISP_WDMA0_MT8173 BIT(16)
> > +#define MUTEX_MOD_DISP_WDMA1_MT8173 BIT(17)
> > +#define MUTEX_MOD_DISP_COLOR0_MT8173 BIT(18)
> > +#define MUTEX_MOD_DISP_COLOR1_MT8173 BIT(19)
> > +#define MUTEX_MOD_DISP_AAL_MT8173 BIT(20)
> > +#define MUTEX_MOD_DISP_GAMMA_MT8173 BIT(21)
> > +#define MUTEX_MOD_DISP_UFOE_MT8173 BIT(22)
> > +#define MUTEX_MOD_DISP_PWM0_MT8173 BIT(23)
> > +#define MUTEX_MOD_DISP_PWM1_MT8173 BIT(24)
> > +#define MUTEX_MOD_DISP_OD_MT8173 BIT(25)
>
> Just a random fly-by comment: this looks like a hardware spinlock, have
> you ever considered implementing this as a hwspinlock driver? See the
> drivers/hwspinlock subdirectory for existing examples.
>
> Thierry
I see the drivers/hwspinlock and Documentation/hwspinlock.txt
Yes, we can implement this like a hardware spinlock. But I have some
questions, the document says:
"Hardware spinlock modules provide hardware assistance for
synchronization and mutual exclusion between heterogeneous processors
and those not operating under a single, shared operating system"
The mutex here is a handshake interface between software and hardware.
The hardware is the display controller, the software is the drm display
driver, and no other consumers need to access this mutex. So I think
that using hwspinlock to implement a bit too complicated, am I right?
I will use iopoll macros to implement this part in the next version.
Thanks.
yt.shen
next prev parent reply other threads:[~2016-06-01 9:09 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-20 15:05 [RFC v2 0/5] MT2701 DRM support yt.shen
2016-05-20 15:05 ` [RFC v2 1/5] drm/mediatek: rename macros, add chip suffix yt.shen
2016-05-27 9:30 ` Emil Velikov
2016-05-30 10:23 ` YT Shen
2016-05-30 10:41 ` Thierry Reding
2016-06-01 9:09 ` YT Shen [this message]
2016-05-20 15:05 ` [RFC v2 2/5] drm/mediatke: add support for Mediatek SoC MT2701 yt.shen
2016-05-23 9:09 ` CK Hu
2016-05-27 7:29 ` YT Shen
2016-05-27 9:35 ` Emil Velikov
2016-05-30 10:24 ` YT Shen
2016-05-20 15:05 ` [RFC v2 3/5] drm/mediatek: add *driver_data for different hardware settings yt.shen
2016-05-23 9:43 ` CK Hu
2016-05-27 7:31 ` YT Shen
2016-05-27 9:24 ` Emil Velikov
2016-05-30 10:26 ` YT Shen
2016-05-30 10:45 ` Thierry Reding
2016-06-01 9:10 ` YT Shen
2016-05-20 15:05 ` [RFC v2 4/5] drm/mediatek: add shadow register support yt.shen
2016-05-20 15:05 ` [RFC v2 5/5] arm: dts: mt2701: Add display subsystem related nodes for MT2701 yt.shen
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