Re: [PATCH v3] PCI: mediatek-gen3: Disable DVFSRC voltage request

From: Jianjun Wang <jianjun.wang@mediatek.com>
To: "Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Ryder Lee" <ryder.lee@mediatek.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>
Cc: <linux-pci@vger.kernel.org>, <linux-mediatek@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<qizhong.cheng@mediatek.com>, <Ryan-JH.Yu@mediatek.com>,
	Tzung-Bi Shih <tzungbi@google.com>
Subject: Re: [PATCH v3] PCI: mediatek-gen3: Disable DVFSRC voltage request
Date: Mon, 29 Nov 2021 10:51:59 +0800	[thread overview]
Message-ID: <253e497abbcff425428ac8b7f30cebce718a63c9.camel@mediatek.com> (raw)
In-Reply-To: <b18f74b8831492c4a75f45fa778c359fd80184d0.camel@mediatek.com>

Hi Maintainers,

Just gentle ping for this patch, is there anything I need to do to get
this patch merged?

Thanks.

On Tue, 2021-11-09 at 14:10 +0800, Jianjun Wang wrote:
> 
> On Fri, 2021-10-15 at 14:36 +0800, Jianjun Wang wrote:
> > When the DVFSRC (dynamic voltage and frequency scaling resource
> > collector)
> > feature is not implemented, the PCIe hardware will assert a voltage
> > request
> > signal when exit from the L1 PM Substates to request a specific
> > Vcore
> > voltage, but cannot receive the voltage ready signal, which will
> > cause
> > the link to fail to exit the L1 PM Substates.
> > 
> > Disable DVFSRC voltage request by default, we need to find a common
> > way to
> > enable it in the future.
> > 
> > Fixes: d3bf75b579b9 ("PCI: mediatek-gen3: Add MediaTek Gen3 driver
> > for MT8192")
> > Signed-off-by: Jianjun Wang <jianjun.wang@mediatek.com>
> > Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
> > Tested-by: Qizhong Cheng <qizhong.cheng@mediatek.com>
> > ---
> >  drivers/pci/controller/pcie-mediatek-gen3.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c
> > b/drivers/pci/controller/pcie-mediatek-gen3.c
> > index f3aeb8d4eaca..79fb12fca6a9 100644
> > --- a/drivers/pci/controller/pcie-mediatek-gen3.c
> > +++ b/drivers/pci/controller/pcie-mediatek-gen3.c
> > @@ -79,6 +79,9 @@
> >  #define PCIE_ICMD_PM_REG		0x198
> >  #define PCIE_TURN_OFF_LINK		BIT(4)
> >  
> > +#define PCIE_MISC_CTRL_REG		0x348
> > +#define PCIE_DISABLE_DVFSRC_VLT_REQ	BIT(1)
> > +
> >  #define PCIE_TRANS_TABLE_BASE_REG	0x800
> >  #define PCIE_ATR_SRC_ADDR_MSB_OFFSET	0x4
> >  #define PCIE_ATR_TRSL_ADDR_LSB_OFFSET	0x8
> > @@ -297,6 +300,11 @@ static int mtk_pcie_startup_port(struct
> > mtk_pcie_port *port)
> >  	val &= ~PCIE_INTX_ENABLE;
> >  	writel_relaxed(val, port->base + PCIE_INT_ENABLE_REG);
> >  
> > +	/* Disable DVFSRC voltage request */
> > +	val = readl_relaxed(port->base + PCIE_MISC_CTRL_REG);
> > +	val |= PCIE_DISABLE_DVFSRC_VLT_REQ;
> > +	writel_relaxed(val, port->base + PCIE_MISC_CTRL_REG);
> > +
> >  	/* Assert all reset signals */
> >  	val = readl_relaxed(port->base + PCIE_RST_CTRL_REG);
> >  	val |= PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB |
> > PCIE_PE_RSTB;
> 
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