RE: [PATCH v2] PCI: dwc: Add support to add GEN3 related equalization quirks

From: Pankaj Dubey
Date: Mon Oct 14 2019 - 22:58:33 EST




> -----Original Message-----
> From: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Sent: Monday, October 14, 2019 8:44 PM
> To: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> bhelgaas@xxxxxxxxxx; andrew.murray@xxxxxxx;
> gustavo.pimentel@xxxxxxxxxxxx; jingoohan1@xxxxxxxxx; vidyas@xxxxxxxxxx;
> Anvesh Salveru <anvesh.s@xxxxxxxxxxx>
> Subject: Re: [PATCH v2] PCI: dwc: Add support to add GEN3 related
equalization
> quirks
>
> On Mon, Oct 14, 2019 at 12:48:29PM +0530, Pankaj Dubey wrote:
> > From: Anvesh Salveru <anvesh.s@xxxxxxxxxxx>
> >
> > In some platforms, PCIe PHY may have issues which will prevent linkup
> > to happen in GEN3 or higher speed. In case equalization fails, link
> > will fallback to GEN1.
> >
> > DesignWare controller gives flexibility to disable GEN3 equalization
> > completely or only phase 2 and 3 of equalization.
> >
> > This patch enables the DesignWare driver to disable the PCIe GEN3
> > equalization by enabling one of the following quirks:
> > - DWC_EQUALIZATION_DISABLE: To disable GEN3 equalization all phases
> > - DWC_EQ_PHASE_2_3_DISABLE: To disable GEN3 equalization phase 2 & 3
> >
> > Platform drivers can set these quirks via "quirk" variable of "dw_pcie"
> > struct.
> >
> > Signed-off-by: Anvesh Salveru <anvesh.s@xxxxxxxxxxx>
> > Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
> > Acked-by: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
> > Reviewed-by: Andrew Murray <andrew.murray@xxxxxxx>
> > Reviewed-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> > ---
> > Changes w.r.t v1:
> > - Rebased on latest linus/master
> > - Added Reviewed-by and Acked-by
> >
> > drivers/pci/controller/dwc/pcie-designware.c | 12 ++++++++++++
> > drivers/pci/controller/dwc/pcie-designware.h | 9 +++++++++
> > 2 files changed, 21 insertions(+)
>
> So this is v3 not v2, right ?
>

Yes, you are right. I missed this.
This can be discarded, I will resend the patch with v3 tag.

> Here is v2:
>
> https://protect2.fireeye.com/url?k=47b7cdf58f33e5e1.47b646ba-
> 8ad463719e64eba8&u=https://patchwork.ozlabs.org/patch/1161958/
>
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.c
> > b/drivers/pci/controller/dwc/pcie-designware.c
> > index 820488d..e247d6d 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware.c
> > @@ -556,4 +556,16 @@ void dw_pcie_setup(struct dw_pcie *pci)
> > PCIE_PL_CHK_REG_CHK_REG_START;
> > dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS,
> val);
> > }
> > +
> > + if (pci->quirk & DWC_EQUALIZATION_DISABLE) {
> > + val = dw_pcie_readl_dbi(pci, PCIE_PORT_GEN3_RELATED);
> > + val |= PORT_LOGIC_GEN3_EQ_DISABLE;
> > + dw_pcie_writel_dbi(pci, PCIE_PORT_GEN3_RELATED, val);
> > + }
> > +
> > + if (pci->quirk & DWC_EQ_PHASE_2_3_DISABLE) {
> > + val = dw_pcie_readl_dbi(pci, PCIE_PORT_GEN3_RELATED);
> > + val |= PORT_LOGIC_GEN3_EQ_PHASE_2_3_DISABLE;
> > + dw_pcie_writel_dbi(pci, PCIE_PORT_GEN3_RELATED, val);
> > + }
> > }
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.h
> > b/drivers/pci/controller/dwc/pcie-designware.h
> > index 5a18e94..7d3fe6f 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > @@ -29,6 +29,10 @@
> > #define LINK_WAIT_MAX_IATU_RETRIES 5
> > #define LINK_WAIT_IATU 9
> >
> > +/* Parameters for GEN3 related quirks */
> > +#define DWC_EQUALIZATION_DISABLE BIT(1)
> > +#define DWC_EQ_PHASE_2_3_DISABLE BIT(2)
> > +
> > /* Synopsys-specific PCIe configuration registers */
> > #define PCIE_PORT_LINK_CONTROL 0x710
> > #define PORT_LINK_MODE_MASK GENMASK(21, 16)
> > @@ -60,6 +64,10 @@
> > #define PCIE_MSI_INTR0_MASK 0x82C
> > #define PCIE_MSI_INTR0_STATUS 0x830
> >
> > +#define PCIE_PORT_GEN3_RELATED 0x890
> > +#define PORT_LOGIC_GEN3_EQ_PHASE_2_3_DISABLE BIT(9)
> > +#define PORT_LOGIC_GEN3_EQ_DISABLE BIT(16)
> > +
> > #define PCIE_ATU_VIEWPORT 0x900
> > #define PCIE_ATU_REGION_INBOUND BIT(31)
> > #define PCIE_ATU_REGION_OUTBOUND 0
> > @@ -253,6 +261,7 @@ struct dw_pcie {
> > struct dw_pcie_ep ep;
> > const struct dw_pcie_ops *ops;
> > unsigned int version;
> > + unsigned int quirk;
> > };
> >
> > #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie,
> > pp)
> > --
> > 2.7.4
> >