Capitalize subject to match the rest of the series.
"Add support to handle .." is redundant; "Add support for ..." would
be equivalent and shorter.
But this patch actually doesn't add anything at all by itself, since
it checks pci->phy_zrxdc_compliant but never sets it.
On Thu, Jan 07, 2021 at 08:58:40PM +0530, Shradha Todi wrote:
> From: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
>
> Many platforms use DesignWare controller but the PHY can be different in
> different platforms. If the PHY is compliant is to ZRX-DC specification it
> helps in low power consumption during power states.
s/is to/to/
Even with that, this sentence doesn't quite parse correctly. Do you
mean something like this?
If the PHY is compliant to the ZRX-DC specification, it reduces
power consumption in low power Link states.
(I assume this is related to Link power states (L0, L1, etc), not
device power states (D0, D3hot, etc)).
> If current data rate is 8.0 GT/s or higher and PHY is not compliant to
> ZRX-DC specification, then after every 100ms link should transition to
> recovery state during the low power states.
Not sure this makes sense. If the Link is in a low power state for 10
seconds, it must transition to the Recovery state every 100ms during
that 10 seconds, i.e., 100 times?
> DesignWare controller provides GEN3_ZRXDC_NONCOMPL field in
> GEN3_RELATED_OFF to specify about ZRX-DC compliant PHY.
>
> Platforms with ZRX-DC compliant PHY can set phy_zrxdc_compliant variable to
> specify this property to the controller.
If this is a DesignWare-generic register and the "phy-zrxdc-compliant"
property can be used by any DesignWare-based driver, why isn't the
code to look for it in the DesignWare-generic part?
Is there a link to the ZRX-DC specification you can mention somewhere
in this series?
> Signed-off-by: Anvesh Salveru <anvesh.salveru@xxxxxxxxx>
> Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
> Signed-off-by: Shradha Todi <shradha.t@xxxxxxxxxxx>
> Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
> Cc: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Cc: Rob Herring <robh@xxxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> ---
> drivers/pci/controller/dwc/pcie-designware.c | 6 ++++++
> drivers/pci/controller/dwc/pcie-designware.h | 4 ++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index 645fa18..74590c7 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -722,4 +722,10 @@ 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->phy_zrxdc_compliant) {
> + val = dw_pcie_readl_dbi(pci, PCIE_PORT_GEN3_RELATED);
> + val &= ~PORT_LOGIC_GEN3_ZRXDC_NONCOMPL;
> + 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 0207840..8b905a2 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -74,6 +74,9 @@
> #define PCIE_MSI_INTR0_MASK 0x82C
> #define PCIE_MSI_INTR0_STATUS 0x830
>
> +#define PCIE_PORT_GEN3_RELATED 0x890
> +#define PORT_LOGIC_GEN3_ZRXDC_NONCOMPL BIT(0)
> +
> #define PCIE_PORT_MULTI_LANE_CTRL 0x8C0
> #define PORT_MLTI_UPCFG_SUPPORT BIT(7)
>
> @@ -273,6 +276,7 @@ struct dw_pcie {
> u8 n_fts[2];
> bool iatu_unroll_enabled: 1;
> bool io_cfg_atu_shared: 1;
> + bool phy_zrxdc_compliant;
I raise my eyebrows a little at "bool xx : 1". I think it's probably
*correct*, but "unsigned int xx : 1" is the overwhelming favorite and
I doubt bool gives any advantage.
$ git grep -E "int\s+\S+\s*:\s*1" | egrep "^\S*\.[ch]" | wc -l
3129
$ git grep -E "bool\s+\S+\s*:\s*1" | egrep "^\S*\.[ch]" | wc -l
637
pcie-designware.h is the only user in drivers/pci. But you're
following the existing style in the file, which is good.
> };
>
> #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp)
> --
> 2.7.4
>
