linux-kernel - Re: [PATCH v3] PCI: qcom: Allow L1 and its sub states

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Message-ID: <20220729171825.GA465668@bhelgaas>
Date:   Fri, 29 Jul 2022 12:18:25 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Krishna chaitanya chundru <quic_krichai@...cinc.com>
Cc:     linux-pci@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, mka@...omium.org,
        quic_vbadigan@...cinc.com, quic_hemantk@...cinc.com,
        quic_nitegupt@...cinc.com, quic_skananth@...cinc.com,
        quic_ramkri@...cinc.com, manivannan.sadhasivam@...aro.org,
        swboyd@...omium.org, dmitry.baryshkov@...aro.org,
        Stanimir Varbanov <svarbanov@...sol.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH v3] PCI: qcom: Allow L1 and its sub states

On Fri, Jul 15, 2022 at 05:29:25PM +0530, Krishna chaitanya chundru wrote:
> Allow L1 and its sub-states in the qcom pcie driver.
> By default this is disabled in the qcom specific hardware.
> So enabling it explicitly only for controllers belonging to
> 2_7_0.
> 
> This patch will not affect any link capability registers, this
> will allow the link transitions to L1 and its sub states only
> if they are already supported.
> 
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@...cinc.com>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>

Applied to pci/ctrl/qcom for v5.20, thanks!

> ----
> 
> Changes since v1 & v2:
> 	- Update in the commit text only.
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index a7202f0..5ef444f 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -41,6 +41,9 @@
>  #define L23_CLK_RMV_DIS				BIT(2)
>  #define L1_CLK_RMV_DIS				BIT(1)
>  
> +#define PCIE20_PARF_PM_CTRL			0x20
> +#define REQ_NOT_ENTR_L1				BIT(5)
> +
>  #define PCIE20_PARF_PHY_CTRL			0x40
>  #define PHY_CTRL_PHY_TX0_TERM_OFFSET_MASK	GENMASK(20, 16)
>  #define PHY_CTRL_PHY_TX0_TERM_OFFSET(x)		((x) << 16)
> @@ -1261,6 +1264,11 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
>  	val |= BIT(4);
>  	writel(val, pcie->parf + PCIE20_PARF_MHI_CLOCK_RESET_CTRL);
>  
> +	/* Enable L1 and L1ss */
> +	val = readl(pcie->parf + PCIE20_PARF_PM_CTRL);
> +	val &= ~REQ_NOT_ENTR_L1;
> +	writel(val, pcie->parf + PCIE20_PARF_PM_CTRL);
> +
>  	if (IS_ENABLED(CONFIG_PCI_MSI)) {
>  		val = readl(pcie->parf + PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT);
>  		val |= BIT(31);
> -- 
> 2.7.4
>