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Date: Tue, 6 Jun 2023 13:48:52 +0300
From: Georgi Djakov <djakov@...nel.org>
To: Krishna chaitanya chundru <quic_krichai@...cinc.com>,
manivannan.sadhasivam@...aro.org
Cc: quic_vbadigan@...cinc.com, quic_ramkri@...cinc.com,
Manivannan Sadhasivam <mani@...nel.org>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Krzysztof Wilczyński <kw@...ux.com>,
Rob Herring <robh@...nel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
"open list:PCIE ENDPOINT DRIVER FOR QUALCOMM"
<linux-pci@...r.kernel.org>,
"open list:PCIE ENDPOINT DRIVER FOR QUALCOMM"
<linux-arm-msm@...r.kernel.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] PCI: qcom-ep: Add ICC bandwidth voting support
Hi Krishna,
Thanks for the patch!
On 6.06.23 8:49, Krishna chaitanya chundru wrote:
> Add support to vote for ICC bandwidth based up on the link
> speed and width.
>
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@...cinc.com>
> ---
> drivers/pci/controller/dwc/pcie-qcom-ep.c | 73 +++++++++++++++++++++++++++++++
> 1 file changed, 73 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> index 19b3283..79e7559 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> @@ -17,6 +17,7 @@
> #include <linux/phy/pcie.h>
> #include <linux/phy/phy.h>
> #include <linux/platform_device.h>
> +#include <linux/interconnect.h>
> #include <linux/pm_domain.h>
> #include <linux/regmap.h>
> #include <linux/reset.h>
> @@ -28,6 +29,7 @@
> #define PARF_SYS_CTRL 0x00
> #define PARF_DB_CTRL 0x10
> #define PARF_PM_CTRL 0x20
> +#define PARF_PM_STTS 0x24
> #define PARF_MHI_CLOCK_RESET_CTRL 0x174
> #define PARF_MHI_BASE_ADDR_LOWER 0x178
> #define PARF_MHI_BASE_ADDR_UPPER 0x17c
> @@ -128,6 +130,9 @@
> /* DBI register fields */
> #define DBI_CON_STATUS_POWER_STATE_MASK GENMASK(1, 0)
>
> +#define DBI_LINKCTRLSTATUS 0x80
> +#define DBI_LINKCTRKSTATUS_SHIFT 16
> +
> #define XMLH_LINK_UP 0x400
> #define CORE_RESET_TIME_US_MIN 1000
> #define CORE_RESET_TIME_US_MAX 1005
> @@ -187,6 +192,8 @@ struct qcom_pcie_ep {
> enum qcom_pcie_ep_link_status link_status;
> int global_irq;
> int perst_irq;
> +
> + struct icc_path *icc;
> };
>
> static int qcom_pcie_ep_core_reset(struct qcom_pcie_ep *pcie_ep)
> @@ -253,9 +260,56 @@ static void qcom_pcie_dw_stop_link(struct dw_pcie *pci)
> disable_irq(pcie_ep->perst_irq);
> }
>
> +static void qcom_pcie_icc_update(struct qcom_pcie_ep *pcie_ep)
> +{
> + struct dw_pcie *pci = &pcie_ep->pci;
> + u32 val, bw;
> + int speed, width;
> + int ret;
> +
> + if (!pcie_ep->icc)
> + return;
> +
> + val = dw_pcie_readl_dbi(pci, DBI_LINKCTRLSTATUS);
> + val = val >> DBI_LINKCTRKSTATUS_SHIFT;
> +
> + speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, val);
> + width = FIELD_GET(PCI_EXP_LNKSTA_NLW, val);
> +
> + /*
> + * ICC needs avg bw in KBps.
> + *
> + * For example for 2Gbps the avg BW = 2x1000x1000x1000/8*1000 = 250000
> + */
> + switch (speed) {
> + case 1:
> + bw = 250000; /* avg bw for GEN1 per lane: 2Gbps, peak bw: no vote */
> + break;
> + case 2:
> + bw = 500000; /* avg bw for GEN2 per lane: 4Gbps, peak bw no vote */
> + break;
> + case 3:
> + bw = 1000000; /* avg bw for GEN3 per lane: 8Gbps, peak bw no vote */
> + break;
> + default:
> + WARN_ON_ONCE(1);
> + fallthrough;
> + case 4:
> + bw = 2000000; /* avg bw for GEN4 per lane: 16Gbps, peak bw no vote */
> + break;
> + }
> +
> + ret = icc_set_bw(pcie_ep->icc, width * bw, 0);
Here you should use a non-zero value for peak bandwidth. You can use the average value also as peak.
There are some existing macros like GBps_to_icc(). Please use them.
> + if (ret) {
> + dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n",
> + ret);
> + }
> +}
> +
> static int qcom_pcie_enable_resources(struct qcom_pcie_ep *pcie_ep)
> {
> int ret;
> + struct dw_pcie *pci = &pcie_ep->pci;
>
> ret = clk_bulk_prepare_enable(pcie_ep->num_clks, pcie_ep->clks);
> if (ret)
> @@ -277,6 +331,20 @@ static int qcom_pcie_enable_resources(struct qcom_pcie_ep *pcie_ep)
> if (ret)
> goto err_phy_exit;
>
> + /*
> + * Some Qualcomm platforms require interconnect bandwidth constraints
> + * to be set before enabling interconnect clocks.
> + *
> + * Set an initial average bandwidth corresponding to single-lane Gen 1
> + * for the pcie to mem path.
> + */
> + ret = icc_set_bw(pcie_ep->icc, 250000, 0); /* avg bw: 2Gbps, peak bw: no vote */
Ditto.
> + if (ret) {
> + dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n",
> + ret);
> + goto err_phy_exit;
> + }
> +
> return 0;
>
> err_phy_exit:
> @@ -550,6 +618,10 @@ static int qcom_pcie_ep_get_resources(struct platform_device *pdev,
> if (IS_ERR(pcie_ep->phy))
> ret = PTR_ERR(pcie_ep->phy);
>
> + pcie_ep->icc = devm_of_icc_get(dev, "pci");
Is this "pci" path documented in the bindings?
Thanks,
Georgi
> + if (IS_ERR(pcie_ep->icc))
> + ret = PTR_ERR(pcie_ep->icc);
> +
> return ret;
> }
>
> @@ -572,6 +644,7 @@ static irqreturn_t qcom_pcie_ep_global_irq_thread(int irq, void *data)
> } else if (FIELD_GET(PARF_INT_ALL_BME, status)) {
> dev_dbg(dev, "Received BME event. Link is enabled!\n");
> pcie_ep->link_status = QCOM_PCIE_EP_LINK_ENABLED;
> + qcom_pcie_icc_update(pcie_ep);
> } else if (FIELD_GET(PARF_INT_ALL_PM_TURNOFF, status)) {
> dev_dbg(dev, "Received PM Turn-off event! Entering L23\n");
> val = readl_relaxed(pcie_ep->parf + PARF_PM_CTRL);
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