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Message-ID: <93063313-7462-1b7a-4116-0f613c5470b2@quicinc.com>
Date: Wed, 7 Jun 2023 21:52:21 +0530
From: Krishna Chaitanya Chundru <quic_krichai@...cinc.com>
To: Manivannan Sadhasivam <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
On 6/6/2023 4:54 PM, Manivannan Sadhasivam wrote:
> On Tue, Jun 06, 2023 at 11:19:29AM +0530, Krishna chaitanya chundru wrote:
>> Add support to vote for ICC bandwidth based up on the link
> based on
done
>
>> speed and width.
>>
> Looks like the code got inspiration from pcie-qcom driver. So it should be
> mentioned in the commit message.
done
>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@...cinc.com>
> Devicetree bindings update should precede this patch.
done
>> ---
>> 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>
> Includes are sorted alphabetically
>
>> #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
> Use GENMASK macro
>
>> +
>> #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;
> Place this under debugfs entry.
done
>> };
>>
>> 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)
> qcom_pcie_ep_icc_update
done
>> +{
>> + struct dw_pcie *pci = &pcie_ep->pci;
>> + u32 val, bw;
>> + int speed, width;
>> + int ret;
>> +
> Follow reverse Xmas tree order for local variables.
>
>> + if (!pcie_ep->icc)
>> + return;
>> +
>> + val = dw_pcie_readl_dbi(pci, DBI_LINKCTRLSTATUS);
>> + val = val >> DBI_LINKCTRKSTATUS_SHIFT;
>> +
> Use FIELD_GET macro combined with GENMASK
I didn't get this logic you are suggesting can you please elaborate
>> + speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, val);
>> + width = FIELD_GET(PCI_EXP_LNKSTA_NLW, val);
>> +
>> + /*
>> + * ICC needs avg bw in KBps.
> s/avg bw/BW
> ...everywhere
done
>> + *
>> + * 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 */
> To align with pcie-qcom driver, specify the value in MBps. Also, use the
> MBps_to_icc() macro.
done
>> + 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);
> AFAIU, avg bandwidth should be less than peak bandwidth. So use the vote for
> peak bandwidth, leaving 0 as avg. Also, the comment above should be adjusted
> accordingly.
done
>> + 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 */
> Same as above
done
>> + 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");
> This should specify the icc path like pcie-mem as specified in pcie-qcom driver.
> This helps in adding other icc paths if required in the future.
>
> - Mani
done
Thanks,
Krishna chaitanya.
>> + 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);
>> --
>> 2.7.4
>>
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