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Message-ID: <Z5JrXsDDM2IManp+@lizhi-Precision-Tower-5810>
Date: Thu, 23 Jan 2025 11:16:30 -0500
From: Frank Li <Frank.li@....com>
To: Hans Zhang <18255117159@....com>
Cc: jingoohan1@...il.com, manivannan.sadhasivam@...aro.org,
lpieralisi@...nel.org, kw@...ux.com, robh@...nel.org,
bhelgaas@...gle.com, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, rockswang7@...il.com
Subject: Re: [PATCH] PCI: dwc: Add the sysfs property to provide the LTSSM
status of the PCIe link
On Thu, Jan 23, 2025 at 03:13:26PM +0800, Hans Zhang wrote:
> Add the sysfs property to provide a view of the current link's LTSSM
> status from the root port device.
>
> /sys/bus/pci/devices/<dev>/ltssm_status
>
Thank, I like this.
> Signed-off-by: Hans Zhang <18255117159@....com>
> ---
> .../pci/controller/dwc/pcie-designware-host.c | 86 +++++++++++++++++++
> drivers/pci/controller/dwc/pcie-designware.h | 32 +++++++
> drivers/pci/pci-sysfs.c | 3 +
> drivers/pci/pci.h | 4 +
> 4 files changed, 125 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index d2291c3ceb8b..8ec0e35cca8f 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -418,6 +418,92 @@ static void dw_pcie_host_request_msg_tlp_res(struct dw_pcie_rp *pp)
> }
> }
>
> +static char *dw_ltssm_sts_string(enum dw_pcie_ltssm ltssm)
> +{
> + char *str;
> +
> + switch (ltssm) {
> +#define DW_PCIE_LTSSM_NAME(n) case n: str = #n; break
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_DETECT_QUIET);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_DETECT_ACT);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_POLL_ACTIVE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_POLL_COMPLIANCE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_POLL_CONFIG);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_PRE_DETECT_QUIET);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_DETECT_WAIT);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_CFG_LINKWD_START);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_CFG_LINKWD_ACEPT);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_CFG_LANENUM_WAI);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_CFG_LANENUM_ACEPT);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_CFG_COMPLETE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_CFG_IDLE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_RCVRY_LOCK);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_RCVRY_SPEED);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_RCVRY_RCVRCFG);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_RCVRY_IDLE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_L0);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_L0S);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_L123_SEND_EIDLE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_L1_IDLE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_L2_IDLE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_L2_WAKE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_DISABLED_ENTRY);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_DISABLED_IDLE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_DISABLED);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_LPBK_ENTRY);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_LPBK_ACTIVE);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_LPBK_EXIT);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_LPBK_EXIT_TIMEOUT);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_HOT_RESET_ENTRY);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_HOT_RESET);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_RCVRY_EQ0);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_RCVRY_EQ1);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_RCVRY_EQ2);
> + DW_PCIE_LTSSM_NAME(DW_PCIE_LTSSM_RCVRY_EQ3);
> + default:
> + str = "DW_PCIE_LTSSM_UNKNOWN";
> + break;
I prefer
const char * str[] =
{
"detect_quitet",
"detect_act",
...
}
return str[ltssm];
Or
#define DW_PCIE_LTSSM_NAME(n) case n: return #n;
...
default:
return "DW_PCIE_LTSSM_UNKNOWN";
> + }
> +
> + return str;
> +}
> +
> +static ssize_t ltssm_status_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct pci_dev *pdev = to_pci_dev(dev);
> + struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus);
> + struct dw_pcie_rp *pp = bridge->sysdata;
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +
> + return sysfs_emit(buf, "%s\n",
> + dw_ltssm_sts_string(dw_pcie_get_ltssm(pci)));
Suggest dump raw value also
val = dw_pcie_get_ltssm(pci);
return sysfs_emit(buf, "%s (0x%02x)\n",
dw_ltssm_sts_string(val), val);
Frank
> +}
> +static DEVICE_ATTR_RO(ltssm_status);
> +
> +static struct attribute *ltssm_status_attrs[] __ro_after_init = {
> + &dev_attr_ltssm_status.attr, NULL
> +};
> +
> +static umode_t ltssm_status_attrs_are_visible(struct kobject *kobj,
> + struct attribute *a, int n)
> +{
> + struct device *dev = kobj_to_dev(kobj);
> + struct pci_dev *pdev = to_pci_dev(dev);
> +
> + if ((a == &dev_attr_ltssm_status.attr) &&
> + ((pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT) &&
> + (pci_pcie_type(pdev) != PCI_EXP_TYPE_RC_EC)))
> + return 0;
> +
> + return a->mode;
> +}
> +
> +const struct attribute_group dw_ltssm_status_attr_group = {
> + .attrs = ltssm_status_attrs,
> + .is_visible = ltssm_status_attrs_are_visible,
> +};
> +
> int dw_pcie_host_init(struct dw_pcie_rp *pp)
> {
> struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 347ab74ac35a..fb7e3c14e523 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -330,8 +330,40 @@ enum dw_pcie_ltssm {
> /* Need to align with PCIE_PORT_DEBUG0 bits 0:5 */
> DW_PCIE_LTSSM_DETECT_QUIET = 0x0,
> DW_PCIE_LTSSM_DETECT_ACT = 0x1,
> + DW_PCIE_LTSSM_POLL_ACTIVE = 0x2,
> + DW_PCIE_LTSSM_POLL_COMPLIANCE = 0x3,
> + DW_PCIE_LTSSM_POLL_CONFIG = 0x4,
> + DW_PCIE_LTSSM_PRE_DETECT_QUIET = 0x5,
> + DW_PCIE_LTSSM_DETECT_WAIT = 0x6,
> + DW_PCIE_LTSSM_CFG_LINKWD_START = 0x7,
> + DW_PCIE_LTSSM_CFG_LINKWD_ACEPT = 0x8,
> + DW_PCIE_LTSSM_CFG_LANENUM_WAI = 0x9,
> + DW_PCIE_LTSSM_CFG_LANENUM_ACEPT = 0xa,
> + DW_PCIE_LTSSM_CFG_COMPLETE = 0xb,
> + DW_PCIE_LTSSM_CFG_IDLE = 0xc,
> + DW_PCIE_LTSSM_RCVRY_LOCK = 0xd,
> + DW_PCIE_LTSSM_RCVRY_SPEED = 0xe,
> + DW_PCIE_LTSSM_RCVRY_RCVRCFG = 0xf,
> + DW_PCIE_LTSSM_RCVRY_IDLE = 0x10,
> DW_PCIE_LTSSM_L0 = 0x11,
> + DW_PCIE_LTSSM_L0S = 0x12,
> + DW_PCIE_LTSSM_L123_SEND_EIDLE = 0x13,
> + DW_PCIE_LTSSM_L1_IDLE = 0x14,
> DW_PCIE_LTSSM_L2_IDLE = 0x15,
> + DW_PCIE_LTSSM_L2_WAKE = 0x16,
> + DW_PCIE_LTSSM_DISABLED_ENTRY = 0x17,
> + DW_PCIE_LTSSM_DISABLED_IDLE = 0x18,
> + DW_PCIE_LTSSM_DISABLED = 0x19,
> + DW_PCIE_LTSSM_LPBK_ENTRY = 0x1a,
> + DW_PCIE_LTSSM_LPBK_ACTIVE = 0x1b,
> + DW_PCIE_LTSSM_LPBK_EXIT = 0x1c,
> + DW_PCIE_LTSSM_LPBK_EXIT_TIMEOUT = 0x1d,
> + DW_PCIE_LTSSM_HOT_RESET_ENTRY = 0x1e,
> + DW_PCIE_LTSSM_HOT_RESET = 0x1f,
> + DW_PCIE_LTSSM_RCVRY_EQ0 = 0x20,
> + DW_PCIE_LTSSM_RCVRY_EQ1 = 0x21,
> + DW_PCIE_LTSSM_RCVRY_EQ2 = 0x22,
> + DW_PCIE_LTSSM_RCVRY_EQ3 = 0x23,
>
> DW_PCIE_LTSSM_UNKNOWN = 0xFFFFFFFF,
> };
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 7679d75d71e5..c23d188323f4 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -1696,6 +1696,9 @@ const struct attribute_group *pci_dev_attr_groups[] = {
> #endif
> #ifdef CONFIG_PCIEASPM
> &aspm_ctrl_attr_group,
> +#endif
> +#ifdef CONFIG_PCIE_DW_HOST
> + &dw_ltssm_status_attr_group,
> #endif
> NULL,
> };
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 2e40fc63ba31..3775841b5714 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -960,6 +960,10 @@ static inline pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
> extern const struct attribute_group aspm_ctrl_attr_group;
> #endif
>
> +#ifdef CONFIG_PCIE_DW_HOST
> +extern const struct attribute_group dw_ltssm_status_attr_group;
> +#endif
> +
> extern const struct attribute_group pci_dev_reset_method_attr_group;
>
> #ifdef CONFIG_X86_INTEL_MID
>
> base-commit: 7004a2e46d1693848370809aa3d9c340a209edbb
> --
> 2.25.1
>
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