From: Alexandru Gagniuc <mr.nuke.me@gmail.com>
To: bhelgaas@google.com
Cc: austin_bolen@dell.com, alex_gagniuc@dellteam.com,
keith.busch@intel.com, Shyam_Iyer@Dell.com, lukas@wunner.de,
okaya@kernel.org, linux-pci@vger.kernel.org,
Alexandru Gagniuc <mr.nuke.me@gmail.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Oza Pawandeep <poza@codeaurora.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH RFC v2 1/4] PCI: hotplug: Add support for disabling in-band presence
Date: Tue, 19 Feb 2019 19:20:27 -0600 [thread overview]
Message-ID: <20190220012031.10741-2-mr.nuke.me@gmail.com> (raw)
In-Reply-To: <20190220012031.10741-1-mr.nuke.me@gmail.com>
The presence detect state (PDS) is normally a logical or of in-band
and out-of-band presence. In PCIe 4.0, there is the option to disable
in-band presence so that the PDS bit always reflects the state of the
out-of-band presence.
The recommendation of the PCIe spec is to disable in-band presence
whenever supported.
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
---
drivers/pci/hotplug/pciehp.h | 1 +
drivers/pci/hotplug/pciehp_hpc.c | 12 +++++++++++-
include/linux/pci.h | 1 +
include/uapi/linux/pci_regs.h | 2 ++
4 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 506e1d923a1f..6f729ce4a7b9 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -98,6 +98,7 @@ struct controller {
struct pcie_device *pcie;
u32 slot_cap; /* capabilities and quirks */
+ unsigned int inband_presence_disabled:1;
u16 slot_ctrl; /* control register access */
struct mutex ctrl_lock;
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 7dd443aea5a5..f77dc7c38f9a 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -824,7 +824,7 @@ static inline void dbg_ctrl(struct controller *ctrl)
struct controller *pcie_init(struct pcie_device *dev)
{
struct controller *ctrl;
- u32 slot_cap, link_cap;
+ u32 slot_cap, slot_cap2, link_cap;
u8 poweron;
struct pci_dev *pdev = dev->port;
struct pci_bus *subordinate = pdev->subordinate;
@@ -846,6 +846,9 @@ struct controller *pcie_init(struct pcie_device *dev)
if (pdev->is_thunderbolt)
slot_cap |= PCI_EXP_SLTCAP_NCCS;
+ if (pdev->no_in_band_presence)
+ ctrl->inband_presence_disabled = 1;
+
ctrl->slot_cap = slot_cap;
mutex_init(&ctrl->ctrl_lock);
mutex_init(&ctrl->state_lock);
@@ -882,6 +885,13 @@ struct controller *pcie_init(struct pcie_device *dev)
FLAG(link_cap, PCI_EXP_LNKCAP_DLLLARC),
pdev->broken_cmd_compl ? " (with Cmd Compl erratum)" : "");
+ pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP2, &slot_cap2);
+ if (slot_cap2 & PCI_EXP_SLTCAP2_IBPD) {
+ pcie_write_cmd_nowait(ctrl, PCI_EXP_SLTCTL_IBPD_DISABLE,
+ PCI_EXP_SLTCTL_IBPD_DISABLE);
+ ctrl->inband_presence_disabled = 1;
+ }
+
/*
* If empty slot's power status is on, turn power off. The IRQ isn't
* requested yet, so avoid triggering a notification with this command.
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 65f1d8c2f082..9d08cdbca459 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -413,6 +413,7 @@ struct pci_dev {
unsigned int non_compliant_bars:1; /* Broken BARs; ignore them */
unsigned int is_probed:1; /* Device probing in progress */
unsigned int link_active_reporting:1;/* Device capable of reporting link active */
+ unsigned int no_in_band_presence:1; /* Device does not report in-band presence */
unsigned int no_vf_scan:1; /* Don't scan for VFs after IOV enablement */
pci_dev_flags_t dev_flags;
atomic_t enable_cnt; /* pci_enable_device has been called */
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index e1e9888c85e6..5423dc476c77 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -597,6 +597,7 @@
#define PCI_EXP_SLTCTL_PWR_OFF 0x0400 /* Power Off */
#define PCI_EXP_SLTCTL_EIC 0x0800 /* Electromechanical Interlock Control */
#define PCI_EXP_SLTCTL_DLLSCE 0x1000 /* Data Link Layer State Changed Enable */
+#define PCI_EXP_SLTCTL_IBPD_DISABLE 0x4000 /* In-band PD disable */
#define PCI_EXP_SLTSTA 26 /* Slot Status */
#define PCI_EXP_SLTSTA_ABP 0x0001 /* Attention Button Pressed */
#define PCI_EXP_SLTSTA_PFD 0x0002 /* Power Fault Detected */
@@ -667,6 +668,7 @@
#define PCI_EXP_LNKSTA2 50 /* Link Status 2 */
#define PCI_CAP_EXP_ENDPOINT_SIZEOF_V2 52 /* v2 endpoints with link end here */
#define PCI_EXP_SLTCAP2 52 /* Slot Capabilities 2 */
+#define PCI_EXP_SLTCAP2_IBPD 0x0001 /* In-band PD Disable Supported */
#define PCI_EXP_SLTCTL2 56 /* Slot Control 2 */
#define PCI_EXP_SLTSTA2 58 /* Slot Status 2 */
--
2.19.2
next prev parent reply other threads:[~2019-02-20 1:20 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-20 1:20 [PATCH RFC v2 0/4] PCI: pciehp: Do not turn off slot if presence comes up after link Alexandru Gagniuc
2019-02-20 1:20 ` Alexandru Gagniuc [this message]
2019-02-21 7:19 ` [PATCH RFC v2 1/4] PCI: hotplug: Add support for disabling in-band presence Lukas Wunner
2019-02-21 18:05 ` Alex_Gagniuc
2019-02-20 1:20 ` [PATCH RFC v2 2/4] PCI: pciehp: Do not turn off slot if presence comes up after link Alexandru Gagniuc
2019-02-21 7:36 ` Lukas Wunner
2019-02-22 19:56 ` Alex_Gagniuc
2019-02-23 6:49 ` Lukas Wunner
2019-02-24 22:27 ` Alex_Gagniuc
2019-02-20 1:20 ` [PATCH RFC v2 3/4] PCI: hotplug: Wait for PDS when in-band presence is disabled Alexandru Gagniuc
2019-02-20 1:20 ` [PATCH RFC v2 4/4] PCI: hotplug: Add quirk For Dell nvme pcie switches Alexandru Gagniuc
2019-02-21 7:56 ` Lukas Wunner
2019-02-21 18:35 ` Alex_Gagniuc
2019-02-22 1:20 ` Joe Perches
2019-02-22 2:04 ` Oliver
2019-02-22 19:19 ` Alex_Gagniuc
2019-02-21 15:38 ` [PATCH RFC v2 0/4] PCI: pciehp: Do not turn off slot if presence comes up after link Lukas Wunner
2019-02-21 18:17 ` Alex_Gagniuc
2019-04-19 0:01 ` Bjorn Helgaas
2019-04-19 15:22 ` [PATCH v3 " Alexandru Gagniuc
2019-04-19 15:22 ` [PATCH v3 1/4] PCI: hotplug: Add support for disabling in-band presence Alexandru Gagniuc
2019-04-19 15:22 ` [PATCH v3 2/4] PCI: pciehp: Do not turn off slot if presence comes up after link Alexandru Gagniuc
2019-04-19 15:22 ` [PATCH v3 3/4] PCI: hotplug: Wait for PDS when in-band presence is disabled Alexandru Gagniuc
2019-04-19 15:22 ` [PATCH v3 4/4] PCI: hotplug: Add quirk For Dell nvme pcie switches Alexandru Gagniuc
2019-04-19 21:00 ` Alan J. Wylie
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