git: b5bc47f1e1ab - stable/14 - pci: Clear active PME# and disable PME# generation

The branch stable/14 has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=b5bc47f1e1ab31086c1bf2e68944ea0331059c2c

commit b5bc47f1e1ab31086c1bf2e68944ea0331059c2c
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2025-03-27 20:53:24 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2025-04-29 14:44:25 +0000

    pci: Clear active PME# and disable PME# generation
    
    The PCI power management specification requires that the OS clear any
    pending PME# interrupt and generation of PME# interrupts during
    "initial operating system load".  Note that clearing a pending PME#
    interrupt requires writing a 1 to the Read/Write-Clear PME bit in the
    power management status register.  To handle the boot time case, clear
    PME# state in pci_read_cap() when scanning new PCI devices.  This
    should also cover hotplug devices.
    
    In addition, clear this state on every PCI device after resume from
    sleep in pci_resume_child before invoking the driver's DEVICE_RESUME
    method.
    
    Reviewed by:    imp
    Differential Revision:  https://reviews.freebsd.org/D49222
    
    (cherry picked from commit 82d692771239f1d156a875087dff4cf09f0e8b80)
---
 share/man/man9/Makefile   |  1 +
 share/man/man9/pci.9      |  8 ++++++++
 sys/dev/cardbus/cardbus.c |  1 +
 sys/dev/pci/pci.c         | 18 ++++++++++++++++++
 sys/dev/pci/pcivar.h      |  1 +
 5 files changed, 29 insertions(+)

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 3ee1d2bb0108..dcaf1d4ac5ed 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1781,6 +1781,7 @@ MLINKS+=panic.9 vpanic.9 \
 	panic.9 KERNEL_PANICKED.9
 MLINKS+=pci.9 pci_alloc_msi.9 \
 	pci.9 pci_alloc_msix.9 \
+	pci.9 pci_clear_pme.9 \
 	pci.9 pci_disable_busmaster.9 \
 	pci.9 pci_disable_io.9 \
 	pci.9 pci_enable_busmaster.9 \
diff --git a/share/man/man9/pci.9 b/share/man/man9/pci.9
index 3c3e54bf8760..0f3fc92c23e7 100644
--- a/share/man/man9/pci.9
+++ b/share/man/man9/pci.9
@@ -30,6 +30,7 @@
 .Nm pci ,
 .Nm pci_alloc_msi ,
 .Nm pci_alloc_msix ,
+.Nm pci_clear_pme ,
 .Nm pci_disable_busmaster ,
 .Nm pci_disable_io ,
 .Nm pci_enable_busmaster ,
@@ -81,6 +82,8 @@
 .Fn pci_alloc_msi "device_t dev" "int *count"
 .Ft int
 .Fn pci_alloc_msix "device_t dev" "int *count"
+.Ft void
+.Fn pci_clear_pme "device_t dev"
 .Ft int
 .Fn pci_disable_busmaster "device_t dev"
 .Ft int
@@ -670,6 +673,11 @@ then the function will fail with
 .Er EOPNOTSUPP .
 .Pp
 The
+.Fn pci_clear_pme
+function is used to clear any pending PME# signal and disable generation
+of power management events.
+.Pp
+The
 .Fn pci_iov_attach
 function is used to advertise that the given device
 .Pq and associated device driver
diff --git a/sys/dev/cardbus/cardbus.c b/sys/dev/cardbus/cardbus.c
index 261e9a5205ae..8dd543c68677 100644
--- a/sys/dev/cardbus/cardbus.c
+++ b/sys/dev/cardbus/cardbus.c
@@ -223,6 +223,7 @@ cardbus_attach_card(device_t cbdev)
 			DEVPRINTF((cbdev, "Warning: Bogus CIS ignored\n"));
 		pci_cfg_save(dinfo->pci.cfg.dev, &dinfo->pci, 0);
 		pci_cfg_restore(dinfo->pci.cfg.dev, &dinfo->pci);
+		pci_clear_pme(child);
 		cardbus_device_setup_regs(&dinfo->pci.cfg);
 		pci_add_resources(cbdev, child, 1, dinfo->mprefetchable);
 		pci_print_verbose(&dinfo->pci);
diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index 7107fbe4884b..a99c34271f96 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -2921,6 +2921,22 @@ pci_get_powerstate_method(device_t dev, device_t child)
 	return (result);
 }
 
+/* Clear any active PME# and disable PME# generation. */
+void
+pci_clear_pme(device_t dev)
+{
+	struct pci_devinfo *dinfo = device_get_ivars(dev);
+	pcicfgregs *cfg = &dinfo->cfg;
+	uint16_t status;
+
+	if (cfg->pp.pp_cap != 0) {
+		status = pci_read_config(dev, dinfo->cfg.pp.pp_status, 2);
+		status &= ~PCIM_PSTAT_PMEENABLE;
+		status |= PCIM_PSTAT_PME;
+		pci_write_config(dev, dinfo->cfg.pp.pp_status, status, 2);
+	}
+}
+
 /*
  * Some convenience functions for PCI device drivers.
  */
@@ -4466,6 +4482,7 @@ pci_add_child(device_t bus, struct pci_devinfo *dinfo)
 	resource_list_init(&dinfo->resources);
 	pci_cfg_save(dev, dinfo, 0);
 	pci_cfg_restore(dev, dinfo);
+	pci_clear_pme(dev);
 	pci_print_verbose(dinfo);
 	pci_add_resources(bus, dev, 0, 0);
 	if (pci_enable_mps_tune)
@@ -4665,6 +4682,7 @@ pci_resume_child(device_t dev, device_t child)
 
 	dinfo = device_get_ivars(child);
 	pci_cfg_restore(child, dinfo);
+	pci_clear_pme(child);
 	if (!device_is_attached(child))
 		pci_cfg_save(child, dinfo, 1);
 
diff --git a/sys/dev/pci/pcivar.h b/sys/dev/pci/pcivar.h
index 888159d59c1a..d365b9132069 100644
--- a/sys/dev/pci/pcivar.h
+++ b/sys/dev/pci/pcivar.h
@@ -685,6 +685,7 @@ void	pci_restore_state(device_t dev);
 void	pci_save_state(device_t dev);
 int	pci_set_max_read_req(device_t dev, int size);
 int	pci_power_reset(device_t dev);
+void	pci_clear_pme(device_t dev);
 uint32_t pcie_read_config(device_t dev, int reg, int width);
 void	pcie_write_config(device_t dev, int reg, uint32_t value, int width);
 uint32_t pcie_adjust_config(device_t dev, int reg, uint32_t mask,