git: a64357f31b7c - stable/14 - acpi_pci: Add quirk for PSTAT_PME-before-detach

The branch stable/14 has been updated by cperciva:

URL: https://cgit.FreeBSD.org/src/commit/?id=a64357f31b7c798452e7aca4e6ec34c2842a4fc1

commit a64357f31b7c798452e7aca4e6ec34c2842a4fc1
Author:     Colin Percival <cperciva@FreeBSD.org>
AuthorDate: 2025-02-27 00:31:08 +0000
Commit:     Colin Percival <cperciva@FreeBSD.org>
CommitDate: 2025-04-01 17:43:58 +0000

    acpi_pci: Add quirk for PSTAT_PME-before-detach
    
    In order to signal to Graviton [123] systems that a device is ready
    to be "ejected" (after a detach request is made via the EC2 API) we
    need to set PCIM_PSTAT_PME to 1 and PCIM_PSTAT_PMEENABLE to 0.  We are
    not aware of any rationale for this requirement beyond "another OS
    kernel happens to do this", i.e. this is effectively bug-for-bug
    compatibility.
    
    Arguably this should be done by the ACPI _EJ0 method on these systems,
    but it is not.
    
    Create a new ACPI_Q_CLEAR_PME_ON_DETACH quirk and set it in EC2 AMIs,
    and add the PCI register write to acpi_pci_device_notify_handler when
    that quirk is set.
    
    Reviewed by:    jhb
    MFC after:      1 month
    Sponsored by:   Amazon
    Differential Revision:  https://reviews.freebsd.org/D49146
    
    (cherry picked from commit d70bac252d30adec4feba0c866dabe2c16a756d9)
---
 release/tools/ec2.conf    | 7 +++++--
 sys/dev/acpica/acpi_pci.c | 9 +++++++++
 sys/dev/acpica/acpivar.h  | 3 +++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/release/tools/ec2.conf b/release/tools/ec2.conf
index 1fe44118fd3e..21ea56d109ca 100644
--- a/release/tools/ec2.conf
+++ b/release/tools/ec2.conf
@@ -65,8 +65,11 @@ ec2_common() {
 
 	# Graviton 1 through Graviton 4 have a bug in their ACPI where they
 	# mark the PL061's pins as needing to be configured in PullUp mode
-	# (in fact the PL061 has no pullup/pulldown resistors).
-	echo 'debug.acpi.quirks="8"' >> ${DESTDIR}/boot/loader.conf
+	# (in fact the PL061 has no pullup/pulldown resistors).  Graviton 1
+	# through Graviton 3 have non-functional PCI _EJ0 and need a value
+	# written to the PCI power status register in order to eject a
+	# device.
+	echo 'debug.acpi.quirks="24"' >> ${DESTDIR}/boot/loader.conf
 
 	# Load the kernel module for the Amazon "Elastic Network Adapter"
 	echo 'if_ena_load="YES"' >> ${DESTDIR}/boot/loader.conf
diff --git a/sys/dev/acpica/acpi_pci.c b/sys/dev/acpica/acpi_pci.c
index 6411af02ee58..97704111839b 100644
--- a/sys/dev/acpica/acpi_pci.c
+++ b/sys/dev/acpica/acpi_pci.c
@@ -391,6 +391,8 @@ acpi_pci_device_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
 {
 	device_t child, dev;
 	ACPI_STATUS status;
+	int pmc;
+	uint16_t pmstat;
 	int error;
 
 	dev = context;
@@ -416,6 +418,13 @@ acpi_pci_device_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
 			    device_get_nameunit(child), error);
 			return;
 		}
+		if ((acpi_quirks & ACPI_Q_CLEAR_PME_ON_DETACH) &&
+		    (pci_find_cap(child, PCIY_PMG, &pmc) == 0)) {
+			pmstat = pci_read_config(child, pmc + PCIR_POWER_STATUS, 2);
+			pmstat &= ~PCIM_PSTAT_PMEENABLE;
+			pmstat |= PCIM_PSTAT_PME;
+			pci_write_config(child, pmc + PCIR_POWER_STATUS, pmstat, 2);
+		}
 		status = acpi_SetInteger(h, "_EJ0", 1);
 		if (ACPI_FAILURE(status)) {
 			bus_topo_unlock();
diff --git a/sys/dev/acpica/acpivar.h b/sys/dev/acpica/acpivar.h
index 668d0b51a1f3..830764434f48 100644
--- a/sys/dev/acpica/acpivar.h
+++ b/sys/dev/acpica/acpivar.h
@@ -230,6 +230,8 @@ extern struct mtx			acpi_mutex;
  *	compatible flag and ignoring overrides that redirect IRQ 0 to pin 2.
  * ACPI_Q_AEI_NOPULL: Specifies that _AEI objects incorrectly designate pins
  *	as "PullUp" and they should be treated as "NoPull" instead.
+ * ACPI_Q_CLEAR_PME_ON_DETACH: Specifies that PCIM_PSTAT_(PME & ~PMEENABLE)
+ *	should be written to the power status register as part of ACPI Eject.
  */
 extern int	acpi_quirks;
 #define ACPI_Q_OK		0
@@ -237,6 +239,7 @@ extern int	acpi_quirks;
 #define ACPI_Q_TIMER		(1 << 1)
 #define ACPI_Q_MADT_IRQ0	(1 << 2)
 #define ACPI_Q_AEI_NOPULL	(1 << 3)
+#define ACPI_Q_CLEAR_PME_ON_DETACH	(1 << 4)
 
 #if defined(__amd64__) || defined(__i386__)
 /*