From 072de836f53be56a70cecf70b43ae43b7ce17376 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 10:08:36 +0000
Subject: [PATCH] mk-rootfs.sh

---
 kernel/drivers/acpi/pci_root.c |   74 ++++++++++++++++++++++--------------
 1 files changed, 45 insertions(+), 29 deletions(-)

diff --git a/kernel/drivers/acpi/pci_root.c b/kernel/drivers/acpi/pci_root.c
index e465e72..c12b5fb 100644
--- a/kernel/drivers/acpi/pci_root.c
+++ b/kernel/drivers/acpi/pci_root.c
@@ -1,22 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 40 $)
  *
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
- *
- * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or (at
- *  your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful, but
- *  WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- *  General Public License for more details.
- *
- * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */
 
 #include <linux/kernel.h>
@@ -28,7 +15,6 @@
 #include <linux/pm_runtime.h>
 #include <linux/pci.h>
 #include <linux/pci-acpi.h>
-#include <linux/pci-aspm.h>
 #include <linux/dmar.h>
 #include <linux/acpi.h>
 #include <linux/slab.h>
@@ -38,8 +24,6 @@
 
 #include "internal.h"
 
-#define _COMPONENT		ACPI_PCI_COMPONENT
-ACPI_MODULE_NAME("pci_root");
 #define ACPI_PCI_ROOT_CLASS		"pci_bridge"
 #define ACPI_PCI_ROOT_DEVICE_NAME	"PCI Root Bridge"
 static int acpi_pci_root_add(struct acpi_device *device,
@@ -76,7 +60,7 @@
 
 /**
  * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
- * @handle - the ACPI CA node in question.
+ * @handle:  the ACPI CA node in question.
  *
  * Note: we could make this API take a struct acpi_device * instead, but
  * for now, it's more convenient to operate on an acpi_handle.
@@ -145,6 +129,8 @@
 	{ OSC_PCI_CLOCK_PM_SUPPORT, "ClockPM" },
 	{ OSC_PCI_SEGMENT_GROUPS_SUPPORT, "Segments" },
 	{ OSC_PCI_MSI_SUPPORT, "MSI" },
+	{ OSC_PCI_EDR_SUPPORT, "EDR" },
+	{ OSC_PCI_HPX_TYPE_3_SUPPORT, "HPX-Type3" },
 };
 
 static struct pci_osc_bit_struct pci_osc_control_bit[] = {
@@ -154,6 +140,7 @@
 	{ OSC_PCI_EXPRESS_AER_CONTROL, "AER" },
 	{ OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" },
 	{ OSC_PCI_EXPRESS_LTR_CONTROL, "LTR" },
+	{ OSC_PCI_EXPRESS_DPC_CONTROL, "DPC" },
 };
 
 static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
@@ -166,7 +153,7 @@
 	buf[0] = '\0';
 	for (i = 0, entry = table; i < size; i++, entry++)
 		if (word & entry->bit)
-			len += snprintf(buf + len, sizeof(buf) - len, "%s%s",
+			len += scnprintf(buf + len, sizeof(buf) - len, "%s%s",
 					len ? " " : "", entry->desc);
 
 	dev_info(&root->device->dev, "_OSC: %s [%s]\n", msg, buf);
@@ -421,7 +408,8 @@
 }
 EXPORT_SYMBOL(acpi_pci_osc_control_set);
 
-static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
+static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
+				 bool is_pcie)
 {
 	u32 support, control, requested;
 	acpi_status status;
@@ -445,20 +433,28 @@
 	 * PCI domains, so we indicate this in _OSC support capabilities.
 	 */
 	support = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
+	support |= OSC_PCI_HPX_TYPE_3_SUPPORT;
 	if (pci_ext_cfg_avail())
 		support |= OSC_PCI_EXT_CONFIG_SUPPORT;
 	if (pcie_aspm_support_enabled())
 		support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT;
 	if (pci_msi_enabled())
 		support |= OSC_PCI_MSI_SUPPORT;
+	if (IS_ENABLED(CONFIG_PCIE_EDR))
+		support |= OSC_PCI_EDR_SUPPORT;
 
 	decode_osc_support(root, "OS supports", support);
 	status = acpi_pci_osc_support(root, support);
 	if (ACPI_FAILURE(status)) {
+		*no_aspm = 1;
+
+		/* _OSC is optional for PCI host bridges */
+		if ((status == AE_NOT_FOUND) && !is_pcie)
+			return;
+
 		dev_info(&device->dev, "_OSC failed (%s)%s\n",
 			 acpi_format_exception(status),
 			 pcie_aspm_support_enabled() ? "; disabling ASPM" : "");
-		*no_aspm = 1;
 		return;
 	}
 
@@ -485,13 +481,17 @@
 	if (IS_ENABLED(CONFIG_HOTPLUG_PCI_SHPC))
 		control |= OSC_PCI_SHPC_NATIVE_HP_CONTROL;
 
-	if (pci_aer_available()) {
-		if (aer_acpi_firmware_first())
-			dev_info(&device->dev,
-				 "PCIe AER handled by firmware\n");
-		else
-			control |= OSC_PCI_EXPRESS_AER_CONTROL;
-	}
+	if (pci_aer_available())
+		control |= OSC_PCI_EXPRESS_AER_CONTROL;
+
+	/*
+	 * Per the Downstream Port Containment Related Enhancements ECN to
+	 * the PCI Firmware Spec, r3.2, sec 4.5.1, table 4-5,
+	 * OSC_PCI_EXPRESS_DPC_CONTROL indicates the OS supports both DPC
+	 * and EDR.
+	 */
+	if (IS_ENABLED(CONFIG_PCIE_DPC) && IS_ENABLED(CONFIG_PCIE_EDR))
+		control |= OSC_PCI_EXPRESS_DPC_CONTROL;
 
 	requested = control;
 	status = acpi_pci_osc_control_set(handle, &control,
@@ -534,6 +534,7 @@
 	acpi_handle handle = device->handle;
 	int no_aspm = 0;
 	bool hotadd = system_state == SYSTEM_RUNNING;
+	bool is_pcie;
 
 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 	if (!root)
@@ -591,7 +592,8 @@
 
 	root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle);
 
-	negotiate_os_control(root, &no_aspm);
+	is_pcie = strcmp(acpi_device_hid(device), "PNP0A08") == 0;
+	negotiate_os_control(root, &no_aspm, is_pcie);
 
 	/*
 	 * TBD: Need PCI interface for enumeration/configuration of roots.
@@ -884,6 +886,7 @@
 	int node = acpi_get_node(device->handle);
 	struct pci_bus *bus;
 	struct pci_host_bridge *host_bridge;
+	union acpi_object *obj;
 
 	info->root = root;
 	info->bridge = device;
@@ -919,6 +922,19 @@
 		host_bridge->native_pme = 0;
 	if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
 		host_bridge->native_ltr = 0;
+	if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
+		host_bridge->native_dpc = 0;
+
+	/*
+	 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it
+	 * exists and returns 0, we must preserve any PCI resource
+	 * assignments made by firmware for this host bridge.
+	 */
+	obj = acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 1,
+				DSM_PCI_PRESERVE_BOOT_CONFIG, NULL);
+	if (obj && obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 0)
+		host_bridge->preserve_config = 1;
+	ACPI_FREE(obj);
 
 	pci_scan_child_bus(bus);
 	pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info,

--
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