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From:   Xuesong Chen <xuesong.chen@linux.alibaba.com>
To:     helgaas@kernel.org
Cc:     catalin.marinas@arm.com, lorenzo.pieralisi@arm.com,
        james.morse@arm.com, will@kernel.org, rafael@kernel.org,
        tony.luck@intel.com, bp@alien8.de, mingo@kernel.org,
        bhelgaas@google.com, linux-pci@vger.kernel.org,
        linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, xuesong.chen@linux.alibaba.com
Subject: [PATCH v4 1/4] PCI: MCFG: Consolidate the separate PCI MCFG table entry list
Date:   Wed, 27 Oct 2021 16:12:10 +0800
Message-Id: <20211027081210.53494-1-xuesong.chen@linux.alibaba.com>
In-Reply-To: <20211027081035.53370-1-xuesong.chen@linux.alibaba.com>
References: <20211027081035.53370-1-xuesong.chen@linux.alibaba.com>
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The PCI MCFG entry list is redundant on x86 and other arches like ARM64
in current implementation, this list variable can be consolidated for
unnecessary duplication and other purposes, for example, we can remove
some of the arch-specific codes in the APEI/EINJ module and re-implement
it in a more common arch-agnostic way.

To reduce the redundancy, it:
  - Moves the "struct pci_mmcfg_region" definition from
    arch/x86/include/asm/pci_x86.h to include/linux/pci.h, where it
    can be shared across arches.

  - Moves pci_mmcfg_list (a list of pci_mmcfg_region structs) from
    arch/x86/pci/mmconfig-shared.c to drivers/pci/pci.c, where it can
    be shared across arches.

  - On x86 (which does not enable CONFIG_ACPI_MCFG), pci_mmcfg_list is
    built in arch/x86/pci/mmconfig-shared.c as before.

  - Removes the "struct mcfg_entry" from drivers/acpi/pci_mcfg.c.

  - Replaces pci_mcfg_list (previously a list of mcfg_entry structs)
    in drivers/acpi/pci_mcfg.c with the newly-shared pci_mmcfg_list (a
    list of pci_mmcfg_region structs).

  - On ARM64 (which does enable CONFIG_ACPI_MCFG), pci_mmcfg_list is
    built in drivers/acpi/pci_mcfg.c.

Signed-off-by: Xuesong Chen <xuesong.chen@linux.alibaba.com>
---
 arch/x86/include/asm/pci_x86.h | 17 +----------------
 arch/x86/pci/mmconfig-shared.c |  2 --
 drivers/acpi/pci_mcfg.c        | 35 ++++++++++++++---------------------
 drivers/pci/pci.c              |  2 ++
 include/linux/pci.h            | 17 +++++++++++++++++
 5 files changed, 34 insertions(+), 39 deletions(-)

diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index 490411d..1f4257c 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -146,20 +146,7 @@ static inline int  __init pci_acpi_init(void)
 extern void pcibios_fixup_irqs(void);
 
 /* pci-mmconfig.c */
-
-/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
-#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
-
-struct pci_mmcfg_region {
-	struct list_head list;
-	struct resource res;
-	u64 address;
-	char __iomem *virt;
-	u16 segment;
-	u8 start_bus;
-	u8 end_bus;
-	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
-};
+struct pci_mmcfg_region;
 
 extern int __init pci_mmcfg_arch_init(void);
 extern void __init pci_mmcfg_arch_free(void);
@@ -174,8 +161,6 @@ extern struct pci_mmcfg_region *__init pci_mmconfig_add(int segment, int start,
 
 extern struct list_head pci_mmcfg_list;
 
-#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
-
 /*
  * On AMD Fam10h CPUs, all PCI MMIO configuration space accesses must use
  * %eax.  No other source or target registers may be used.  The following
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 758cbfe..0b961fe6 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -31,8 +31,6 @@
 static DEFINE_MUTEX(pci_mmcfg_lock);
 #define pci_mmcfg_lock_held() lock_is_held(&(pci_mmcfg_lock).dep_map)
 
-LIST_HEAD(pci_mmcfg_list);
-
 static void __init pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
 {
 	if (cfg->res.parent)
diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
index 53cab97..6ce467f 100644
--- a/drivers/acpi/pci_mcfg.c
+++ b/drivers/acpi/pci_mcfg.c
@@ -13,14 +13,7 @@
 #include <linux/pci-acpi.h>
 #include <linux/pci-ecam.h>
 
-/* Structure to hold entries from the MCFG table */
-struct mcfg_entry {
-	struct list_head	list;
-	phys_addr_t		addr;
-	u16			segment;
-	u8			bus_start;
-	u8			bus_end;
-};
+extern struct list_head pci_mmcfg_list;
 
 #ifdef CONFIG_PCI_QUIRKS
 struct mcfg_fixup {
@@ -214,16 +207,13 @@ static void pci_mcfg_apply_quirks(struct acpi_pci_root *root,
 #endif
 }
 
-/* List to save MCFG entries */
-static LIST_HEAD(pci_mcfg_list);
-
 int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
 		    const struct pci_ecam_ops **ecam_ops)
 {
 	const struct pci_ecam_ops *ops = &pci_generic_ecam_ops;
 	struct resource *bus_res = &root->secondary;
 	u16 seg = root->segment;
-	struct mcfg_entry *e;
+	struct pci_mmcfg_region *e;
 	struct resource res;
 
 	/* Use address from _CBA if present, otherwise lookup MCFG */
@@ -233,10 +223,10 @@ int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
 	/*
 	 * We expect the range in bus_res in the coverage of MCFG bus range.
 	 */
-	list_for_each_entry(e, &pci_mcfg_list, list) {
-		if (e->segment == seg && e->bus_start <= bus_res->start &&
-		    e->bus_end >= bus_res->end) {
-			root->mcfg_addr = e->addr;
+	list_for_each_entry(e, &pci_mmcfg_list, list) {
+		if (e->segment == seg && e->start_bus <= bus_res->start &&
+		    e->end_bus >= bus_res->end) {
+			root->mcfg_addr = e->address;
 		}
 
 	}
@@ -268,7 +258,7 @@ static __init int pci_mcfg_parse(struct acpi_table_header *header)
 {
 	struct acpi_table_mcfg *mcfg;
 	struct acpi_mcfg_allocation *mptr;
-	struct mcfg_entry *e, *arr;
+	struct pci_mmcfg_region *e, *arr;
 	int i, n;
 
 	if (header->length < sizeof(struct acpi_table_mcfg))
@@ -285,10 +275,13 @@ static __init int pci_mcfg_parse(struct acpi_table_header *header)
 
 	for (i = 0, e = arr; i < n; i++, mptr++, e++) {
 		e->segment = mptr->pci_segment;
-		e->addr =  mptr->address;
-		e->bus_start = mptr->start_bus_number;
-		e->bus_end = mptr->end_bus_number;
-		list_add(&e->list, &pci_mcfg_list);
+		e->address =  mptr->address;
+		e->start_bus = mptr->start_bus_number;
+		e->end_bus = mptr->end_bus_number;
+		e->res.start = e->address + PCI_MMCFG_BUS_OFFSET(e->start_bus);
+		e->res.end = e->address + PCI_MMCFG_BUS_OFFSET(e->end_bus + 1) - 1;
+		e->res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+		list_add(&e->list, &pci_mmcfg_list);
 	}
 
 #ifdef CONFIG_PCI_QUIRKS
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e01b21a..4e8386c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -47,6 +47,8 @@
 int pci_pci_problems;
 EXPORT_SYMBOL(pci_pci_problems);
 
+LIST_HEAD(pci_mmcfg_list);
+
 unsigned int pci_pm_d3hot_delay;
 
 static void pci_pme_list_scan(struct work_struct *work);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index b4dbcc8..34b0cbb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -55,6 +55,23 @@
 #define PCI_RESET_PROBE		true
 #define PCI_RESET_DO_RESET	false
 
+#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
+
+/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
+#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
+
+/* pci mcfg region */
+struct pci_mmcfg_region {
+	struct list_head list;
+	struct resource res;
+	u64 address;
+	char __iomem *virt;
+	u16 segment;
+	u8 start_bus;
+	u8 end_bus;
+	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
+};
+
 /*
  * The PCI interface treats multi-function devices as independent
  * devices.  The slot/function address of each device is encoded
-- 
1.8.3.1