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From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: tglx@linutronix.de, bp@alien8.de, linux-kernel@vger.kernel.org,
	ak@linux.intel.com, helgaas@kernel.org, eranian@google.com,
	mingo@kernel.org, hpa@zytor.com, peterz@infradead.org
Subject: [tip:x86/platform] x86/PCI/mmcfg: Switch to ECAM config mode if possible
Date: Wed, 28 Jun 2017 23:45:52 -0700	[thread overview]
Message-ID: <tip-b5b0f00c760b6e9673ab79b88ede2f3c7a039f74@git.kernel.org> (raw)
In-Reply-To: <20170316215057.452220163@linutronix.de>

Commit-ID:  b5b0f00c760b6e9673ab79b88ede2f3c7a039f74
Gitweb:     http://git.kernel.org/tip/b5b0f00c760b6e9673ab79b88ede2f3c7a039f74
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 16 Mar 2017 22:50:09 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 29 Jun 2017 08:41:54 +0200

x86/PCI/mmcfg: Switch to ECAM config mode if possible

To allow lockless access to the whole PCI configuration space the mmconfig
based accessor functions need to be propagated to the pci_root_ops.

Unfortunatly this cannot be done before the PCI subsystem initialization
happens even if mmconfig access is already available. The reason is that
some of the special platform PCI implementations must be able to overrule
that setting before further accesses happen.

The earliest possible point is after x86_init.pci.init() has been run. This
is at a point in the boot process where nothing actually uses the PCI
devices so the accessor function pointers can be updated lockless w/o risk.

The switch to full ECAM mode depends on the availability of mmconfig and
unchanged default accessors.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <helgaas@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: linux-pci@vger.kernel.org
Link: http://lkml.kernel.org/r/20170316215057.452220163@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/include/asm/pci_x86.h | 20 ++++++++++++--------
 arch/x86/pci/common.c          | 16 ++++++++++++++++
 arch/x86/pci/legacy.c          |  1 +
 arch/x86/pci/mmconfig-shared.c | 30 ++++++++++++++++++++++++++++++
 arch/x86/pci/mmconfig_32.c     |  8 ++++----
 arch/x86/pci/mmconfig_64.c     |  8 ++++----
 6 files changed, 67 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index 9f1b21f..65e1303 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -48,20 +48,14 @@ enum pci_bf_sort_state {
 	pci_dmi_bf,
 };
 
-/* pci-i386.c */
-
 void pcibios_resource_survey(void);
 void pcibios_set_cache_line_size(void);
 
-/* pci-pc.c */
-
 extern int pcibios_last_bus;
 extern struct pci_ops pci_root_ops;
 
 void pcibios_scan_specific_bus(int busn);
 
-/* pci-irq.c */
-
 struct irq_info {
 	u8 bus, devfn;			/* Bus, device and function */
 	struct {
@@ -122,11 +116,10 @@ extern void __init dmi_check_skip_isa_align(void);
 extern int __init pci_acpi_init(void);
 extern void __init pcibios_irq_init(void);
 extern int __init pcibios_init(void);
+extern void __init pcibios_select_ops(void);
 extern int pci_legacy_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)
 
@@ -141,6 +134,12 @@ struct pci_mmcfg_region {
 	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
 };
 
+#ifdef CONFIG_PCI_MMCONFIG
+extern void __init pci_mmcfg_select_ops(void);
+#else
+static inline void pci_mmcfg_select_ops(void) { }
+#endif
+
 extern int __init pci_mmcfg_arch_init(void);
 extern void __init pci_mmcfg_arch_free(void);
 extern int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg);
@@ -197,6 +196,11 @@ static inline void mmio_config_writel(void __iomem *pos, u32 val)
 	asm volatile("movl %%eax,(%1)" : : "a" (val), "r" (pos) : "memory");
 }
 
+int pci_mmcfg_read(unsigned int seg, unsigned int bus,
+		   unsigned int devfn, int reg, int len, u32 *value);
+int pci_mmcfg_write(unsigned int seg, unsigned int bus,
+		    unsigned int devfn, int reg, int len, u32 value);
+
 #ifdef CONFIG_PCI
 # ifdef CONFIG_ACPI
 #  define x86_default_pci_init		pci_acpi_init
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index cfd1a89..81e4d21 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -157,6 +157,22 @@ static void pcibios_fixup_device_resources(struct pci_dev *dev)
 }
 
 /*
+ * Called after the last possible modification to raw_pci_[ext_]ops.
+ *
+ * Verify that root_pci_ops have not been overwritten by any implementation
+ * of x86_init.pci.arch_init() and x86_init.pci.init().
+ *
+ * If not, let the mmconfig code decide whether the ops can be switched
+ * over to the ECAM accessor functions.
+ */
+void __init pcibios_select_ops(void)
+{
+	if (pci_root_ops.read != pci_read || pci_root_ops.write != pci_write)
+		return;
+	pci_mmcfg_select_ops();
+}
+
+/*
  *  Called after each bus is probed, but before its children
  *  are examined.
  */
diff --git a/arch/x86/pci/legacy.c b/arch/x86/pci/legacy.c
index 1cb01ab..80ea40e 100644
--- a/arch/x86/pci/legacy.c
+++ b/arch/x86/pci/legacy.c
@@ -65,6 +65,7 @@ static int __init pci_subsys_init(void)
 		}
 	}
 
+	pcibios_select_ops();
 	pcibios_fixup_peer_bridges();
 	x86_init.pci.init_irq();
 	pcibios_init();
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index d1b47d5..6af6351 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -816,3 +816,33 @@ int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
 
 	return -ENOENT;
 }
+
+static int pci_ecam_read(struct pci_bus *bus, unsigned int devfn, int reg,
+			 int size, u32 *value)
+{
+	return pci_mmcfg_read(pci_domain_nr(bus), bus->number, devfn, reg,
+			      size, value);
+}
+
+static int pci_ecam_write(struct pci_bus *bus, unsigned int devfn, int reg,
+			  int size, u32 value)
+{
+	return pci_mmcfg_write(pci_domain_nr(bus), bus->number, devfn, reg,
+			       size, value);
+}
+
+void __init pci_mmcfg_select_ops(void)
+{
+	if (raw_pci_ext_ops != &pci_mmcfg)
+		return;
+
+	/*
+	 * The pointer to root_pci_ops has been handed in to ACPI already
+	 * and is already set in the busses.
+	 *
+	 * Switch the functions over to ECAM for all config space accesses.
+	 */
+	pci_root_ops.read = pci_ecam_read;
+	pci_root_ops.write = pci_ecam_write;
+	pr_info("PCI: Switch to ECAM configuration mode\n");
+}
diff --git a/arch/x86/pci/mmconfig_32.c b/arch/x86/pci/mmconfig_32.c
index 3e9e166..d0975f1 100644
--- a/arch/x86/pci/mmconfig_32.c
+++ b/arch/x86/pci/mmconfig_32.c
@@ -49,8 +49,8 @@ static void pci_exp_set_dev_base(unsigned int base, int bus, int devfn)
 	}
 }
 
-static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
-			  unsigned int devfn, int reg, int len, u32 *value)
+int pci_mmcfg_read(unsigned int seg, unsigned int bus,
+		   unsigned int devfn, int reg, int len, u32 *value)
 {
 	unsigned long flags;
 	u32 base;
@@ -88,8 +88,8 @@ err:		*value = -1;
 	return 0;
 }
 
-static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
-			   unsigned int devfn, int reg, int len, u32 value)
+int pci_mmcfg_write(unsigned int seg, unsigned int bus,
+		    unsigned int devfn, int reg, int len, u32 value)
 {
 	unsigned long flags;
 	u32 base;
diff --git a/arch/x86/pci/mmconfig_64.c b/arch/x86/pci/mmconfig_64.c
index f1c1aa0..64949dd 100644
--- a/arch/x86/pci/mmconfig_64.c
+++ b/arch/x86/pci/mmconfig_64.c
@@ -24,8 +24,8 @@ static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned i
 	return NULL;
 }
 
-static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
-			  unsigned int devfn, int reg, int len, u32 *value)
+int pci_mmcfg_read(unsigned int seg, unsigned int bus,
+		   unsigned int devfn, int reg, int len, u32 *value)
 {
 	char __iomem *addr;
 
@@ -58,8 +58,8 @@ err:		*value = -1;
 	return 0;
 }
 
-static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
-			   unsigned int devfn, int reg, int len, u32 value)
+int pci_mmcfg_write(unsigned int seg, unsigned int bus,
+		    unsigned int devfn, int reg, int len, u32 value)
 {
 	char __iomem *addr;
 

  parent reply	other threads:[~2017-06-29  6:51 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-16 21:50 [patch 0/7] x86/pci: Switch to lockless ECAM configuration mode Thomas Gleixner
2017-03-16 21:50 ` [patch 1/7] x86/pci: Remove duplicate defines Thomas Gleixner
2017-06-27 20:57   ` Bjorn Helgaas
2017-06-28 20:43   ` [tip:x86/platform] x86/PCI: " tip-bot for Thomas Gleixner
2017-03-16 21:50 ` [patch 2/7] x86/pci: Abort if legacy init fails Thomas Gleixner
2017-06-27 20:59   ` Bjorn Helgaas
2017-06-28 20:44   ` [tip:x86/platform] x86/PCI: " tip-bot for Thomas Gleixner
2017-03-16 21:50 ` [patch 3/7] x86/pci/ce4100: Properly lock accessor functions Thomas Gleixner
2017-03-17  0:28   ` Andi Kleen
2017-06-27 21:00   ` Bjorn Helgaas
2017-06-28 20:44   ` [tip:x86/platform] x86/PCI/ce4100: " tip-bot for Thomas Gleixner
2017-03-16 21:50 ` [patch 4/7] PCI: Provide Kconfig option for lockless config space accessors Thomas Gleixner
2017-06-27 21:11   ` Bjorn Helgaas
2017-06-28 20:31     ` Thomas Gleixner
2017-06-28 20:45   ` [tip:x86/platform] " tip-bot for Thomas Gleixner
2017-03-16 21:50 ` [patch 5/7] x86/pci: Select CONFIG_PCI_LOCKLESS_CONFIG Thomas Gleixner
2017-06-28 20:45   ` [tip:x86/platform] x86/PCI: " tip-bot for Thomas Gleixner
2017-03-16 21:50 ` [patch 6/7] x86/pci/mmcfg: Include 32/64 bit code into shared code Thomas Gleixner
2017-03-17  0:25   ` Andi Kleen
2017-03-17  8:41     ` Thomas Gleixner
2017-03-16 21:50 ` [patch 7/7] x86/pci/mmcfg: Switch to ECAM config mode if possible Thomas Gleixner
2017-03-17  0:26   ` Andi Kleen
2017-03-17  6:15     ` Thomas Gleixner
2017-06-27 21:31       ` Bjorn Helgaas
2017-06-28 20:46   ` [tip:x86/platform] x86/PCI/mmcfg: " tip-bot for Thomas Gleixner
2017-06-29  6:45   ` tip-bot for Thomas Gleixner [this message]
2017-06-29 23:26     ` Yinghai Lu
2017-06-30  3:18       ` Andi Kleen
2017-06-30 14:30         ` Thomas Gleixner
2017-06-30 17:16           ` Linus Torvalds
2017-06-30 18:30             ` Ivan Kokshaysky
2017-06-30 18:46             ` Thomas Gleixner
2017-06-13  0:25 ` [patch 0/7] x86/pci: Switch to lockless ECAM configuration mode Andi Kleen
2017-06-21 22:28   ` Thomas Gleixner
2017-06-27 20:55     ` Bjorn Helgaas

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