diff mbox

[1/7] PCI: Pull PCI 'latency timer' setup up into the core

Message ID 20110830165616.337.96910.stgit@amt.stowe (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Myron Stowe Aug. 30, 2011, 4:56 p.m. UTC 
From: Myron Stowe <mstowe@redhat.com>

The 'latency timer' of PCI devices, both Type 0 and Type 1,
is setup in architecture-specific code [see: 'pcibios_set_master()'].
There are two approaches being taken by all the architectures - check
if the 'latency timer' is currently set between 16 and 255 and if not
bring it within bounds, or, do nothing (and then there is the
gratuitously different parisc implementation).

There is nothing architecture-specific about PCI's 'latency timer' so
this patch pulls its setup functionality up into the PCI core by
creating a generic 'pcibios_set_master()' function using the 'weak'
attribute which can be used by all architectures as a default which,
if absolutely necessary, can then be over-ridden by architecture-
specific code.

No functional change.

Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
---

 arch/arm/common/it8152.c                |    7 -------
 arch/frv/mb93090-mb00/pci-frv.c         |    6 ------
 arch/frv/mb93090-mb00/pci-frv.h         |    2 --
 arch/mips/pci/pci.c                     |    6 ------
 arch/mn10300/unit-asb2305/pci-asb2305.c |    6 ------
 arch/mn10300/unit-asb2305/pci-asb2305.h |    2 --
 arch/sh/drivers/pci/pci.c               |    6 ------
 arch/x86/include/asm/pci_x86.h          |    2 --
 arch/x86/pci/i386.c                     |    6 ------
 drivers/pci/pci.c                       |   29 +++++++++++++++++++++++++++++
 include/linux/pci.h                     |    5 +++++
 11 files changed, 34 insertions(+), 43 deletions(-)


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diff mbox

Patch

diff --git a/arch/arm/common/it8152.c b/arch/arm/common/it8152.c
index a7934ba..7bfbab7 100644
--- a/arch/arm/common/it8152.c
+++ b/arch/arm/common/it8152.c
@@ -319,13 +319,6 @@  err0:
 	return -EBUSY;
 }
 
-/*
- * If we set up a device for bus mastering, we need to check the latency
- * timer as we don't have even crappy BIOSes to set it properly.
- * The implementation is from arch/i386/pci/i386.c
- */
-unsigned int pcibios_max_latency = 255;
-
 void pcibios_set_master(struct pci_dev *dev)
 {
 	u8 lat;
diff --git a/arch/frv/mb93090-mb00/pci-frv.c b/arch/frv/mb93090-mb00/pci-frv.c
index 6b4fb28..6a0cd64 100644
--- a/arch/frv/mb93090-mb00/pci-frv.c
+++ b/arch/frv/mb93090-mb00/pci-frv.c
@@ -195,12 +195,6 @@  void __init pcibios_resource_survey(void)
 	pcibios_assign_resources();
 }
 
-/*
- *  If we set up a device for bus mastering, we need to check the latency
- *  timer as certain crappy BIOSes forget to set it properly.
- */
-unsigned int pcibios_max_latency = 255;
-
 void pcibios_set_master(struct pci_dev *dev)
 {
 	u8 lat;
diff --git a/arch/frv/mb93090-mb00/pci-frv.h b/arch/frv/mb93090-mb00/pci-frv.h
index f3fe559..089eeba 100644
--- a/arch/frv/mb93090-mb00/pci-frv.h
+++ b/arch/frv/mb93090-mb00/pci-frv.h
@@ -26,8 +26,6 @@  extern unsigned int __nongpreldata pci_probe;
 
 /* pci-frv.c */
 
-extern unsigned int pcibios_max_latency;
-
 void pcibios_resource_survey(void);
 
 /* pci-vdk.c */
diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
index 33bba7b..a6de9b8 100644
--- a/arch/mips/pci/pci.c
+++ b/arch/mips/pci/pci.c
@@ -204,12 +204,6 @@  static int pcibios_enable_resources(struct pci_dev *dev, int mask)
 	return 0;
 }
 
-/*
- *  If we set up a device for bus mastering, we need to check the latency
- *  timer as certain crappy BIOSes forget to set it properly.
- */
-static unsigned int pcibios_max_latency = 255;
-
 void pcibios_set_master(struct pci_dev *dev)
 {
 	u8 lat;
diff --git a/arch/mn10300/unit-asb2305/pci-asb2305.c b/arch/mn10300/unit-asb2305/pci-asb2305.c
index 8e6763e..2b299c4 100644
--- a/arch/mn10300/unit-asb2305/pci-asb2305.c
+++ b/arch/mn10300/unit-asb2305/pci-asb2305.c
@@ -213,12 +213,6 @@  void __init pcibios_resource_survey(void)
 	pcibios_allocate_resources(1);
 }
 
-/*
- *  If we set up a device for bus mastering, we need to check the latency
- *  timer as certain crappy BIOSes forget to set it properly.
- */
-unsigned int pcibios_max_latency = 255;
-
 void pcibios_set_master(struct pci_dev *dev)
 {
 	u8 lat;
diff --git a/arch/mn10300/unit-asb2305/pci-asb2305.h b/arch/mn10300/unit-asb2305/pci-asb2305.h
index c3fa294..1194fe4 100644
--- a/arch/mn10300/unit-asb2305/pci-asb2305.h
+++ b/arch/mn10300/unit-asb2305/pci-asb2305.h
@@ -31,8 +31,6 @@  extern unsigned int pci_probe;
 
 /* pci-asb2305.c */
 
-extern unsigned int pcibios_max_latency;
-
 extern void pcibios_resource_survey(void);
 
 /* pci.c */
diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c
index 194231c..a0c92fd 100644
--- a/arch/sh/drivers/pci/pci.c
+++ b/arch/sh/drivers/pci/pci.c
@@ -242,12 +242,6 @@  int pcibios_enable_device(struct pci_dev *dev, int mask)
 	return pci_enable_resources(dev, mask);
 }
 
-/*
- *  If we set up a device for bus mastering, we need to check and set
- *  the latency timer as it may not be properly set.
- */
-static unsigned int pcibios_max_latency = 255;
-
 void pcibios_set_master(struct pci_dev *dev)
 {
 	u8 lat;
diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index 7045267..497c8a3 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -44,8 +44,6 @@  enum pci_bf_sort_state {
 
 /* pci-i386.c */
 
-extern unsigned int pcibios_max_latency;
-
 void pcibios_resource_survey(void);
 void pcibios_set_cache_line_size(void);
 
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 494f2e7..5663bc2 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -253,12 +253,6 @@  void __init pcibios_resource_survey(void)
  */
 fs_initcall(pcibios_assign_resources);
 
-/*
- *  If we set up a device for bus mastering, we need to check the latency
- *  timer as certain crappy BIOSes forget to set it properly.
- */
-unsigned int pcibios_max_latency = 255;
-
 void pcibios_set_master(struct pci_dev *dev)
 {
 	u8 lat;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 466fad6..a50e643 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -88,6 +88,12 @@  enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_PERFORMANCE;
 u8 pci_dfl_cache_line_size __devinitdata = L1_CACHE_BYTES >> 2;
 u8 pci_cache_line_size;
 
+/*
+ * If we set up a device for bus mastering, we need to check the latency
+ * timer as certain BIOSes forget to set it properly.
+ */
+unsigned int pcibios_max_latency = 255;
+
 /**
  * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children
  * @bus: pointer to PCI bus structure to search
@@ -2590,6 +2596,29 @@  static void __pci_set_master(struct pci_dev *dev, bool enable)
 }
 
 /**
+ * pcibios_set_master - enable PCI bus-mastering for device dev
+ * @dev: the PCI device to enable
+ *
+ * Enables PCI bus-mastering for the device.  This is the default
+ * implementation.  Architecture specific implementations can override
+ * this if necessary.
+ */
+void __weak pcibios_set_master(struct pci_dev *dev)
+{
+	u8 lat;
+
+	pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
+	if (lat < 16)
+		lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
+	else if (lat > pcibios_max_latency)
+		lat = pcibios_max_latency;
+	else
+		return;
+	dev_printk(KERN_DEBUG, &dev->dev, "setting latency timer to %d\n", lat);
+	pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
+}
+
+/**
  * pci_set_master - enables bus-mastering for device dev
  * @dev: the PCI device to enable
  *
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8c230cb..182b93d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -790,8 +790,11 @@  static inline int pci_is_managed(struct pci_dev *pdev)
 }
 
 void pci_disable_device(struct pci_dev *dev);
+
+extern unsigned int pcibios_max_latency;
 void pci_set_master(struct pci_dev *dev);
 void pci_clear_master(struct pci_dev *dev);
+
 int pci_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state);
 int pci_set_cacheline_size(struct pci_dev *dev);
 #define HAVE_PCI_SET_MWI
@@ -1440,8 +1443,10 @@  extern u8 pci_cache_line_size;
 extern unsigned long pci_hotplug_io_size;
 extern unsigned long pci_hotplug_mem_size;
 
+/* Architecture specific versions may override these (weak) */
 int pcibios_add_platform_entries(struct pci_dev *dev);
 void pcibios_disable_device(struct pci_dev *dev);
+void pcibios_set_master(struct pci_dev *dev);
 int pcibios_set_pcie_reset_state(struct pci_dev *dev,
 				 enum pcie_reset_state state);