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authorAlexander Sverdlin <alexander.sverdlin@nokia.com>2015-03-18 14:05:21 +0100
committerRalf Baechle <ralf@linux-mips.org>2015-04-10 15:41:42 +0200
commit73bf3c2a500b2db8ac966469591196bf55afb409 (patch)
tree1ca3d97a0cf83fce6287ce201af6acdb2ee60e3f /arch
parent4d46a67a3eb827ccf1125959936fd51ba318dabc (diff)
downloadop-kernel-dev-73bf3c2a500b2db8ac966469591196bf55afb409.zip
op-kernel-dev-73bf3c2a500b2db8ac966469591196bf55afb409.tar.gz
MIPS: Octeon: Remove udelay() causing huge IRQ latency
udelay() in PCI/PCIe read/write callbacks cause 30ms IRQ latency on Octeon platforms because these operations are called from PCI_OP_READ() and PCI_OP_WRITE() under raw_spin_lock_irqsave(). Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Cc: linux-mips@linux-mips.org Cc: David Daney <ddaney@cavium.com> Cc: Rob Herring <robh@kernel.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Masanari Iida <standby24x7@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Mathias <mathias.rulf@nokia.com> Patchwork: https://patchwork.linux-mips.org/patch/9576/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/include/asm/octeon/pci-octeon.h3
-rw-r--r--arch/mips/pci/pci-octeon.c6
-rw-r--r--arch/mips/pci/pcie-octeon.c8
3 files changed, 0 insertions, 17 deletions
diff --git a/arch/mips/include/asm/octeon/pci-octeon.h b/arch/mips/include/asm/octeon/pci-octeon.h
index 64ba56a..1884609 100644
--- a/arch/mips/include/asm/octeon/pci-octeon.h
+++ b/arch/mips/include/asm/octeon/pci-octeon.h
@@ -11,9 +11,6 @@
#include <linux/pci.h>
-/* Some PCI cards require delays when accessing config space. */
-#define PCI_CONFIG_SPACE_DELAY 10000
-
/*
* The physical memory base mapped by BAR1. 256MB at the end of the
* first 4GB.
diff --git a/arch/mips/pci/pci-octeon.c b/arch/mips/pci/pci-octeon.c
index a04af55..01c604a 100644
--- a/arch/mips/pci/pci-octeon.c
+++ b/arch/mips/pci/pci-octeon.c
@@ -271,9 +271,6 @@ static int octeon_read_config(struct pci_bus *bus, unsigned int devfn,
pci_addr.s.func = devfn & 0x7;
pci_addr.s.reg = reg;
-#if PCI_CONFIG_SPACE_DELAY
- udelay(PCI_CONFIG_SPACE_DELAY);
-#endif
switch (size) {
case 4:
*val = le32_to_cpu(cvmx_read64_uint32(pci_addr.u64));
@@ -308,9 +305,6 @@ static int octeon_write_config(struct pci_bus *bus, unsigned int devfn,
pci_addr.s.func = devfn & 0x7;
pci_addr.s.reg = reg;
-#if PCI_CONFIG_SPACE_DELAY
- udelay(PCI_CONFIG_SPACE_DELAY);
-#endif
switch (size) {
case 4:
cvmx_write64_uint32(pci_addr.u64, cpu_to_le32(val));
diff --git a/arch/mips/pci/pcie-octeon.c b/arch/mips/pci/pcie-octeon.c
index 1bb0b2b..99f3db4 100644
--- a/arch/mips/pci/pcie-octeon.c
+++ b/arch/mips/pci/pcie-octeon.c
@@ -1762,14 +1762,6 @@ static int octeon_pcie_write_config(unsigned int pcie_port, struct pci_bus *bus,
default:
return PCIBIOS_FUNC_NOT_SUPPORTED;
}
-#if PCI_CONFIG_SPACE_DELAY
- /*
- * Delay on writes so that devices have time to come up. Some
- * bridges need this to allow time for the secondary busses to
- * work
- */
- udelay(PCI_CONFIG_SPACE_DELAY);
-#endif
return PCIBIOS_SUCCESSFUL;
}
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