lkml.org 
[lkml]   [2015]   [Sep]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 2.6.32 33/62] MIPS: Octeon: Remove udelay() causing huge IRQ latency
2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Sverdlin <alexander.sverdlin@nokia.com>

commit 73bf3c2a500b2db8ac966469591196bf55afb409 upstream.

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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from commit 53493d44a771a3155ee12b6ac668fb2543d21a7a)

Signed-off-by: Willy Tarreau <w@1wt.eu>
---
arch/mips/include/asm/octeon/pci-octeon.h | 3 ---
arch/mips/pci/pci-octeon.c | 6 ------
arch/mips/pci/pcie-octeon.c | 3 ---
3 files changed, 12 deletions(-)

diff --git a/arch/mips/include/asm/octeon/pci-octeon.h b/arch/mips/include/asm/octeon/pci-octeon.h
index 6ac5d3e..5eda9f0 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
-
/*
* pcibios_map_irq() is defined inside pci-octeon.c. All it does is
* call the Octeon specific version pointed to by this variable. This
diff --git a/arch/mips/pci/pci-octeon.c b/arch/mips/pci/pci-octeon.c
index 9cb0c80..dae7ff7 100644
--- a/arch/mips/pci/pci-octeon.c
+++ b/arch/mips/pci/pci-octeon.c
@@ -274,9 +274,6 @@ 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));
@@ -311,9 +308,6 @@ 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 6aa5c54..97813f3 100644
--- a/arch/mips/pci/pcie-octeon.c
+++ b/arch/mips/pci/pcie-octeon.c
@@ -1192,9 +1192,6 @@ static inline int octeon_pcie_write_config(int pcie_port, struct pci_bus *bus,
devfn & 0x7, reg, val);
return PCIBIOS_SUCCESSFUL;
}
-#if PCI_CONFIG_SPACE_DELAY
- udelay(PCI_CONFIG_SPACE_DELAY);
-#endif
return PCIBIOS_FUNC_NOT_SUPPORTED;
}

--
1.7.12.2.21.g234cd45.dirty




\
 
 \ /
  Last update: 2015-09-13 01:41    [W:0.253 / U:11.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site