This is a note to let you know that I've just added the patch titled
MIPS: Octeon: Remove udelay() causing huge IRQ latency
to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mips-octeon-remove-udelay-causing-huge-irq-latency.patch
and it can be found in the queue-4.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ralf@xxxxxxxxxxxxxx Fri May 8 16:24:52 2015
From: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Date: Wed, 18 Mar 2015 14:05:21 +0100
Subject: MIPS: Octeon: Remove udelay() causing huge IRQ latency
To: stable@xxxxxxxxxxxxxxx
Message-ID: <0d6db65f5dd6fb417f1f45bac283d0e23814fe34.1431087908.git.ralf@xxxxxxxxxxxxxx>
From: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
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@xxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: David Daney <ddaney@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Masanari Iida <standby24x7@xxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Mathias <mathias.rulf@xxxxxxxxx>
Patchwork: https://patchwork.linux-mips.org/patch/9576/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/include/asm/octeon/pci-octeon.h | 3 ---
arch/mips/pci/pci-octeon.c | 6 ------
arch/mips/pci/pcie-octeon.c | 8 --------
3 files changed, 17 deletions(-)
--- 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.
--- 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
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 pc
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));
--- a/arch/mips/pci/pcie-octeon.c
+++ b/arch/mips/pci/pcie-octeon.c
@@ -1762,14 +1762,6 @@ static int octeon_pcie_write_config(unsi
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;
}
Patches currently in stable-queue which might be from ralf@xxxxxxxxxxxxxx are
queue-4.0/mips-octeon-remove-udelay-causing-huge-irq-latency.patch
queue-4.0/mips-makefile-fix-mips-ase-detection-code.patch
queue-4.0/mips-r4kcache-use-correct-base-register-for-mips-r6-cache-flushes.patch
queue-4.0/mips-fix-cpu_has_mips_r2_exec_hazard.patch
queue-4.0/mips-ralink-fix-bad-config-symbol-in-pci-makefile.patch
queue-4.0/revert-mips-remove-race-window-in-page-fault-handling.patch
queue-4.0/mips-fix-race-condition-in-lazy-cache-flushing.patch
queue-4.0/mips-bcm63xx-move-bcm63xx_gpio_init-to-bcm63xx_register_devices.patch
queue-4.0/mips-octeon-delete-override-of-cpu_has_mips_r2_exec_hazard.patch
queue-4.0/mips-asm-spinlock-fix-addiu-instruction-for-r10000_llsc_war-case.patch
queue-4.0/mips-kconfig-disable-smp-cps-for-64-bit.patch
queue-4.0/mips-bcm47xx-fix-detecting-microsoft-mn-700-asus-wl500g.patch
queue-4.0/mips-octeon-use-correct-csr-to-soft-reset.patch
queue-4.0/revert-mips-avoid-pipeline-stalls-on-some-mips32r2-cores.patch
queue-4.0/mips-octeon-dma-octeon-fix-ohci-usb-config-check.patch
queue-4.0/mips-octeon-fix-pci-interrupt-mapping-for-d-link-dsr-1000n.patch
queue-4.0/mips-kconfig-fix-typo-for-the-r2-to-r6-emulator-kernel-parameter.patch
queue-4.0/ssb-fix-kconfig-dependencies.patch
queue-4.0/mips-kernel-entry.s-set-correct-isa-level-for-mips_ihb.patch
queue-4.0/mips-netlogic-fix-for-sata-phy-init.patch
queue-4.0/mips-ralink-add-missing-symbol-for-ralink_ill_acc.patch
queue-4.0/mips-asm-elf-set-o32-default-fpu-flags.patch
queue-4.0/mips-smp-cps-cpu_set-fpu-mask-if-fpu-present.patch
--
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