On 03/18/2015 06:05 AM, Alexander Sverdlin wrote:
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>
Can you say how it was tested. In principle I have no objections, but
it would be nice to know how it was validated.
Thanks,
David Daney
---
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, 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;
}
