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>

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 64ba56a02843..1884609741a8 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 a04af55d89f1..01c604a5ac36 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 1bb0b2bf8d6e..99f3db4f0a9b 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;
 }