PCI: determine CLS more intelligently

Till now, CLS has been determined either by arch code or as
L1_CACHE_BYTES.  Only x86 and ia64 set CLS explicitly and x86 doesn't
always get it right.  On most configurations, the chance is that
firmware configures the correct value during boot.

This patch makes pci_init() determine CLS by looking at what firmware
has configured.  It scans all devices and if all non-zero values
agree, the value is used.  If none is configured or there is a
disagreement, pci_dfl_cache_line_size is used.  arch can set the dfl
value (via PCI_CACHE_LINE_BYTES or pci_dfl_cache_line_size) or
override the actual one.

ia64, x86 and sparc64 updated to set the default cls instead of the
actual one.

While at it, declare pci_cache_line_size and pci_dfl_cache_line_size
in pci.h and drop private declarations from arch code.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David Miller <davem@davemloft.net>
Acked-by: Greg KH <gregkh@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 3 insertions, 5 deletions

diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 1331fcf2614..fbeec31316c 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -410,8 +410,6 @@ struct pci_bus * __devinit pcibios_scan_root(int busnum)
         return bus;
 }
 
-extern u8 pci_cache_line_size;
-
 int __init pcibios_init(void)
 {
         struct cpuinfo_x86 *c = &boot_cpu_data;
@@ -426,11 +424,11 @@ int __init pcibios_init(void)
          * and P4. It's also good for 386/486s (which actually have 16)
          * as quite a few PCI devices do not support smaller values.
          */
-        pci_cache_line_size = 32 >> 2;
+        pci_dfl_cache_line_size = 32 >> 2;
         if (c->x86 >= 6 && c->x86_vendor == X86_VENDOR_AMD)
-                pci_cache_line_size = 64 >> 2;  /* K7 & K8 */
+                pci_dfl_cache_line_size = 64 >> 2;      /* K7 & K8 */
         else if (c->x86 > 6 && c->x86_vendor == X86_VENDOR_INTEL)
-                pci_cache_line_size = 128 >> 2; /* P4 */
+                pci_dfl_cache_line_size = 128 >> 2;     /* P4 */
 
         pcibios_resource_survey();