From ac1aa47b131416a6ff37eb1005a0a1d2541aad6c Mon Sep 17 00:00:00 2001 From: Jesse Barnes Date: Mon, 26 Oct 2009 13:20:44 -0700 Subject: 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 Acked-by: David Miller Acked-by: Greg KH Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Tony Luck Signed-off-by: Jesse Barnes --- drivers/pci/quirks.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'drivers/pci/quirks.c') diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 245d2cdb476..1812ae7698d 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -2595,9 +2595,37 @@ void pci_fixup_device(enum pci_fixup_pass pass, struct pci_dev *dev) static int __init pci_apply_final_quirks(void) { struct pci_dev *dev = NULL; + u8 cls = 0; + u8 tmp; + + if (pci_cache_line_size) + printk(KERN_DEBUG "PCI: CLS %u bytes\n", + pci_cache_line_size << 2); while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) { pci_fixup_device(pci_fixup_final, dev); + /* + * If arch hasn't set it explicitly yet, use the CLS + * value shared by all PCI devices. If there's a + * mismatch, fall back to the default value. + */ + if (!pci_cache_line_size) { + pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &tmp); + if (!cls) + cls = tmp; + if (!tmp || cls == tmp) + continue; + + printk(KERN_DEBUG "PCI: CLS mismatch (%u != %u), " + "using %u bytes\n", cls << 2, tmp << 2, + pci_dfl_cache_line_size << 2); + pci_cache_line_size = pci_dfl_cache_line_size; + } + } + if (!pci_cache_line_size) { + printk(KERN_DEBUG "PCI: CLS %u bytes, default %u\n", + cls << 2, pci_dfl_cache_line_size << 2); + pci_cache_line_size = cls; } return 0; -- cgit v1.2.3