1 files changed, 104 insertions, 0 deletions
diff --git a/arch/x86_64/pci/mmconfig.c b/arch/x86_64/pci/mmconfig.c
new file mode 100644
index 000000000000..b693c232fd07
--- /dev/null
+++ b/arch/x86_64/pci/mmconfig.c
@@ -0,0 +1,104 @@
+/*
+ * mmconfig.c - Low-level direct PCI config space access via MMCONFIG
+ * 
+ * This is an 64bit optimized version that always keeps the full mmconfig
+ * space mapped. This allows lockless config space operation.
+ */
+
+#include <linux/pci.h>
+#include <linux/init.h>
+#include "pci.h"
+
+#define MMCONFIG_APER_SIZE (256*1024*1024)
+
+/* The physical address of the MMCONFIG aperture.  Set from ACPI tables. */
+u32 pci_mmcfg_base_addr;
+
+/* Static virtual mapping of the MMCONFIG aperture */
+char *pci_mmcfg_virt;
+
+static inline char *pci_dev_base(unsigned int bus, unsigned int devfn)
+{
+	return pci_mmcfg_virt + ((bus << 20) | (devfn << 12));
+}
+
+static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
+			  unsigned int devfn, int reg, int len, u32 *value)
+{
+	char *addr = pci_dev_base(bus, devfn); 
+
+	if (unlikely(!value || (bus > 255) || (devfn > 255) || (reg > 4095)))
+		return -EINVAL;
+
+	switch (len) {
+	case 1:
+		*value = readb(addr + reg);
+		break;
+	case 2:
+		*value = readw(addr + reg);
+		break;
+	case 4:
+		*value = readl(addr + reg);
+		break;
+	}
+
+	return 0;
+}
+
+static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
+			   unsigned int devfn, int reg, int len, u32 value)
+{
+	char *addr = pci_dev_base(bus,devfn);
+
+	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
+		return -EINVAL;
+
+	switch (len) {
+	case 1:
+		writeb(value, addr + reg);
+		break;
+	case 2:
+		writew(value, addr + reg);
+		break;
+	case 4:
+		writel(value, addr + reg);
+		break;
+	}
+
+	return 0;
+}
+
+static struct pci_raw_ops pci_mmcfg = {
+	.read =		pci_mmcfg_read,
+	.write =	pci_mmcfg_write,
+};
+
+static int __init pci_mmcfg_init(void)
+{
+	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
+		return 0;
+	if (!pci_mmcfg_base_addr)
+		return 0;
+
+	/* Kludge for now. Don't use mmconfig on AMD systems because
+	   those have some busses where mmconfig doesn't work,
+	   and we don't parse ACPI MCFG well enough to handle that. 
+	   Remove when proper handling is added. */
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+		return 0; 
+
+	/* RED-PEN i386 doesn't do _nocache right now */
+	pci_mmcfg_virt = ioremap_nocache(pci_mmcfg_base_addr, MMCONFIG_APER_SIZE);
+	if (!pci_mmcfg_virt) { 
+		printk("PCI: Cannot map mmconfig aperture\n");
+		return 0;
+	}	
+
+	printk(KERN_INFO "PCI: Using MMCONFIG at %x\n", pci_mmcfg_base_addr);
+	raw_pci_ops = &pci_mmcfg;
+	pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
+
+	return 0;
+}
+
+arch_initcall(pci_mmcfg_init);