aboutsummaryrefslogtreecommitdiff
path: root/arch/x86_64/pci/mmconfig.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86_64/pci/mmconfig.c')
-rw-r--r--arch/x86_64/pci/mmconfig.c104
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);