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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/x86/pci/mmconfig_64.c
Initial import
Diffstat (limited to 'arch/x86/pci/mmconfig_64.c')
-rw-r--r--arch/x86/pci/mmconfig_64.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/arch/x86/pci/mmconfig_64.c b/arch/x86/pci/mmconfig_64.c
new file mode 100644
index 000000000..bea52496a
--- /dev/null
+++ b/arch/x86/pci/mmconfig_64.c
@@ -0,0 +1,153 @@
+/*
+ * 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 <linux/acpi.h>
+#include <linux/bitmap.h>
+#include <linux/rcupdate.h>
+#include <asm/e820.h>
+#include <asm/pci_x86.h>
+
+#define PREFIX "PCI: "
+
+static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
+{
+ struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
+
+ if (cfg && cfg->virt)
+ return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));
+ return NULL;
+}
+
+static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
+ unsigned int devfn, int reg, int len, u32 *value)
+{
+ char __iomem *addr;
+
+ /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
+ if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
+err: *value = -1;
+ return -EINVAL;
+ }
+
+ rcu_read_lock();
+ addr = pci_dev_base(seg, bus, devfn);
+ if (!addr) {
+ rcu_read_unlock();
+ goto err;
+ }
+
+ switch (len) {
+ case 1:
+ *value = mmio_config_readb(addr + reg);
+ break;
+ case 2:
+ *value = mmio_config_readw(addr + reg);
+ break;
+ case 4:
+ *value = mmio_config_readl(addr + reg);
+ break;
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
+
+static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
+ unsigned int devfn, int reg, int len, u32 value)
+{
+ char __iomem *addr;
+
+ /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
+ if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
+ return -EINVAL;
+
+ rcu_read_lock();
+ addr = pci_dev_base(seg, bus, devfn);
+ if (!addr) {
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+
+ switch (len) {
+ case 1:
+ mmio_config_writeb(addr + reg, value);
+ break;
+ case 2:
+ mmio_config_writew(addr + reg, value);
+ break;
+ case 4:
+ mmio_config_writel(addr + reg, value);
+ break;
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
+
+const struct pci_raw_ops pci_mmcfg = {
+ .read = pci_mmcfg_read,
+ .write = pci_mmcfg_write,
+};
+
+static void __iomem *mcfg_ioremap(struct pci_mmcfg_region *cfg)
+{
+ void __iomem *addr;
+ u64 start, size;
+ int num_buses;
+
+ start = cfg->address + PCI_MMCFG_BUS_OFFSET(cfg->start_bus);
+ num_buses = cfg->end_bus - cfg->start_bus + 1;
+ size = PCI_MMCFG_BUS_OFFSET(num_buses);
+ addr = ioremap_nocache(start, size);
+ if (addr)
+ addr -= PCI_MMCFG_BUS_OFFSET(cfg->start_bus);
+ return addr;
+}
+
+int __init pci_mmcfg_arch_init(void)
+{
+ struct pci_mmcfg_region *cfg;
+
+ list_for_each_entry(cfg, &pci_mmcfg_list, list)
+ if (pci_mmcfg_arch_map(cfg)) {
+ pci_mmcfg_arch_free();
+ return 0;
+ }
+
+ raw_pci_ext_ops = &pci_mmcfg;
+
+ return 1;
+}
+
+void __init pci_mmcfg_arch_free(void)
+{
+ struct pci_mmcfg_region *cfg;
+
+ list_for_each_entry(cfg, &pci_mmcfg_list, list)
+ pci_mmcfg_arch_unmap(cfg);
+}
+
+int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg)
+{
+ cfg->virt = mcfg_ioremap(cfg);
+ if (!cfg->virt) {
+ pr_err(PREFIX "can't map MMCONFIG at %pR\n", &cfg->res);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg)
+{
+ if (cfg && cfg->virt) {
+ iounmap(cfg->virt + PCI_MMCFG_BUS_OFFSET(cfg->start_bus));
+ cfg->virt = NULL;
+ }
+}