1 files changed, 156 insertions, 0 deletions
diff --git a/arch/x86/pci/mmconfig_32.c b/arch/x86/pci/mmconfig_32.c
new file mode 100644
index 000000000..bfa789875
--- /dev/null
+++ b/arch/x86/pci/mmconfig_32.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2004 Matthew Wilcox <matthew@wil.cx>
+ * Copyright (C) 2004 Intel Corp.
+ */
+
+/*
+ * mmconfig.c - Low-level direct PCI config space access via MMCONFIG
+ */
+
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/rcupdate.h>
+#include <asm/e820/api.h>
+#include <asm/pci_x86.h>
+
+/* Assume systems with more busses have correct MCFG */
+#define mmcfg_virt_addr ((void __iomem *) fix_to_virt(FIX_PCIE_MCFG))
+
+/* The base address of the last MMCONFIG device accessed */
+static u32 mmcfg_last_accessed_device;
+static int mmcfg_last_accessed_cpu;
+
+/*
+ * Functions for accessing PCI configuration space with MMCONFIG accesses
+ */
+static u32 get_base_addr(unsigned int seg, int bus, unsigned devfn)
+{
+	struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
+
+	if (cfg)
+		return cfg->address;
+	return 0;
+}
+
+/*
+ * This is always called under pci_config_lock
+ */
+static void pci_exp_set_dev_base(unsigned int base, int bus, int devfn)
+{
+	u32 dev_base = base | PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12);
+	int cpu = smp_processor_id();
+	if (dev_base != mmcfg_last_accessed_device ||
+	    cpu != mmcfg_last_accessed_cpu) {
+		mmcfg_last_accessed_device = dev_base;
+		mmcfg_last_accessed_cpu = cpu;
+		set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
+	}
+}
+
+static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
+			  unsigned int devfn, int reg, int len, u32 *value)
+{
+	unsigned long flags;
+	u32 base;
+
+	if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
+err:		*value = -1;
+		return -EINVAL;
+	}
+
+	rcu_read_lock();
+	base = get_base_addr(seg, bus, devfn);
+	if (!base) {
+		rcu_read_unlock();
+		goto err;
+	}
+
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+
+	pci_exp_set_dev_base(base, bus, devfn);
+
+	switch (len) {
+	case 1:
+		*value = mmio_config_readb(mmcfg_virt_addr + reg);
+		break;
+	case 2:
+		*value = mmio_config_readw(mmcfg_virt_addr + reg);
+		break;
+	case 4:
+		*value = mmio_config_readl(mmcfg_virt_addr + reg);
+		break;
+	}
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+	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)
+{
+	unsigned long flags;
+	u32 base;
+
+	if ((bus > 255) || (devfn > 255) || (reg > 4095))
+		return -EINVAL;
+
+	rcu_read_lock();
+	base = get_base_addr(seg, bus, devfn);
+	if (!base) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+
+	pci_exp_set_dev_base(base, bus, devfn);
+
+	switch (len) {
+	case 1:
+		mmio_config_writeb(mmcfg_virt_addr + reg, value);
+		break;
+	case 2:
+		mmio_config_writew(mmcfg_virt_addr + reg, value);
+		break;
+	case 4:
+		mmio_config_writel(mmcfg_virt_addr + reg, value);
+		break;
+	}
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+	rcu_read_unlock();
+
+	return 0;
+}
+
+const struct pci_raw_ops pci_mmcfg = {
+	.read =		pci_mmcfg_read,
+	.write =	pci_mmcfg_write,
+};
+
+int __init pci_mmcfg_arch_init(void)
+{
+	printk(KERN_INFO "PCI: Using MMCONFIG for extended config space\n");
+	raw_pci_ext_ops = &pci_mmcfg;
+	return 1;
+}
+
+void __init pci_mmcfg_arch_free(void)
+{
+}
+
+int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg)
+{
+	return 0;
+}
+
+void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg)
+{
+	unsigned long flags;
+
+	/* Invalidate the cached mmcfg map entry. */
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+	mmcfg_last_accessed_device = 0;
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+}