1 files changed, 315 insertions, 0 deletions
diff --git a/arch/x86/pci/direct.c b/arch/x86/pci/direct.c
new file mode 100644
index 000000000..a51074c55
--- /dev/null
+++ b/arch/x86/pci/direct.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * direct.c - Low-level direct PCI config space access
+ */
+
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/dmi.h>
+#include <asm/pci_x86.h>
+
+/*
+ * Functions for accessing PCI base (first 256 bytes) and extended
+ * (4096 bytes per PCI function) configuration space with type 1
+ * accesses.
+ */
+
+#define PCI_CONF1_ADDRESS(bus, devfn, reg) \
+	(0x80000000 | ((reg & 0xF00) << 16) | (bus << 16) \
+	| (devfn << 8) | (reg & 0xFC))
+
+static int pci_conf1_read(unsigned int seg, unsigned int bus,
+			  unsigned int devfn, int reg, int len, u32 *value)
+{
+	unsigned long flags;
+
+	if (seg || (bus > 255) || (devfn > 255) || (reg > 4095)) {
+		*value = -1;
+		return -EINVAL;
+	}
+
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+
+	outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8);
+
+	switch (len) {
+	case 1:
+		*value = inb(0xCFC + (reg & 3));
+		break;
+	case 2:
+		*value = inw(0xCFC + (reg & 2));
+		break;
+	case 4:
+		*value = inl(0xCFC);
+		break;
+	}
+
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+
+	return 0;
+}
+
+static int pci_conf1_write(unsigned int seg, unsigned int bus,
+			   unsigned int devfn, int reg, int len, u32 value)
+{
+	unsigned long flags;
+
+	if (seg || (bus > 255) || (devfn > 255) || (reg > 4095))
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+
+	outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8);
+
+	switch (len) {
+	case 1:
+		outb((u8)value, 0xCFC + (reg & 3));
+		break;
+	case 2:
+		outw((u16)value, 0xCFC + (reg & 2));
+		break;
+	case 4:
+		outl((u32)value, 0xCFC);
+		break;
+	}
+
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+
+	return 0;
+}
+
+#undef PCI_CONF1_ADDRESS
+
+const struct pci_raw_ops pci_direct_conf1 = {
+	.read =		pci_conf1_read,
+	.write =	pci_conf1_write,
+};
+
+
+/*
+ * Functions for accessing PCI configuration space with type 2 accesses
+ */
+
+#define PCI_CONF2_ADDRESS(dev, reg)	(u16)(0xC000 | (dev << 8) | reg)
+
+static int pci_conf2_read(unsigned int seg, unsigned int bus,
+			  unsigned int devfn, int reg, int len, u32 *value)
+{
+	unsigned long flags;
+	int dev, fn;
+
+	WARN_ON(seg);
+	if ((bus > 255) || (devfn > 255) || (reg > 255)) {
+		*value = -1;
+		return -EINVAL;
+	}
+
+	dev = PCI_SLOT(devfn);
+	fn = PCI_FUNC(devfn);
+
+	if (dev & 0x10) 
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+
+	outb((u8)(0xF0 | (fn << 1)), 0xCF8);
+	outb((u8)bus, 0xCFA);
+
+	switch (len) {
+	case 1:
+		*value = inb(PCI_CONF2_ADDRESS(dev, reg));
+		break;
+	case 2:
+		*value = inw(PCI_CONF2_ADDRESS(dev, reg));
+		break;
+	case 4:
+		*value = inl(PCI_CONF2_ADDRESS(dev, reg));
+		break;
+	}
+
+	outb(0, 0xCF8);
+
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+
+	return 0;
+}
+
+static int pci_conf2_write(unsigned int seg, unsigned int bus,
+			   unsigned int devfn, int reg, int len, u32 value)
+{
+	unsigned long flags;
+	int dev, fn;
+
+	WARN_ON(seg);
+	if ((bus > 255) || (devfn > 255) || (reg > 255)) 
+		return -EINVAL;
+
+	dev = PCI_SLOT(devfn);
+	fn = PCI_FUNC(devfn);
+
+	if (dev & 0x10) 
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	raw_spin_lock_irqsave(&pci_config_lock, flags);
+
+	outb((u8)(0xF0 | (fn << 1)), 0xCF8);
+	outb((u8)bus, 0xCFA);
+
+	switch (len) {
+	case 1:
+		outb((u8)value, PCI_CONF2_ADDRESS(dev, reg));
+		break;
+	case 2:
+		outw((u16)value, PCI_CONF2_ADDRESS(dev, reg));
+		break;
+	case 4:
+		outl((u32)value, PCI_CONF2_ADDRESS(dev, reg));
+		break;
+	}
+
+	outb(0, 0xCF8);    
+
+	raw_spin_unlock_irqrestore(&pci_config_lock, flags);
+
+	return 0;
+}
+
+#undef PCI_CONF2_ADDRESS
+
+static const struct pci_raw_ops pci_direct_conf2 = {
+	.read =		pci_conf2_read,
+	.write =	pci_conf2_write,
+};
+
+
+/*
+ * Before we decide to use direct hardware access mechanisms, we try to do some
+ * trivial checks to ensure it at least _seems_ to be working -- we just test
+ * whether bus 00 contains a host bridge (this is similar to checking
+ * techniques used in XFree86, but ours should be more reliable since we
+ * attempt to make use of direct access hints provided by the PCI BIOS).
+ *
+ * This should be close to trivial, but it isn't, because there are buggy
+ * chipsets (yes, you guessed it, by Intel and Compaq) that have no class ID.
+ */
+static int __init pci_sanity_check(const struct pci_raw_ops *o)
+{
+	u32 x = 0;
+	int devfn;
+
+	if (pci_probe & PCI_NO_CHECKS)
+		return 1;
+	/* Assume Type 1 works for newer systems.
+	   This handles machines that don't have anything on PCI Bus 0. */
+	if (dmi_get_bios_year() >= 2001)
+		return 1;
+
+	for (devfn = 0; devfn < 0x100; devfn++) {
+		if (o->read(0, 0, devfn, PCI_CLASS_DEVICE, 2, &x))
+			continue;
+		if (x == PCI_CLASS_BRIDGE_HOST || x == PCI_CLASS_DISPLAY_VGA)
+			return 1;
+
+		if (o->read(0, 0, devfn, PCI_VENDOR_ID, 2, &x))
+			continue;
+		if (x == PCI_VENDOR_ID_INTEL || x == PCI_VENDOR_ID_COMPAQ)
+			return 1;
+	}
+
+	DBG(KERN_WARNING "PCI: Sanity check failed\n");
+	return 0;
+}
+
+static int __init pci_check_type1(void)
+{
+	unsigned long flags;
+	unsigned int tmp;
+	int works = 0;
+
+	local_irq_save(flags);
+
+	outb(0x01, 0xCFB);
+	tmp = inl(0xCF8);
+	outl(0x80000000, 0xCF8);
+	if (inl(0xCF8) == 0x80000000 && pci_sanity_check(&pci_direct_conf1)) {
+		works = 1;
+	}
+	outl(tmp, 0xCF8);
+	local_irq_restore(flags);
+
+	return works;
+}
+
+static int __init pci_check_type2(void)
+{
+	unsigned long flags;
+	int works = 0;
+
+	local_irq_save(flags);
+
+	outb(0x00, 0xCFB);
+	outb(0x00, 0xCF8);
+	outb(0x00, 0xCFA);
+	if (inb(0xCF8) == 0x00 && inb(0xCFA) == 0x00 &&
+	    pci_sanity_check(&pci_direct_conf2)) {
+		works = 1;
+	}
+
+	local_irq_restore(flags);
+
+	return works;
+}
+
+void __init pci_direct_init(int type)
+{
+	if (type == 0)
+		return;
+	printk(KERN_INFO "PCI: Using configuration type %d for base access\n",
+		 type);
+	if (type == 1) {
+		raw_pci_ops = &pci_direct_conf1;
+		if (raw_pci_ext_ops)
+			return;
+		if (!(pci_probe & PCI_HAS_IO_ECS))
+			return;
+		printk(KERN_INFO "PCI: Using configuration type 1 "
+		       "for extended access\n");
+		raw_pci_ext_ops = &pci_direct_conf1;
+		return;
+	}
+	raw_pci_ops = &pci_direct_conf2;
+}
+
+int __init pci_direct_probe(void)
+{
+	if ((pci_probe & PCI_PROBE_CONF1) == 0)
+		goto type2;
+	if (!request_region(0xCF8, 8, "PCI conf1"))
+		goto type2;
+
+	if (pci_check_type1()) {
+		raw_pci_ops = &pci_direct_conf1;
+		port_cf9_safe = true;
+		return 1;
+	}
+	release_region(0xCF8, 8);
+
+ type2:
+	if ((pci_probe & PCI_PROBE_CONF2) == 0)
+		return 0;
+	if (!request_region(0xCF8, 4, "PCI conf2"))
+		return 0;
+	if (!request_region(0xC000, 0x1000, "PCI conf2"))
+		goto fail2;
+
+	if (pci_check_type2()) {
+		raw_pci_ops = &pci_direct_conf2;
+		port_cf9_safe = true;
+		return 2;
+	}
+
+	release_region(0xC000, 0x1000);
+ fail2:
+	release_region(0xCF8, 4);
+	return 0;
+}