1 files changed, 288 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/eeh_cache.c b/arch/powerpc/kernel/eeh_cache.c
new file mode 100644
index 000000000..bf3270426
--- /dev/null
+++ b/arch/powerpc/kernel/eeh_cache.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PCI address cache; allows the lookup of PCI devices based on I/O address
+ *
+ * Copyright IBM Corporation 2004
+ * Copyright Linas Vepstas <linas@austin.ibm.com> 2004
+ */
+
+#include <linux/list.h>
+#include <linux/pci.h>
+#include <linux/rbtree.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/atomic.h>
+#include <asm/pci-bridge.h>
+#include <asm/debugfs.h>
+#include <asm/ppc-pci.h>
+
+
+/**
+ * DOC: Overview
+ *
+ * The pci address cache subsystem.  This subsystem places
+ * PCI device address resources into a red-black tree, sorted
+ * according to the address range, so that given only an i/o
+ * address, the corresponding PCI device can be **quickly**
+ * found. It is safe to perform an address lookup in an interrupt
+ * context; this ability is an important feature.
+ *
+ * Currently, the only customer of this code is the EEH subsystem;
+ * thus, this code has been somewhat tailored to suit EEH better.
+ * In particular, the cache does *not* hold the addresses of devices
+ * for which EEH is not enabled.
+ *
+ * (Implementation Note: The RB tree seems to be better/faster
+ * than any hash algo I could think of for this problem, even
+ * with the penalty of slow pointer chases for d-cache misses).
+ */
+
+struct pci_io_addr_range {
+	struct rb_node rb_node;
+	resource_size_t addr_lo;
+	resource_size_t addr_hi;
+	struct eeh_dev *edev;
+	struct pci_dev *pcidev;
+	unsigned long flags;
+};
+
+static struct pci_io_addr_cache {
+	struct rb_root rb_root;
+	spinlock_t piar_lock;
+} pci_io_addr_cache_root;
+
+static inline struct eeh_dev *__eeh_addr_cache_get_device(unsigned long addr)
+{
+	struct rb_node *n = pci_io_addr_cache_root.rb_root.rb_node;
+
+	while (n) {
+		struct pci_io_addr_range *piar;
+		piar = rb_entry(n, struct pci_io_addr_range, rb_node);
+
+		if (addr < piar->addr_lo)
+			n = n->rb_left;
+		else if (addr > piar->addr_hi)
+			n = n->rb_right;
+		else
+			return piar->edev;
+	}
+
+	return NULL;
+}
+
+/**
+ * eeh_addr_cache_get_dev - Get device, given only address
+ * @addr: mmio (PIO) phys address or i/o port number
+ *
+ * Given an mmio phys address, or a port number, find a pci device
+ * that implements this address.  I/O port numbers are assumed to be offset
+ * from zero (that is, they do *not* have pci_io_addr added in).
+ * It is safe to call this function within an interrupt.
+ */
+struct eeh_dev *eeh_addr_cache_get_dev(unsigned long addr)
+{
+	struct eeh_dev *edev;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
+	edev = __eeh_addr_cache_get_device(addr);
+	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
+	return edev;
+}
+
+#ifdef DEBUG
+/*
+ * Handy-dandy debug print routine, does nothing more
+ * than print out the contents of our addr cache.
+ */
+static void eeh_addr_cache_print(struct pci_io_addr_cache *cache)
+{
+	struct rb_node *n;
+	int cnt = 0;
+
+	n = rb_first(&cache->rb_root);
+	while (n) {
+		struct pci_io_addr_range *piar;
+		piar = rb_entry(n, struct pci_io_addr_range, rb_node);
+		pr_info("PCI: %s addr range %d [%pap-%pap]: %s\n",
+		       (piar->flags & IORESOURCE_IO) ? "i/o" : "mem", cnt,
+		       &piar->addr_lo, &piar->addr_hi, pci_name(piar->pcidev));
+		cnt++;
+		n = rb_next(n);
+	}
+}
+#endif
+
+/* Insert address range into the rb tree. */
+static struct pci_io_addr_range *
+eeh_addr_cache_insert(struct pci_dev *dev, resource_size_t alo,
+		      resource_size_t ahi, unsigned long flags)
+{
+	struct rb_node **p = &pci_io_addr_cache_root.rb_root.rb_node;
+	struct rb_node *parent = NULL;
+	struct pci_io_addr_range *piar;
+
+	/* Walk tree, find a place to insert into tree */
+	while (*p) {
+		parent = *p;
+		piar = rb_entry(parent, struct pci_io_addr_range, rb_node);
+		if (ahi < piar->addr_lo) {
+			p = &parent->rb_left;
+		} else if (alo > piar->addr_hi) {
+			p = &parent->rb_right;
+		} else {
+			if (dev != piar->pcidev ||
+			    alo != piar->addr_lo || ahi != piar->addr_hi) {
+				pr_warn("PIAR: overlapping address range\n");
+			}
+			return piar;
+		}
+	}
+	piar = kzalloc(sizeof(struct pci_io_addr_range), GFP_ATOMIC);
+	if (!piar)
+		return NULL;
+
+	piar->addr_lo = alo;
+	piar->addr_hi = ahi;
+	piar->edev = pci_dev_to_eeh_dev(dev);
+	piar->pcidev = dev;
+	piar->flags = flags;
+
+	eeh_edev_dbg(piar->edev, "PIAR: insert range=[%pap:%pap]\n",
+		 &alo, &ahi);
+
+	rb_link_node(&piar->rb_node, parent, p);
+	rb_insert_color(&piar->rb_node, &pci_io_addr_cache_root.rb_root);
+
+	return piar;
+}
+
+static void __eeh_addr_cache_insert_dev(struct pci_dev *dev)
+{
+	struct eeh_dev *edev;
+	int i;
+
+	edev = pci_dev_to_eeh_dev(dev);
+	if (!edev) {
+		pr_warn("PCI: no EEH dev found for %s\n",
+			pci_name(dev));
+		return;
+	}
+
+	/* Skip any devices for which EEH is not enabled. */
+	if (!edev->pe) {
+		dev_dbg(&dev->dev, "EEH: Skip building address cache\n");
+		return;
+	}
+
+	/*
+	 * Walk resources on this device, poke the first 7 (6 normal BAR and 1
+	 * ROM BAR) into the tree.
+	 */
+	for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
+		resource_size_t start = pci_resource_start(dev,i);
+		resource_size_t end = pci_resource_end(dev,i);
+		unsigned long flags = pci_resource_flags(dev,i);
+
+		/* We are interested only bus addresses, not dma or other stuff */
+		if (0 == (flags & (IORESOURCE_IO | IORESOURCE_MEM)))
+			continue;
+		if (start == 0 || ~start == 0 || end == 0 || ~end == 0)
+			 continue;
+		eeh_addr_cache_insert(dev, start, end, flags);
+	}
+}
+
+/**
+ * eeh_addr_cache_insert_dev - Add a device to the address cache
+ * @dev: PCI device whose I/O addresses we are interested in.
+ *
+ * In order to support the fast lookup of devices based on addresses,
+ * we maintain a cache of devices that can be quickly searched.
+ * This routine adds a device to that cache.
+ */
+void eeh_addr_cache_insert_dev(struct pci_dev *dev)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
+	__eeh_addr_cache_insert_dev(dev);
+	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
+}
+
+static inline void __eeh_addr_cache_rmv_dev(struct pci_dev *dev)
+{
+	struct rb_node *n;
+
+restart:
+	n = rb_first(&pci_io_addr_cache_root.rb_root);
+	while (n) {
+		struct pci_io_addr_range *piar;
+		piar = rb_entry(n, struct pci_io_addr_range, rb_node);
+
+		if (piar->pcidev == dev) {
+			eeh_edev_dbg(piar->edev, "PIAR: remove range=[%pap:%pap]\n",
+				 &piar->addr_lo, &piar->addr_hi);
+			rb_erase(n, &pci_io_addr_cache_root.rb_root);
+			kfree(piar);
+			goto restart;
+		}
+		n = rb_next(n);
+	}
+}
+
+/**
+ * eeh_addr_cache_rmv_dev - remove pci device from addr cache
+ * @dev: device to remove
+ *
+ * Remove a device from the addr-cache tree.
+ * This is potentially expensive, since it will walk
+ * the tree multiple times (once per resource).
+ * But so what; device removal doesn't need to be that fast.
+ */
+void eeh_addr_cache_rmv_dev(struct pci_dev *dev)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
+	__eeh_addr_cache_rmv_dev(dev);
+	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
+}
+
+/**
+ * eeh_addr_cache_init - Initialize a cache of I/O addresses
+ *
+ * Initialize a cache of pci i/o addresses.  This cache will be used to
+ * find the pci device that corresponds to a given address.
+ */
+void eeh_addr_cache_init(void)
+{
+	spin_lock_init(&pci_io_addr_cache_root.piar_lock);
+}
+
+static int eeh_addr_cache_show(struct seq_file *s, void *v)
+{
+	struct pci_io_addr_range *piar;
+	struct rb_node *n;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pci_io_addr_cache_root.piar_lock, flags);
+	for (n = rb_first(&pci_io_addr_cache_root.rb_root); n; n = rb_next(n)) {
+		piar = rb_entry(n, struct pci_io_addr_range, rb_node);
+
+		seq_printf(s, "%s addr range [%pap-%pap]: %s\n",
+		       (piar->flags & IORESOURCE_IO) ? "i/o" : "mem",
+		       &piar->addr_lo, &piar->addr_hi, pci_name(piar->pcidev));
+	}
+	spin_unlock_irqrestore(&pci_io_addr_cache_root.piar_lock, flags);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(eeh_addr_cache);
+
+void eeh_cache_debugfs_init(void)
+{
+	debugfs_create_file_unsafe("eeh_address_cache", 0400,
+			powerpc_debugfs_root, NULL,
+			&eeh_addr_cache_fops);
+}