1 files changed, 444 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/dart_iommu.c b/arch/powerpc/sysdev/dart_iommu.c
new file mode 100644
index 000000000..98096bbfd
--- /dev/null
+++ b/arch/powerpc/sysdev/dart_iommu.c
@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * arch/powerpc/sysdev/dart_iommu.c
+ *
+ * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
+ * Copyright (C) 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
+ *                    IBM Corporation
+ *
+ * Based on pSeries_iommu.c:
+ * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
+ * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
+ *
+ * Dynamic DMA mapping support, Apple U3, U4 & IBM CPC925 "DART" iommu.
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/pci.h>
+#include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
+#include <linux/suspend.h>
+#include <linux/memblock.h>
+#include <linux/gfp.h>
+#include <linux/kmemleak.h>
+#include <linux/of_address.h>
+#include <asm/io.h>
+#include <asm/iommu.h>
+#include <asm/pci-bridge.h>
+#include <asm/machdep.h>
+#include <asm/cacheflush.h>
+#include <asm/ppc-pci.h>
+
+#include "dart.h"
+
+/* DART table address and size */
+static u32 *dart_tablebase;
+static unsigned long dart_tablesize;
+
+/* Mapped base address for the dart */
+static unsigned int __iomem *dart;
+
+/* Dummy val that entries are set to when unused */
+static unsigned int dart_emptyval;
+
+static struct iommu_table iommu_table_dart;
+static int iommu_table_dart_inited;
+static int dart_dirty;
+static int dart_is_u4;
+
+#define DART_U4_BYPASS_BASE	0x8000000000ull
+
+#define DBG(...)
+
+static DEFINE_SPINLOCK(invalidate_lock);
+
+static inline void dart_tlb_invalidate_all(void)
+{
+	unsigned long l = 0;
+	unsigned int reg, inv_bit;
+	unsigned long limit;
+	unsigned long flags;
+
+	spin_lock_irqsave(&invalidate_lock, flags);
+
+	DBG("dart: flush\n");
+
+	/* To invalidate the DART, set the DARTCNTL_FLUSHTLB bit in the
+	 * control register and wait for it to clear.
+	 *
+	 * Gotcha: Sometimes, the DART won't detect that the bit gets
+	 * set. If so, clear it and set it again.
+	 */
+
+	limit = 0;
+
+	inv_bit = dart_is_u4 ? DART_CNTL_U4_FLUSHTLB : DART_CNTL_U3_FLUSHTLB;
+retry:
+	l = 0;
+	reg = DART_IN(DART_CNTL);
+	reg |= inv_bit;
+	DART_OUT(DART_CNTL, reg);
+
+	while ((DART_IN(DART_CNTL) & inv_bit) && l < (1L << limit))
+		l++;
+	if (l == (1L << limit)) {
+		if (limit < 4) {
+			limit++;
+			reg = DART_IN(DART_CNTL);
+			reg &= ~inv_bit;
+			DART_OUT(DART_CNTL, reg);
+			goto retry;
+		} else
+			panic("DART: TLB did not flush after waiting a long "
+			      "time. Buggy U3 ?");
+	}
+
+	spin_unlock_irqrestore(&invalidate_lock, flags);
+}
+
+static inline void dart_tlb_invalidate_one(unsigned long bus_rpn)
+{
+	unsigned int reg;
+	unsigned int l, limit;
+	unsigned long flags;
+
+	spin_lock_irqsave(&invalidate_lock, flags);
+
+	reg = DART_CNTL_U4_ENABLE | DART_CNTL_U4_IONE |
+		(bus_rpn & DART_CNTL_U4_IONE_MASK);
+	DART_OUT(DART_CNTL, reg);
+
+	limit = 0;
+wait_more:
+	l = 0;
+	while ((DART_IN(DART_CNTL) & DART_CNTL_U4_IONE) && l < (1L << limit)) {
+		rmb();
+		l++;
+	}
+
+	if (l == (1L << limit)) {
+		if (limit < 4) {
+			limit++;
+			goto wait_more;
+		} else
+			panic("DART: TLB did not flush after waiting a long "
+			      "time. Buggy U4 ?");
+	}
+
+	spin_unlock_irqrestore(&invalidate_lock, flags);
+}
+
+static void dart_cache_sync(unsigned int *base, unsigned int count)
+{
+	/*
+	 * We add 1 to the number of entries to flush, following a
+	 * comment in Darwin indicating that the memory controller
+	 * can prefetch unmapped memory under some circumstances.
+	 */
+	unsigned long start = (unsigned long)base;
+	unsigned long end = start + (count + 1) * sizeof(unsigned int);
+	unsigned int tmp;
+
+	/* Perform a standard cache flush */
+	flush_dcache_range(start, end);
+
+	/*
+	 * Perform the sequence described in the CPC925 manual to
+	 * ensure all the data gets to a point the cache incoherent
+	 * DART hardware will see.
+	 */
+	asm volatile(" sync;"
+		     " isync;"
+		     " dcbf 0,%1;"
+		     " sync;"
+		     " isync;"
+		     " lwz %0,0(%1);"
+		     " isync" : "=r" (tmp) : "r" (end) : "memory");
+}
+
+static void dart_flush(struct iommu_table *tbl)
+{
+	mb();
+	if (dart_dirty) {
+		dart_tlb_invalidate_all();
+		dart_dirty = 0;
+	}
+}
+
+static int dart_build(struct iommu_table *tbl, long index,
+		       long npages, unsigned long uaddr,
+		       enum dma_data_direction direction,
+		       unsigned long attrs)
+{
+	unsigned int *dp, *orig_dp;
+	unsigned int rpn;
+	long l;
+
+	DBG("dart: build at: %lx, %lx, addr: %x\n", index, npages, uaddr);
+
+	orig_dp = dp = ((unsigned int*)tbl->it_base) + index;
+
+	/* On U3, all memory is contiguous, so we can move this
+	 * out of the loop.
+	 */
+	l = npages;
+	while (l--) {
+		rpn = __pa(uaddr) >> DART_PAGE_SHIFT;
+
+		*(dp++) = DARTMAP_VALID | (rpn & DARTMAP_RPNMASK);
+
+		uaddr += DART_PAGE_SIZE;
+	}
+	dart_cache_sync(orig_dp, npages);
+
+	if (dart_is_u4) {
+		rpn = index;
+		while (npages--)
+			dart_tlb_invalidate_one(rpn++);
+	} else {
+		dart_dirty = 1;
+	}
+	return 0;
+}
+
+
+static void dart_free(struct iommu_table *tbl, long index, long npages)
+{
+	unsigned int *dp, *orig_dp;
+	long orig_npages = npages;
+
+	/* We don't worry about flushing the TLB cache. The only drawback of
+	 * not doing it is that we won't catch buggy device drivers doing
+	 * bad DMAs, but then no 32-bit architecture ever does either.
+	 */
+
+	DBG("dart: free at: %lx, %lx\n", index, npages);
+
+	orig_dp = dp  = ((unsigned int *)tbl->it_base) + index;
+
+	while (npages--)
+		*(dp++) = dart_emptyval;
+
+	dart_cache_sync(orig_dp, orig_npages);
+}
+
+static void __init allocate_dart(void)
+{
+	unsigned long tmp;
+
+	/* 512 pages (2MB) is max DART tablesize. */
+	dart_tablesize = 1UL << 21;
+
+	/*
+	 * 16MB (1 << 24) alignment. We allocate a full 16Mb chuck since we
+	 * will blow up an entire large page anyway in the kernel mapping.
+	 */
+	dart_tablebase = memblock_alloc_try_nid_raw(SZ_16M, SZ_16M,
+					MEMBLOCK_LOW_LIMIT, SZ_2G,
+					NUMA_NO_NODE);
+	if (!dart_tablebase)
+		panic("Failed to allocate 16MB below 2GB for DART table\n");
+
+	/* There is no point scanning the DART space for leaks*/
+	kmemleak_no_scan((void *)dart_tablebase);
+
+	/* Allocate a spare page to map all invalid DART pages. We need to do
+	 * that to work around what looks like a problem with the HT bridge
+	 * prefetching into invalid pages and corrupting data
+	 */
+	tmp = memblock_phys_alloc(DART_PAGE_SIZE, DART_PAGE_SIZE);
+	if (!tmp)
+		panic("DART: table allocation failed\n");
+
+	dart_emptyval = DARTMAP_VALID | ((tmp >> DART_PAGE_SHIFT) &
+					 DARTMAP_RPNMASK);
+
+	printk(KERN_INFO "DART table allocated at: %p\n", dart_tablebase);
+}
+
+static int __init dart_init(struct device_node *dart_node)
+{
+	unsigned int i;
+	unsigned long base, size;
+	struct resource r;
+
+	/* IOMMU disabled by the user ? bail out */
+	if (iommu_is_off)
+		return -ENODEV;
+
+	/*
+	 * Only use the DART if the machine has more than 1GB of RAM
+	 * or if requested with iommu=on on cmdline.
+	 *
+	 * 1GB of RAM is picked as limit because some default devices
+	 * (i.e. Airport Extreme) have 30 bit address range limits.
+	 */
+
+	if (!iommu_force_on && memblock_end_of_DRAM() <= 0x40000000ull)
+		return -ENODEV;
+
+	/* Get DART registers */
+	if (of_address_to_resource(dart_node, 0, &r))
+		panic("DART: can't get register base ! ");
+
+	/* Map in DART registers */
+	dart = ioremap(r.start, resource_size(&r));
+	if (dart == NULL)
+		panic("DART: Cannot map registers!");
+
+	/* Allocate the DART and dummy page */
+	allocate_dart();
+
+	/* Fill initial table */
+	for (i = 0; i < dart_tablesize/4; i++)
+		dart_tablebase[i] = dart_emptyval;
+
+	/* Push to memory */
+	dart_cache_sync(dart_tablebase, dart_tablesize / sizeof(u32));
+
+	/* Initialize DART with table base and enable it. */
+	base = ((unsigned long)dart_tablebase) >> DART_PAGE_SHIFT;
+	size = dart_tablesize >> DART_PAGE_SHIFT;
+	if (dart_is_u4) {
+		size &= DART_SIZE_U4_SIZE_MASK;
+		DART_OUT(DART_BASE_U4, base);
+		DART_OUT(DART_SIZE_U4, size);
+		DART_OUT(DART_CNTL, DART_CNTL_U4_ENABLE);
+	} else {
+		size &= DART_CNTL_U3_SIZE_MASK;
+		DART_OUT(DART_CNTL,
+			 DART_CNTL_U3_ENABLE |
+			 (base << DART_CNTL_U3_BASE_SHIFT) |
+			 (size << DART_CNTL_U3_SIZE_SHIFT));
+	}
+
+	/* Invalidate DART to get rid of possible stale TLBs */
+	dart_tlb_invalidate_all();
+
+	printk(KERN_INFO "DART IOMMU initialized for %s type chipset\n",
+	       dart_is_u4 ? "U4" : "U3");
+
+	return 0;
+}
+
+static struct iommu_table_ops iommu_dart_ops = {
+	.set = dart_build,
+	.clear = dart_free,
+	.flush = dart_flush,
+};
+
+static void iommu_table_dart_setup(void)
+{
+	iommu_table_dart.it_busno = 0;
+	iommu_table_dart.it_offset = 0;
+	/* it_size is in number of entries */
+	iommu_table_dart.it_size = dart_tablesize / sizeof(u32);
+	iommu_table_dart.it_page_shift = IOMMU_PAGE_SHIFT_4K;
+
+	/* Initialize the common IOMMU code */
+	iommu_table_dart.it_base = (unsigned long)dart_tablebase;
+	iommu_table_dart.it_index = 0;
+	iommu_table_dart.it_blocksize = 1;
+	iommu_table_dart.it_ops = &iommu_dart_ops;
+	if (!iommu_init_table(&iommu_table_dart, -1, 0, 0))
+		panic("Failed to initialize iommu table");
+
+	/* Reserve the last page of the DART to avoid possible prefetch
+	 * past the DART mapped area
+	 */
+	set_bit(iommu_table_dart.it_size - 1, iommu_table_dart.it_map);
+}
+
+static void pci_dma_bus_setup_dart(struct pci_bus *bus)
+{
+	if (!iommu_table_dart_inited) {
+		iommu_table_dart_inited = 1;
+		iommu_table_dart_setup();
+	}
+}
+
+static bool dart_device_on_pcie(struct device *dev)
+{
+	struct device_node *np = of_node_get(dev->of_node);
+
+	while(np) {
+		if (of_device_is_compatible(np, "U4-pcie") ||
+		    of_device_is_compatible(np, "u4-pcie")) {
+			of_node_put(np);
+			return true;
+		}
+		np = of_get_next_parent(np);
+	}
+	return false;
+}
+
+static void pci_dma_dev_setup_dart(struct pci_dev *dev)
+{
+	if (dart_is_u4 && dart_device_on_pcie(&dev->dev))
+		dev->dev.archdata.dma_offset = DART_U4_BYPASS_BASE;
+	set_iommu_table_base(&dev->dev, &iommu_table_dart);
+}
+
+static bool iommu_bypass_supported_dart(struct pci_dev *dev, u64 mask)
+{
+	return dart_is_u4 &&
+		dart_device_on_pcie(&dev->dev) &&
+		mask >= DMA_BIT_MASK(40);
+}
+
+void __init iommu_init_early_dart(struct pci_controller_ops *controller_ops)
+{
+	struct device_node *dn;
+
+	/* Find the DART in the device-tree */
+	dn = of_find_compatible_node(NULL, "dart", "u3-dart");
+	if (dn == NULL) {
+		dn = of_find_compatible_node(NULL, "dart", "u4-dart");
+		if (dn == NULL)
+			return;	/* use default direct_dma_ops */
+		dart_is_u4 = 1;
+	}
+
+	/* Initialize the DART HW */
+	if (dart_init(dn) != 0) {
+		of_node_put(dn);
+		return;
+	}
+	/*
+	 * U4 supports a DART bypass, we use it for 64-bit capable devices to
+	 * improve performance.  However, that only works for devices connected
+	 * to the U4 own PCIe interface, not bridged through hypertransport.
+	 * We need the device to support at least 40 bits of addresses.
+	 */
+	controller_ops->dma_dev_setup = pci_dma_dev_setup_dart;
+	controller_ops->dma_bus_setup = pci_dma_bus_setup_dart;
+	controller_ops->iommu_bypass_supported = iommu_bypass_supported_dart;
+
+	/* Setup pci_dma ops */
+	set_pci_dma_ops(&dma_iommu_ops);
+	of_node_put(dn);
+}
+
+#ifdef CONFIG_PM
+static void iommu_dart_restore(void)
+{
+	dart_cache_sync(dart_tablebase, dart_tablesize / sizeof(u32));
+	dart_tlb_invalidate_all();
+}
+
+static int __init iommu_init_late_dart(void)
+{
+	if (!dart_tablebase)
+		return 0;
+
+	ppc_md.iommu_restore = iommu_dart_restore;
+
+	return 0;
+}
+
+late_initcall(iommu_init_late_dart);
+#endif /* CONFIG_PM */