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authorLinus Torvalds <torvalds@linux-foundation.org>2015-04-17 16:19:26 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-17 16:19:26 -0400
commite2fdae7e7c5a690b10b2d2891ec819e554dc033d (patch)
tree7b48f55eba9519aeee554a58be9d1ff8a8adffd6 /lib
parent6b6e177d632ee251c7c78d8f266a851ab9704879 (diff)
parentcb97201cb060d13da0b87fd1bf68208c7389c5b1 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc
Pull sparc updates from David Miller: "The PowerPC folks have a really nice scalable IOMMU pool allocator that we wanted to make use of for sparc. So here we have a series that abstracts out their code into a common layer that anyone can make use of. Sparc is converted, and the PowerPC folks have reviewed and ACK'd this series and plan to convert PowerPC over as well" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc: iommu-common: Fix PARISC compile-time warnings sparc: Make LDC use common iommu poll management functions sparc: Make sparc64 use scalable lib/iommu-common.c functions sparc: Break up monolithic iommu table/lock into finer graularity pools and lock
Diffstat (limited to 'lib')
-rw-r--r--lib/Makefile2
-rw-r--r--lib/iommu-common.c224
2 files changed, 225 insertions, 1 deletions
diff --git a/lib/Makefile b/lib/Makefile
index da6116b21555..6c37933336a0 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -106,7 +106,7 @@ obj-$(CONFIG_AUDIT_GENERIC) += audit.o
obj-$(CONFIG_AUDIT_COMPAT_GENERIC) += compat_audit.o
obj-$(CONFIG_SWIOTLB) += swiotlb.o
-obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
+obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o iommu-common.o
obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o
obj-$(CONFIG_NOTIFIER_ERROR_INJECTION) += notifier-error-inject.o
obj-$(CONFIG_CPU_NOTIFIER_ERROR_INJECT) += cpu-notifier-error-inject.o
diff --git a/lib/iommu-common.c b/lib/iommu-common.c
new file mode 100644
index 000000000000..fac4f35250c9
--- /dev/null
+++ b/lib/iommu-common.c
@@ -0,0 +1,224 @@
+/*
+ * IOMMU mmap management and range allocation functions.
+ * Based almost entirely upon the powerpc iommu allocator.
+ */
+
+#include <linux/export.h>
+#include <linux/bitmap.h>
+#include <linux/bug.h>
+#include <linux/iommu-helper.h>
+#include <linux/iommu-common.h>
+#include <linux/dma-mapping.h>
+
+#ifndef DMA_ERROR_CODE
+#define DMA_ERROR_CODE (~(dma_addr_t)0x0)
+#endif
+
+#define IOMMU_LARGE_ALLOC 15
+
+/*
+ * Initialize iommu_pool entries for the iommu_table. `num_entries'
+ * is the number of table entries. If `large_pool' is set to true,
+ * the top 1/4 of the table will be set aside for pool allocations
+ * of more than IOMMU_LARGE_ALLOC pages.
+ */
+extern void iommu_tbl_pool_init(struct iommu_table *iommu,
+ unsigned long num_entries,
+ u32 page_table_shift,
+ const struct iommu_tbl_ops *iommu_tbl_ops,
+ bool large_pool, u32 npools)
+{
+ unsigned int start, i;
+ struct iommu_pool *p = &(iommu->large_pool);
+
+ if (npools == 0)
+ iommu->nr_pools = IOMMU_NR_POOLS;
+ else
+ iommu->nr_pools = npools;
+ BUG_ON(npools > IOMMU_NR_POOLS);
+
+ iommu->page_table_shift = page_table_shift;
+ iommu->iommu_tbl_ops = iommu_tbl_ops;
+ start = 0;
+ if (large_pool)
+ iommu->flags |= IOMMU_HAS_LARGE_POOL;
+
+ if (!large_pool)
+ iommu->poolsize = num_entries/iommu->nr_pools;
+ else
+ iommu->poolsize = (num_entries * 3 / 4)/iommu->nr_pools;
+ for (i = 0; i < iommu->nr_pools; i++) {
+ spin_lock_init(&(iommu->arena_pool[i].lock));
+ iommu->arena_pool[i].start = start;
+ iommu->arena_pool[i].hint = start;
+ start += iommu->poolsize; /* start for next pool */
+ iommu->arena_pool[i].end = start - 1;
+ }
+ if (!large_pool)
+ return;
+ /* initialize large_pool */
+ spin_lock_init(&(p->lock));
+ p->start = start;
+ p->hint = p->start;
+ p->end = num_entries;
+}
+EXPORT_SYMBOL(iommu_tbl_pool_init);
+
+unsigned long iommu_tbl_range_alloc(struct device *dev,
+ struct iommu_table *iommu,
+ unsigned long npages,
+ unsigned long *handle,
+ unsigned int pool_hash)
+{
+ unsigned long n, end, start, limit, boundary_size;
+ struct iommu_pool *arena;
+ int pass = 0;
+ unsigned int pool_nr;
+ unsigned int npools = iommu->nr_pools;
+ unsigned long flags;
+ bool large_pool = ((iommu->flags & IOMMU_HAS_LARGE_POOL) != 0);
+ bool largealloc = (large_pool && npages > IOMMU_LARGE_ALLOC);
+ unsigned long shift;
+
+ /* Sanity check */
+ if (unlikely(npages == 0)) {
+ printk_ratelimited("npages == 0\n");
+ return DMA_ERROR_CODE;
+ }
+
+ if (largealloc) {
+ arena = &(iommu->large_pool);
+ spin_lock_irqsave(&arena->lock, flags);
+ pool_nr = 0; /* to keep compiler happy */
+ } else {
+ /* pick out pool_nr */
+ pool_nr = pool_hash & (npools - 1);
+ arena = &(iommu->arena_pool[pool_nr]);
+
+ /* find first available unlocked pool */
+ while (!spin_trylock_irqsave(&(arena->lock), flags)) {
+ pool_nr = (pool_nr + 1) & (iommu->nr_pools - 1);
+ arena = &(iommu->arena_pool[pool_nr]);
+ }
+ }
+
+ again:
+ if (pass == 0 && handle && *handle &&
+ (*handle >= arena->start) && (*handle < arena->end))
+ start = *handle;
+ else
+ start = arena->hint;
+
+ limit = arena->end;
+
+ /* The case below can happen if we have a small segment appended
+ * to a large, or when the previous alloc was at the very end of
+ * the available space. If so, go back to the beginning and flush.
+ */
+ if (start >= limit) {
+ start = arena->start;
+ if (iommu->iommu_tbl_ops->reset != NULL)
+ iommu->iommu_tbl_ops->reset(iommu);
+ }
+
+ if (dev)
+ boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
+ 1 << iommu->page_table_shift);
+ else
+ boundary_size = ALIGN(1ULL << 32, 1 << iommu->page_table_shift);
+
+ shift = iommu->page_table_map_base >> iommu->page_table_shift;
+ boundary_size = boundary_size >> iommu->page_table_shift;
+ /*
+ * if the iommu has a non-trivial cookie <-> index mapping, we set
+ * things up so that iommu_is_span_boundary() merely checks if the
+ * (index + npages) < num_tsb_entries
+ */
+ if (iommu->iommu_tbl_ops->cookie_to_index != NULL) {
+ shift = 0;
+ boundary_size = iommu->poolsize * iommu->nr_pools;
+ }
+ n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
+ boundary_size, 0);
+ if (n == -1) {
+ if (likely(pass == 0)) {
+ /* First failure, rescan from the beginning. */
+ arena->hint = arena->start;
+ if (iommu->iommu_tbl_ops->reset != NULL)
+ iommu->iommu_tbl_ops->reset(iommu);
+ pass++;
+ goto again;
+ } else if (!largealloc && pass <= iommu->nr_pools) {
+ spin_unlock(&(arena->lock));
+ pool_nr = (pool_nr + 1) & (iommu->nr_pools - 1);
+ arena = &(iommu->arena_pool[pool_nr]);
+ while (!spin_trylock(&(arena->lock))) {
+ pool_nr = (pool_nr + 1) & (iommu->nr_pools - 1);
+ arena = &(iommu->arena_pool[pool_nr]);
+ }
+ arena->hint = arena->start;
+ pass++;
+ goto again;
+ } else {
+ /* give up */
+ spin_unlock_irqrestore(&(arena->lock), flags);
+ return DMA_ERROR_CODE;
+ }
+ }
+
+ end = n + npages;
+
+ arena->hint = end;
+
+ /* Update handle for SG allocations */
+ if (handle)
+ *handle = end;
+ spin_unlock_irqrestore(&(arena->lock), flags);
+
+ return n;
+}
+EXPORT_SYMBOL(iommu_tbl_range_alloc);
+
+static struct iommu_pool *get_pool(struct iommu_table *tbl,
+ unsigned long entry)
+{
+ struct iommu_pool *p;
+ unsigned long largepool_start = tbl->large_pool.start;
+ bool large_pool = ((tbl->flags & IOMMU_HAS_LARGE_POOL) != 0);
+
+ /* The large pool is the last pool at the top of the table */
+ if (large_pool && entry >= largepool_start) {
+ p = &tbl->large_pool;
+ } else {
+ unsigned int pool_nr = entry / tbl->poolsize;
+
+ BUG_ON(pool_nr >= tbl->nr_pools);
+ p = &tbl->arena_pool[pool_nr];
+ }
+ return p;
+}
+
+void iommu_tbl_range_free(struct iommu_table *iommu, u64 dma_addr,
+ unsigned long npages, bool do_demap, void *demap_arg)
+{
+ unsigned long entry;
+ struct iommu_pool *pool;
+ unsigned long flags;
+ unsigned long shift = iommu->page_table_shift;
+
+ if (iommu->iommu_tbl_ops->cookie_to_index != NULL) {
+ entry = (*iommu->iommu_tbl_ops->cookie_to_index)(dma_addr,
+ demap_arg);
+ } else {
+ entry = (dma_addr - iommu->page_table_map_base) >> shift;
+ }
+ pool = get_pool(iommu, entry);
+
+ spin_lock_irqsave(&(pool->lock), flags);
+ if (do_demap && iommu->iommu_tbl_ops->demap != NULL)
+ (*iommu->iommu_tbl_ops->demap)(demap_arg, entry, npages);
+
+ bitmap_clear(iommu->map, entry, npages);
+ spin_unlock_irqrestore(&(pool->lock), flags);
+}
+EXPORT_SYMBOL(iommu_tbl_range_free);

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