/* * arch/ppc64/kernel/iommu.c * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation * * Rewrite, cleanup, new allocation schemes, virtual merging: * Copyright (C) 2004 Olof Johansson, IBM Corporation * and Ben. Herrenschmidt, IBM Corporation * * Dynamic DMA mapping support, bus-independent parts. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/config.h> #include <linux/init.h> #include <linux/types.h> #include <linux/slab.h> #include <linux/mm.h> #include <linux/spinlock.h> #include <linux/string.h> #include <linux/dma-mapping.h> #include <linux/init.h> #include <linux/bitops.h> #include <asm/io.h> #include <asm/prom.h> #include <asm/iommu.h> #include <asm/pci-bridge.h> #include <asm/machdep.h> #define DBG(...) #ifdef CONFIG_IOMMU_VMERGE static int novmerge = 0; #else static int novmerge = 1; #endif static int __init setup_iommu(char *str) { if (!strcmp(str, "novmerge")) novmerge = 1; else if (!strcmp(str, "vmerge")) novmerge = 0; return 1; } __setup("iommu=", setup_iommu); static unsigned long iommu_range_alloc(struct iommu_table *tbl, unsigned long npages, unsigned long *handle, unsigned int align_order) { unsigned long n, end, i, start; unsigned long limit; int largealloc = npages > 15; int pass = 0; unsigned long align_mask; align_mask = 0xffffffffffffffffl >> (64 - align_order); /* This allocator was derived from x86_64's bit string search */ /* Sanity check */ if (unlikely(npages) == 0) { if (printk_ratelimit()) WARN_ON(1); return DMA_ERROR_CODE; } if (handle && *handle) start = *handle; else start = largealloc ? tbl->it_largehint : tbl->it_hint; /* Use only half of the table for small allocs (15 pages or less) */ limit = largealloc ? tbl->it_size : tbl->it_halfpoint; if (largealloc && start < tbl->it_halfpoint) start = tbl->it_halfpoint; /* 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 initial start. */ if (start >= limit) start = largealloc ? tbl->it_largehint : tbl->it_hint; again: n = find_next_zero_bit(tbl->it_map, limit, start); /* Align allocation */ n = (n + align_mask) & ~align_mask; end = n + npages; if (unlikely(end >= limit)) { if (likely(pass < 2)) { /* First failure, just rescan the half of the table. * Second failure, rescan the other half of the table. */ start = (largealloc ^ pass) ? tbl->it_halfpoint : 0; limit = pass ? tbl->it_size : limit; pass++; goto again; } else { /* Third failure, give up */ return DMA_ERROR_CODE; } } for (i = n; i < end; i++) if (test_bit(i, tbl->it_map)) { start = i+1; goto again; } for (i = n; i < end; i++) __set_bit(i, tbl->it_map); /* Bump the hint to a new block for small allocs. */ if (largealloc) { /* Don't bump to new block to avoid fragmentation */ tbl->it_largehint = end; } else { /* Overflow will be taken care of at the next allocation */ tbl->it_hint = (end + tbl->it_blocksize - 1) & ~(tbl->it_blocksize - 1); } /* Update handle for SG allocations */ if (handle) *handle = end; return n; } static dma_addr_t iommu_alloc(struct iommu_table *tbl, void *page, unsigned int npages, enum dma_data_direction direction, unsigned int align_order) { unsigned long entry, flags; dma_addr_t ret = DMA_ERROR_CODE; spin_lock_irqsave(&(tbl->it_lock), flags); entry = iommu_range_alloc(tbl, npages, NULL, align_order); if (unlikely(entry == DMA_ERROR_CODE)) { spin_unlock_irqrestore(&(tbl->it_lock), flags); return DMA_ERROR_CODE; } entry += tbl->it_offset; /* Offset into real TCE table */ ret = entry << PAGE_SHIFT; /* Set the return dma address */ /* Put the TCEs in the HW table */ ppc_md.tce_build(tbl, entry, npages, (unsigned long)page & PAGE_MASK, direction); /* Flush/invalidate TLB caches if necessary */ if (ppc_md.tce_flush) ppc_md.tce_flush(tbl); spin_unlock_irqrestore(&(tbl->it_lock), flags); /* Make sure updates are seen by hardware */ mb(); return ret; } static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr, unsigned int npages) { unsigned long entry, free_entry; unsigned long i; entry = dma_addr >> PAGE_SHIFT; free_entry = entry - tbl->it_offset; if (((free_entry + npages) > tbl->it_size) || (entry < tbl->it_offset)) { if (printk_ratelimit()) { printk(KERN_INFO "iommu_free: invalid entry\n"); printk(KERN_INFO "\tentry = 0x%lx\n", entry); printk(KERN_INFO "\tdma_addr = 0x%lx\n", (u64)dma_addr); printk(KERN_INFO "\tTable = 0x%lx\n", (u64)tbl); printk(KERN_INFO "\tbus# = 0x%lx\n", (u64)tbl->it_busno); printk(KERN_INFO "\tsize = 0x%lx\n", (u64)tbl->it_size); printk(KERN_INFO "\tstartOff = 0x%lx\n", (u64)tbl->it_offset); printk(KERN_INFO "\tindex = 0x%lx\n", (u64)tbl->it_index); WARN_ON(1); } return; } ppc_md.tce_free(tbl, entry, npages); for (i = 0; i < npages; i++) __clear_bit(free_entry+i, tbl->it_map); } static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr, unsigned int npages) { unsigned long flags; spin_lock_irqsave(&(tbl->it_lock), flags); __iommu_free(tbl, dma_addr, npages); /* Make sure TLB cache is flushed if the HW needs it. We do * not do an mb() here on purpose, it is not needed on any of * the current platforms. */ if (ppc_md.tce_flush) ppc_md.tce_flush(tbl); spin_unlock_irqrestore(&(tbl->it_lock), flags); } int iommu_map_sg(struct device *dev, struct iommu_table *tbl, struct scatterlist *sglist, int nelems, enum dma_data_direction direction) { dma_addr_t dma_next = 0, dma_addr; unsigned long flags; struct scatterlist *s, *outs, *segstart; int outcount; unsigned long handle; BUG_ON(direction == DMA_NONE); if ((nelems == 0) || !tbl) return 0; outs = s = segstart = &sglist[0]; outcount = 1; handle = 0; /* Init first segment length for backout at failure */ outs->dma_length = 0; DBG("mapping %d elements:\n", nelems); spin_lock_irqsave(&(tbl->it_lock), flags); for (s = outs; nelems; nelems--, s++) { unsigned long vaddr, npages, entry, slen; slen = s->length; /* Sanity check */ if (slen == 0) { dma_next = 0; continue; } /* Allocate iommu entries for that segment */ vaddr = (unsigned long)page_address(s->page) + s->offset; npages = PAGE_ALIGN(vaddr + slen) - (vaddr & PAGE_MASK); npages >>= PAGE_SHIFT; entry = iommu_range_alloc(tbl, npages, &handle, 0); DBG(" - vaddr: %lx, size: %lx\n", vaddr, slen); /* Handle failure */ if (unlikely(entry == DMA_ERROR_CODE)) { if (printk_ratelimit()) printk(KERN_INFO "iommu_alloc failed, tbl %p vaddr %lx" " npages %lx\n", tbl, vaddr, npages); goto failure; } /* Convert entry to a dma_addr_t */ entry += tbl->it_offset; dma_addr = entry << PAGE_SHIFT; dma_addr |= s->offset; DBG(" - %lx pages, entry: %lx, dma_addr: %lx\n", npages, entry, dma_addr); /* Insert into HW table */ ppc_md.tce_build(tbl, entry, npages, vaddr & PAGE_MASK, direction); /* If we are in an open segment, try merging */ if (segstart != s) { DBG(" - trying merge...\n"); /* We cannot merge if: * - allocated dma_addr isn't contiguous to previous allocation */ if (novmerge || (dma_addr != dma_next)) { /* Can't merge: create a new segment */ segstart = s; outcount++; outs++; DBG(" can't merge, new segment.\n"); } else { outs->dma_length += s->length; DBG(" merged, new len: %lx\n", outs->dma_length); } } if (segstart == s) { /* This is a new segment, fill entries */ DBG(" - filling new segment.\n"); outs->dma_address = dma_addr; outs->dma_length = slen; } /* Calculate next page pointer for contiguous check */ dma_next = dma_addr + slen; DBG(" - dma next is: %lx\n", dma_next); } /* Flush/invalidate TLB caches if necessary */ if (ppc_md.tce_flush) ppc_md.tce_flush(tbl); spin_unlock_irqrestore(&(tbl->it_lock), flags); /* Make sure updates are seen by hardware */ mb(); DBG("mapped %d elements:\n", outcount); /* For the sake of iommu_free_sg, we clear out the length in the * next entry of the sglist if we didn't fill the list completely */ if (outcount < nelems) { outs++; outs->dma_address = DMA_ERROR_CODE; outs->dma_length = 0; } return outcount; failure: for (s = &sglist[0]; s <= outs; s++) { if (s->dma_length != 0) { unsigned long vaddr, npages; vaddr = s->dma_address & PAGE_MASK; npages = (PAGE_ALIGN(s->dma_address + s->dma_length) - vaddr) >> PAGE_SHIFT; __iommu_free(tbl, vaddr, npages); } } spin_unlock_irqrestore(&(tbl->it_lock), flags); return 0; } void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist, int nelems, enum dma_data_direction direction) { unsigned long flags; BUG_ON(direction == DMA_NONE); if (!tbl) return; spin_lock_irqsave(&(tbl->it_lock), flags); while (nelems--) { unsigned int npages; dma_addr_t dma_handle = sglist->dma_address; if (sglist->dma_length == 0) break; npages = (PAGE_ALIGN(dma_handle + sglist->dma_length) - (dma_handle & PAGE_MASK)) >> PAGE_SHIFT; __iommu_free(tbl, dma_handle, npages); sglist++; } /* Flush/invalidate TLBs if necessary. As for iommu_free(), we * do not do an mb() here, the affected platforms do not need it * when freeing. */ if (ppc_md.tce_flush) ppc_md.tce_flush(tbl); spin_unlock_irqrestore(&(tbl->it_lock), flags); } /* * Build a iommu_table structure. This contains a bit map which * is used to manage allocation of the tce space. */ struct iommu_table *iommu_init_table(struct iommu_table *tbl) { unsigned long sz; static int welcomed = 0; /* Set aside 1/4 of the table for large allocations. */ tbl->it_halfpoint = tbl->it_size * 3 / 4; /* number of bytes needed for the bitmap */ sz = (tbl->it_size + 7) >> 3; tbl->it_map = (unsigned long *)__get_free_pages(GFP_ATOMIC, get_order(sz)); if (!tbl->it_map) panic("iommu_init_table: Can't allocate %ld bytes\n", sz); memset(tbl->it_map, 0, sz); tbl->it_hint = 0; tbl->it_largehint = tbl->it_halfpoint; spin_lock_init(&tbl->it_lock); if (!welcomed) { printk(KERN_INFO "IOMMU table initialized, virtual merging %s\n", novmerge ? "disabled" : "enabled"); welcomed = 1; } return tbl; } void iommu_free_table(struct device_node *dn) { struct iommu_table *tbl = dn->iommu_table; unsigned long bitmap_sz, i; unsigned int order; if (!tbl || !tbl->it_map) { printk(KERN_ERR "%s: expected TCE map for %s\n", __FUNCTION__, dn->full_name); return; } /* verify that table contains no entries */ /* it_size is in entries, and we're examining 64 at a time */ for (i = 0; i < (tbl->it_size/64); i++) { if (tbl->it_map[i] != 0) { printk(KERN_WARNING "%s: Unexpected TCEs for %s\n", __FUNCTION__, dn->full_name); break; } } /* calculate bitmap size in bytes */ bitmap_sz = (tbl->it_size + 7) / 8; /* free bitmap */ order = get_order(bitmap_sz); free_pages((unsigned long) tbl->it_map, order); /* free table */ kfree(tbl); } /* Creates TCEs for a user provided buffer. The user buffer must be * contiguous real kernel storage (not vmalloc). The address of the buffer * passed here is the kernel (virtual) address of the buffer. The buffer * need not be page aligned, the dma_addr_t returned will point to the same * byte within the page as vaddr. */ dma_addr_t iommu_map_single(struct iommu_table *tbl, void *vaddr, size_t size, enum dma_data_direction direction) { dma_addr_t dma_handle = DMA_ERROR_CODE; unsigned long uaddr; unsigned int npages; BUG_ON(direction == DMA_NONE); uaddr = (unsigned long)vaddr; npages = PAGE_ALIGN(uaddr + size) - (uaddr & PAGE_MASK); npages >>= PAGE_SHIFT; if (tbl) { dma_handle = iommu_alloc(tbl, vaddr, npages, direction, 0); if (dma_handle == DMA_ERROR_CODE) { if (printk_ratelimit()) { printk(KERN_INFO "iommu_alloc failed, " "tbl %p vaddr %p npages %d\n", tbl, vaddr, npages); } } else dma_handle |= (uaddr & ~PAGE_MASK); } return dma_handle; } void iommu_unmap_single(struct iommu_table *tbl, dma_addr_t dma_handle, size_t size, enum dma_data_direction direction) { BUG_ON(direction == DMA_NONE); if (tbl) iommu_free(tbl, dma_handle, (PAGE_ALIGN(dma_handle + size) - (dma_handle & PAGE_MASK)) >> PAGE_SHIFT); } /* Allocates a contiguous real buffer and creates mappings over it. * Returns the virtual address of the buffer and sets dma_handle * to the dma address (mapping) of the first page. */ void *iommu_alloc_coherent(struct iommu_table *tbl, size_t size, dma_addr_t *dma_handle, unsigned int __nocast flag) { void *ret = NULL; dma_addr_t mapping; unsigned int npages, order; size = PAGE_ALIGN(size); npages = size >> PAGE_SHIFT; order = get_order(size); /* * Client asked for way too much space. This is checked later * anyway. It is easier to debug here for the drivers than in * the tce tables. */ if (order >= IOMAP_MAX_ORDER) { printk("iommu_alloc_consistent size too large: 0x%lx\n", size); return NULL; } if (!tbl) return NULL; /* Alloc enough pages (and possibly more) */ ret = (void *)__get_free_pages(flag, order); if (!ret) return NULL; memset(ret, 0, size); /* Set up tces to cover the allocated range */ mapping = iommu_alloc(tbl, ret, npages, DMA_BIDIRECTIONAL, order); if (mapping == DMA_ERROR_CODE) { free_pages((unsigned long)ret, order); ret = NULL; } else *dma_handle = mapping; return ret; } void iommu_free_coherent(struct iommu_table *tbl, size_t size, void *vaddr, dma_addr_t dma_handle) { unsigned int npages; if (tbl) { size = PAGE_ALIGN(size); npages = size >> PAGE_SHIFT; iommu_free(tbl, dma_handle, npages); free_pages((unsigned long)vaddr, get_order(size)); } }