diff options
Diffstat (limited to 'kernel/arch/powerpc/mm/dma-noncoherent.c')
| -rw-r--r-- | kernel/arch/powerpc/mm/dma-noncoherent.c | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/kernel/arch/powerpc/mm/dma-noncoherent.c b/kernel/arch/powerpc/mm/dma-noncoherent.c new file mode 100644 index 000000000..169aba446 --- /dev/null +++ b/kernel/arch/powerpc/mm/dma-noncoherent.c @@ -0,0 +1,420 @@ +/* + * PowerPC version derived from arch/arm/mm/consistent.c + * Copyright (C) 2001 Dan Malek (dmalek@jlc.net) + * + * Copyright (C) 2000 Russell King + * + * Consistent memory allocators. Used for DMA devices that want to + * share uncached memory with the processor core. The function return + * is the virtual address and 'dma_handle' is the physical address. + * Mostly stolen from the ARM port, with some changes for PowerPC. + * -- Dan + * + * Reorganized to get rid of the arch-specific consistent_* functions + * and provide non-coherent implementations for the DMA API. -Matt + * + * Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent() + * implementation. This is pulled straight from ARM and barely + * modified. -Matt + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/highmem.h> +#include <linux/dma-mapping.h> +#include <linux/export.h> + +#include <asm/tlbflush.h> +#include <asm/dma.h> + +#include "mmu_decl.h" + +/* + * This address range defaults to a value that is safe for all + * platforms which currently set CONFIG_NOT_COHERENT_CACHE. It + * can be further configured for specific applications under + * the "Advanced Setup" menu. -Matt + */ +#define CONSISTENT_BASE (IOREMAP_TOP) +#define CONSISTENT_END (CONSISTENT_BASE + CONFIG_CONSISTENT_SIZE) +#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT) + +/* + * This is the page table (2MB) covering uncached, DMA consistent allocations + */ +static DEFINE_SPINLOCK(consistent_lock); + +/* + * VM region handling support. + * + * This should become something generic, handling VM region allocations for + * vmalloc and similar (ioremap, module space, etc). + * + * I envisage vmalloc()'s supporting vm_struct becoming: + * + * struct vm_struct { + * struct vm_region region; + * unsigned long flags; + * struct page **pages; + * unsigned int nr_pages; + * unsigned long phys_addr; + * }; + * + * get_vm_area() would then call vm_region_alloc with an appropriate + * struct vm_region head (eg): + * + * struct vm_region vmalloc_head = { + * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list), + * .vm_start = VMALLOC_START, + * .vm_end = VMALLOC_END, + * }; + * + * However, vmalloc_head.vm_start is variable (typically, it is dependent on + * the amount of RAM found at boot time.) I would imagine that get_vm_area() + * would have to initialise this each time prior to calling vm_region_alloc(). + */ +struct ppc_vm_region { + struct list_head vm_list; + unsigned long vm_start; + unsigned long vm_end; +}; + +static struct ppc_vm_region consistent_head = { + .vm_list = LIST_HEAD_INIT(consistent_head.vm_list), + .vm_start = CONSISTENT_BASE, + .vm_end = CONSISTENT_END, +}; + +static struct ppc_vm_region * +ppc_vm_region_alloc(struct ppc_vm_region *head, size_t size, gfp_t gfp) +{ + unsigned long addr = head->vm_start, end = head->vm_end - size; + unsigned long flags; + struct ppc_vm_region *c, *new; + + new = kmalloc(sizeof(struct ppc_vm_region), gfp); + if (!new) + goto out; + + spin_lock_irqsave(&consistent_lock, flags); + + list_for_each_entry(c, &head->vm_list, vm_list) { + if ((addr + size) < addr) + goto nospc; + if ((addr + size) <= c->vm_start) + goto found; + addr = c->vm_end; + if (addr > end) + goto nospc; + } + + found: + /* + * Insert this entry _before_ the one we found. + */ + list_add_tail(&new->vm_list, &c->vm_list); + new->vm_start = addr; + new->vm_end = addr + size; + + spin_unlock_irqrestore(&consistent_lock, flags); + return new; + + nospc: + spin_unlock_irqrestore(&consistent_lock, flags); + kfree(new); + out: + return NULL; +} + +static struct ppc_vm_region *ppc_vm_region_find(struct ppc_vm_region *head, unsigned long addr) +{ + struct ppc_vm_region *c; + + list_for_each_entry(c, &head->vm_list, vm_list) { + if (c->vm_start == addr) + goto out; + } + c = NULL; + out: + return c; +} + +/* + * Allocate DMA-coherent memory space and return both the kernel remapped + * virtual and bus address for that space. + */ +void * +__dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp) +{ + struct page *page; + struct ppc_vm_region *c; + unsigned long order; + u64 mask = ISA_DMA_THRESHOLD, limit; + + if (dev) { + mask = dev->coherent_dma_mask; + + /* + * Sanity check the DMA mask - it must be non-zero, and + * must be able to be satisfied by a DMA allocation. + */ + if (mask == 0) { + dev_warn(dev, "coherent DMA mask is unset\n"); + goto no_page; + } + + if ((~mask) & ISA_DMA_THRESHOLD) { + dev_warn(dev, "coherent DMA mask %#llx is smaller " + "than system GFP_DMA mask %#llx\n", + mask, (unsigned long long)ISA_DMA_THRESHOLD); + goto no_page; + } + } + + + size = PAGE_ALIGN(size); + limit = (mask + 1) & ~mask; + if ((limit && size >= limit) || + size >= (CONSISTENT_END - CONSISTENT_BASE)) { + printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n", + size, mask); + return NULL; + } + + order = get_order(size); + + /* Might be useful if we ever have a real legacy DMA zone... */ + if (mask != 0xffffffff) + gfp |= GFP_DMA; + + page = alloc_pages(gfp, order); + if (!page) + goto no_page; + + /* + * Invalidate any data that might be lurking in the + * kernel direct-mapped region for device DMA. + */ + { + unsigned long kaddr = (unsigned long)page_address(page); + memset(page_address(page), 0, size); + flush_dcache_range(kaddr, kaddr + size); + } + + /* + * Allocate a virtual address in the consistent mapping region. + */ + c = ppc_vm_region_alloc(&consistent_head, size, + gfp & ~(__GFP_DMA | __GFP_HIGHMEM)); + if (c) { + unsigned long vaddr = c->vm_start; + struct page *end = page + (1 << order); + + split_page(page, order); + + /* + * Set the "dma handle" + */ + *handle = page_to_phys(page); + + do { + SetPageReserved(page); + map_page(vaddr, page_to_phys(page), + pgprot_val(pgprot_noncached(PAGE_KERNEL))); + page++; + vaddr += PAGE_SIZE; + } while (size -= PAGE_SIZE); + + /* + * Free the otherwise unused pages. + */ + while (page < end) { + __free_page(page); + page++; + } + + return (void *)c->vm_start; + } + + if (page) + __free_pages(page, order); + no_page: + return NULL; +} +EXPORT_SYMBOL(__dma_alloc_coherent); + +/* + * free a page as defined by the above mapping. + */ +void __dma_free_coherent(size_t size, void *vaddr) +{ + struct ppc_vm_region *c; + unsigned long flags, addr; + + size = PAGE_ALIGN(size); + + spin_lock_irqsave(&consistent_lock, flags); + + c = ppc_vm_region_find(&consistent_head, (unsigned long)vaddr); + if (!c) + goto no_area; + + if ((c->vm_end - c->vm_start) != size) { + printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n", + __func__, c->vm_end - c->vm_start, size); + dump_stack(); + size = c->vm_end - c->vm_start; + } + + addr = c->vm_start; + do { + pte_t *ptep; + unsigned long pfn; + + ptep = pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(addr), + addr), + addr), + addr); + if (!pte_none(*ptep) && pte_present(*ptep)) { + pfn = pte_pfn(*ptep); + pte_clear(&init_mm, addr, ptep); + if (pfn_valid(pfn)) { + struct page *page = pfn_to_page(pfn); + __free_reserved_page(page); + } + } + addr += PAGE_SIZE; + } while (size -= PAGE_SIZE); + + flush_tlb_kernel_range(c->vm_start, c->vm_end); + + list_del(&c->vm_list); + + spin_unlock_irqrestore(&consistent_lock, flags); + + kfree(c); + return; + + no_area: + spin_unlock_irqrestore(&consistent_lock, flags); + printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n", + __func__, vaddr); + dump_stack(); +} +EXPORT_SYMBOL(__dma_free_coherent); + +/* + * make an area consistent. + */ +void __dma_sync(void *vaddr, size_t size, int direction) +{ + unsigned long start = (unsigned long)vaddr; + unsigned long end = start + size; + + switch (direction) { + case DMA_NONE: + BUG(); + case DMA_FROM_DEVICE: + /* + * invalidate only when cache-line aligned otherwise there is + * the potential for discarding uncommitted data from the cache + */ + if ((start & (L1_CACHE_BYTES - 1)) || (size & (L1_CACHE_BYTES - 1))) + flush_dcache_range(start, end); + else + invalidate_dcache_range(start, end); + break; + case DMA_TO_DEVICE: /* writeback only */ + clean_dcache_range(start, end); + break; + case DMA_BIDIRECTIONAL: /* writeback and invalidate */ + flush_dcache_range(start, end); + break; + } +} +EXPORT_SYMBOL(__dma_sync); + +#ifdef CONFIG_HIGHMEM +/* + * __dma_sync_page() implementation for systems using highmem. + * In this case, each page of a buffer must be kmapped/kunmapped + * in order to have a virtual address for __dma_sync(). This must + * not sleep so kmap_atomic()/kunmap_atomic() are used. + * + * Note: yes, it is possible and correct to have a buffer extend + * beyond the first page. + */ +static inline void __dma_sync_page_highmem(struct page *page, + unsigned long offset, size_t size, int direction) +{ + size_t seg_size = min((size_t)(PAGE_SIZE - offset), size); + size_t cur_size = seg_size; + unsigned long flags, start, seg_offset = offset; + int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE; + int seg_nr = 0; + + local_irq_save(flags); + + do { + start = (unsigned long)kmap_atomic(page + seg_nr) + seg_offset; + + /* Sync this buffer segment */ + __dma_sync((void *)start, seg_size, direction); + kunmap_atomic((void *)start); + seg_nr++; + + /* Calculate next buffer segment size */ + seg_size = min((size_t)PAGE_SIZE, size - cur_size); + + /* Add the segment size to our running total */ + cur_size += seg_size; + seg_offset = 0; + } while (seg_nr < nr_segs); + + local_irq_restore(flags); +} +#endif /* CONFIG_HIGHMEM */ + +/* + * __dma_sync_page makes memory consistent. identical to __dma_sync, but + * takes a struct page instead of a virtual address + */ +void __dma_sync_page(struct page *page, unsigned long offset, + size_t size, int direction) +{ +#ifdef CONFIG_HIGHMEM + __dma_sync_page_highmem(page, offset, size, direction); +#else + unsigned long start = (unsigned long)page_address(page) + offset; + __dma_sync((void *)start, size, direction); +#endif +} +EXPORT_SYMBOL(__dma_sync_page); + +/* + * Return the PFN for a given cpu virtual address returned by + * __dma_alloc_coherent. This is used by dma_mmap_coherent() + */ +unsigned long __dma_get_coherent_pfn(unsigned long cpu_addr) +{ + /* This should always be populated, so we don't test every + * level. If that fails, we'll have a nice crash which + * will be as good as a BUG_ON() + */ + pgd_t *pgd = pgd_offset_k(cpu_addr); + pud_t *pud = pud_offset(pgd, cpu_addr); + pmd_t *pmd = pmd_offset(pud, cpu_addr); + pte_t *ptep = pte_offset_kernel(pmd, cpu_addr); + + if (pte_none(*ptep) || !pte_present(*ptep)) + return 0; + return pte_pfn(*ptep); +} |