From 84532a0fc3d5811dca8e3726fe4d372ea87bd7c6 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 27 May 2009 13:33:14 +1000 Subject: Revert "powerpc: Rework dma-noncoherent to use generic vmalloc layer" This reverts commit 33f00dcedb0e22cdb156a23632814fc580fcfcf8. While it was a good idea to try to use the mm/vmalloc.c allocator instead of our own (in fact, ours is itself a dup on an old variant of the vmalloc one), unfortunately, the approach is terminally busted since dma_alloc_coherent() can be called at interrupt time or in atomic contexts and there's little chances we'll make the code in mm/vmalloc.c cope with\ that :-( Until we can get the generic code to forbid that idiocy and fix all drivers abusing it, we pretty much have no choice but revert to our custom virtual space allocator. There's also a problem with SMP safety since freeing such mapping would require an IPI which cannot be done at interrupt time. However, right now, I don't think we support any platform that is both SMP and has non-coherent DMA (don't laugh, I know such things do exist !) so we can sort that out later. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/Kconfig | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'arch/powerpc/Kconfig') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index a0d1146a0578..3bb43adce44d 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -868,6 +868,31 @@ config TASK_SIZE default "0x80000000" if PPC_PREP || PPC_8xx default "0xc0000000" +config CONSISTENT_START_BOOL + bool "Set custom consistent memory pool address" + depends on ADVANCED_OPTIONS && NOT_COHERENT_CACHE + help + This option allows you to set the base virtual address + of the consistent memory pool. This pool of virtual + memory is used to make consistent memory allocations. + +config CONSISTENT_START + hex "Base virtual address of consistent memory pool" if CONSISTENT_START_BOOL + default "0xfd000000" if (NOT_COHERENT_CACHE && 8xx) + default "0xff100000" if NOT_COHERENT_CACHE + +config CONSISTENT_SIZE_BOOL + bool "Set custom consistent memory pool size" + depends on ADVANCED_OPTIONS && NOT_COHERENT_CACHE + help + This option allows you to set the size of the + consistent memory pool. This pool of virtual memory + is used to make consistent memory allocations. + +config CONSISTENT_SIZE + hex "Size of consistent memory pool" if CONSISTENT_SIZE_BOOL + default "0x00200000" if NOT_COHERENT_CACHE + config PIN_TLB bool "Pinned Kernel TLBs (860 ONLY)" depends on ADVANCED_OPTIONS && 8xx -- cgit v1.2.3 From 8b31e49d1d75729c1da9009664ba52abd1adc628 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 27 May 2009 13:50:33 +1000 Subject: powerpc: Fix up dma_alloc_coherent() on platforms without cache coherency. The implementation we just revived has issues, such as using a Kconfig-defined virtual address area in kernel space that nothing actually carves out (and thus will overlap whatever is there), or having some dependencies on being self contained in a single PTE page which adds unnecessary constraints on the kernel virtual address space. This fixes it by using more classic PTE accessors and automatically locating the area for consistent memory, carving an appropriate hole in the kernel virtual address space, leaving only the size of that area as a Kconfig option. It also brings some dma-mask related fixes from the ARM implementation which was almost identical initially but grew its own fixes. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/Kconfig | 13 ---- arch/powerpc/include/asm/dma-mapping.h | 6 +- arch/powerpc/include/asm/pgtable-ppc32.h | 4 ++ arch/powerpc/kernel/dma.c | 2 +- arch/powerpc/mm/dma-noncoherent.c | 108 ++++++++++++------------------- arch/powerpc/mm/mem.c | 4 ++ 6 files changed, 54 insertions(+), 83 deletions(-) (limited to 'arch/powerpc/Kconfig') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 3bb43adce44d..cdc9a6ff4be8 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -868,19 +868,6 @@ config TASK_SIZE default "0x80000000" if PPC_PREP || PPC_8xx default "0xc0000000" -config CONSISTENT_START_BOOL - bool "Set custom consistent memory pool address" - depends on ADVANCED_OPTIONS && NOT_COHERENT_CACHE - help - This option allows you to set the base virtual address - of the consistent memory pool. This pool of virtual - memory is used to make consistent memory allocations. - -config CONSISTENT_START - hex "Base virtual address of consistent memory pool" if CONSISTENT_START_BOOL - default "0xfd000000" if (NOT_COHERENT_CACHE && 8xx) - default "0xff100000" if NOT_COHERENT_CACHE - config CONSISTENT_SIZE_BOOL bool "Set custom consistent memory pool size" depends on ADVANCED_OPTIONS && NOT_COHERENT_CACHE diff --git a/arch/powerpc/include/asm/dma-mapping.h b/arch/powerpc/include/asm/dma-mapping.h index c69f2b5f0cc4..cb448d68452c 100644 --- a/arch/powerpc/include/asm/dma-mapping.h +++ b/arch/powerpc/include/asm/dma-mapping.h @@ -26,7 +26,9 @@ * allocate the space "normally" and use the cache management functions * to ensure it is consistent. */ -extern void *__dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp); +struct device; +extern void *__dma_alloc_coherent(struct device *dev, size_t size, + dma_addr_t *handle, gfp_t gfp); extern void __dma_free_coherent(size_t size, void *vaddr); extern void __dma_sync(void *vaddr, size_t size, int direction); extern void __dma_sync_page(struct page *page, unsigned long offset, @@ -37,7 +39,7 @@ extern void __dma_sync_page(struct page *page, unsigned long offset, * Cache coherent cores. */ -#define __dma_alloc_coherent(gfp, size, handle) NULL +#define __dma_alloc_coherent(dev, gfp, size, handle) NULL #define __dma_free_coherent(size, addr) ((void)0) #define __dma_sync(addr, size, rw) ((void)0) #define __dma_sync_page(pg, off, sz, rw) ((void)0) diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h index 28fe9d4bae35..c9ff9d75990e 100644 --- a/arch/powerpc/include/asm/pgtable-ppc32.h +++ b/arch/powerpc/include/asm/pgtable-ppc32.h @@ -71,7 +71,11 @@ extern int icache_44x_need_flush; * until mem_init() at which point this becomes the top of the vmalloc * and ioremap space */ +#ifdef CONFIG_NOT_COHERENT_CACHE +#define IOREMAP_TOP ((KVIRT_TOP - CONFIG_CONSISTENT_SIZE) & PAGE_MASK) +#else #define IOREMAP_TOP KVIRT_TOP +#endif /* * Just any arbitrary offset to the start of the vmalloc VM area: the diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c index 53c7788cba78..6b02793dc75b 100644 --- a/arch/powerpc/kernel/dma.c +++ b/arch/powerpc/kernel/dma.c @@ -32,7 +32,7 @@ void *dma_direct_alloc_coherent(struct device *dev, size_t size, { void *ret; #ifdef CONFIG_NOT_COHERENT_CACHE - ret = __dma_alloc_coherent(size, dma_handle, flag); + ret = __dma_alloc_coherent(dev, size, dma_handle, flag); if (ret == NULL) return NULL; *dma_handle += get_dma_direct_offset(dev); diff --git a/arch/powerpc/mm/dma-noncoherent.c b/arch/powerpc/mm/dma-noncoherent.c index b7dc4c19f582..36692f5c9a76 100644 --- a/arch/powerpc/mm/dma-noncoherent.c +++ b/arch/powerpc/mm/dma-noncoherent.c @@ -32,20 +32,21 @@ #include +#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 (CONFIG_CONSISTENT_START) -#define CONSISTENT_END (CONFIG_CONSISTENT_START + CONFIG_CONSISTENT_SIZE) +#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 pte_t *consistent_pte; static DEFINE_SPINLOCK(consistent_lock); /* @@ -148,22 +149,38 @@ static struct ppc_vm_region *ppc_vm_region_find(struct ppc_vm_region *head, unsi * virtual and bus address for that space. */ void * -__dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp) +__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 = 0x00ffffff, limit; /* ISA default */ + u64 mask = ISA_DMA_THRESHOLD, limit; - if (!consistent_pte) { - printk(KERN_ERR "%s: not initialised\n", __func__); - dump_stack(); - return NULL; + 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)) { + 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; @@ -171,6 +188,7 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp) order = get_order(size); + /* Might be useful if we ever have a real legacy DMA zone... */ if (mask != 0xffffffff) gfp |= GFP_DMA; @@ -195,7 +213,6 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp) gfp & ~(__GFP_DMA | __GFP_HIGHMEM)); if (c) { unsigned long vaddr = c->vm_start; - pte_t *pte = consistent_pte + CONSISTENT_OFFSET(vaddr); struct page *end = page + (1 << order); split_page(page, order); @@ -206,13 +223,10 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp) *handle = page_to_phys(page); do { - BUG_ON(!pte_none(*pte)); - SetPageReserved(page); - set_pte_at(&init_mm, vaddr, - pte, mk_pte(page, pgprot_noncached(PAGE_KERNEL))); + map_page(vaddr, page_to_phys(page), + pgprot_noncached(PAGE_KERNEL)); page++; - pte++; vaddr += PAGE_SIZE; } while (size -= PAGE_SIZE); @@ -241,8 +255,7 @@ void __dma_free_coherent(size_t size, void *vaddr) { struct ppc_vm_region *c; unsigned long flags, addr; - pte_t *ptep; - + size = PAGE_ALIGN(size); spin_lock_irqsave(&consistent_lock, flags); @@ -258,29 +271,26 @@ void __dma_free_coherent(size_t size, void *vaddr) size = c->vm_end - c->vm_start; } - ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start); addr = c->vm_start; do { - pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep); + pte_t *ptep; unsigned long pfn; - ptep++; - addr += PAGE_SIZE; - - if (!pte_none(pte) && pte_present(pte)) { - pfn = pte_pfn(pte); - + 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); - ClearPageReserved(page); + ClearPageReserved(page); __free_page(page); - continue; } } - - printk(KERN_CRIT "%s: bad page in kernel page table\n", - __func__); + addr += PAGE_SIZE; } while (size -= PAGE_SIZE); flush_tlb_kernel_range(c->vm_start, c->vm_end); @@ -300,42 +310,6 @@ void __dma_free_coherent(size_t size, void *vaddr) } EXPORT_SYMBOL(__dma_free_coherent); -/* - * Initialise the consistent memory allocation. - */ -static int __init dma_alloc_init(void) -{ - pgd_t *pgd; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - int ret = 0; - - do { - pgd = pgd_offset(&init_mm, CONSISTENT_BASE); - pud = pud_alloc(&init_mm, pgd, CONSISTENT_BASE); - pmd = pmd_alloc(&init_mm, pud, CONSISTENT_BASE); - if (!pmd) { - printk(KERN_ERR "%s: no pmd tables\n", __func__); - ret = -ENOMEM; - break; - } - - pte = pte_alloc_kernel(pmd, CONSISTENT_BASE); - if (!pte) { - printk(KERN_ERR "%s: no pte tables\n", __func__); - ret = -ENOMEM; - break; - } - - consistent_pte = pte; - } while (0); - - return ret; -} - -core_initcall(dma_alloc_init); - /* * make an area consistent. */ diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index d3a4e67561fa..579382c163a9 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -387,6 +387,10 @@ void __init mem_init(void) pr_info(" * 0x%08lx..0x%08lx : highmem PTEs\n", PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP)); #endif /* CONFIG_HIGHMEM */ +#ifdef CONFIG_NOT_COHERENT_CACHE + pr_info(" * 0x%08lx..0x%08lx : consistent mem\n", + IOREMAP_TOP, IOREMAP_TOP + CONFIG_CONSISTENT_SIZE); +#endif /* CONFIG_NOT_COHERENT_CACHE */ pr_info(" * 0x%08lx..0x%08lx : early ioremap\n", ioremap_bot, IOREMAP_TOP); pr_info(" * 0x%08lx..0x%08lx : vmalloc & ioremap\n", -- cgit v1.2.3