diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/xen/mm.c | 34 |
1 files changed, 32 insertions, 2 deletions
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c index 28ebf3ecee4e..351b24a979d4 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c @@ -12,6 +12,7 @@ #include <linux/swiotlb.h> #include <xen/xen.h> +#include <xen/interface/grant_table.h> #include <xen/interface/memory.h> #include <xen/swiotlb-xen.h> @@ -24,12 +25,14 @@ enum dma_cache_op { DMA_UNMAP, DMA_MAP, }; +static bool hypercall_cflush = false; /* functions called by SWIOTLB */ static void dma_cache_maint(dma_addr_t handle, unsigned long offset, size_t size, enum dma_data_direction dir, enum dma_cache_op op) { + struct gnttab_cache_flush cflush; unsigned long pfn; size_t left = size; @@ -39,7 +42,26 @@ static void dma_cache_maint(dma_addr_t handle, unsigned long offset, do { size_t len = left; - /* TODO: cache flush */ + /* buffers in highmem or foreign pages cannot cross page + * boundaries */ + if (len + offset > PAGE_SIZE) + len = PAGE_SIZE - offset; + + cflush.op = 0; + cflush.a.dev_bus_addr = pfn << PAGE_SHIFT; + cflush.offset = offset; + cflush.length = len; + + if (op == DMA_UNMAP && dir != DMA_TO_DEVICE) + cflush.op = GNTTAB_CACHE_INVAL; + if (op == DMA_MAP) { + if (dir == DMA_FROM_DEVICE) + cflush.op = GNTTAB_CACHE_INVAL; + else + cflush.op = GNTTAB_CACHE_CLEAN; + } + if (cflush.op) + HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); offset = 0; pfn++; @@ -104,7 +126,7 @@ bool xen_arch_need_swiotlb(struct device *dev, unsigned long pfn, unsigned long mfn) { - return ((pfn != mfn) && !is_device_dma_coherent(dev)); + return (!hypercall_cflush && (pfn != mfn) && !is_device_dma_coherent(dev)); } int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, @@ -147,10 +169,18 @@ static struct dma_map_ops xen_swiotlb_dma_ops = { int __init xen_mm_init(void) { + struct gnttab_cache_flush cflush; if (!xen_initial_domain()) return 0; xen_swiotlb_init(1, false); xen_dma_ops = &xen_swiotlb_dma_ops; + + cflush.op = 0; + cflush.a.dev_bus_addr = 0; + cflush.offset = 0; + cflush.length = 0; + if (HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1) != -ENOSYS) + hypercall_cflush = true; return 0; } arch_initcall(xen_mm_init); |