[PATCH v6 12/15] swiotlb: Add restricted DMA alloc/free support.
From: Claire Chang <hidden>
Date: 2021-05-10 09:54:38
Also in:
dri-devel, intel-gfx, linux-devicetree, linux-iommu, linux-pci, lkml, nouveau, xen-devel
Subsystem:
dma mapping helpers, the rest · Maintainers:
Marek Szyprowski, Linus Torvalds
Add the functions, swiotlb_{alloc,free} to support the memory allocation
from restricted DMA pool.
Signed-off-by: Claire Chang <redacted>
---
include/linux/swiotlb.h | 4 ++++
kernel/dma/swiotlb.c | 35 +++++++++++++++++++++++++++++++++--
2 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 0c5a18d9cf89..e8cf49bd90c5 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h@@ -134,6 +134,10 @@ unsigned int swiotlb_max_segment(void); size_t swiotlb_max_mapping_size(struct device *dev); bool is_swiotlb_active(struct device *dev); void __init swiotlb_adjust_size(unsigned long size); +#ifdef CONFIG_DMA_RESTRICTED_POOL +struct page *swiotlb_alloc(struct device *dev, size_t size); +bool swiotlb_free(struct device *dev, struct page *page, size_t size); +#endif /* CONFIG_DMA_RESTRICTED_POOL */ #else #define swiotlb_force SWIOTLB_NO_FORCE static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index fa11787e4b95..d99d5f902259 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c@@ -457,8 +457,9 @@ static int find_slots(struct device *dev, phys_addr_t orig_addr, index = wrap = wrap_index(mem, ALIGN(mem->index, stride)); do { - if ((slot_addr(tbl_dma_addr, index) & iotlb_align_mask) != - (orig_addr & iotlb_align_mask)) { + if (orig_addr && + (slot_addr(tbl_dma_addr, index) & iotlb_align_mask) != + (orig_addr & iotlb_align_mask)) { index = wrap_index(mem, index + 1); continue; }
@@ -701,6 +702,36 @@ late_initcall(swiotlb_create_default_debugfs); #endif #ifdef CONFIG_DMA_RESTRICTED_POOL +struct page *swiotlb_alloc(struct device *dev, size_t size) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + phys_addr_t tlb_addr; + int index; + + if (!mem) + return NULL; + + index = find_slots(dev, 0, size); + if (index == -1) + return NULL; + + tlb_addr = slot_addr(mem->start, index); + + return pfn_to_page(PFN_DOWN(tlb_addr)); +} + +bool swiotlb_free(struct device *dev, struct page *page, size_t size) +{ + phys_addr_t tlb_addr = page_to_phys(page); + + if (!is_swiotlb_buffer(dev, tlb_addr)) + return false; + + release_slots(dev, tlb_addr); + + return true; +} + static int rmem_swiotlb_device_init(struct reserved_mem *rmem, struct device *dev) {
--
2.31.1.607.g51e8a6a459-goog