1 files changed, 145 insertions, 0 deletions

diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c
new file mode 100644
index 000000000..38d3d9143
--- /dev/null
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2000  Ani Joshi <ajoshi@unixbox.com>
+ * Copyright (C) 2000, 2001, 06  Ralf Baechle <ralf@linux-mips.org>
+ * swiped from i386, and cloned for MIPS by Geert, polished by Ralf.
+ */
+#include <linux/dma-direct.h>
+#include <linux/dma-map-ops.h>
+#include <linux/highmem.h>
+
+#include <asm/cache.h>
+#include <asm/cpu-type.h>
+#include <asm/dma-coherence.h>
+#include <asm/io.h>
+
+/*
+ * The affected CPUs below in 'cpu_needs_post_dma_flush()' can speculatively
+ * fill random cachelines with stale data at any time, requiring an extra
+ * flush post-DMA.
+ *
+ * Warning on the terminology - Linux calls an uncached area coherent;  MIPS
+ * terminology calls memory areas with hardware maintained coherency coherent.
+ *
+ * Note that the R14000 and R16000 should also be checked for in this condition.
+ * However this function is only called on non-I/O-coherent systems and only the
+ * R10000 and R12000 are used in such systems, the SGI IP28 Indigo² rsp.
+ * SGI IP32 aka O2.
+ */
+static inline bool cpu_needs_post_dma_flush(void)
+{
+        switch (boot_cpu_type()) {
+        case CPU_R10000:
+        case CPU_R12000:
+        case CPU_BMIPS5000:
+        case CPU_LOONGSON2EF:
+                return true;
+        default:
+                /*
+                 * Presence of MAARs suggests that the CPU supports
+                 * speculatively prefetching data, and therefore requires
+                 * the post-DMA flush/invalidate.
+                 */
+                return cpu_has_maar;
+        }
+}
+
+void arch_dma_prep_coherent(struct page *page, size_t size)
+{
+        dma_cache_wback_inv((unsigned long)page_address(page), size);
+}
+
+void *arch_dma_set_uncached(void *addr, size_t size)
+{
+        return (void *)(__pa(addr) + UNCAC_BASE);
+}
+
+static inline void dma_sync_virt_for_device(void *addr, size_t size,
+                enum dma_data_direction dir)
+{
+        switch (dir) {
+        case DMA_TO_DEVICE:
+                dma_cache_wback((unsigned long)addr, size);
+                break;
+        case DMA_FROM_DEVICE:
+                dma_cache_inv((unsigned long)addr, size);
+                break;
+        case DMA_BIDIRECTIONAL:
+                dma_cache_wback_inv((unsigned long)addr, size);
+                break;
+        default:
+                BUG();
+        }
+}
+
+static inline void dma_sync_virt_for_cpu(void *addr, size_t size,
+                enum dma_data_direction dir)
+{
+        switch (dir) {
+        case DMA_TO_DEVICE:
+                break;
+        case DMA_FROM_DEVICE:
+        case DMA_BIDIRECTIONAL:
+                dma_cache_inv((unsigned long)addr, size);
+                break;
+        default:
+                BUG();
+        }
+}
+
+/*
+ * A single sg entry may refer to multiple physically contiguous pages.  But
+ * we still need to process highmem pages individually.  If highmem is not
+ * configured then the bulk of this loop gets optimized out.
+ */
+static inline void dma_sync_phys(phys_addr_t paddr, size_t size,
+                enum dma_data_direction dir, bool for_device)
+{
+        struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
+        unsigned long offset = paddr & ~PAGE_MASK;
+        size_t left = size;
+
+        do {
+                size_t len = left;
+                void *addr;
+
+                if (PageHighMem(page)) {
+                        if (offset + len > PAGE_SIZE)
+                                len = PAGE_SIZE - offset;
+                }
+
+                addr = kmap_atomic(page);
+                if (for_device)
+                        dma_sync_virt_for_device(addr + offset, len, dir);
+                else
+                        dma_sync_virt_for_cpu(addr + offset, len, dir);
+                kunmap_atomic(addr);
+
+                offset = 0;
+                page++;
+                left -= len;
+        } while (left);
+}
+
+void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
+                enum dma_data_direction dir)
+{
+        dma_sync_phys(paddr, size, dir, true);
+}
+
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
+                enum dma_data_direction dir)
+{
+        if (cpu_needs_post_dma_flush())
+                dma_sync_phys(paddr, size, dir, false);
+}
+#endif
+
+#ifdef CONFIG_DMA_PERDEV_COHERENT
+void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                const struct iommu_ops *iommu, bool coherent)
+{
+        dev->dma_coherent = coherent;
+}
+#endif