Merge tag 'xtensa-20180225' of git://github.com/jcmvbkbc/linux-xtensa

Pull Xtensa fixes from Max Filippov:
 "Two fixes for reserved memory/DMA buffers allocation in high memory on
  xtensa architecture

   - fix memory accounting when reserved memory is in high memory region

   - fix DMA allocation from high memory"

* tag 'xtensa-20180225' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: support DMA buffers in high memory
  xtensa: fix high memory/reserved memory collision

2 files changed, 93 insertions, 17 deletions

diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index 623720a11143..732631ce250f 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -16,6 +16,7 @@
  */
 
 #include <linux/dma-contiguous.h>
+#include <linux/dma-direct.h>
 #include <linux/gfp.h>
 #include <linux/highmem.h>
 #include <linux/mm.h>
@@ -123,7 +124,7 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
                               unsigned long attrs)
 {
         unsigned long ret;
-        unsigned long uncached = 0;
+        unsigned long uncached;
         unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
         struct page *page = NULL;
 
@@ -144,15 +145,27 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
         if (!page)
                 return NULL;
 
-        ret = (unsigned long)page_address(page);
+        *handle = phys_to_dma(dev, page_to_phys(page));
 
-        /* We currently don't support coherent memory outside KSEG */
+#ifdef CONFIG_MMU
+        if (PageHighMem(page)) {
+                void *p;
 
+                p = dma_common_contiguous_remap(page, size, VM_MAP,
+                                                pgprot_noncached(PAGE_KERNEL),
+                                                __builtin_return_address(0));
+                if (!p) {
+                        if (!dma_release_from_contiguous(dev, page, count))
+                                __free_pages(page, get_order(size));
+                }
+                return p;
+        }
+#endif
+        ret = (unsigned long)page_address(page);
         BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
                ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 
         uncached = ret + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
-        *handle = virt_to_bus((void *)ret);
         __invalidate_dcache_range(ret, size);
 
         return (void *)uncached;
@@ -161,13 +174,20 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
 static void xtensa_dma_free(struct device *dev, size_t size, void *vaddr,
                             dma_addr_t dma_handle, unsigned long attrs)
 {
-        unsigned long addr = (unsigned long)vaddr +
-                XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
-        struct page *page = virt_to_page(addr);
         unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
-        BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
-               addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
+        unsigned long addr = (unsigned long)vaddr;
+        struct page *page;
+
+        if (addr >= XCHAL_KSEG_BYPASS_VADDR &&
+            addr - XCHAL_KSEG_BYPASS_VADDR < XCHAL_KSEG_SIZE) {
+                addr += XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
+                page = virt_to_page(addr);
+        } else {
+#ifdef CONFIG_MMU
+                dma_common_free_remap(vaddr, size, VM_MAP);
+#endif
+                page = pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_handle)));
+        }
 
         if (!dma_release_from_contiguous(dev, page, count))
                 __free_pages(page, get_order(size));
diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index d776ec0d7b22..34aead7dcb48 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -79,19 +79,75 @@ void __init zones_init(void)
         free_area_init_node(0, zones_size, ARCH_PFN_OFFSET, NULL);
 }
 
+#ifdef CONFIG_HIGHMEM
+static void __init free_area_high(unsigned long pfn, unsigned long end)
+{
+        for (; pfn < end; pfn++)
+                free_highmem_page(pfn_to_page(pfn));
+}
+
+static void __init free_highpages(void)
+{
+        unsigned long max_low = max_low_pfn;
+        struct memblock_region *mem, *res;
+
+        reset_all_zones_managed_pages();
+        /* set highmem page free */
+        for_each_memblock(memory, mem) {
+                unsigned long start = memblock_region_memory_base_pfn(mem);
+                unsigned long end = memblock_region_memory_end_pfn(mem);
+
+                /* Ignore complete lowmem entries */
+                if (end <= max_low)
+                        continue;
+
+                if (memblock_is_nomap(mem))
+                        continue;
+
+                /* Truncate partial highmem entries */
+                if (start < max_low)
+                        start = max_low;
+
+                /* Find and exclude any reserved regions */
+                for_each_memblock(reserved, res) {
+                        unsigned long res_start, res_end;
+
+                        res_start = memblock_region_reserved_base_pfn(res);
+                        res_end = memblock_region_reserved_end_pfn(res);
+
+                        if (res_end < start)
+                                continue;
+                        if (res_start < start)
+                                res_start = start;
+                        if (res_start > end)
+                                res_start = end;
+                        if (res_end > end)
+                                res_end = end;
+                        if (res_start != start)
+                                free_area_high(start, res_start);
+                        start = res_end;
+                        if (start == end)
+                                break;
+                }
+
+                /* And now free anything which remains */
+                if (start < end)
+                        free_area_high(start, end);
+        }
+}
+#else
+static void __init free_highpages(void)
+{
+}
+#endif
+
 /*
  * Initialize memory pages.
  */
 
 void __init mem_init(void)
 {
-#ifdef CONFIG_HIGHMEM
-        unsigned long tmp;
-
-        reset_all_zones_managed_pages();
-        for (tmp = max_low_pfn; tmp < max_pfn; tmp++)
-                free_highmem_page(pfn_to_page(tmp));
-#endif
+        free_highpages();
 
         max_mapnr = max_pfn - ARCH_PFN_OFFSET;
         high_memory = (void *)__va(max_low_pfn << PAGE_SHIFT);