MIPS: Add support for uncached accelerated mappings.

Loongson2f support video acceleration.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/624/
Patchwork: http://patchwork.linux-mips.org/patch/625/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/arch/mips/loongson/common/mem.c b/arch/mips/loongson/common/mem.c
index 981e9190f393..ceacd092b446 100644
--- a/arch/mips/loongson/common/mem.c
+++ b/arch/mips/loongson/common/mem.c
@@ -58,3 +58,61 @@ int __uncached_access(struct file *file, unsigned long addr)
                 ((addr >= LOONGSON_MMIO_MEM_START) &&
                  (addr < LOONGSON_MMIO_MEM_END));
 }
+
+#ifdef CONFIG_CPU_SUPPORTS_UNCACHED_ACCELERATED
+
+#include <linux/pci.h>
+#include <linux/sched.h>
+#include <asm/current.h>
+
+static unsigned long uca_start, uca_end;
+
+pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
+                              unsigned long size, pgprot_t vma_prot)
+{
+        unsigned long offset = pfn << PAGE_SHIFT;
+        unsigned long end = offset + size;
+
+        if (__uncached_access(file, offset)) {
+                if (((uca_start && offset) >= uca_start) &&
+                    (end <= uca_end))
+                        return __pgprot((pgprot_val(vma_prot) &
+                                         ~_CACHE_MASK) |
+                                        _CACHE_UNCACHED_ACCELERATED);
+                else
+                        return pgprot_noncached(vma_prot);
+        }
+        return vma_prot;
+}
+
+static int __init find_vga_mem_init(void)
+{
+        struct pci_dev *dev = 0;
+        struct resource *r;
+        int idx;
+
+        if (uca_start)
+                return 0;
+
+        for_each_pci_dev(dev) {
+                if ((dev->class >> 8) == PCI_CLASS_DISPLAY_VGA) {
+                        for (idx = 0; idx < PCI_NUM_RESOURCES; idx++) {
+                                r = &dev->resource[idx];
+                                if (!r->start && r->end)
+                                        continue;
+                                if (r->flags & IORESOURCE_IO)
+                                        continue;
+                                if (r->flags & IORESOURCE_MEM) {
+                                        uca_start = r->start;
+                                        uca_end = r->end;
+                                        return 0;
+                                }
+                        }
+                }
+        }
+
+        return 0;
+}
+
+late_initcall(find_vga_mem_init);
+#endif /* !CONFIG_CPU_SUPPORTS_UNCACHED_ACCELERATED */