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>

3 files changed, 74 insertions, 0 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 51e4e5b02f9d..e2116b1f968e 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1336,6 +1336,7 @@ config SYS_HAS_CPU_LOONGSON2F
         bool
         select CPU_SUPPORTS_CPUFREQ
         select CPU_SUPPORTS_ADDRWINCFG if 64BIT
+        select CPU_SUPPORTS_UNCACHED_ACCELERATED
 
 config SYS_HAS_CPU_MIPS32_R1
         bool
@@ -1451,6 +1452,8 @@ config CPU_SUPPORTS_ADDRWINCFG
         bool
 config CPU_SUPPORTS_HUGEPAGES
         bool
+config CPU_SUPPORTS_UNCACHED_ACCELERATED
+        bool
 config MIPS_PGD_C0_CONTEXT
         bool
         default y if 64BIT && CPU_MIPSR2
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index d6eb6134abec..1854336e56a2 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -390,6 +390,19 @@ static inline int io_remap_pfn_range(struct vm_area_struct *vma,
 #include <asm-generic/pgtable.h>
 
 /*
+ * uncached accelerated TLB map for video memory access
+ */
+#ifdef CONFIG_CPU_SUPPORTS_UNCACHED_ACCELERATED
+#define __HAVE_PHYS_MEM_ACCESS_PROT
+
+struct file;
+pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
+                unsigned long size, pgprot_t vma_prot);
+int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
+                unsigned long size, pgprot_t *vma_prot);
+#endif
+
+/*
  * We provide our own get_unmapped area to cope with the virtual aliasing
  * constraints placed on us by the cache architecture.
  */
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 */