drm/ast: Try to use MMIO registers when PIO isn't supported

If the PIO resources haven't been assigned, then we have no choice
but try to use the MMIO version. This is the case for example on
POWER8 which doesn't support PIO at all.

Chips rev 0x20 or later have MMIO decoding enabled by default.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index cb91c2acc3cbaf4624ee21e5fbaa1dd6ed48b5d7..a24cad4d1322c1c112220c68f72dc5e120fe99ed 100644 (file)
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -125,8 +125,9 @@ struct ast_gem_object;
 
 #define AST_IO_AR_PORT_WRITE           (0x40)
 #define AST_IO_MISC_PORT_WRITE         (0x42)
+#define AST_IO_VGA_ENABLE_PORT         (0x43)
 #define AST_IO_SEQ_PORT                        (0x44)
-#define AST_DAC_INDEX_READ             (0x3c7)
+#define AST_IO_DAC_INDEX_READ          (0x47)
 #define AST_IO_DAC_INDEX_WRITE         (0x48)
 #define AST_IO_DAC_DATA                        (0x49)
 #define AST_IO_GR_PORT                 (0x4E)
@@ -134,6 +135,8 @@ struct ast_gem_object;
 #define AST_IO_INPUT_STATUS1_READ      (0x5A)
 #define AST_IO_MISC_PORT_READ          (0x4C)
 
+#define AST_IO_MM_OFFSET               (0x380)
+
 #define __ast_read(x) \
 static inline u##x ast_read##x(struct ast_private *ast, u32 reg) { \
 u##x val = 0;\

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index a2cc6be97983fe327cd4f67a4c3204cd4985691c..c2ff7933a90e1de369f57e741448a48a2ff5d09f 100644 (file)
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -359,10 +359,24 @@ int ast_driver_load(struct drm_device *dev, unsigned long flags)
                ret = -EIO;
                goto out_free;
        }
-       ast->ioregs = pci_iomap(dev->pdev, 2, 0);
+
+       /*
+        * If we don't have IO space at all, use MMIO now and
+        * assume the chip has MMIO enabled by default (rev 0x20
+        * and higher).
+        */
+       if (!(pci_resource_flags(dev->pdev, 2) & IORESOURCE_IO)) {
+               DRM_INFO("platform has no IO space, trying MMIO\n");
+               ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
+       }
+
+       /* "map" IO regs if the above hasn't done so already */
        if (!ast->ioregs) {
-               ret = -EIO;
-               goto out_free;
+               ast->ioregs = pci_iomap(dev->pdev, 2, 0);
+               if (!ast->ioregs) {
+                       ret = -EIO;
+                       goto out_free;
+               }
        }
 
        ast_detect_chip(dev);