drm/radeon/kms: add support to atom parser for FB read/write

FB read/write really doesn't need to access the actual VRAM, we
can just use a scratch area. This is required for using atom displayport
calls later.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/atom.c

@@ -263,10 +263,10 @@ static uint32_t atom_get_src_int(atom_exec_context *ctx, uint8_t attr,
 	case ATOM_ARG_FB:
 		idx = U8(*ptr);
 		(*ptr)++;
+		val = gctx->scratch[((gctx->fb_base + idx) / 4)];
 		if (print)
 			DEBUG("FB[0x%02X]", idx);
-		printk(KERN_INFO "FB access is not implemented.\n");
-		return 0;
+		break;
 	case ATOM_ARG_IMM:
 		switch (align) {
 		case ATOM_SRC_DWORD:
@@ -488,9 +488,9 @@ static void atom_put_dst(atom_exec_context *ctx, int arg, uint8_t attr,
 	case ATOM_ARG_FB:
 		idx = U8(*ptr);
 		(*ptr)++;
+		gctx->scratch[((gctx->fb_base + idx) / 4)] = val;
 		DEBUG("FB[0x%02X]", idx);
-		printk(KERN_INFO "FB access is not implemented.\n");
-		return;
+		break;
 	case ATOM_ARG_PLL:
 		idx = U8(*ptr);
 		(*ptr)++;

drivers/gpu/drm/radeon/atom.h

@@ -132,6 +132,7 @@ struct atom_context {
 	uint8_t shift;
 	int cs_equal, cs_above;
 	int io_mode;
+	uint32_t *scratch;
 };
 
 extern int atom_debug;
@@ -142,6 +143,7 @@ int atom_asic_init(struct atom_context *);
 void atom_destroy(struct atom_context *);
 void atom_parse_data_header(struct atom_context *ctx, int index, uint16_t *size, uint8_t *frev, uint8_t *crev, uint16_t *data_start);
 void atom_parse_cmd_header(struct atom_context *ctx, int index, uint8_t *frev, uint8_t *crev);
+int atom_allocate_fb_scratch(struct atom_context *ctx);
 #include "atom-types.h"
 #include "atombios.h"
 #include "ObjectID.h"

drivers/gpu/drm/radeon/radeon_device.c

@@ -481,11 +481,13 @@ int radeon_atombios_init(struct radeon_device *rdev)
 
 	rdev->mode_info.atom_context = atom_parse(atom_card_info, rdev->bios);
 	radeon_atom_initialize_bios_scratch_regs(rdev->ddev);
+	atom_allocate_fb_scratch(rdev->mode_info.atom_context);
 	return 0;
 }
 
 void radeon_atombios_fini(struct radeon_device *rdev)
 {
+	kfree(rdev->mode_info.atom_context->scratch);
 	kfree(rdev->mode_info.atom_context);
 	kfree(rdev->mode_info.atom_card_info);
 }