New patch to review for coreboot: 3e1dbdb ivybridge native gfx init: Adjust state to be compatible with OPROM.

[Vladimir Serbinenko]

Vladimir Serbinenko ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/10205

-gerrit

commit 3e1dbdb2eec103ebd3d6cd1e26a84bc4adf5f075
Author: Vladimir Serbinenko 
Date:   Wed May 13 09:30:09 2015 +0200

ivybridge native gfx init: Adjust state to be compatible with OPROM.

My main payload is GRUB and I load SeaBIOS as secondary payload when for some
    reason I want to boot windows. In this scenario SeaBIOS runs VGA oprom
    (SeaVGABIOS is not good enough with intel gfx). VGA oprom expects either
    completely uninited gfx or some special state in gmbus and software scratch
    registers. Provide this state.

The only alternative without this patch for such usecase is to use oprom and
    I'd like to avoid doing so when going my main boot path to GNU/Linux.

Change-Id: I38e78fb845e43b81df084cd4d65f4618bfb2506d
    Signed-off-by: Vladimir Serbinenko 
---
 src/drivers/intel/gma/edid.c                           | 18 ++++++++++++++++++
 src/drivers/intel/gma/edid.h                           |  1 +
 src/northbridge/intel/sandybridge/gma_ivybridge_lvds.c | 11 +++++++++--
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/src/drivers/intel/gma/edid.c b/src/drivers/intel/gma/edid.c
index 36d8813..225c782 100644
--- a/src/drivers/intel/gma/edid.c
+++ b/src/drivers/intel/gma/edid.c
@@ -37,6 +37,24 @@ static void wait_rdy(u8 *mmio)
    }
 }

+void intel_gmbus_stop(u8 *mmio)
+{
+	wait_rdy(mmio);
+	write32(mmio + 4 * 0, 6);
+	wait_rdy(mmio);
+	write32(mmio + 4 * 5, 0);
+	write32(mmio + 4 * 1, 0x4e0400a1);
+	wait_rdy(mmio);
+	write32(mmio + 4 * 5, 0);
+	write32(mmio + 4 * 1, 0x80000000);
+	write32(mmio + 4 * 1, 0x00000000);
+	wait_rdy(mmio);
+	write32(mmio + 4 * 1, 0x480000a0);
+	wait_rdy(mmio);
+	write32(mmio + 4 * 0, 0x48000000);
+	write32(mmio + 4 * 2, 0x00008000);
+}
+
 void intel_gmbus_read_edid(u8 *mmio, u8 bus, u8 slave, u8 *edid, u32 edid_size)
 {
    int i;
diff --git a/src/drivers/intel/gma/edid.h b/src/drivers/intel/gma/edid.h
index c476391..d8214cf 100644
--- a/src/drivers/intel/gma/edid.h
+++ b/src/drivers/intel/gma/edid.h
@@ -1 +1,2 @@
 void intel_gmbus_read_edid(u8 *gmbus_mmio, u8 bus, u8 slave, u8 *edid, u32 edid_size);
+void intel_gmbus_stop(u8 *gmbus_mmio);
diff --git a/src/northbridge/intel/sandybridge/gma_ivybridge_lvds.c b/src/northbridge/intel/sandybridge/gma_ivybridge_lvds.c
index 6c1295a..8fa780f 100644
--- a/src/northbridge/intel/sandybridge/gma_ivybridge_lvds.c
+++ b/src/northbridge/intel/sandybridge/gma_ivybridge_lvds.c
@@ -206,6 +206,7 @@ int i915lightup_sandy(const struct i915_gpu_controller_info *info,
    enable_port(mmio);

intel_gmbus_read_edid(mmio + PCH_GMBUS0, 3, 0x50, edid_data, 128);
+	intel_gmbus_stop(mmio + PCH_GMBUS0);
    decode_edid(edid_data,
    	    sizeof(edid_data), &edid);

@@ -236,9 +237,8 @@ int i915lightup_sandy(const struct i915_gpu_controller_info *info,
    u32 pixel_m1 = 1;
    u32 pixel_m2 = 1;

-#if !IS_ENABLED(CONFIG_FRAMEBUFFER_KEEP_VESA_MODE)
    vga_textmode_init();
-#else
+#if IS_ENABLED(CONFIG_FRAMEBUFFER_KEEP_VESA_MODE)
    vga_sr_write(1, 1);
    vga_sr_write(0x2, 0xf);
    vga_sr_write(0x3, 0x0);
@@ -513,6 +513,13 @@ int i915lightup_sandy(const struct i915_gpu_controller_info *info,
    set_vbe_mode_info_valid(&edid, lfb);
 #endif

+	/* Doesn't change any hw behaviour but vga oprom expects it there. */
+	write32(mmio + 0x0004f040, 0x01000008);
+	write32(mmio + 0x0004f044, 0x00001800);
+	write32(mmio + 0x0004f04c, 0x7f7f0000);
+	write32(mmio + 0x0004f054, 0x0000422d);
+	write32(mmio + 0x0004f05c, 0x00000008);
+
    /* Linux relies on VBT for panel info.  */
    generate_fake_intel_oprom(info, dev_find_slot(0, PCI_DEVFN(2, 0)),
    			  "$VBT SNB/IVB-MOBILE ");