ARM: OMAP2PLUS: DSS: Ensure DSS works correctly if display is enabled in bootloader

Resetting DISPC when a DISPC output is enabled causes the DSS to go into an
inconsistent state. Thus if the bootloader has enabled a display, the hwmod code
cannot reset the DISPC module just like that, but the outputs need to be
disabled first.

Add function dispc_disable_outputs() which disables all active overlay manager
and ensure all frame transfers are completed.

Modify omap_dss_reset() to call this function and clear DSS_CONTROL,
DSS_SDI_CONTROL and DSS_PLL_CONTROL so that DSS is in a clean state when the
DSS2 driver starts.

This resolves the hang issue(caused by a L3 error during boot) seen on the
beagle board C3, which has a factory bootloader that enables display. The issue
is resolved with this patch.

Thanks to Tomi and Sricharan for some additional testing.

Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Tested-by: R, Sricharan <r.sricharan@ti.com>
Signed-off-by: Archit Taneja <archit@ti.com>
[paul@pwsan.com: restructured code, removed omap_{read,write}l(), removed
 cpu_is_omap*() calls and converted to dev_attr]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap_hwmod_common_data.h b/arch/arm/mach-omap2/omap_hwmod_common_data.h
index 39a7c37f4587..ad5d8f04c0b8 100644
--- a/arch/arm/mach-omap2/omap_hwmod_common_data.h
+++ b/arch/arm/mach-omap2/omap_hwmod_common_data.h
@@ -16,6 +16,8 @@
 
 #include <plat/omap_hwmod.h>
 
+#include "display.h"
+
 /* Common address space across OMAP2xxx */
 extern struct omap_hwmod_addr_space omap2xxx_uart1_addr_space[];
 extern struct omap_hwmod_addr_space omap2xxx_uart2_addr_space[];
@@ -111,4 +113,6 @@ extern struct omap_hwmod_class omap2xxx_dma_hwmod_class;
 extern struct omap_hwmod_class omap2xxx_mailbox_hwmod_class;
 extern struct omap_hwmod_class omap2xxx_mcspi_class;
 
+extern struct omap_dss_dispc_dev_attr omap2_3_dss_dispc_dev_attr;
+
 #endif