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

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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>
This commit is contained in:
Archit Taneja
2011-10-06 18:04:08 -06:00
committed by Paul Walmsley
parent 13662dc5b1
commit b923d40dd4
8 changed files with 170 additions and 0 deletions
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arch/arm/mach-omap2/omap_hwmod_2420_data.c
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@@ -943,6 +943,7 @@ static struct omap_hwmod omap2420_dss_dispc_hwmod = {
.slaves = omap2420_dss_dispc_slaves,
.slaves_cnt = ARRAY_SIZE(omap2420_dss_dispc_slaves),
.flags = HWMOD_NO_IDLEST,
.dev_attr = &omap2_3_dss_dispc_dev_attr
};
/* l4_core -> dss_rfbi */