ARM: OMAP2+: clockdomain: another fix for v4.6-rc

For DRA7xx platforms, add a workaround for missed timer interrupts
that appears to be due to an integration bug (erratum i874)

Basic build, boot, and PM test logs are available here:

http://www.pwsan.com/omap/testlogs/omap-fixes-b-for-v4.6-rc/20160413020850/

(The DRA7xx board here has not yet been added into the testbed.)
ARM: DRA7: clockdomain: Implement timer workaround for errata i874

Errata Title:
i874: TIMER5/6/7/8 interrupts not propagated

Description:
When TIMER5, TIMER6, TIMER7, or TIMER8 clocks are enabled
(CM_IPU_TIMER5/6/7/8_CLKCTRL[0:1]MODULEMODE=0x2:ENABLE) and the CD-IPU
is in HW_AUTO mode (CM_IPU_CLKSTCTRL[0:1]CLKTRCTRL=0x3:HW_AUTO) the
corresponding TIMER will continue counting, but enabled interrupts
will not be propagated to the destinations (MPU, DSP, etc) in the
SoC until the TIMER registers are accessed from the CPUs (MPU, DSP
etc.). This can result in missed timer interrupts.

Workaround:
In order for TIMER5/6/7/8 interrupts to be propagated and serviced
correctly the CD_IPU domain should be set to SW_WKUP mode
(CM_IPU_CLKSTCTRL[0:1]CLKTRCTRL=0x2:SW_WKUP).

The above workaround is achieved by switching the IPU clockdomain
flags from HWSUP_SWSUP to SWSUP only.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
1 file changed