Re: [PATCH] ARM: pxa: prevent PXA270 occasional reboot freezes

2013-12-10 Thread Haojian Zhuang
On 12/11/2013 02:31 AM, Marek Vasut wrote: On Tuesday, December 10, 2013 at 11:48:59 AM, Daniel Mack wrote: On 12/10/2013 09:43 AM, Haojian Zhuang wrote: On 12/10/2013 12:39 PM, Sergei Ianovich wrote: Erratum 71 of PXA270M Processor Family Specification Update (April 19, 2010) explains that wa

Re: [PATCH] ARM: pxa: prevent PXA270 occasional reboot freezes

2013-12-10 Thread Marek Vasut
On Tuesday, December 10, 2013 at 11:48:59 AM, Daniel Mack wrote: > On 12/10/2013 09:43 AM, Haojian Zhuang wrote: > > On 12/10/2013 12:39 PM, Sergei Ianovich wrote: > >> Erratum 71 of PXA270M Processor Family Specification Update > >> (April 19, 2010) explains that watchdog reset time is just > >> 8

Re: [PATCH] ARM: pxa: prevent PXA270 occasional reboot freezes

2013-12-10 Thread Daniel Mack
On 12/10/2013 09:43 AM, Haojian Zhuang wrote: > On 12/10/2013 12:39 PM, Sergei Ianovich wrote: >> Erratum 71 of PXA270M Processor Family Specification Update >> (April 19, 2010) explains that watchdog reset time is just >> 8us insead of 10ms in EMTS. >> >> If SDRAM is not reset, it causes memory bu

Re: [PATCH] ARM: pxa: prevent PXA270 occasional reboot freezes

2013-12-10 Thread Haojian Zhuang
On 12/10/2013 12:39 PM, Sergei Ianovich wrote: Erratum 71 of PXA270M Processor Family Specification Update (April 19, 2010) explains that watchdog reset time is just 8us insead of 10ms in EMTS. If SDRAM is not reset, it causes memory bus congestion and the device hangs. We put SDRAM in selfresh

[PATCH] ARM: pxa: prevent PXA270 occasional reboot freezes

2013-12-09 Thread Sergei Ianovich
Erratum 71 of PXA270M Processor Family Specification Update (April 19, 2010) explains that watchdog reset time is just 8us insead of 10ms in EMTS. If SDRAM is not reset, it causes memory bus congestion and the device hangs. We put SDRAM in selfresh mode before watchdog reset, removing potential fr