On Mon, Mar 7, 2011 at 11:19 PM, Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > Hi David, Hi Laurent, > > On Monday 07 March 2011 20:41:21 David Cohen wrote: >> On Mon, Mar 7, 2011 at 9:25 PM, Guzman Lugo, Fernando wrote: >> > On Mon, Mar 7, 2011 at 1:19 PM, David Cohen wrote: >> >> On Mon, Mar 7, 2011 at 9:17 PM, Guzman Lugo, Fernando wrote: >> >>> On Mon, Mar 7, 2011 at 7:10 AM, Michael Jones wrote: >> >>>> From e7dbe4c4b64eb114f9b0804d6af3a3ca0e78acc8 Mon Sep 17 00:00:00 2001 >> >>>> From: Michael Jones <michael.jones@xxxxxxxxxxxxxxxx> >> >>>> Date: Mon, 7 Mar 2011 13:36:15 +0100 >> >>>> Subject: [PATCH] omap: iommu: disallow mapping NULL address >> >>>> >> >>>> commit c7f4ab26e3bcdaeb3e19ec658e3ad9092f1a6ceb allowed mapping >> >>>> the NULL address if da_start==0. ÂForce da_start to exclude the >> >>>> first page. >> >>> >> >>> what about devices that uses page 0? ipu after reset always starts >> >>> from 0x00000000 how could we map that address?? >> >> >> >> from 0x0? The driver sees da == 0 as error. May I ask you why do you >> >> want it? >> > >> > unlike DSP that you can load a register with the addres the DSP will >> > boot, IPU core always starts from address 0x00000000, so if you take >> > IPU out of reset it will try to access address 0x0 if not map it, >> > there will be a mmu fault. >> >> Hm. Looks like the iommu should not restrict any da. The valid da >> range should rely only on pdata. >> Michael, what about just update ISP's da_start on omap-iommu.c file? >> Set it to 0x1000. > > What about patching the OMAP3 ISP driver to use a non-zero value (maybe -1) as > an invalid/freed pointer ? I wouldn't be comfortable to use 0 (or NULL) value as valid address on ISP driver. The 'da' range (da_start and da_end) is defined per VM and specified as platform data. IMO, to set da_start = 0x1000 seems to be a correct approach for ISP as it's the only client for its IOMMU instance. Regards, David > > -- > Regards, > > Laurent Pinchart > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
