Re: [PATCH] mtd: rawnand: Do not check for bad block if bbt is unavailable

Miquel Raynal
2021-02-04T09:00:41Z

Hi Manivannan,

Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> wrote on Thu,
4 Feb 2021 14:22:21 +0530:

> On Thu, Feb 04, 2021 at 09:13:36AM +0100, Miquel Raynal wrote:
> > Hi Manivannan,
> >
> > Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> wrote on Wed,
> > 03 Feb 2021 17:11:31 +0530:
> >
> > > On 3 February 2021 4:54:22 PM IST, Boris Brezillon <boris.brezillon@collabora.com> wrote:
> > > >On Wed, 03 Feb 2021 16:22:42 +0530
> > > >Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> wrote:
> > > >
> > > >> On 3 February 2021 3:49:14 PM IST, Boris Brezillon
> > > ><boris.brezillon@collabora.com> wrote:
> > > >> >On Wed, 03 Feb 2021 15:42:02 +0530
> > > >> >Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> wrote:
> > > >> >
> > > >> >> >>
> > > >> >> >> I got more information from the vendor, Telit. The access to
> > > >the
> > > >> >3rd
> > > >> >> >partition is protected by Trustzone and any access in non
> > > >privileged
> > > >> >> >mode (where Linux kernel runs) causes kernel panic and the device
> > > >> >> >reboots.
> > > >> >
> > > >> >Out of curiosity, is it a per-CS-line thing or is this section
> > > >> >protected on all CS?
> > > >> >
> > > >>
> > > >> Sorry, I didn't get your question.
> > > >
> > > >The qcom controller can handle several chips, each connected through a
> > > >different CS (chip-select) line, right? I'm wondering if the firmware
> > > >running in secure mode has the ability to block access for a specific
> > > >CS line or if all CS lines have the same constraint. That will impact
> > > >the way you describe it in your DT (in one case the secure-region
> > > >property should be under the controller node, in the other case it
> > > >should be under the NAND chip node).
> > >
> > > Right. I believe the implementation is common to all NAND chips so the property should be in the controller node.
> >
> > Looks weird: do you mean that each of the chips will have a secure area?
>
> I way I said is, the "secure-region" property will be present in the controller
> node and not in the NAND chip node since this is not related to the device
> functionality.
>
> But for referencing the NAND device, the property can have the phandle as below:
>
> secure-region = <&nand0 0xffff>;

Probably more like:

secure-region = <&nand0 0x0 0xFFFF>; // of_node, start, size

but yeah, looks fine by me.

Thanks,
Miquèl